An important discussion / evaluation on recent blind shootout.

[davef]

Upon receiving many emails and private messages regarding the recent GTG at Craig Chase’s home, I decided to look a bit deeper at some of the various comments and results.

Some of the comments I read regarding the performance of our 340 SE were very far off from the thousands of actual customers and professional reviewers who either own or who have auditioned the 340 SE. Upon further investigation, I realized that Craig had purchased a pair of our 340 SE “Recert” speakers. These are used speakers but have been recertified using brand new woofers and tweeters, the one caveat being that the tweeter is a non-magnetically shielded unit compared to our stock model.

A warning sign went off in my head --- could it be that this tweeter was somehow not performing to spec? From a technical perspective, performance should be identical but had I missed something?

After spending a week running an intense suite of measurements, I have concluded that there is no difference between these non-shielded tweeters and our stock shielded models. Performance is identical.

I then looked a bit deeper into the results of the listening sessions and found a glaring discrepancy – something I found quite disturbing. In every single comparison test, the speaker with higher sensitivity scored lower. In fact, it seems that the larger the discrepancy in speaker sensitivity, the greater the difference in the result scoring.

I would expect from a “blind” listening session such as this that perhaps 50% of the higher sensitivity loudspeakers to be preferred and 50% of the lower, or at least perhaps 40% - 60% -- but DEFINITELY NOT 100%. Once again, a few warning signs went off in my head… What exactly was taking place? I know Craig was level matching but just how was he doing this?

Further research revealed that Craig was using a passive remote switchbox. This is a speaker selector box that is placed directly in-between the loudspeakers and the amplifier. This particular switch box is made up of high-power potentiometers, which are variable resistors. In order to level match, series resistance is used to pad down the power being received by one of the two speaker pairs. The higher sensitivity speaker must have series resistance applied to the signal in order to bring the output level down enough to match the lower sensitivity speaker (which would not have resistance applied).

This is a problem and a “No-No” in the audio world. Adding series resistance to a loudspeaker completely changes the character of the loudspeaker’s crossover and complex impedance. It can be very dramatic as I will detail. A loudspeaker crossover is designed specifically to “see” a very specific impedance load, the load presented by the drivers. Adding series resistance changes that complex impedance load and the crossover no longer functions as it has been designed to. If we have an 8ohm rated loudspeaker and we add 4ohms of resistance, the loudspeaker now becomes a 12ohm loudspeaker yet the crossover components have been optimized for an 8ohm load.

Generally speaking, and this depends on the design of the crossover, the more complex the crossover the worse the effects. As an example, if we have a 4 ohm loudspeaker, whereby 4 ohms of resistance have been added – in order to keep all things being equal, all inductor values would have to be doubled and capacitor values halved to keep things consistent with the addition of the series resistance. While this it is not as simple as my example here, from a mathematical standpoint, it is correct.

Furthermore, information obtained from the company that supplied Craig with the remote speaker switcher confirmed my suspicions. The speaker selector does indeed use straight series resistance in order to level match speakers…

I do not believe that any of this was done knowingly and I certainly would not blame anyone (especially Craig) however, this was most certainly not an “all things being equal” blind listening session. In every case, the higher sensitivity loudspeaker was at a definite disadvantage, it was being handicapped (unknowingly, but nevertheless - handicapped) and both the results and information we have obtained regarding how the speaker switch box is built confirm this.

I have personally conducted many blind A/B tests (on a professional level and for myself personally). There is only one way to properly level match loudspeakers (and even this can be argued by some as still not infallible) – level matching must always be performed at the pre-amp level – never at the output of an amplifier (high-level). In the manner I mentioned, the crossover of the loudspeaker and the amplifier itself are seeing the correct impedance load. I truly hate to say this, but I feel from a technical standpoint I must – the scoring / results from that listening session are invalid (at least where A/B testing was performed).

I have attached several illustrations of exactly how series resistance will affect the CMT-340 SE crossover. To be as precise as possible, the electrical graphs below were taken from a random 340 SE sample, in the middle of a production run. Wires were run from the tweeter and woofer to the outside of the cabinet through the port tube so they can be measured with reference standard equipment. I used several resistor values to illustrate the effect. It is also important to note that the resistors I used are good quality wire-wound models, which are used in the vast majority of quality crossovers. These resistors offer much lower inductance and distortion than any variable resistor I know of. In other words, signal degradation from the passive speaker selector will be worse. And finally, all aspects of crossover performance are affected by series resistance, frequency response, phase, filter slopes and Q. Imagine running 1 set of loudspeakers with speaker cable that presents a resistive load of 0.1 ohm (typical for decent cable) and another set of speakers off of cable that presents a resistive load of 4 ohms?

I somewhat blame myself for not stepping in and preventing this. However, as many of you know – I have much going on in my personal life and while I knew that Craig was performing some form of blind listening session, I did not conduct my typical due diligence and I regret this. In the past, Craig had always called and asked our permission to use our products for such an event. It did not happen this time, which might have prompted me to do a bit more research, but I admit, I should have been more on the ball. I know there will be a TON of mudslinging from this but you can not blame Craig --- Craig hosted a wonderful event and truly put himself “out there” for the benefit of the industry.

Test Results are precisely conclusive. Winner in Red, higher sensitivity speaker in Blue.

1. NHT Classic 2 86dB vs. Swan D2.1SE: 85dB
2. PSB Image B25 89dB vs. SVS SCS-01 87dB
3. Ascend 340SE 91dB vs. Acculine A1 87dB
4. AV123 xl-s 87dB vs. Ascend Sierra 86.5 dB
5. Dana Model 630 86dB vs. B&W 805S 89dB
6. Swan D2.1 SE 85dB vs. Ascend Sierra 86.5dB


Measurements:

To effectively match the sensitivity of the Acculine A1, I estimate that approximately 4 ohms of resistance was added inline to the 340 SE, resulting in a drop of about 3-4dB. As you can see from the electrical response graph, as little as 2 ohms of added resistance will result in rather dramatic changes.

The results of this are clearly evident on the in-room frequency response graph of the 340 SE, comparing stock configuration to one with 4 ohms of inline resistance applied. Notice the dramatic difference in the 100Hz – 800Hz range. This range is now subdued by about 5dB compared to the 1 kHz – 3 kHz range (nearly 1/4 the output), whereas without inline resistance, the ranges are of equal amplitude. This is considerable and will have a dramatic affect on the balance of vocals and midrange instruments. In addition highs become subdued in comparison to the lower frequency range (< 100Hz) and subdued when compared to the 1 kHz – 3 kHz range. This will result in the speaker sounding a bit dull and lifeless, lacking detail. All closely matching the 340SE comments from the listeners at the get together…

I must detail an important point, the facts I presented here hold true for any of the loudspeakers that had to be padded down to match a lower sensitivity speaker. I picked the 340 SE as an example simply because it is our product and easy for me to modify to accommodate this type of tests. While inline resistance will affect different speakers in different ways, the results will always be that the speaker is no longer performing to specification. I hope many of you will find the information I posted helpful and, perhaps, influence much needed changes for any future listening sessions…

[JasonColeman]

Wow...teriffically informative post, Dave! That's very interesting and I don't know if anybody else made the connection between efficiency and performance, but it's clear to see and understand why it would "handicap" the more efficient speaker. Nice catch!

J.

[boludaso]

Here's a virtual punch in the neck for Craig.

Maybe you should be a detective Dave.

[BradJudy]

Interesting write-up Dave - I like the graphs, it's good to see how simply adding a series load can do more than just attenuate the levels.

[BradJudy]

Here's a virtual punch in the neck for Craig.


I think we can do without this. I expect Craig didn't know that this approach would have this kind of impact - it's not like he's out to get all speakers with higher sensitivity specs.

