Ascend Acoustics Sierra LX Review

[AscendDF]

This whole distortion thing is really peculiar. @AscendDF have you gotten a chance to write up your investigation on this distortion claim yet?

I have run over a dozen full range listening tests since that review, specifically targeting the audibility of MTON distortion with our LX, even hitting measured volume level peaks of 110dB at 11-12 feet running full range. These were random listeners, including several musicians as well as critical listeners. I too am a critical listener, and I have spent an insane amount of time trying to hear this as well. Nothing..

We even had an upper level management employee from SEAS visit us here at our shop to go over everything in detail, which also led to a 2-hour long team meeting with the engineers and President of SEAS a few weeks later.

I have also compared our LX woofer against many other top shelf woofers, including Scan Speak, SB, Purifi and other SEAS models - basically any woofer that can reproduce similar (or close) deep bass (although none truly matched what our LX woofer can do) and the results favored our LX woofer. I even compared against a woofer that I consider the best I have ever measured... This particular woofer had a slight edge in midrange clarity, but it wasn't due to lower IM distortion, more so the cone material combined with a specialized highly advanced new motor system. This was also confirmed with experienced listeners, they actually preferred the incredible punch of the LX woofer which this woofer could not match.

Not everything that is measurable relates to what we hear, and it is critically important to deeply evaluate just what is being measured, including the signal a speaker is receiving to generate said measurements. I have not stopped working on this since then and now that our 170SE2 is in production and shipping, my priority is to properly address this in a "politically correct" manner as to not cause any drama. Not a simple task but it's coming.

Including purchasing Klippel's MTON module, and the costs of about a dozen various sample woofers - we have now invested over $12K into researching this issue and the only change we have made to the LX after all this time and expense was having SEAS use even tighter tolerances for pass/fail frequency response measurements of each woofer (which they agreed to) I have not found a woofer that sounds better at low to even very high volume levels than our LX woofer in this application, and that has been confirmed by multiple listeners.

 

[PristineSound]

I have run over a dozen full range listening tests since that review, specifically targeting the audibility of MTON distortion with our LX, even hitting measured volume level peaks of 110dB at 11-12 feet running full range. These were random listeners, including several musicians as well as critical listeners. I too am a critical listener, and I have spent an insane amount of time trying to hear this as well. Nothing..

We even had an upper level management employee from SEAS visit us here at our shop to go over everything in detail, which also led to a 2-hour long team meeting with the engineers and President of SEAS a few weeks later.

I have also compared our LX woofer against many other top shelf woofers, including Scan Speak, SB, Purifi and other SEAS models - basically any woofer that can reproduce similar (or close) deep bass (although none truly matched what our LX woofer can do) and the results favored our LX woofer. I even compared against a woofer that I consider the best I have ever measured... This particular woofer had a slight edge in midrange clarity, but it wasn't due to lower IM distortion, more so the cone material combined with a specialized highly advanced new motor system. This was also confirmed with experienced listeners, they actually preferred the incredible punch of the LX woofer which this woofer could not match.

Not everything that is measurable relates to what we hear, and it is critically important to deeply evaluate just what is being measured, including the signal a speaker is receiving to generate said measurements. I have not stopped working on this since then and now that our 170SE2 is in production and shipping, my priority is to properly address this in a "politically correct" manner as to not cause any drama. Not a simple task but it's coming.

Including purchasing Klippel's MTON module, and the costs of about a dozen various sample woofers - we have now invested over $12K into researching this issue and the only change we have made to the LX after all this time and expense was having SEAS use even tighter tolerances for pass/fail frequency response measurements of each woofer (which they agreed to) I have not found a woofer that sounds better at low to even very high volume levels than our LX woofer in this application, and that has been confirmed by multiple listeners.

Geesh, this does not sound like an investigation, it sounds like you were hunting for a needle in a haystack, and appears none exists.

And a significant amount of investment (time, your time and other people's time. . .and money) was made while doing so.

I wonder what other manufacturer would go this far. I'm really looking forward to reading this write up, not for the "rebuttal" but for the educational knowledge and information. If this quick write up is telling, I am expecting a master class.

