Tower speaker help

Somewhat new around here. I’ve been hanging around the forums and reading reviews and have a few of questions.
I’m looking for a substantial upgrade for my speakers (Music only). I currently own Polk LSi’s towers (3- 7.5” woofers; 2- 5.25” mid range and 1- 1” tweeter) driven by NAD C375BEE. Looking at moving them to my HT room and finding very good tower speakers for music listening. The Polks sound good but they are really more geared for movies and I want to hear what the next “level” is. Currently looking at Martin Logan Motion 60XT’s and Def Tech BP-9060ST. Of the two, the Martin Logans sounded better to me. The Def Tech’s were way too bright…
Since I can not listen to the Sierra Towers, I have the following questions:

Are the Sierra Towers better than the ML’s?
Is the ribbon tweeter worth it for music? ( I listen to all kinds of music, rock, classical, new age, chill jazz)
Are the Sierras better than the Polks I own?
I have a hard time believing that (2) 5.25” woofers on the Sierra towers can sound better than (3) 7.5” woofers of my Polks. (the same for the midrange) Can someone comment?

Thanks

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Originally Posted by robpar

Are the Sierra Towers better than the ML’s?

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I have not heard the MLs, but when I was shopping for bookshelves when I bought my Sierras, the MLs were not competitive. However, that was a while ago. My understanding is that the current 60XTs are pretty good, though, so that may have changed.

The one thing I always keep in mind that some % of what you pay for a speaker like ML goes to support a dealer network. That has upside—it means you can find a dealer and go listen for yourself. But it also has downside; lower overhead for ID makes means more of your money supports engineering, not marketing.

That might not mean anything, though—it all depends on your preferences. If you really like the MLs, that's really important. Buying something you like is kind of the point, right?

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Are the Sierras better than the Polks I own?

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I have never heard anything by Polk that is remotely competitive with anything of similar price by Ascend, but admittedly I haven't heard the most recent generation of LSi towers. I also haven't heard a lot of buzz for the Polks, though, which isn't a great sign, but maybe they're diamonds in the rough.

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I have a hard time believing that (2) 5.25” woofers on the Sierra towers can sound better than (3) 7.5” woofers of my Polks. (the same for the midrange) Can someone comment?

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Woofer size does not equate to sounding better overall. Can the Polks move more air? Probably. Does moving more air mean they sound better? Not at all. SQ is a function of a lot of things, and woofer size is only one of a whole host of other factors.

Referencing my own experience: the bass is better (clearer, more detailed, lower extension) on my 5.25" Sierra bookshelves than it was on the competing Paradigm bookshelves, even though the Paradigms have 7" woofers. (This is not to cast aspersions, the Paradigms are very good speakers and were definitely my second choice.) Similarly, the bass from my 8" Emotiva subwoofer is substantially better than from any number of well-known 12" subs from the likes of Dayton, Klipsch, BIC, etc.

That said, the Polks do advertise lower extension than the Sierra Towers (22Hz vs. 34Hz), and that part probably is a function of woofer size. For most music in your genres, I don't think sub 40Hz is really where it's at (if you were a big EDM or hip-hop fan it might be more of a thing). So I wouldn't be evaluating speakers solely or even mostly on the basis of bass extension, but YMMV.

I had polk monitor 70 series2 for 3 years. Then i upgraded to polk lsim 705 and had it for 2 years.
Then i bought sierra 2 and a svs sb16 sub and recently out of curiosity i bought sierra tower with raal.

i listen to music 70% of time and movies/tv 30%. I can tell you clearly that even though polks are good, sierra 2 is totally in a different league. Its amazingly good for music. I can not imagine any other speaker better than it for music. I home demoed multiple speaker brands (svs, b&w etc) but sierra 2 is just WoW!! You cant go wrong with it. It has superb clarity, vocal, imaging, midrange, highs, bass and everything else. I listen to all genre of music from rock, pop, classic rock, metal etc and it performs amazingly well for all types of music. I will strongly suggest you to get sierra 2. if you are not satisfied you can return.
Also regarding RAAL, they are very very clear without any harshness. It has an "AIRY" signature which i only understood after listening.
Do not compare size of speakers to quality. Just listen to sierra 2 and you will understand and shocked.