I imagine one of the few ways to do a good level-matched blind test would be to have a pre-amp with multiple outputs that allows you to set a fixed attenuation on each output. I know the Meridians will let you set different attenuations on inputs, but I don't know if they will do outputs.

[JasonColeman]

I think we can do without this.
Definitely agreed...Craig works his butt of doing these tests and opens his home to folks from all over. If this indeed was the culprit (if there is a culprit), I don't think that it's something that would have easily been foreseen...heck, it took Dave several days to come across his findings.

J.

[Mag_Neato]

Agreed. As a guest and participant at Craig's that day, I can assure everyone that there was no intentional bias towards any speaker over another. Craig put out a monumental outlay of time, effort and expense to put this together, and had the best intentions. Too bad Dave had more urgent, personal issues to attend to, or I'm sure this would have been addressed.

Maybe Craig can correct for this next September!

[Mike^S]

This is unfortunate news! :eek:

[curtis]

There are some more comments here:
http://forums.soundandvisionmag.com/audiovideo/board/message?board.id=40&thread.id=80710&page=4

[curtis]

Definitely agreed...Craig works his butt of doing these tests and opens his home to folks from all over. If this indeed was the culprit (if there is a culprit), I don't think that it's something that would have easily been foreseen...heck, it took Dave several days to come across his findings.

J.
I don't think anybody really understood what kind of device Craig was using to do the switching, and maybe we still don't know the full story. It is generally known, at least among speaker designers/engineers, that passive resistance between the amp and speaker causes changes to how the crossover behaves.

[davef]

I think we can do without this. I expect Craig didn't know that this approach would have this kind of impact - it's not like he's out to get all speakers with higher sensitivity specs.

Agreed... there is no blame in any of this. Nevertheless, it is important to understand that no one should use these results as a basis to make a purchase. This is a learning process and I am sure things will be corrected next time.


I imagine one of the few ways to do a good level-matched blind test would be to have a pre-amp with multiple outputs that allows you to set a fixed attenuation on each output. I know the Meridians will let you set different attenuations on inputs, but I don't know if they will do outputs.

This is one way or someone could build up a low-level switching device. I use a low-level switch box, 2 pre-amplifiers and a multi-channel amp.

[Mike^S]

Unfortunately, I have a feeling the S will hit the fan when this reaches AVS. Everyone will throw a big fit, and Craig will declare that he'll never do another speaker review again. :rolleyes:

Oh, and at some point in the thread, Pulliam will reaffirm the FACT that Def Tech speakers are the best speakers in the world. :p

[randyb]

What I am a little baffled about is that Axiom would not know? They made the switch and apparently use one in their own evaluations. My sources tell me that they have hired a reputable journalist that used to work with Floyd Toole so I am at a loss to understand what is going on from their point of view.

[boludaso]

BradJudy, looking at your avitar I can see why you are so sensitive to the vitual punch in the neck.

That is something my brothers and I share whenever we pull a bonehead move.

I agree with everyone else that Craig does contribute alot. Obviously he didnt see the pattern that Dave did. Had he...

Next time I'll go with the virtual toe stomp instead. We need a sarcasm icon thingy. Is there one?

[davef]

What I am a little baffled about is that Axiom would not know? They made the switch and apparently use one in their own evaluations. My sources tell me that they have hired a reputable journalist that used to work with Floyd Toole so I am at a loss to understand what is going on from their point of view.

I was surprised at this too. Although I don't know what Axiom uses in-house for speaker comparisons. From my understanding, these switches were made several years ago. Reallistically, there isn't anyway around this if level matching and switching are done after the power amplifier. I would guess it is a matter of convenience, a quick comparison rather than critical listening.

One option is to build a variable stereo L-Pad, this could lessen the effect of series resistance but still not an all-things-being equal situation. It is complicated.

[mziegler]

So it is back to square one.

Let's remember another thing--even if Craig's methods were perfect, it is not as if one can definitively prove anything in a momentary shoot-out. Time matters.

And perhaps the Swan is a better speaker. :rolleyes:

Not that it really matters to me. Ascend Acoustics has reintroduced music into my life in ways I never imagined.

[davef]

So it is back to square one.

Let's remember another thing--even if Craig's methods were perfect, it is not as if one can definitively prove anything in a momentary shoot-out. Time matters.

And perhaps the Swan is a better speaker. :rolleyes:

Not that it really matters to me. Ascend Acoustics has reintroduced music into my life in ways I never imagined.

Thanks mzeigler... It is really not about what is the "better" speaker. This was a technical discussion. I was happy with how our Sierra-1 did, but in one of the tests in which it was rated higher, the competing speaker had to be attenuated so I consider this comparison invalid too, even though the results favored our product.

The overall knowledge level of the online audio community is increasing dramatically. In some ways, I suspect the average online audio enthusiast who reads and participates in the various forums is armed with more knowledge than your typical B&M salesperson. This is a good thing of course and it should continue.

[wesley63]

Hello all,

Craig Chase's response:

http://www.avsforum.com/avs-vb/showthread.php?p=11849414#post11849414

[randyb]

I was surprised at this too. Although I don't know what Axiom uses in-house for speaker comparisons. From my understanding, these switches were made several years ago. Reallistically, there isn't anyway around this if level matching and switching are done after the power amplifier. I would guess it is a matter of convenience, a quick comparison rather than critical listening.

One option is to build a variable stereo L-Pad, this could lessen the effect of series resistance but still not an all-things-being equal situation. It is complicated.

That makes sense. Since we don't know how they use it or what they a/b, hard to say.

[audibleconnoisseur]

I just love to listen and I have hearing that allows me to hear near every sound audible and some that should be inaudible. Wouldn't one assume the best way to compare (allowing for money to be no expense) speakers is to have multiple receivers of the exact same model & settings hooked up and then use an SPL from the LP and then start testing?

[JasonColeman]

I just love to listen and I have hearing that allows me to hear near every sound audible and some that should be inaudible. Wouldn't one assume the best way to compare (allowing for money to be no expense) speakers is to have multiple receivers of the exact same model & settings hooked up and then use an SPL from the LP and then start testing?

But you'd also have to use identical amping, cabling, sourcing, etc which could end up being cost prohibitive. All things being equal...

FWIW, I think that this thread title should be changed to remove the quotation marks around the word "blind". I think that it insinuates that the error (if there was/is one) was intentional and it seems a bit defensive and critical when the Sierras actually performed very well in the shootout. Just my opinion, but I feel that it's an additional jab at Craig that isn't necessary.

Jason

[audibleconnoisseur]

But you'd also have to use identical amping, cabling, sourcing, etc which could end up being cost prohibitive. All things being equal...

Yes, this what I am saying. If money is no issue, isn't the best way to test them - is to use same amp and settings that are adjusted by SPL at the LP?

[Mag_Neato]

It was a blind test. No one knew what speakers were behind the screen(black grill cloth) at any time during the tests. The participants were given about 20 minutes per round to listen, Craig used a remote to operate the switcher, waiting about 30 seconds to a minute between switching. There was 3 rows of seating, and listeners rotated on intervals a'la volleyball style. This gave listeners all possible listening positions in the room. If one speaker sounded better in one position, it was worse in another. The Sierra was a favorite, only falling to the Swans in this instance. Craig stated before and after testing that he paired the test speakers based on closeness of sensitivity, to avoid needing to apply excessive amounts of attenuation with the switcher. I think he took all conditions into account given the information/equipment available. All Craig did was host and setup the event. The scoring was done by the testees. It is much more difficult to score speakers than I had imagined. It is very subjective.

Let's give Craig a little credit here, and if we have doubts, try doing this on your own. It's not easy.

[JasonColeman]

The scoring was done by the testees.
Ha, ha, ha...! He said testees...:D

I agree with your post and wish I could have been there, too. Craig worked very hard here and didn't ask for anything in return.

Jason

[mziegler]

Once Craig went officially public in Affordable Audio everything about the procedures became fair game.