 

[thewas]

Glad to know you are now enjoying the LX. IM distortion (in a speaker) is not going to change with changing an amplifier. Your Denon PMA 1700NE is a bit low powered for the LX, so what you were hearing wasn't IM distortion, it was clipping.

I respectfully have to disagree, in my experience the PMA-1700NE has with its measured

Power output (<1% THD, 8/4ohm)	92W / 175W
Dynamic power (<1% THD, 8/4/2/1ohm)	97W / 186W / 348W / 265W

Source: https://www.hifinews.com/content/denon-dcdpma-1700ne-sacd-playeramplifier-lab-report

has enough power to bring any similar sized home audio 2-way one midwoofer loudspeaker to its woofer distortion limits at its lower frequency range which also leads to significant and audible multitone distortion, but I am happy to be proven wrong with the corresponding measurements since you have the needed Klippel modules.

This can be seen also at the measurements from EAC where its distortion and compression are significant already at 96 dB:

 

[AVKS]

I respectfully have to disagree, in my experience the PMA-1700NE has with its measured

Power output (<1% THD, 8/4ohm)	92W / 175W
Dynamic power (<1% THD, 8/4/2/1ohm)	97W / 186W / 348W / 265W

Source: https://www.hifinews.com/content/denon-dcdpma-1700ne-sacd-playeramplifier-lab-report

has enough power to bring any similar sized home audio 2-way one midwoofer loudspeaker to its woofer distortion limits at its lower frequency range which also leads to significant and audible multitone distortion, but I am happy to be proven wrong with the corresponding measurements since you have the needed Klippel modules.

This can be seen also at the measurements from EAC where its distortion and compression are significant already at 96 dB:

View attachment 545401

View attachment 545403

To play devil's advocate here, the PMA-600NE was not the cleanest amplifier when measured here on ASR. The 1700NE is a different product of course but product lines like these oftentimes share similar performance. Happy to be proven wrong if that information exists for the 1700NE, and if it does it may negate my next comment.

Denon PMA-600NE Integrated Amplifier Review

This is a review and detailed measurements of the Denon PMA-600NE integrated amplifier with Bluetooth support and DAC. It is on kind loan from a member and costs US $499. I like the look of the unit especially for the price. Somewhat dismayed though that the input selector is not lined up with...

www.audiosciencereview.com

I know that my recent move from an Audiolab 6000a to a Fosi ZA3 has resulted in an audible improvement from my LXs. This is most likely related to the improvement in SINAD rather than power, but the same type of thing could be happening here. @Rischa, did you also change your DAC when moving to the Buckeye (e.g. were using the Denon as an integrated) or is the source the same?

 

[mck22mck]

I'd like to add one highly unscientific opinion. I've had a pair of LX's for about 18 months in my bedroom/home office space (I live in a Manhattan apartment.) where I listen both at distances of about 15 feet and 3 feet. They are powered by a late 1990s Classe 70, so clean power and good current but not a huge amount of either. I listen to a lot of vocal music, mostly classically trained and typically recorded with a goal of naturalism. I haven't noticed any distortion that is not present on the recording itself. I obviously don't need, and my lease would be jeopardized by very high volumes. I have tried both the solid and hollow port plugs, but came back to the open port. I appreciate the bass extension without a need for a sub. I'm not really a gear head, but I want voices, both human and instrumental, to sound as natural and identifiable as possible. The LX's give me that.

 

[PristineSound]

I'd like to add one highly unscientific opinion. I've had a pair of LX's for about 18 months in my bedroom/home office space (I live in a Manhattan apartment.) where I listen both at distances of about 15 feet and 3 feet. They are powered by a late 1990s Classe 70, so clean power and good current but not a huge amount of either. I listen to a lot of vocal music, mostly classically trained and typically recorded with a goal of naturalism. I haven't noticed any distortion that is not present on the recording itself. I obviously don't need, and my lease would be jeopardized by very high volumes. I have tried both the solid and hollow port plugs, but came back to the open port. I appreciate the bass extension without a need for a sub. I not really a gear head, but I want voices, both human and instrumental, to sound as natural and identifiable as possible. The LX's give me that.

I think I mentioned this in one of my previous posts on this thread, when I owned the LX, I have not heard any distortion. However, I too don't play loud because I don't need to nor do I want to for the preservation of my hearing.