i can not comment regarding sierra tower with RAAL which i received 2 days ago. But initial impression is that sierra 2 sounds same as tower and its really unbelievable and shockingly good given the size of them vs towers. Once i have listened to them for 2 weeks, i can give my comments.
Without any doubt i will recommend sierra 2 to anyone for music (with an amazing good sub).

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Originally Posted by robpar

Somewhat new around here. I’ve been hanging around the forums and reading reviews and have a few of questions.
I’m looking for a substantial upgrade for my speakers (Music only). I currently own Polk LSi’s towers (3- 7.5” woofers; 2- 5.25” mid range and 1- 1” tweeter) driven by NAD C375BEE. Looking at moving them to my HT room and finding very good tower speakers for music listening. The Polks sound good but they are really more geared for movies and I want to hear what the next “level” is. Currently looking at Martin Logan Motion 60XT’s and Def Tech BP-9060ST. Of the two, the Martin Logans sounded better to me. The Def Tech’s were way too bright…
Since I can not listen to the Sierra Towers, I have the following questions:

Are the Sierra Towers better than the ML’s?
Is the ribbon tweeter worth it for music? ( I listen to all kinds of music, rock, classical, new age, chill jazz)
Are the Sierras better than the Polks I own?
I have a hard time believing that (2) 5.25” woofers on the Sierra towers can sound better than (3) 7.5” woofers of my Polks. (the same for the midrange) Can someone comment?

Thanks

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Hi robpar,

Welcome to our community!

Only your ears can determine what sounds good to you but I can tell you that woofer "size" has absolutely no correlation with sound quality. The only characteristic a larger woofer provides is higher efficiency - meaning that it will provide more volume within its rated bandwidth compared to a smaller woofer within the same bandwidth...

In fact, in most cases - just the opposite is true - you never want a woofer reproducing frequencies whereby the wavelength of the frequency they are producing is smaller than the woofer diameter. In more technical terms, truly high performance speakers should not have any drivers operating outside of their piston range. Among other issues (cone breakup for example), doing so creates what is often referred to as "beaming" -- whereby the frequencies being reproduced higher than the drivers piston range become extremely directional.

Thank you guys.. a couple of more questions:
Are Sierra 2 a bookshelf version of the Sierra towers?
So, generally speaking I should try the RAAL tweeter for music? BTW, I also listen to a lot of electronic chill and ambient music.
As you can understand, spending this kind of money without listening to a set of speakers makes me very nervous so I'm just trying to get as much info as possible. I had not heard about Sierra until about a few months ago so I want to make sure I don't make "lateral move"...
Thanks

Quote:

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Originally Posted by robpar

Thank you guys.. a couple of more questions:
Are Sierra 2 a bookshelf version of the Sierra towers?
So, generally speaking I should try the RAAL tweeter for music? BTW, I also listen to a lot of electronic chill and ambient music.
As you can understand, spending this kind of money without listening to a set of speakers makes me very nervous so I'm just trying to get as much info as possible. I had not heard about Sierra until about a few months ago so I want to make sure I don't make "lateral move"...
Thanks

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Yes sierra 2 is a bookshelf.
RAAL ribbon tweeters are amazing for music.
I was on same boat as you when i started to research about my next upgrade. I had never heard about ascend because they are internet direct companies and never advertise.