[Mag_Neato]

Ha, ha, ha...! He said testees...:D

I agree with your post and wish I could have been there, too. Craig worked very hard here and didn't ask for anything in return.

Jason

Well, Craig did refer to himself as a di**head!:D

[Sam1000]

Let's give Craig a little credit here, and if we have doubts, try doing this on your own. It's not easy.

I'm all for giving credit when it's due. However, I have seen some posts from Craig himself ridiculing someone else's efforts. I think the reviewer at the time criticized the Minis from av123. You might find those posts on av123's forum.

[randyb]

I'm all for giving credit when it's due. However, I have seen some posts from Craig himself ridiculing someone else's efforts. I think the reviewer at the time criticized the Minis from av123. You might find those posts on av123's forum.
I believe it originated from a review done by a regular and respected member on the Sound and Vision forum.

[BradJudy]

It's good to see Craig's notes as well. I like that he picked pairings that required the minimal amount of adjustment to level match.

I agree that the use of quotes around the word blind is not appropriate here. The participants did not know which speakers were playing when they did their scoring.

I expect it could be impossible to come up with a comparison approach that made everyone happy, just look at some of the other issues people on the S&V forum brought up.

In the end, the reason there is conflict on these subjects is the opposing views of the consumers. Some think you should only judge for yourself, some want comparisons to narrow the options, some want comparisons so they can pick something sight unseen, some want specs and graphs, some want qualitative descriptions, etc. Not to mention the huge variety of opinions of what makes a proper room, proper other equipment and even a proper listener. Add to that the general subjectivity of opinions and it can be a futile effort to get any consensus.

Whatever you think of Craig's event, he tried much harder than most people to make it impartial, so I salute that effort.

I fall into the camp of: "Buy whatever the hell you want and don't worry about what other people think". Buy it because it sounds nice, because the specs look good, because the salesman's name is Frank, because it's purple, because it fits in the back of your car and the other ones don't, because you like the website, because it's what you want to buy.

[bikeman]

Whatever you think of Craig's event, he tried much harder than most people to make it impartial, so I salute that effort.
As one of the participants, I also salute him. I thought it was fairly obvious that no one should make a buying decision based solely on these tests. Considering the number of speakers, number of participants and limitations of the testing area, it was amazing that anything useful was derived at all. Craig is one of the few who could pull it off. None of my fellow participants who I spoke to felt we would make a buying decision based on what we heard during the demos. We were all well aware of the limitations. The listening session wasn't even a main topic of conversation at dinner. It was fun and a different way to experience the hobby. It was all good. Just not anywhere near definitive. I'd do it again if given the opportunity. Thanks, Craig.

David

[davef]

FWIW, I think that this thread title should be changed to remove the quotation marks around the word "blind". I think that it insinuates that the error (if there was/is one) was intentional and it seems a bit defensive and critical when the Sierras actually performed very well in the shootout. Just my opinion, but I feel that it's an additional jab at Craig that isn't necessary.

I agree --- that was certainly not meant as a jab towards Craig but I can see that it can be taken the wrong way. Personally, I don't have any problem with the process that Craig used, it was definitely what I would consider "blind" (thus the quotes).. My only issue was directed towards that passive level matching switch box, which Craig had no control over. I will change the thread title.

[JasonColeman]

Thanks, Dave.

Jason

[Jonnyozero3]

This is amazingly informative. It really is too bad that Craig put in so much time and effort to stumble upon what looks like an oversight, such as this. I'm thinking the mag will have to print something to cover their bases on this. I really enjoyed the read, too :(.

Nice catch, Dave. I'm duly impressed, as always.

[bikeman]

It really is too bad that Craig put in so much time and effort to stumble upon an oversight like this. As much as it is unfortunate to do, I think the mag needs to retract the article. I really enjoyed the read, too :(.
Nice catch, Dave. I'm duly impressed, as always.
I guess we'll just disagree on this. I don't see where it's been determined to be an "oversight." Could it have been done better? In a private home? A retraction? Have I missed something?

David

[randyb]

I guess we'll just disagree on this. I don't see where it's been determined to be an "oversight." Could it have been done better? In a private home? A retraction? Have I missed something?

David

I don't think a "retraction" is needed. I think after more tests and data collection that perhaps an editors note would be appropriate. I see that as fairly common in the print magazines. I don't think the baby needs to be thrown out with the bathwater, but on the other hand any foilbles with the actual listening tests should be pointed out in print if valid.

In other words, if the the switch is shown to affect response, an editors note in bold letters would be appropriate in my opinion. Whether the parties can agree on that is not definite, but if there is any doubt, the appropriate note would be the right thing to do IMHO.

[Mike^S]

If you take a look at Craig's response, he says that there was never greater than a 1dB difference in sensitivity between any pair. He also says that the Acculine was actually 0.5 dB more sensitive than the 340SE (which is weird).

If this is so, then it would seem the switcher had a less detrimental effect then we thought.

[bikeman]

In other words, if the the switch is shown to affect response, an editors note in bold letters would be appropriate in my opinion. Whether the parties can agree on that is not definite, but if there is any doubt, the appropriate note would be the right thing to do IMHO.
"if there is any doubt" is going to be used as a criteria, then we'll have to have more footnotes than space for the article. The switchbox was hardly the only variable. Any listening session is going to have lots of variables. Craig did a excellent job minimizing the problems given the issues he was working with.
No footnotes, retractions or anything else is called for. We can always make something better by throwing more money at it. More than enough money was thrown in this instance.

David

[randyb]

"if there is any doubt" is going to be used as a criteria, then we'll have to have more footnotes than space for the article. The switchbox was hardly the only variable. Any listening session is going to have lots of variables. Craig did a excellent job minimizing the problems given the issues he was working with.
No footnotes, retractions or anything else is called for. We can always make something better by throwing more money at it. More than enough money was thrown in this instance.

David


All true, but if the switch did (and I don't know if it did-just relying on David) alter the sound of some speakers more than others from the get go, I think it is worth noting. I am sure you would raise your eyebrows if you went into a store and auditioned speakers and afterwards the vendor said, you know there are alot of variables but you should be able to make a decision on what sounds the best and oh yea, the switch I used altered the basic sound of the more sensitive speaker. Certainly, DavidF seems to think that issue was more important than all the rest of the variables combined are he wouldn't have spent so much time analyzing and then posting. Especially, since he is smart enough to know it would tend to start shall we say a vigorous discussion.

[bikeman]

Certainly, DavidF seems to think that issue was more important than all the rest of the variables combined are he wouldn't have spent so much time analyzing and then posting. Especially, since he is smart enough to know it would tend to start shall we say a vigorous discussion.
As much as I admire Dave as both a person and an engineer (I've purchased eight speakers from Ascend), it's not reasonable to add multiple footnotes or total retractions based on speculation no matter how knowledgeable the source. If Dave had been present, I'm sure, like so many of us in attendance, he could have zeroed in on several areas that made this listening session less than ideal. This event wasn't constructed to be the end all in speaker comparisons. I haven't seen anyone who attended frame it as such.
This was an opportunity for some very serious audio nuts to get together and experience what would otherwise have been impossible. For me it was nine hours of driving that day. For some others it was way too much time spent in airports and airplanes. Those factors alone would have effected the results to a good degree. How would you handle that as a footnote?
The session was what it was. I could nitpik it to death. That would add nothing. The session was a data point. Nothing more. Dinner and the comradery were not data points. They were the stars of the show. No one will forget having spent the day at Craig's. But few of us will remember what speakers we auditioned in the years to come. The listening session was fun and informative but not for the scores.