I am considering getting the LX again for another system for a larger space, which may result in my playing it louder, which is why I am particularly interested and closely following this thread.

 

[thewas]

To play devil's advocate here, the PMA-600NE was not the cleanest amplifier when measured here on ASR. The 1700NE is a different product of course but product lines like these oftentimes share similar performance. Happy to be proven wrong if that information exists for the 1700NE, and if it does it may negate my next comment.

Denon PMA-600NE Integrated Amplifier Review

This is a review and detailed measurements of the Denon PMA-600NE integrated amplifier with Bluetooth support and DAC. It is on kind loan from a member and costs US $499. I like the look of the unit especially for the price. Somewhat dismayed though that the input selector is not lined up with...

www.audiosciencereview.com

I know that my recent move from an Audiolab 6000a to a Fosi ZA3 has resulted in an audible improvement from my LXs. This is most likely related to the improvement in SINAD rather than power, but the same type of thing could be happening here. @Rischa, did you also change your DAC when moving to the Buckeye (e.g. were using the Denon as an integrated) or is the source the same?

The 1700NE is a different tier, which can be seen also from its linked above measurements:

A-wtd S/N ratio is a generous 91dB (re. 0dBW) and distortion consistently low at ~0.0025% from 1W-50W/8ohm through the midrange (up to 0.015%/20kHz), only increasing to 0.003%/1kHz at the rated 2x70W/8ohm. In practice the amplifier's true power output is closer to 2x92W/8ohm and 2x175W/4ohm.

In my experience such figures are inaudible, even more when listened with loudspeakers which as above reach close to two digit percentage distortion at high levels.

 

[Chrispy]

To play devil's advocate here, the PMA-600NE was not the cleanest amplifier when measured here on ASR. The 1700NE is a different product of course but product lines like these oftentimes share similar performance. Happy to be proven wrong if that information exists for the 1700NE, and if it does it may negate my next comment.

Denon PMA-600NE Integrated Amplifier Review

This is a review and detailed measurements of the Denon PMA-600NE integrated amplifier with Bluetooth support and DAC. It is on kind loan from a member and costs US $499. I like the look of the unit especially for the price. Somewhat dismayed though that the input selector is not lined up with...

www.audiosciencereview.com

I know that my recent move from an Audiolab 6000a to a Fosi ZA3 has resulted in an audible improvement from my LXs. This is most likely related to the improvement in SINAD rather than power, but the same type of thing could be happening here. @Rischa, did you also change your DAC when moving to the Buckeye (e.g. were using the Denon as an integrated) or is the source the same?

How did you compare the hardware particularly, tho? Hard to do and likely your comparison lacks in a few ways.

 

[AVKS]

The 1700NE is a different tier, which can be seen also from its linked above measurements:

A-wtd S/N ratio is a generous 91dB (re. 0dBW) and distortion consistently low at ~0.0025% from 1W-50W/8ohm through the midrange (up to 0.015%/20kHz), only increasing to 0.003%/1kHz at the rated 2x70W/8ohm. In practice the amplifier's true power output is closer to 2x92W/8ohm and 2x175W/4ohm.

In my experience such figures are inaudible, even more when listened with loudspeakers which as above reach close to two digit percentage distortion at high levels.

FWIW both the 600 and the 1700 are spec'd almost exactly the same by Denon on their site with respect to the THD and S/N numbers and both are very low. Again, I'm not saying there isn't a difference, just tossing out a scenario as a possibility; the 600s performance at ASR was surprising as well.

How did you compare the hardware particularly, tho? Hard to do and likely your comparison lacks in a few ways.

True that I didn't take literal measurements. I do listen to them at a distance of less than 2 ft. on my desk in a quiet house, and listen to them for hours a day most working days (~95,000 minutes streamed on Spotify last year). As I noted in my post, the biggest thing was adding 1.5 dB back into my bass shelf reduction. It's not scientific and I don't claim it to be, but the SINAD difference between the Fosi and the Audiolab is large and could support my perceived improvement. Could be a similar thing for the other listener.