But as soon as i googled best audiophile speakers and started reading some forums, i found lot of people talking and recommending ascend.
I decided to get sierra 2 from ascend as its easier to ship and return. I also auditioned many other brands at home for 30 days (svs, b&w, monitor audio etc) and kept returning them.
As soon as i got sierra 2, even my wife who doesn’t listen lot of music and usually not able to tell difference between speakers sound quality said WOW!! She wondered how come music is so clear like singer is in the room.
From my experience i can strongy assure you that this will be totally a big tier upgrade from what you have been listening to. It handles all genres of music amazingly well. You can always return if you dont like. But i highly doubt ascend speakers are ever returned 😊

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Originally Posted by vicky

Yes sierra 2 is a bookshelf.
RAAL ribbon tweeters are amazing for music.
I was on same boat as you when i started to research about my next upgrade. I had never heard about ascend because they are internet direct companies and never advertise.

But as soon as i googled best audiophile speakers and started reading some forums, i found lot of people talking and recommending ascend.
I decided to get sierra 2 from ascend as its easier to ship and return. I also auditioned many other brands at home for 30 days (svs, b&w, monitor audio etc) and kept returning them.
As soon as i got sierra 2, even my wife who doesn’t listen lot of music and usually not able to tell difference between speakers sound quality said WOW!! She wondered how come music is so clear like singer is in the room.
From my experience i can strongy assure you that this will be totally a big tier upgrade from what you have been listening to. It handles all genres of music amazingly well. You can always return if you dont like. But i highly doubt ascend speakers are ever returned ��

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I can totally relate to this. I was in the same boat, never heard of Ascend, read a thread that got me interested (here), started researching Ascend, was concerned about purchasing speakers that I had never heard, and exchanged some emails with Dave (one of my concerns was about returns). Afterwards I read somewhere that someone considered return shipping cost like a rental fee, which made some sense to me.

So in March 2016 I purchased a set of Sierra towers and a Horizon all with RAAL since I am almost 99% music. These were replacing my Polk RT3000p towers and CSi-A6 center. I purchased the RT3000p in 1997 and enjoyed them for many years. Each RT3000p base unit has 2 8" woofers and I shared robpar's concern about the smaller woofers in the Sierras. However after listening to the Sierras I found them to be not as loud but more accurate -- the RT3000p sounded bloated in comparison.

My wife also doesn't "listen" to music, it's more of a background filler for her. But she had the exact same response as vicky's wife.

So to try to answer robpar's questions:
Are the Sierra Towers better than the ML’s?
Sorry, unlike vicky I didn't demo other speakers. I purchased the Ascends with the intent of returning them if I didn't totally love them (I'm an old fart and this will be my last set of speakers). After listening to them I decided there's no way these are going back.

Is the ribbon tweeter worth it for music? ( I listen to all kinds of music, rock, classical, new age, chill jazz)
I also listen to a variety of music and as vicky said "RAAL ribbon tweeters are amazing for music." I hemmed and hawed whether or not to go with the RAAL upgrade (I was trying to keep the price down). Since I mostly listen to music, Dave suggested the RAAL but said the NrT would be great too. Decided to go with the RAAL and love them.

Are the Sierras better than the Polks I own?
I have a hard time believing that (2) 5.25” woofers on the Sierra towers can sound better than (3) 7.5” woofers of my Polks. (the same for the midrange) Can someone comment?
I haven't heard the Polks you own, but they certainly sound better than the Polks I had, which in 1997 cost $3000. Almost 20 years later 2016 the Sierra towers w/RAAL cost $2698+shipping. Considering the upgrade in sound quality, detail and sound-stage I call that quite a deal.

I'm not trying to push you towards the Ascends, but I wanted to tell you my experience since we had some of the same concerns.

Good luck with your decision!
Jack

Thanks again for the comments...
Should the Sierra towers be or can be bi-amped? I could not tell very well by the images...
I forgot to mention my speakers are currently bi-amped (NAD C375BEE integrated and NAD C275BEE amp)
Would they be a good match to the NAD's?
What would return shipping typically run? (from Atlanta)
These may end up being my last set of speakers; I can't afford 10K speakers ; )

I listened to a lot of speakers including the ML and DT models you mentioned. I prefer my RAAL towers. Speaker preference is very subjective, but I don’t think anyone would disagree that the Ascend towers at least compete with the dealer brand speakers that cost somewhere around 2-2.5 times the price (I would argue they beat them handily - but again, subjectivity)

Is there no one in your area who can host a demo? Did you ask on the forum? This seems to be a fairly helpful community.