David

[Galwin]

It appears to me that a group of hobbyists interested in comparing the relative performance and value of loudspeakers have crossed over into a different realm. Through the power of the internet, they now have the capacity to influence sales. Publishing the GTG results that include not only qualitative but quantitative (numerical) comparisons in a magazine suggests, in spite of the caveats indicated in the article, that one speaker is better than another. Comments on the internet forums suggest that many individuals will be making their purchasing decisions based on the results. Consequently, it seems only right that the intentions and methods of the GTG be held to a higher level of scrutiny.

I always take audio reviews, and most anything I see/hear in public media with several grains of salt. How much do advertising dollars influence the perception of the reviewer? This situation is no different. The flags went up for me when representatives of organizations who have a financial interest in the findings participated in the forum discussions before and after the event. One actually attended the GTG. The flags also went up when the description of the sound of the 340SE, the speaker I own, was so different from my personal experience. The article in Affordable Audio states that the listeners heard subdued horns, felt vocals were hard to follow, and experienced the sounds as sitting in row 50, and not row 5. That’s nothing like how the speakers sound in my room. How can you account for such a difference?

It may all be very innocent. I suspect that it is but I have no way of knowing for sure. When does a get together of audio enthusiasts become a mechanism for marketing? Again, there is no way to know for sure. That said, I appreciate the efforts of the group and think that they offer valuable information. I just keep those grains of salt handy.

For folks with a financial interest, like David, the stakes can be high. Scrutiny of the results is completely justified.

[randyb]

As much as I admire Dave as both a person and an engineer (I've purchased eight speakers from Ascend), it's not reasonable to add multiple footnotes or total retractions based on speculation no matter how knowledgeable the source. If Dave had been present, I'm sure, like so many of us in attendance, he could have zeroed in on several areas that made this listening session less than ideal. This event wasn't constructed to be the end all in speaker comparisons. I haven't seen anyone who attended frame it as such.
This was an opportunity for some very serious audio nuts to get together and experience what would otherwise have been impossible. For me it was nine hours of driving that day. For some others it was way too much time spent in airports and airplanes. Those factors alone would have effected the results to a good degree. How would you handle that as a footnote?
The session was what it was. I could nitpik it to death. That would add nothing. The session was a data point. Nothing more. Dinner and the comradery were not data points. They were the stars of the show. No one will forget having spent the day at Craig's. But few of us will remember what speakers we auditioned in the years to come. The listening session was fun and informative but not for the scores.

David

I am not trying to take anything away from the get together, it sounds like a lot of fun, but we both know that people who read about it do make conclusions based on the results regardless of what the participants think. I think you are talking as a participant that experienced the event and I am talking about the effect the event has on people who didn't experience the event. To answer your question, I wouldn't handle that footnote because you obviously can't. I am not really trying to nitpick. I'm just expressing my opinion. Ours differ I am sure for a couple reasons, but one is that you were there enjoyed a great time and experience. I am not trying to denigrate that at all and I really don't have anything to gain by even posting. I am just looking at it from a point of view of fairness to the mfg. of the speakers in the test. If you think the test was fair to the mfg and vendors involved, then perhaps it was.

[BradJudy]

The most common way such things are handled in the print mags is through vendor responses to reviews, which are usually published in the same or next issue (print mags usually send vendors a copy of the review before it goes to print, so often a response makes it into the same issue). The vendor responses are usually something like "good review, but this item is incorrect...". Sometimes the publisher or author will add a note about the response like "we double-checked this and the vendor is correct" or "the vendor's assertions do not match our experience".

The publisher decides how they handle articles/footnotes/responses/etc, so I suggest you contact them if you would like to see something specific. Arguing the point here doesn't seem productive.

[randyb]

Arguing the point here doesn't seem productive.I agree it does not seem productive and I don't really care whether there is any note at all. It certainly should not come from me as I wasn't participant nor am I technically qualified to make the point. I did, however, have an opinion, stated it, and now will vanish into the night

[JasonColeman]

Whooshing Sound

:) Please let me know how you like your stands and be sure to post pics once you've got them all set up!

J.

[davef]

Hi Guys,

I am certainly not calling for a retraction from the print mag. That is not what my study and comments were about.

However, I do think that for the sake of that particular magazine, they should indeed be careful as they have crossed a line that has not been broken before. That is, publishing a review based on an event sponsored by a non-affiliated consumer. They can indeed open themselves up to potential legal problems from larger companies. Right or wrong, I am sure they do not have the resources to defend litigation and I have seen this before.

Don't get me wrong, I love this particular publication and I APPLAUD what they are doing. I personally have no problem with the publication of the article (believe me, if I did - they would have heard from me already)

I conducted my study, as previously mentioned, because the comments received about the performance of the 340SE were very far off from nearly every 340 SE owner and professional reviewer. When one of my products that I am intimately familiar with is not performing as it should, be that in a customer's home or at a listening session, I am going to look into it. These are not mass market loudspeakers; I personally measure each and every loudspeaker that leaves our factory.

I also do my due diligence and let me just say that my sensitivity measurements (taken with reference standard gear and using several different methods) do not correlate with what was reported from the listening session. I don't know the cause of this discrepancy but I certainly invite anyone to do the comparison in their own home. The difference in sensitivity is audible...

Again, this is not what this is about though... This was a study detailing the effects of series resistance on loudspeaker performance. The effects are real; even 1 ohm of series resistance can alter performance by as much as 2-3 dB. I am not trying to take anything away from Craig's efforts, I am trying to improve the process for the next time -- and I am rather confident that this will now occur…

[davef]

My photoshop skills are bad but below is an overlay of graphs posted by Craig. These are measurements that he took of his 340 SE in his room in response to me taking issue with the passive level-matching switcher which was used. The first graph is with the speakers behind the screen with no attenuation (switcher being used but no padding). The second is with 2dB attenuation and the third is with 4dB attenuation.

I normalized the graphs to keep the relative sensitivity levels the same between 1 kHz and 2 kHz. It is fairly easy to see the effects of the inline resistance (attenuation).

Only 2dB of attenuation caused a 4dB drop in the 6 kHz + range relative to the 1 kHz – 2 kHz range, and a 3dB drop starting from about 2.5 kHz. Additionally, the graph also clearly shows the beginning of the dramatic midrange dropout starting at about 700Hz and lower (as indicated on the graphs I posted). I must say once again that this would constitute a dramatic change in the character of any loudspeaker.

A "neutral" loudspeaker will now have its mids and highs recessed, sounding very laid back, a term that was indeed used to describe many of the higher efficiency speakers. A bright or overly forward sounding speaker will now sound more neutral.

It is also important to note that Craig's frequency response graphs clearly show the nasty effect of any attenuation and these effects are identical to the measurements I originally posted. At no fault of Craig's, his graphs do not show the change in filter slopes and Q (which is what my electrical response graph reveals) which also have a dramatic effect on loudspeaker performance, even though these effects may or may not show up in a simple frequency response graph. For example, even though an on-axis graph between two different speakers may look exactly the same, they will not sound the same because the crossover points are different and the filter slopes and Q are different. It is the shape and the "blending" of these crossover filters that precisely control phase and off-axis response....

I must additionally stress that even 1 dB of attenuation will result in similar performance degradations.

In my opinion, it is a bit silly to go back and forth with this -- the proof is right there. Regardless of which speaker is being claimed as the more sensitive -- even as little as 1dB of attenuation for any of the loudspeakers changes the performance of that particular loudspeaker. It is simply not a valid way to compare 2 different loudspeakers. That issue is not subject for debate.

[GirgleMirt]

Hi David, do you think the screen they put up in front of the speakers could also have had an influence?

[davef]

Hi David, do you think the screen they put up in front of the speakers could also have had an influence?

The screen does not concern me, it would have equal influence on both speakers being compared. The switch box will affect one set of speakers but not the other.

The screen will influence the sound for all of the speakers, such that any of the speakers being compared at the listening session might sound different with the screen removed.

After further thought, a screen such as this will attenuate the high-frequency response equally from one speaker to another. A bright speaker will sound less bright while a neutral speaker might sound a bit dull. However, I don't see any other way to have a blind listening session with so many attendees without using such a screen.

