Diamond Tweeter?

[DavidD]

Always a good time and everyone is welcome of course. I am thinking late March early April....

Please count me in if there is room...

[Asliang]

I took some measurements using REW and UMIK-1 mic, I think my room has a node around 90hz which is why there's a distortion peak at that frequency it seems with all the monitors. I am very curious on how the new curv woofer in this monitor will stack up to the Scanspeak illuminator. I remember someone pointing out there's a slight THD peak in the 1KHz range with the Seas U16RCY curv cone which seems to have been picked up by my measurements.

I think in my measurements I was most surprised that the Paradigm beryllium woofers actually had pretty high 3rd and 5th harmonic distortion compared to polypropylene (Dynaudio) and paper drivers (Salk). I guess metal drivers naturally have more of these odd harmonics which give it a "metallic" sound?

If the new modified curv woofer can keep up with the diamond dome I would love it hear it, it may be my end game speakers. I'd be excited to see measurements and to listen to them.


Ascend Sierra 2
Ascend Sierra 2 640.jpg
https://i.imgur.com/aQIraEQ.jpg

Dynaudio C1
Dynaudio C1 640.jpg
https://i.imgur.com/IGRN8G2.jpg

Paradigm Persona B
Paradigm Persona B 640.jpg
https://i.imgur.com/LWjFpbp.jpg

Salk Silk Monitor
salk silk 640.jpg
https://i.imgur.com/pk7EJBM.jpg

[mikesiskav]

Wow, that is a nice group of speakers to have in your home. What octave smoothing are you using?

[Asliang]

Wow, that is a nice group of speakers to have in your home. What octave smoothing are you using?

I just used the default settings on REW, I have no idea, I am a neophyte here lmao. The speakers aren't all mine, I just borrowed them to measure them because I was curious how they would perform.

That Scanspeak Illuminator is a really impressive woofer though, especially when you consider the Silk Monitor costs only half or less than half as much as the Paradigm or Dynaudio speakers. I can see how it made it's way all the way to the $20,000 Arabesque Minissimo monitor's which also have the Seas diamond tweeter.

[mikesiskav]

Oh nevermind, it says no smoothing at the top. How far away from the speakers did you place the mic?

[Asliang]

Roughly 1.5 meters.

[davef]

Roughly 1.5 meters.

One cannot judge or compare the performance of woofers when they are used within the speaker itself.

The Scan Illuminator 15W is indeed a nice woofer (have a few of them in our lab), but it has a bad cone breakup mode that must be dealt with by trapping it out in the crossover. This creates the need for a more complex crossover which introduces other issues and the notch filter (the "trap") causes phase issues. In a 2-way, I would only use this woofer with a tweeter that can be crossed extremely low, or as the bass woofer in a 3-way.

One should never judge a woofer based on THD --- anything below 1% is entirely inaudible and you really can't properly measure distortion in this manner.

That said, in your measurements, you do realize that the S2 is showing significantly lower overall THD than the Salk Silk, correct? The THD levels are calculated for you, and the Silk is showing a calculated THD of 35.7% while the S2 is calculated at 13.7% (I don't believe either of these)

Unless one has a lot of experience measuring distortion, graphs can be confusing. The distortion graph on the Silk "looks" great - but note the fundamental of the S2 being at 59.2dB while the fundamental of the Silk is at 55.8dB. This means that while you might not have been aware of it, you were either hitting the S2 with more than double the amount of power as the Silk, or the S2 has significantly higher efficiency (which it does). Salk Silk is listed at 83dB while the S2 is 87dB - this accounts for the 4dB difference in the fundamental.

Distortion is calculated at how far down in level from the fundamental the distortion reading is. In other words, distortion levels are based upon the output level, as they should be of course.

Take for example the S2 at 1kHz, the graph shows 2nd order HD at a level of 25dB, or 34.2dB lower than the fundamental (59.2dB - 25dB) or expressed as % = 1.9%

Now with the Silk at the same frequency, we are also showing a level of 25dB, but in this case, the fundamental is at 55.8dB, so a difference of 30.8dB, expressed as a percent = 2.9% (significantly higher level of distortion)

Overall, the S2 is producing 4dB more output than the Silk for these measurements - thus looking at the graphs without full understanding of how this all works can lead to completely wrong conclusions... as I believe has happened here

Additionally, you also don't know how much of that distortion is coming from, for example - your electronics, the crossover of the speaker, your mic-preamp, your laptop, the back-wave of the woofer -- too many uncontrolled variables to list.