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Originally Posted by kongar

I listened to a lot of speakers including the ML and DT models you mentioned. I prefer my RAAL towers. Speaker preference is very subjective, but I don’t think anyone would disagree that the Ascend towers at least compete with the dealer brand speakers that cost somewhere around 2-2.5 times the price (I would argue they beat them handily - but again, subjectivity)

Is there no one in your area who can host a demo? Did you ask on the forum? This seems to be a fairly helpful community.

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Thank you for the suggestion. i will post to see if anybody has them around here... BTW, can the towers be Bi-amped?

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Originally Posted by robpar

Thanks again for the comments...
Should the Sierra towers be or can be bi-amped? I could not tell very well by the images...
I forgot to mention my speakers are currently bi-amped (NAD C375BEE integrated and NAD C275BEE amp)

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Sierra Towers do not come with bi-wire / bi-amp inputs. We do offer this for a $75 per speaker fee, but to be honest - there is no reason to spend the additional money. Passive bi-amping or bi-wiring offers no performance advantage.

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Originally Posted by robpar

Would they be a good match to the NAD's?

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Fantastic match with your NAD electronics. I have been using using NAD electronics since the late 80's ;)

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Originally Posted by robpar

What would return shipping typically run? (from Atlanta)
These may end up being my last set of speakers; I can't afford 10K speakers ; )

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Best to give us a call or send us an email regarding estimated return shipping fees - but I wouldn't be concerned about it. We sell a lot of towers and average only 1-2 pair returned per year. We design these to be the last set of speakers you will ever want ;)

My Polks sound much better bi-amped. The bass is much fuller (I'm not a Sub fan for music).
Still debating whether to pull the trigger...:confused:
Thanks!

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Originally Posted by robpar

My Polks sound much better bi-amped. The bass is much fuller (I'm not a Sub fan for music).
Still debating whether to pull the trigger...:confused:
Thanks!

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Are you using an AVR or separate amps to bi-amp?

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Originally Posted by Beave

Are you using an AVR or separate amps to bi-amp?

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Separate amps. Parasound 2250 for the low end, NAD C375BEE for the high end

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Originally Posted by robpar

Separate amps. Parasound 2250 for the low end, NAD C375BEE for the high end

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So you probably have higher gain going to the low-end compared to the high-end, right? That's why you hear "fuller" bass.

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Originally Posted by Beave

So you probably have higher gain going to the low-end compared to the high-end, right? That's why you hear "fuller" bass.

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I was wondering about that. Do the amplifiers each have the same gain spec.?

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Originally Posted by Beave

So you probably have higher gain going to the low-end compared to the high-end, right? That's why you hear "fuller" bass.

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Exactly - that or the NAD might have been running out of juice...

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Originally Posted by curtis

I was wondering about that. Do the amplifiers each have the same gain spec.?

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Both amps have gain dials to balance them when bi-amping, since I am using the Nad also as a pre-amp I'm using the NAD dial to adjust the gain of the second amp
I guess, what I am asking is if the Sierra towers would benefit from a similar setup?

I own the C375BEE, that's an interesting set up you have. I concur that if you are setting the gain by ear or what "sounds" best, the bass is probably turned way up. There is the risk of overdriving the woofers in this case, but as long as you are careful there should be no trouble.

The best way to get the bass you want is to get a powered subwoofer. A decent sub will easily outperform your Polk LSi's. You could then sell the Parasound amp. If you ordered the Sierra Towers with bi-amp inputs, it's hard to say whether you'd gain any bass over the Lsi's alone, but with the Raal tweeter the upper end would be noticeably better.