Craig could have blindfolded every participant... THAT would have been interesting :p

[wesley63]

The flags went up for me when representatives of organizations who have a financial interest in the findings participated in the forum discussions before and after the event. One actually attended the GTG. The flags also went up when the description of the sound of the 340SE, the speaker I own, was so different from my personal experience. The article in Affordable Audio states that the listeners heard subdued horns, felt vocals were hard to follow, and experienced the sounds as sitting in row 50, and not row 5. That’s nothing like how the speakers sound in my room. How can you account for such a difference?

I assume that you are talking about Mark Schifter of AV123. He did not participate in the listening tests. In fact, in several forum posts when asked which speaker was the best out of the ones that he listened to before and after the blind comparisons, he has stated that it was the Sierra 1. I don't think that your insinuations hold any merit.

I also wanted to point out that Dave F continues to harp on the series attenuation issue, but in the test involving the 340SE, it was the other speaker that was attenuated.

Getting back to your question about how can it be that you experience the 340SE speaker differently: that's easy. The testers were comparing two speakers simultaneously. Notice that some of the testers found the treble on the winner to be overbearing. This would give them a very forward sound. The 340SE may "sound like the 50 row" when directly compared. Who knows. On that day, to those ears, it sounded that way.

There is a very easy way to see if they are correct. The speakers that were in the comparison cost $250.00 per pair and have a 30-day return policy. You can put them on a credit card, do your own comparison and sent them back. You would be out the postage back (which won't be bad since they're not that heavy.)

Jim

[GirgleMirt]

I think his post held merit. There's a lot of stealth marketing out there and as previously mentioned, when reviews are posted by non-reviewers, what's to stop a company to pay someone to write a review and just publish it anywhere as a review by a consumer? Sponsored events to compare the products of a company with the products of another?

Like Galwin pointed out, the point is that to me, who have the 340SEs in my living room and have listened to them for countless hours, in no way do the way they were described seem to fit the way I know they do sound. Be it for whatever reason it was, the screen, switcher...

It becomes even more important when the product reviewed is compared to another. For some reason the speaker didn't seem to sound as it normally sounds and they preferred a 250$ over it. Why? I guess that's what Mr.Fabrikant tried to find out. By your own words, after reading that review, you should buy the 250$ speakers, if only to find out what they said was true. :eek:

[curtis]

Jim...first I want to welcome you to the forum.

I also want to directly respond to this sentence from you:

I also wanted to point out that Dave F continues to harp on the series attenuation issue, but in the test involving the 340SE, it was the other speaker that was attenuated.
First, can we agree that series attenuation is not desired and can alter crossover behavior?

Please refer to this line by David:


I also do my due diligence and let me just say that my sensitivity measurements (taken with reference standard gear and using several different methods) do not correlate with what was reported from the listening session. I don't know the cause of this discrepancy but I certainly invite anyone to do the comparison in their own home. The difference in sensitivity is audible...

It seems as though there is a discrepency as to what is being measured. Dave's is measurements do not seem to correspond with Craig's measurements. Dave is also saying exactly what you are saying....get both and try yourself.

[Quinn]

Doesn't Ascend measure every speaker before it ships? How do those numbers compare with Craig's measurements? Could there be a measuring equipment or technique issue coming into play or shipping damage?

[wesley63]

GirgleMirt: I agree. There is an enormous amount of stealth marketing going on in any of these forums. And that is all most magazine articles are. I don't think that was the case here. The reviewers seemed to have no idea what speaker they were listening to. The mag in question seems to be a respectable group of guys. I liked their review of the Sierra 1 the month before.

I wasn't suggesting to buy and keep anything. I was simply pointing out that for the price of return shipping on the competitions speakers, a 340SE owner could put his mind to rest that their speaker is better. Complaining about the test and just "knowing" that their speaker is better works too.

Curtis: Thanks for the welcome. These are not really the circumstances under which I thought that I would be joining this forum.

Yes, attenuation hurts. It was the competitor in the 340SE comparison that was hurting. The 340SE was flying unhindered. As Dave F mentioned before and Craig pointed out to me on AVS, the speaker fabric probably had an effect. It probably had the most effect.

As for me doing the 340SE comparison: actually I'm saving up my money to do a comparison between the Sierra 1 and the Swan D2.1SE. To listen to them at the same time I must, at least temporarily, put $2000 on my credit cards. Now you can see why I didn't think that $250 on the card for a week was that big a deal.

Jim

[GirgleMirt]

Quinn: Sensitivity (which speaker plays louder with the watts) won't be the same since the mic distance was probably different and also the watts sent to the speakers too. But for some reason, it seems like Craig's measurements were different than what was measured by David... Curtis, were the 340SE & Acculine measurements of David posted anywhere? Maybe if they were we could see the difference with Craig's?

wesley63: I wasn't inferring that the mag/sponsors/participants were dishonest or anything like that, just that there seemed to be some discrepancies in the test which seemed to indicate that maybe there was a setup problem or some factor which influenced the results. 340SE = laid back like you're sitting in the 50th row? Not in my home... The other speaker compared was better in that fashion and I'm sure that it influenced the results.

I don't particularly care about the results. But I can definitely see why Ascend or other companies whose products were involved in that comparison would be, especially if their product didn't seem to be performing as they should. (especially if such event was sponsored by a competitor!) If the participants heard the 340SE as they sound in my home, they would not have described it the way they did and so the results would probably have been different.

Please let us know how the Sierra vs 2.1 turn out :)

[Galwin]

[
QUOTE=wesley63;25325]I assume that you are talking about Mark Schifter of AV123. He did not participate in the listening tests. In fact, in several forum posts when asked which speaker was the best out of the ones that he listened to before and after the blind comparisons, he has stated that it was the Sierra 1. I don't think that your insinuations hold any merit.
I made no insinuation and the names of the individuals and their opinions were not relevant to my point. I take note when individuals with financial interest are involved in an activity that is ostensibly designed to remove bias. I can not make assumptions about the nature of the involvement but it introduces the potential for a different kind of bias. When the results from this activity are published in a magazine that assists consumers with making purchasing decisons, and these results include quantitative scoring, it gives me another reason to pause.


Getting back to your question about how can it be that you experience the 340SE speaker differently: that's easy. The testers were comparing two speakers simultaneously. Notice that some of the testers found the treble on the winner to be overbearing. This would give them a very forward sound. The 340SE may "sound like the 50 row" when directly compared. Who knows. On that day, to those ears, it sounded that way.
I am not sure that the sound character of the speaker providing the point of comparison should result in the other speaker sounding fundamentally different. I would have to try it myself to know. But that aside, the AA article has the effect of creating a buzz about the Acculine at the expense of the 340SE. For internet direct sellers, that on-line buzz equals dollars.

My primary point is that lines between the audio enthusiast/consumer and business interests could have been blurred here. I have no way of knowing if they were. I suspect that in this case they were not. But as a consumer, especially as an internet consumer, I try to keep my eyes open. Sadly, in our times you can't blink without being exposed to some type of marketing, most of it we are scarcely aware of!

[curtis]

It was the competitor in the 340SE comparison that was hurting.

From looking at Dave's post, it looks as though he measured otherwise.


Curtis, were the 340SE & Acculine measurements of David posted anywhere? Maybe if they were we could see the difference with Craig's?
I don't think so, but he is inviting others to measure for themselves, and that the differences are audible.

Like it has been said before, the only way to put this to rest in the minds of the people that care, is for them to check for themselves.

[wesley63]

From the posts, I don't think that Dave ever actually measured the sensitivity of the Acculines. I think that he was quoting published specs on the websites. I may be wrong.