When choosing a woofer for a speaker, THD is by far, the parameter that is of the least concern for professionals.

This is nothing personal of course, but neither you nor anyone else should draw any conclusions from these distortion measurements. The only graph you can really use for judging performance is the overall in-room frequency response of the complete speaker, provided the measurements were taken with both the speaker and mic in the exact same position for each speaker... Of which, all of the in-room response measurements look good, as I would expect from all of these high performance speakers.

Hope this makes sense!

[davef]

Please count me in if there is room...

Certainly....

[Asliang]

One cannot judge or compare the performance of woofers when they are used within the speaker itself.

The Scan Illuminator 15W is indeed a nice woofer (have a few of them in our lab), but it has a bad cone breakup mode that must be dealt with by trapping it out in the crossover. This creates the need for a more complex crossover which introduces other issues and the notch filter (the "trap") causes phase issues. In a 2-way, I would only use this woofer with a tweeter that can be crossed extremely low, or as the bass woofer in a 3-way.

One should never judge a woofer based on THD --- anything below 1% is entirely inaudible and you really can't properly measure distortion in this manner.

That said, in your measurements, you do realize that the S2 is showing significantly lower overall THD than the Salk Silk, correct? The THD levels are calculated for you, and the Silk is showing a calculated THD of 35.7% while the S2 is calculated at 13.7% (I don't believe either of these)

Unless one has a lot of experience measuring distortion, graphs can be confusing. The distortion graph on the Silk "looks" great - but note the fundamental of the S2 being at 59.2dB while the fundamental of the Silk is at 55.8dB. This means that while you might not have been aware of it, you were either hitting the S2 with more than double the amount of power as the Silk, or the S2 has significantly higher efficiency (which it does). Salk Silk is listed at 83dB while the S2 is 87dB - this accounts for the 4dB difference in the fundamental.

Distortion is calculated at how far down in level from the fundamental the distortion reading is. In other words, distortion levels are based upon the output level, as they should be of course.

Take for example the S2 at 1kHz, the graph shows 2nd order HD at a level of 25dB, or 34.2dB lower than the fundamental (59.2dB - 25dB) or expressed as % = 1.9%

Now with the Silk at the same frequency, we are also showing a level of 25dB, but in this case, the fundamental is at 55.8dB, so a difference of 30.8dB, expressed as a percent = 2.9% (significantly higher level of distortion)

Overall, the S2 is producing 4dB more output than the Silk for these measurements - thus looking at the graphs without full understanding of how this all works can lead to completely wrong conclusions... as I believe has happened here

Additionally, you also don't know how much of that distortion is coming from, for example - your electronics, the crossover of the speaker, your mic-preamp, your laptop, the back-wave of the woofer -- too many uncontrolled variables to list.

When choosing a woofer for a speaker, THD is by far, the parameter that is of the least concern for professionals.

This is nothing personal of course, but neither you nor anyone else should draw any conclusions from these distortion measurements. The only graph you can really use for judging performance is the overall in-room frequency response of the complete speaker, provided the measurements were taken with both the speaker and mic in the exact same position for each speaker... Of which, all of the in-room response measurements look good, as I would expect from all of these high performance speakers.

Hope this makes sense!

Interesting! So being that THD is not the important factor here, I guess the major question is will the new Curv woofer have greater bass extension than the one in the S2, or will the difference mainly be power handling? What popped out immediately to me was that the Scan Illuminator played quite a bit deeper.

Regarding the design goal of avoiding a complex crossover, will the diamond tweeter allow a simpler crossover design? What are your opinions of using a lower order crossover, for example Dynaudio has used 1st order crossovers for decades, which seems to create a very good driver integration as seen on the impulse response. And do you think you will be using a lower order crossover for the "Sierra Diamond" speaker?

[Asliang]

diamond5.jpg

Regarding this photo, I assume this was a Sierra Luna the driver was installed into. Is it possible at all to modify the regular Sierra cabinet to be front ported as well? I think you mentioned something about that on the Sierra NRT thread that you made some front ported cabinets but I assume you never decided to mass produce them. Got any of those still sitting around?

Would it be possible to make a Sierra w/ Diamond tweeter that's front ported?