Thanks
I hate subs for music (don't ask why). I have one upstairs for movies (B&W monitors and Sub) and party music...
I can easily remove the Parasound and move it to another room or use it to drive another set of speakers (which I may)
I am also looking very heavily into Aperion Verus II Grand Tower (bi-ampeable, similar good reviews, 60 day return, free shipping both ways) so at this point, I'm doing as much research as possible.
I don't want to order both but I may have to :(
Thank you very much

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Originally Posted by robpar

Thanks
I hate subs for music (don't ask why). I have one upstairs for movies (B&W monitors and Sub) and party music...
I can easily remove the Parasound and move it to another room or use it to drive another set of speakers (which I may)
I am also looking very heavily into Aperion Verus II Grand Tower (bi-ampeable, similar good reviews, 60 day return, free shipping both ways) so at this point, I'm doing as much research as possible.
I don't want to order both but I may have to :(
Thank you very much

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I won't ask why, and can relate to the sub preference.......until I found Rythmik that is. Most subs did not blend properly and seemed sloppy/sluggish and actually ruined the imaging. Not so with the Rythmik's Direct Servo design. Not sure if you have tried a Rythmik but I highly recommend doing so.

FWIW....properly integrated “good” subs should never be detectable.

If someone doesn’t know I had a sub in my system, they wouldn’t be able to figure it out unless they played some deep material and knew enough about my speakers’ capabilities.

On another note...get the Aperions and the Ascends and do a comparison. It’s been done before.

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Originally Posted by robpar

I am also looking very heavily into Aperion Verus II Grand Tower (bi-ampeable, similar good reviews, 60 day return, free shipping both ways) so at this point, I'm doing as much research as possible.
I don't want to order both but I may have to :(
Thank you very much

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I encourage you to order both the Aperion and the Ascend speakers to do an in home comparison. I did the same (actually threw SVS in the mix as well). It was enlightening. I could hear the differences that the Ascend Sierra 2s had over the other two and it was worth the extra cost to me. I actually compared the Aperion Verus Grand Towers and still liked the Sierra 2s more. The other two had return shipping, so I didn't lose out any money there.

That was three years ago and I'm happy that I did the comparison, so that I wouldn't have any doubts.

Thanks guys!

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Originally Posted by robpar

I hate subs for music (don't ask why).

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I've never heard anyone say this who has servo subs. The people who say this typically have conventional subs, which are difficult if not impossible to integrate with their main speakers. Servo subs aren't anything like as difficult to integrate. Mine were startlingly easy. Almost too easy. I didn't have to play with them much at all. And they are ported. Another thing people say is impossible to use for music.

But I've got a pair of Rythmik LVX12s that work a serious treat with my Sierra 2s. For music. And they kick some tail for HT also. For music it sounds the same as the Sierra 2s alone, except that they mysteriously go an effortless two octaves deeper. No difference in sound quality beyond that.

Quote:

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Originally Posted by robpar

Both amps have gain dials to balance them when bi-amping, since I am using the Nad also as a pre-amp I'm using the NAD dial to adjust the gain of the second amp
I guess, what I am asking is if the Sierra towers would benefit from a similar setup?

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It is important to understand that you are not technically benefitting from bi-amping. What you are doing is simply increasing the amplitude of the bass, similar in respect to turning a bass tone control up higher or adding a bit of EQ to the bass. Nothing wrong with doing this of course, but what you are hearing isn't a benefit of bi-amping.

That said, as already mentioned - we can easily offer you bi-amp inputs for the towers so that you can do the same as you are doing now. However, you might find that the balance of the bass to the mids to the highs of our towers is such that you might not want to accentuate the bass.

As others have mentioned, don't compare your other system with a sub to how our towers + sub will sound for music. The vast majority of our customers are very experienced audio purists and when done right - a Rythmik sub becomes completely transparent and you then gain full control of tweaking the bass to however you like it and no tower speaker can compare to how a Rythmik sub produces bass...