When attempting to set the sound-levels for the comparison Craig seemed to be using software running off a PC and using a microphone in the room. You can argue over the quality of the measurement equipment, but both speakers in the comparison were measured in the same manor. The in-room sensitivity measurements led him to believe that the Acculines were .5 dB more sensitive, despite the published specs showing otherwise.

[curtis]

From the posts, I don't think that Dave ever actually measured the sensitivity of the Acculines. I think that he was quoting published specs on the websites. I may be wrong.

He says the difference is audible. I think that implies more than relying on published specs.


I also do my due diligence and let me just say that my sensitivity measurements (taken with reference standard gear and using several different methods) do not correlate with what was reported from the listening session. I don't know the cause of this discrepancy but I certainly invite anyone to do the comparison in their own home. The difference in sensitivity is audible...

Going back and forth on who to believe is no win situation until you try for yourself.

[wesley63]

He says the difference is audible. I think that implies more than relying on published specs.


It implies, yes. I was just pointing out that at no time did Dave come out and say that he had measured the Acculines personally. He does say that he has done his "due diligence." That may include actually purchasing or borrowing the competitors speakers and seeing what's up. I just don't know.

Jim

[curtis]

It will just create more conflict with people siding with Craig and people siding with Dave, just as you posted about Dave harping on the attenuation issue.

The best is for people to try for themselves.

Hey, at least we agree that inline resistance is an issue...regardless of the speaker.

So if I get a pair of A1's and say they are less efficient than 340SE's.....who would you believe? It just doesn't get you anywhere.

[wesley63]

So if I get a pair of A1's and say they are less efficient than 340SE's.....who would you believe? It just doesn't get you anywhere.

True. It would just be another piece of data.

I would imagine that sensitivity measurements are somewhat influenced by the choice of measuring device. In this regard, Dave F or any speaker manufacturer probably has a home solution beat.

Jim

[curtis]

True. It would just be another piece of data.

Right, and in the forums, it becomes another piece of data that gets argued about and someone will claim it is incorrect or bogus.

Heck...we now have the reseller that is involved saying that there is something technically incorrect about the level matching issue and is going to post it on his forum. Plain ridiculous.

[wesley63]

Heck...we now have the reseller that is involved saying that there is something technically incorrect about the level matching issue and is going to post it on his forum. Plain ridiculous.

Umm... how is this any different than Dave bringing it up in the first place? Doesn't everyone have the right to voice and defend their opinion?

[curtis]

Umm... how is this any different than Dave bringing it up in the first place? Doesn't everyone have the right to voice and defend their opinion?
Absolutely he does....but how do you end it all? What do you do to get the "definitive" answer?

Jim....what is your opinion on the matter? Where do you stand?

For me, the attenuation issue with series resistance, I have researched this issue on my own. What I have found agrees with what Dave has posted in regards to it affecting crossover behavior.

The speaker sensitivity, I hope to find out for myself. Until then, it is a "he said", "he said" issue.

[Mag_Neato]

The best way to compare speakers remains the same as always.....in person, using the electronics you will use them with, in the room you will have them in.

I attended the G2G, listened to some of the speakers during the 1st few rounds, then resigned myself to just listening and not trying to keep score. I missed the middle and final rounds since it was a beautiful day, and I got to know some of the other attendees. The comments on the different speakers varied from person to person, which just illustrates how one person's idea of what sounds good is not everyone's.

The in-home trial is the best way with the ID brands. Your room and equipment cannot be duplicated in someone elses house, or a B&M store.

If I had any of the speakers from the shootout I'd be happy. On their own, of course. Once side by side comparisons start, I would be forced to choose based on what mix of sonic ingredients tasted the best to me.

As the designer of the 340SE's, Dave is the authority on it's flavor, and knows what can happen when you add a pinch here, or a dash there.

[wesley63]

Absolutely he does....but how do you end it all? What do you do to get the "definitive" answer?

Jim....what is your opinion on the matter? Where do you stand?


From the context of you mentioning that there is no definitive answer and then asking my opinion, I didn't know if it was a rhetorical question or not. But I'll offer something anyways:

I think that Dave, caring so much for his art, was very disappointed in the comments from some of the reviewers on the 340SE. The series attenuation argument, although true, does not really apply in this situation. I am sure that he will continue the search for an explanation.

As for the magazine article, I think that it was unfortunate that they put the numerical scores in the article without more detail as to how they were calculated. I have heard a few speakers and know what I like in my room, so I would have read the strong treble comments about the Acculine and shied away from it. Regardless of score, I would still choose the 340SE because I know that strong treble in my overly bright room is intolerable. But, your average person, doing a google search and finding the article may glance through it, not reading, except for "76.18 to 66.38, that ones better." This would be a shame. The comments of the listeners are comments of listeners: everyone hears differently.

Of course, the google search would also uncover the many, many great comments about the 340SE also. So in the end it may be a wash.

I assume that we are going to go through all this again after the Stereomojo speaker review comes out. I have no idea the conditions under which that test was conducted. I can say some people will be very happy and others very annoyed.

Jim

[curtis]

The series attenuation argument, although true, does not really apply in this situation. I am sure that he will continue the search for an explanation.
Assuming that Dave did his due diligence before posting his statement that his findings do not match Craig's, it means you believe that statements of one party are true and the other false. Am I fair in saying that?


As for the magazine article, I think that it was unfortunate that they put the numerical scores in the article without more detail as to how they were calculated. I have heard a few speakers and know what I like in my room, so I would have read the strong treble comments about the Acculine and shied away from it. Regardless of score, I would still choose the 340SE because I know that strong treble in my overly bright room is intolerable. But, your average person, doing a google search and finding the article may glance through it, not reading, except for "76.18 to 66.38, that ones better." This would be a shame. The comments of the listeners are comments of listeners: everyone hears differently.
Also, one company is using the scores on their website.

[davef]

It implies, yes. I was just pointing out that at no time did Dave come out and say that he had measured the Acculines personally. He does say that he has done his "due diligence." That may include actually purchasing or borrowing the competitors speakers and seeing what's up. I just don't know.


Hi Jim,

Of course I have measured the acculines. As I have mentioned, I do my due diligence. I will not, however, post those measurements. I made a promise to myself a long time ago that I would not cross that line. While the urge to post is there, I simply will not do it, it crosses a line that violates my own integrity.

I started this business nearly 9 years ago to get *away* from all of that BS, to bring a level of honesty and integrity BACK to audio.

I have not made any performance claims regarding any of the speakers, I posted a technical summary of the effects of series resistance on loudspeaker performance, brought about by my own personal curiosity because of comments I read regarding the performance of Craig's 340 SE. If you look deep into the forum, I have posted many similar technical discussions, since day one. This is what I do, it is who I am.

I am not a marketing person or a salesperson, nor do I even consider myself a businessman and because of this I have often been taken advantage of... I have been told by many industry guru's that what I am doing with Ascend is crazy --- forget the integrity and make money; build everything overseas; why test every loudspeaker; why use expensive components; why not use "stealth" marketing; you should offer people free product to post reviews, sponsor events.. etc. etc. It goes on and on.. I live humbly, Ascend supports my family and a few employees and I am fully satisfied with that. We keep rolling on without any of those games and, I will never resort to that -- it won't happen and I feel good about it.

[randyb]

Hi Jim,

Of course I have measured the acculines. As I have mentioned, I do my due diligence. I will not, however, post those measurements. I made a promise to myself a long time ago that I would not cross that line. While the urge to post is there, I simply will not do it, it crosses a line that violates my own integrity.

I started this business nearly 9 years ago to get *away* from all of that BS, to bring a level of honesty and integrity BACK to audio.

I have not made any performance claims regarding any of the speakers, I posted a technical summary of the effects of series resistance on loudspeaker performance, brought about by my own personal curiosity because of comments I read regarding the performance of Craig's 340 SE. If you look deep into the forum, I have posted many similar technical discussions, since day one. This is what I do, it is who I am.