 

[Chrispy]

True that I didn't take literal measurements. I do listen to them at a distance of less than 2 ft. on my desk in a quiet house, and listen to them for hours a day most working days (~95,000 minutes streamed on Spotify last year). As I noted in my post, the biggest thing was adding 1.5 dB back into my bass shelf reduction. It's not scientific and I don't claim it to be, but the SINAD difference between the Fosi and the Audiolab is large and could support my perceived improvement. Could be a similar thing for the other listener.

Taking measurements would be better, and even better protocol for casual audible comparison. Still doubt you heard any SINAD difference depending on which SINAD component....inherent noise could be a difference but more likely with nothing actually playing. Comparing with different eq just throws any comparison out the window, tho.

 

[AscendDF]

I respectfully have to disagree, in my experience the PMA-1700NE has with its measured

Power output (<1% THD, 8/4ohm)	92W / 175W
Dynamic power (<1% THD, 8/4/2/1ohm)	97W / 186W / 348W / 265W

Source: https://www.hifinews.com/content/denon-dcdpma-1700ne-sacd-playeramplifier-lab-report

has enough power to bring any similar sized home audio 2-way one midwoofer loudspeaker to its woofer distortion limits at its lower frequency range which also leads to significant and audible multitone distortion, but I am happy to be proven wrong with the corresponding measurements since you have the needed Klippel modules.

This can be seen also at the measurements from EAC where its distortion and compression are significant already at 96 dB:

Respectfully, I am not sure what you are disagreeing with.

Customer stated he heard midrange distortion using his Denon. Swapped to a much more powerful amplifier (about 2 1/2 times the power) and the distortion he complained about is now gone. IM and/or MTON distortion being generated by a speaker isn't going to change from one amplifier to another. Surely you agree with that.

Our LX woofer uses a SEAS Excel motor system with a T shaped yoke (pole piece) and a large copper shorting ring. It is designed for low distortion, low inductance, and its THD measurements reflect this.

However, the LX like a lot of power, and when there isn't enough of it - distortion can be audible due to clipping, and is usually most audible in the midrange to lower high frequencies. If this were IM/MTON or Doppler distortion, adding a more powerful amplifier would increase woofer excursion, causing audibly higher MTON distortion, or at a minimum, MTON distortion would have stayed the same, it would not have disappeared like it did for this customer. As such, it is not IM or MTON distortion.

Additionally, as I mentioned, with those MTON distortion measurements, of which by now I have taken thousands - it is important to consider the stimulus being used to generate those measurements. Understand that there must be significant woofer excursion, very deep bass being reproduced at the same time that the woofer is producing mids to generate the multi-tone distortion seen in that measurement. It is absolute worst case scenario for a speaker, and all these frequencies must hit the woofer at the same time. Note: The max peak to peak coil travel of our LX woofer is an insane 24mm and this remarkable little 6" woofer is capable of reproducing 20Hz, it is not suspension limited to avoid such extreme excursion nor will the titanium former hit the backplate (bottom out).

There is a direct correlation with woofer excursion and this type of distortion. While it is difficult to find a 2-way bookshelf speaker with similar deep bass extension as our LX, the Dynaudio Heritage Special comes close and exhibits similar levels of MTON distortion. And the Heritage Special is a larger speaker with a larger woofer.

Pylon Jasper 18, with its 7" Scan Speak Revelator woofer, also has excellent deep bass extension and exhibits similar levels of MTON distortion. The Revelator woofers use advanced motor systems.

And compression at 96dB anechoic looks very good, better than most small 2-way bookshelf speakers, and there is practically zero compression in the midrange frequencies

Compression is very similar to the AsciLab C6B, see below, LX has less compression in the mids, C6B has less in the bass but the LX has deeper bass extension. This compression test is not a standard measurement. I think it represents a fair comparison from one speaker to another for his measurements, but this is his own test, and I am not confident it relates to real world listening. One must take into account the actual stimulus being used to generate these measurements, including the crest factor.

I suggest you have a listen to the LX for yourself, if you should ever have the opportunity. Our customers are not retail customers, they heavily research, ask a bazillion questions - and we run a near 99% customer satisfaction rate on LX.