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Originally Posted by davef

It is important to understand that you are not technically benefitting from bi-amping. What you are doing is simply increasing the amplitude of the bass, similar in respect to turning a bass tone control up higher or adding a bit of EQ to the bass. Nothing wrong with doing this of course, but what you are hearing isn't a benefit of bi-amping.

That said, as already mentioned - we can easily offer you bi-amp inputs for the towers so that you can do the same as you are doing now. However, you might find that the balance of the bass to the mids to the highs of our towers is such that you might not want to accentuate the bass.

As others have mentioned, don't compare your other system with a sub to how our towers + sub will sound for music. The vast majority of our customers are very experienced audio purists and when done right - a Rythmik sub becomes completely transparent and you then gain full control of tweaking the bass to however you like it and no tower speaker can compare to how a Rythmik sub produces bass...

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So... are you saying:
The towers without the sub are comparable to Sierra 2 with Subs?
I would not see the benefits of bi-amping sierra towers even if I were capable of doing it?

Thanks!

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Originally Posted by robpar

So... are you saying:
The towers without the sub are comparable to Sierra 2 with Subs?
I would not see the benefits of bi-amping sierra towers even if I were capable of doing it?

Thanks!

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I don't think you are understanding what is being discussed here. With your current speakers, you are not technically benefitting because of "bi-amping." The bass sounds fuller because you are simply sending more bass to the speakers due to adjusting the gain for the 2nd amp. You can do the exact same thing with our towers if we provide bi-amp inputs for you (there is nothing special about bi-amp inputs) or you can do the exact same thing with a single amp by adjusting a bass tone control, or by adding some bass boost using EQ.

Maybe others here can better explain?

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Originally Posted by davef

I don't think you are understanding what is being discussed here. With your current speakers, you are not technically benefitting because of "bi-amping." The bass sounds fuller because you are simply sending more bass to the speakers due to adjusting the gain for the 2nd amp. You can do the exact same thing with our towers if we provide bi-amp inputs for you (there is nothing special about bi-amp inputs) or you can do the exact same thing with a single amp by adjusting a bass tone control, or by adding some bass boost using EQ.

Maybe others here can better explain?

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You could say that what you're doing with your bi-amped setup is a fancy form of EQ. You are effectively boosting the bass signal so it's fuller.

As a follow up, I know there a lot of misinformation regarding bi amping but here is one article that is interesting:

https://www.qacoustics.co.uk/blog/20...tion-benefits/

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Originally Posted by robpar

As a follow up, I know there a lot of misinformation regarding bi amping but here is one article that is interesting:

https://www.qacoustics.co.uk/blog/20...tion-benefits/

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That article is about bi-wiring, not bi-amping. The two are very different.

Well, sorry, my bad. I thought the findings would be interchangeable with Bi-amping?
Anyway, Thanks!
Now, on another related subject that actually may be more beneficial for me, I am considering placing monitors or good sounding speakers (small though-TWF) in my upstairs living room. I currently have medium in-wall B&W (I can't remember the model but they were very expensive about 10 years ago, around $1000/pair) with a "hidden" sub. If I like the sound, I may be able to convince her that a good, small speaker, that puts more/better sound than the B&W's is the way to go (Sierra 1?). The Sierra 2 may be an overkill?
Would be great if the Sierra's would be available in white though, otherwise piano black would have to do...

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Originally Posted by robpar

As a follow up, I know there a lot of misinformation regarding bi amping but here is one article that is interesting:

https://www.qacoustics.co.uk/blog/20...tion-benefits/

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Sorry, but why did you note that there is "a lot of misinformation regarding bi amping," only to post an article that is nothing but misinformation about bi wiring?

That article is misleading garbage. I say that as an electrical engineer who spent much of my career testing audio electronics and cables. Cables are linear, not nonlinear. They don't introduce nonlinear distortions like intermodulation distortion.

Shame on qacoustics for presenting such a misleading and downright false article.