I am not a marketing person or a salesperson, nor do I even consider myself a businessman and because of this I have often been taken advantage of... I have been told by many industry guru's that what I am doing with Ascend is crazy --- forget the integrity and make money; build everything overseas; why test every loudspeaker; why use expensive components; why not use "stealth" marketing; you should offer people free product to post reviews, sponsor events.. etc. etc. It goes on and on.. I live humbly, Ascend supports my family and a few employees and I am fully satisfied with that. We keep rolling on without any of those games and, I will never resort to that -- it won't happen and I feel good about it.

Well, I guess I won't go quietly into the night:-)

I think your business model is great and the technical stuff is most appreciated. It is unfortunate that marketing stuff seems to be everywhere some of which is dubious in my opinion. Keep up the good work and keep bringing great products to market.

[wesley63]

Assuming that Dave did his due diligence before posting his statement that his findings do not match Craig's, it means you believe that statements of one party are true and the other false. Am I fair in saying that?


When I posted that, I only had the evidence from the posts and believed that Dave was comparing the 340SE to the Acculine's by published specifications only. I didn't believe anyone was lying about their results. I was just assuming that they were different comparisons. Now that Dave has confirmed that he has taken his own measurements I am at a loss. Dave has taken his own measurements and I believe what he has observed. I also can think of no reason why Craig Chase would lie about attenuating the Acculines by .5 dB rather than the 340SE during the test.

Dave,
Thanks for the response. I have enjoyed reading your posts on other forums very much. You often bring a very level headed perspective to some outlandish conversations. Your integrity comes through in your posts. It was one of the reasons that I have been drawn to your products. I am looking forward to listening to the Sierras in the near future in my home (still saving money and fighting the uphill battle of convincing the wife that new speakers are the number one priority in our lives right now.)

Jim

[davef]

When I posted that, I only had the evidence from the posts and believed that Dave was comparing the 340SE to the Acculine's by published specifications only. I didn't believe anyone was lying about their results. I was just assuming that they were different comparisons. Now that Dave has confirmed that he has taken his own measurements I am at a loss. Dave has taken his own measurements and I believe what he has observed. I also can think of no reason why Craig Chase would lie about attenuating the Acculines by .5 dB rather than the 340SE during the test.


Jim,

I am at a loss too but there are many possibilities for the discrepancy. If Craig measured his acculines as having higher sensitivity, and they were both positioned in the exact same position. then either his pair of acculines are different than my pair or his pair of 340 SE are out-of-spec, or there is a fundamental difference in how the sensitivity measurement is being performed.

One thing that bothers me about Craig's response measurements is that with at least the one 340 SE that he measured (no attenuation, no screen), the tweeter level is down about 5dB on average compared to the 2k - 3k region. This could be due to measuring equipment (I am not a fan of Sound Card based measuring systems, too susceptible to noise) and many microphones roll-off highs. The tweeter level of the 340SE should be slightly higher than the upper mids, not lower. Craig purchased the recerts a few months ago, I am going to look up the response curves in our database this evening.

Also, I appreciate the kind words :)

[Mike^S]

Something is definitely strange about Craig's measurement of the 340SE. The upper frequency range is several dB lower than the midrange even with no attenuation on the switcher box.

Here is my measurement of the 340SE that I used to own:

http://img401.imageshack.us/img401/3280/340seecm8000bdi5.th.jpg (http://img401.imageshack.us/my.php?image=340seecm8000bdi5.jpg)
Nice and flat.

[davef]

Something is definitely strange about Craig's measurement of the 340SE. The upper frequency range is several dB lower than the midrange even with no attenuation on the switcher box.

Here is my measurement of the 340SE that I used to own:

http://img401.imageshack.us/img401/3280/340seecm8000bdi5.th.jpg (http://img401.imageshack.us/my.php?image=340seecm8000bdi5.jpg)
Nice and flat.

Yep -- that is EXACTLY how the response of the 340SE should look. Ever so slightly tipped up top end.

Nice measurement by the way. What mic are you using?

[Mike^S]

Thanks Dave! That was an ECM8000 by Behringer. Only $100 for the mic and phantom power.

[davef]

Thanks Dave! That was an ECM8000 by Behringer. Only $100 for the mic and phantom power.

I suspected it was the Behringer.. Slight roll off of the top end starting at about 14kHz, getting steeper as frequency increases. I have a few of them.

You would have to spend several hundred to beat the performance of the Behringer. Not really suitable for engineering grade work, but for the hobbyist it is perfect, there is no reason to spend more.

[davef]

Guys,

This is getting way out of control. We now have a competitor making accusations regarding "anonymous" forum posters etc. etc. I posted this discussion on our forum to avoid this because I thought it was an interesting and informative discussion, worthy of a good read, information worthy of publication.

The competitor in question does quote some good technical info regarding series resistance vs. series-parallel resistance (an L-pad). If the switch box in question uses series-parallel resistance, the net effect of the attenuation would be different as impedance can remain constant, however an L-pad introduces other anomalies but these would not concern me nearly as much.

I did NOT want to have to get into this even deeper. To be quick, I am going to use an example here. To determine the cut-off frequency for a simple 1st order RC high-pass filter (the building block of the tweeter section of a crossover) the formula is F= 1 / (2*pi*R*C) where F = cut off frequency, R = total resistance, C = capacitance). As you can see from the formula, when resistance is increased, the cut off frequency decreases. The more resistance, the lower the cut off point. Let us assume a 6 ohm tweeter, using a capacitor value of 6uF (.000006 Farad). Doing the math, we get a cut off frequency 4423 Hz. If we add even as little as 2 ohms of series resistance (resistance now sums to 8 ohms), the cut off frequency changes to 3317 Hz, considerably lower.

The opposite is true with the woofer section that uses series inductors. As resistance increases, the cut-off frequency increases. Adding series resistance to a parallel crossover network (which is the design of the majority of crossovers out there) will lower the tweeter cut-off frequency and raise the cut-off frequency of the woofer. Additionally, the slope and Q of the filter will change as well -- these formulas also depend on the resistance (impedance) of the circuit. I should mention that it is more complicated than this as most crossovers use higher order filters, but you can clearly see the effect of resistance changes.

The net result of this is interesting actually and it relates to speaker sensitivity as well. I will explain -- the design of a crossover will call for the crossover point (the summation point of the filters we are discussing) to be at a specific level compared to the response when the filter is not engaged. For example, the crossover point might be -9dB down so that both filters will sum to a flat response. If series resistance is added, thereby raising the woofer cut-off frequency and lowering the tweeter's -- that -9dB crossover point might now be -6dB or less so that instead of both filters summing to "flat" -- there is now a 3dB "bump" that will typically span at least two octaves. Look at the various frequency response graphs that both I and Craig measured, notice that as attenuation increases, the range between 1 kHz – 3 kHz becomes exaggerated with respect to the rest of the range.

Depending on the method used to measure sensitivity, it is often calculated by averaging the frequency range of say 1 kHz – 5 kHz. Since the crossover point will be in this range, a 1dB drop in sensitivity (if using this method to determine sensitivity, which is the most common), will cause a far greater drop in sensitivity below this range and above it, since this range becomes bumped up with respect to the rest of the range by adding resistance. While it might appear that sensitivity is only dropping by 1dB, the range above and below the summation range will be attenuated by a much larger amount. In other words, with this method -- what might appear as a 1 dB drop in sensitivity will only be a 1dB drop in perhaps a 2 octave range while the range outside of this will be attenuated much more. In other words, this is not equal attenuation; it does not drop the complete bandwidth by 1 dB. The delicate balance of the speaker is changed.

All of this is easily evidenced by examination of the response measurements, the measurements that I took and third party.