As a follow-up, here is MTON distortion from the Buchardt A10, with its much heralded 6.5" Purifi woofer (the extended excursion model) This is quite a bit higher overall than our LX:

 

[PristineSound]

Dave from Ascend, Tibor from Apollon and John from Benchmark are officially my favorite manufacturers' representative on the Internet.

Coincidentally, I own products from these 3 manufacturers.

Dave, Tibor and John can do no wrong in my eyes.

Sorry for the tangent, I felt the need to make this comment publicly.

 

[AVKS]

Taking measurements would be better, and even better protocol for casual audible comparison. Still doubt you heard any SINAD difference depending on which SINAD component....inherent noise could be a difference but more likely with nothing actually playing. Comparing with different eq just throws any comparison out the window, tho.

Of course measurements would be better, and I changed EQ after listening to the new amp with the prior EQ that I was happy with and hadn't touched for literally years and being dissatisfied.

At this point I don't have anything else to add. My objective in switching had to do with regaining space on my desk and little to nothing to do with audio expectation, so increased enjoyment (placebo or otherwise) is just a bonus. Others may have similar experiences.

 

[thewas]

Respectfully, I am not sure what you are disagreeing with.

Customer stated he heard midrange distortion using his Denon. Swapped to a much more powerful amplifier (about 2 1/2 times the power) and the distortion he complained about is now gone.

As I wrote I disagreed with the statement that such an amp has not sufficient power for such a loudspeaker when in this case the loudspeaker is much earlier the bottleneck, I am sure you know how litte watts of power are needed to reach 96 dB where already MT and compression is an obvious issue. And as you know here in ASR non blinded listening results are not what we just accept as facts.

I agree that the woofer you chose for the LX with its high excursion is one of the better choices but in the end every similar sized 2-way loudspeaker which plays down deep is limited by that, so it is not suitable for very high listening levels or distances especially with music with significant low frequency content. And since you showed some MD of competitors and the compression of the C6B it would be fair to show also their (significantly lower) MDs:

as well of a 3-way which is cheaper than the LX

and since you showed the Buchardt with its Purifi 6.5" midwoofer here is a better implementation with it

This doesn't mean of course the LX is poor but in the end it can also not defy the limitations of physics and its price class, everything is a compromise.

 

[PristineSound]

This doesn't mean of course the LX is poor but in the end it can also not defy the limitations of physics and its price class, everything is a compromise.

I don't think that is controversial by any stretch of the imagination. Certainly no one is disputing that. All Dave is saying is that the cause of the distortion that the customer reported is likely the result of insufficient power.

Even if Dave's technical explanation doesn't cut mustard for you, then how are we to interpret the customer reporting that the distortion magically disappear when that customer switched to a more superior and powerful amp?

Now, I am wondering which amp did Erin used to do his listening test on the LX.

 

[thewas]

All Dave is saying is that the cause of the distortion that the customer reported is likely the result of insufficient power.

And exactly that I questioned by showing the significant measured power of the Denon and asking how many watts are needed to reach 96 dB.

Even if Dave's technical explanation doesn't cut mustard for you, then how are we to interpret the customer reporting that the distortion magically disappear when that customer switched to a more superior and powerful amp?

Like an all such non blind tested assessments for audio, from cables to DAC sound, which usually range from a defect to self deception.

 

[PristineSound]

Like an all such non blind tested assessments for audio, from cables to DAC sound, which usually range from a defect to self deception.

That is a fair point.

Then can Erin's non blind listening test be flawed with self deception as well? That is also a fair question.

I'm still curious which amp Erin used in his listening test on the LX.

 

[PristineSound]

Doesn't look like Erin specified which amp he used on these speakers.

 

[thewas]

That is a fair point.

Then can Erin's non blind listening test be flawed with self deception as well? That is also a fair question.

I'm still curious which amp Erin used in his listening test on the LX.

I also wouldn't take Erin seriously if he would do such claims (which he didn't though), objective data count, the rest is always to be taken with upper cautiousness.

 

[thewas]

Doesn't look like Erin specified which amp he used on these speakers.


View attachment 545693

In the past he mostly used his MCintosh, on the other hand I trust his knowledge that he always uses one with sufficient power and low enough output impedance for the loudspeaker tested.