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Originally Posted by Beave

That article is misleading garbage. I say that as an electrical engineer who spent much of my career testing audio electronics and cables. Cables are linear, not nonlinear. They don't introduce nonlinear distortions like intermodulation distortion.

Shame on qacoustics for presenting such a misleading and downright false article.

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I have to agree with Beave here, this article is pure pseudoscience and the measurements don't prove their hypothesis, just the opposite actually.

It brings back some interesting memories for me. At a previous employer, I had to – on occasion – generate various publishable test results to “prove” marketing hype of various technical features (often that were more marketing than anything else). The simplest way to do this? Use inherently inaccurate test gear, take the measurements dozens of times, and use screen shots of the tests that best prove what marketing was asking me to “prove”. Simple to do if there is no control. I never felt good about doing this, but sadly, it was and still is part of this industry.

This test setup uses hobbyist measurement gear at best. An electrical engineer would never use this same gear to run such a test.

After my 10 yr run as an engineer at M&K and as Ascend Acoustics was getting underway – to pay my bills, I did quite a bit of consulting. One such job was working for a venture capitalist who hired me to prove / disprove a company claiming they developed an external “treatment” for CD’s that “dramatically” improves audio quality.

They provided this venture capitalist with all sorts of measurements that someone without much knowledge would assume proves the viability of the device in question. The venture capitalist was ready to invest – but wanted a professional second opinion, that’s where I came in.

I quickly recognized the equipment used for these measurements, which just happened to also be TrueRTA software combined with a USB Audio Interface and I was able replicate the same test results – problem was, every test I took had slightly different results – about half proved the viability of the device, the other half proved the opposite – all based on a few dB difference in the noise floor (which is inherently inaccurate using this type of test setup)

The next step was to use reference grade testing gear, including proper low distortion oscillators, a digital oscilloscope, and my MLSSA system. Every test I took was 100% repeatable, and every test I took showed absolutely no difference between the “treated” CD’s and non-treated CD’s.

The creator of the device was rather upset, and argued to the venture capitalist that my tests were flawed – but when he read my evaluation and presented it for peer review, it was accepted and as such, the creator of this device never saw a dime (at least from this venture capitalist)

This bi-wire article would never stand up to peer review, and I am going to break it down.

First off, this is not a measurement of intermodulation distortion (this isn’t how one would even going about measuring it, if it even existed in cables, nor could TrueRTA even detect it) This is simply a measurement comparing the noise floor.

The interesting thing here is that the publisher's posted measurements actually prove the opposite of their claims…

They are claiming “IMD reduced dramatically”… Let’s take an actual look… Some minor Photoshop work placing one graph on top of the other and applying some opacity, and using the replace color feature so you can see both graphs – it is easy to see that the noise level - what they claim is IMD - (the blue line on the single wire measurement, green line on bi-wire measurement) - - is actually the exact same between the bi-wire measurement and the single wire measurement.

Here are the 2 measurements positioned on top of each other, and then with heavy zoom:


Attachment 1562

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Attachment 1563

The noise level is exactly the same between the bi-wire and single wire measurements. There is no reduction of anything - not even a reduction in noise at the fundamental bass frequencies (which have been attenuated) -- this is exactly opposite of the claims bi-wiring promotes.

The second part of their claim is that there is a reduction in the measurement of low frequencies in the bi-wire test.

This reduction is actually clearly evident in the measurement they posted. Basically, what they are doing is sending a specific set of tones consisting of 5 low frequencies and 5 high frequencies to a speaker, with one set of measurements with the speaker properly bi-wired, and the other with the speaker not being bi-wired.

In the bi-wire measurement, the bass is reduced by approximately 30dB measured at the tweeter speaker cable, while in the non bi-wire measurement, bass is not reduced in the single cable. This alone proves bi-wiring does not work as claimed as the claims made are that the bass signals would not travel in the tweeter speaker cable. Clearly there is still bass frequencies in the tweeter cable – but the question is, why are they attenuated by 30dB?