Back to my original point, if attenuation was achieved by use of variable series-parallel resistance, the effect on frequency response would be much less evident and in fact, I would not have been all that concerned with the attenuation device. While still not all-fair, use of an L-Pad would have been acceptable to me. However, the measurements taken by Craig clearly show the same affect as I measured using series resistance. And please lay off Craig -- he did not do anything wrong.

Additionally, I mentioned that I do my due diligence. The question was indeed asked of the manufacturer of the switch whether attenuation was achieved by use of series resistance or L-Pad. The answer was straight series resistance, which corresponds exactly with the frequency response graphs taken by Craig when using attenuation on the device.

My discussion here has resulted in complete upheaval -- mud being thrown all over the place. Truth be told, I even tried to handle this off-line with various parties but my emails were conveniently ignored. I am not here to make enemies of people who don't even know me, or what I stand for. I have not called for a retraction of any of the now widely published results and I most certainly can (and probably should), SO GET OVER IT.

If someone can argue that series resistance, even as little as 1 ohm, will not change crossover performance, please proceed. It will be difficult though as they would have to re-write a whole lot of circuit analysis books. Otherwise, there is absolutely nothing more that can be discussed regarding this.

Instead of all the different sides fighting about it, do the listening session again. What better excuse to have another good time? If given enough time, I would even build the appropriate level-matching low-level switcher at my expense that can be used for this, although it would not be remote controlled, but there are other methods. Even better, just do the comparisons in your own home and draw your own conclusions.

I have said my peace regarding the attenuation device. If someone can re-write the laws of physics, please do let me know.... I have several urgent requests at this time.

[davef]

Sorry, one last but important point...

Nowhere in any of this have I discredited any product or any manufacturer. Don't let what is being posted cause you to think otherwise.

I have not placed blame on anyone but myself, for not looking into any of this deeper, beforehand. No *permission* was ever asked of us to use any of our products for this listening session, yet from public postings, it is easy to conclude many conversations occurred well beforehand with the other ID companies. Other companies graciously declined when asked to submit product. I repeat, nothing was asked of us... There were products present from competing companies that aren't even in production yet, I would have loved to have a new product there too -- something that is in limited production right now but has not been discussed at all by me. In all fairness, is this "fair"?

Had conversations between myself and involved parties occurred, I would have looked deeper, changed a few things, made some requests. We produce only 4 loudspeaker models and 3 of ours were at this event. 2 of which were the subject of 3 published comparisons (more than any other brand). Every one of these models being either B-stock or recertified. Not that any of this should matter because I let all of it pass once I started to pay attention. I let all of it go. I didn't want to mention any of this because THIS information would start a war. But now it has gone too far.

Seriously, what manufacturer would want B-stock product at such a large event, being inspected and evaluated by so many people? Performance aside, we all know looks and build quality matter too. I also let this go…

I wasn't even aware of the dates of this event... too much going on in my personal life. It was my friend Mark Schifter who told me he was flying to Craig's house in a few hours that prompted me to start reading that forum. He called me only a few hours before he left, just to see how things were going in the mess that has become my personal life.

I publicly mentioned that in the comparison between the Sierra-1 and a competing product that has higher sensitivity, in which the Sierra-1 scored higher, I consider this invalid -- and it is.

Now, because I published a perfectly respectable study on the effects of series resistance, I am being attacked. I would have conducted the study on the Sierra-1 instead of 340SE, if only I had available inventory (which I don't).

For those slinging mud my way -- please take a deep breath, read everything that I posted, consult with ANY electrical engineer, and then please take a closer look.... at everything.


I have had enough -- and I thank you for your time.

[daman]

Hi Dave,

I read all the results of the blind test while they were being posted. I still ordered a 340 center because I liked what I heard out of the 170's I purchased a while back. It should be here Tuesday, I can't wait LOL. They can post all the blind test they want I'm sold on your product. IMO one of the biggest bargains in audio!

Later, Daman

[chas]

Ok now let's move on to something fun...like:


I would have loved to have a new product there too -- something that is in limited production right now but has not been discussed at all by me.

:)

[buddhadas]

I agree with Chas.

Dave what could this product be?
"I would have loved to have a new product there too -- something that is in limited production right now but has not been discussed at all by me. "
You could email us loyal customers privately, I for one promise to not say a thing!
Just a small note to let you know that my Sierra's sound fantastic in my McIntosh two channel rig. A huge Thank You!!

Peace,

Jim

[JasonColeman]

...still saving money and fighting the uphill battle of convincing the wife that new speakers are the number one priority in our lives right now...
Yeah, good luck with that. Be sure to post the magic solution that convinces her of that! :D Probably something shiny and much more expensive than a pair of Sierras!

J.

[davef]

Ok now let's move on to something fun...like:
:)

Agreed... For those interested, read this thread. http://forum.ascendacoustics.com/showthread.php?t=1674

[muzz]

Shi.tttttttt, sorry Dave, I read your first post(haven't even bothered reading further yet).. and it hit me..

DOH!!

First off, I am NOT an electronics engineer, BUT I do understand impedance, and impedance isn't just resistance( as in the term "OHMS"), it is a combination of Capacitance and Inductance...

I saw they mentioned a "switcher', I never even thought it was just a VERY basic Resistance switching unit....

Arrrrrrrrrrghhhhhhhh!!!

I should have asked questions, I never even thought to........ that's what happens when your away from electronics for awhile.

I should have said something Dave, I just never even thought to do so ( I've been EXTREMELY busy)..

Arrrrrrrgggggggghhhhhhhh, I feel like an idiot.....

BTW- Unless Craig is secretly into Electronics, or was TOLD of this, he wouldn't know this.

Gary

[Jonnyozero3]

I just caught up on this thread today = I had some more thoughts, but I'll keep most of them to myself. They were mostly about tempering my post earlier and saying a full "retraction" or deletion is not what I really meant was necessary. Poor word choice :( And, I think nothing ill of craig, and thought he was doing a wonderful thing hosting that event. Indeed, I wish I could have been there. :o

Just from catching up here, it sounds like this exploded. It's too bad people can't relax and get a grip. Oh well. I don't even want to see what BS is flying around on less...level-headed forums. So, I probably won't even bother. I'm going to go listen to some music and play wii.

One last thing, and this is the most important on my mind:

Dave, take care of your personal life first. That's most important.

Have a good night fellas. I'll raise a glass to those with level-heads and a drop of reason tonight, with a nod to Dave. You, sir, keep your cool like a pro. Impressive.

PS: Bikeman, I tried to shoot you a PM with no luck. :(

[SteveCallas]

In all seriousness, time and effort aside, has Craig ever been able to conduct one legitimate comparison test? I think he would be less prone to this kind of thing if he asked for help from fellow enthusiasts in the setup/measuring department.

[davef]

This multi-quote feature of the new forum software is great! :p


Hi Dave, I read all the results of the blind test while they were being posted. I still ordered a 340 center because I liked what I heard out of the 170's I purchased a while back. It should be here Tuesday, I can't wait LOL. They can post all the blind test they want I'm sold on your product. IMO one of the biggest bargains in audio!

Thanks Daman! Hope you enjoy the center!


Just a small note to let you know that my Sierra's sound fantastic in my McIntosh two channel rig. A huge Thank You!!

Thanks Jim! Hope all is well with you and yours :)


First off, I am NOT an electronics engineer, BUT I do understand impedance, and impedance isn't just resistance( as in the term "OHMS"), it is a combination of Capacitance and Inductance...

I saw they mentioned a "switcher', I never even thought it was just a VERY basic Resistance switching unit....

Arrrrrrrrrrghhhhhhhh!!!

I should have asked questions, I never even thought to........ that's what happens when your away from electronics for awhile.

I should have said something Dave, I just never even thought to do so ( I've been EXTREMELY busy)..

Hey Gary -- Don't worry about it. Few people understand these things, even when presented with the facts (and the math) ;)



Dave, take care of your personal life first. That's most important.


I couldn't agree more.. Thanks Jon!