The answer is very simple… When you bi-wire, you isolate one filter network from the other. Current must be flowing between the + and – amp outputs to form a complete system. The reason the bass is attenuated is because they are measuring the tweeter cable, which only feeds the tweeter filter network when a speaker is bi-wired. And what does the tweeter filter network in a crossover do? It is a high pass filter, thus it dramatically attenuates the bass. And with the bass being ~30dB down at 200Hz, this is basically what I’d expect with a crossover high pass filter.

What is actually happening here is not that bass is being reduced in the tweeter cable due to bi-wiring, it is that the bass is reduced due to the high pass filter in the crossover, which is exactly what should be happening if one isolates the high pass filter network from the low pass filter network.

The reason bass is not reduced in the single cable connection is that the bass frequencies are flowing through the low pass filter network – exactly as it should be since the 2 filter networks are no longer isolated from each other. With bi-wiring, there is no low pass filter network attached to the tweeter cable for the bass to flow freely through - of course it is attenuated because is trying to flow through the high pass filter.

What is a bit alarming though, is that the fundamental in the bi-wire test is different than what is applied to the single cable test.

https://www.qacoustics.co.uk/blog/co...eter-cable.jpg

The fundamental is the red line… See that spike at 50Hz?

That same spike doesn’t exist in the fundamental on the single cable measurement, nor does it exist in the original graph of the fundamental which is the generated test tones on the CD (fundamental is yellow):

https://www.qacoustics.co.uk/blog/co...ingle-wire.jpg

https://www.qacoustics.co.uk/blog/co...est-signal.jpg

In fact, the original CD test signal perfectly matches the fundamental applied to the single wire speaker test but it looks completely different in the bi-wire measurement. Why is this? -- what is that spike? Could be port tube resonance, but if it is - it would also show up on the single wire measurement... hmmm....

So why would a speaker company go through all of this trouble? Promoting claims of bi-wiring benefits allows cable companies to sell a lot more cable at already huge margins. A quick peak at their website indicates they not only sell speakers, but also sell QED cables. Further investigation reveals that Q Acoustics:

https://www.qacoustics.co.uk/contactus

and QED cables are the same company…

http://www.qed.co.uk/contact-qed.htm

Or at least share the same exact office….. :eek::eek:

I'm not arguing against bi-wiring (to each his own), but this article proves zilch...

Quote:

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Originally Posted by robpar

Well, sorry, my bad. I thought the findings would be interchangeable with Bi-amping?
Anyway, Thanks!
Now, on another related subject that actually may be more beneficial for me, I am considering placing monitors or good sounding speakers (small though-TWF) in my upstairs living room. I currently have medium in-wall B&W (I can't remember the model but they were very expensive about 10 years ago, around $1000/pair) with a "hidden" sub. If I like the sound, I may be able to convince her that a good, small speaker, that puts more/better sound than the B&W's is the way to go (Sierra 1?). The Sierra 2 may be an overkill?
Would be great if the Sierra's would be available in white though, otherwise piano black would have to do...

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Bi-wiring and bi-amping are very different. With bi-amping, especially active bi-amping, there are definitely performance benefits. What you are doing is passive bi-amping, powering your speakers with 2 different amplifiers, one amp powering the highs, another the lows. This essentially adds more available headroom, and - as you have found out, you can add (or reduce) the balance of the bass to the mids & highs by adjusting the gain of the amp.

We can do a very nice custom white finish on Sierra cabinets :) Best to contact us directly.

I reread my post from above and felt it came across rather rude to robpar, so I'd like to apologize for that.

As I said above, I worked as an engineer doing audio for many years, so I get really frustrated with the amount of misinformation propagated by the industry. I got annoyed with that and reacted too strongly to robpar's post. I have to remind myself that not everybody has the background that allows them to distinguish what is good information and what is misleading bs. So my frustration should be directed at q acoustics and not at all at robpar.