Ascilab A6B Speaker Review

[Liftro]

Thanks for the test. I'm not a big fan of passive speakers but I have to admit these are really tempting me. Besides measuring excellent, they're very aesthetically pleasing, in my opinion. Amirm thanks for the new distortion graph; it's very easy to understand what's happening with the distortion in the low frequencies. I also think that crossing over a subwoofer at 80Hz solves all the distortion problems at all volume levels?

 

[Matt_Holland]

I have quite a low TV shelf where my speakers are. Would it deteriorate the sound a lot if the speakers point to about the listeners knees instead of the ears on the vertical axis? Finding a way to tilt these in an elegant way might not be easy...?

You can adjust the SubZero so they tilt as well.

 

[Hayabusa]

Frequency response: ±14.9dB 20Hz-20kHz ; ±4.2dB 80Hz-20kHz

how do you get -14.9dB for 20Hz? I see -15dB for 30Hz.
20Hz is more than 30dB down..

 

[lddo133]

The original woofer from Purifi was 86.8dB at 4 ohms, so why is this speaker rated at 82dB? Do you think simply flattening the frequency response curve is all that matters? I believe the main problem with this speaker is its significant loss of original sound.

 

[AsciLab]

The original purifi woofer is 86.8dB at 4 ohms, so why is this speaker 82dB? Do you think that simply flattening the frequency response curve is all that's needed?

Typically baffle step loses -6dB at the bass. So the midrange to high level has to be compensated to the bass level to make it have proper tone balance.
Additionally the series resistance through the crossover also loses a bit of SPL. So 82dB sensitivity from the 86.8dB sensitivity woofer makes sense.
If you have a 86dB sensitivity speaker, then the original sensitivity of the woofer must be around 92dB if the speaker has a flat response.

 

[lddo133]

I asked Chat GPT, and they said that lowering the dB reduces acoustic energy, but that there's a high risk of losing subtle signals as well! Ask Chat GPT yourself. If you reduce 86.8dB to 82dB, is only acoustic energy lost? What else is lost? Ask them this question.

 

[AsciLab]

I asked Chat GPT, and they said that lowering the dB reduces acoustic energy, but that there's a high risk of losing subtle signals as well! Ask Chat GPT yourself. If you reduce 86.8dB to 82dB, is only acoustic energy lost? What else is lost? Ask them this question.

Great! you can copy my answer and ask it to the GPT again.

 

[Ype]

I asked Chat GPT, and they said that lowering the dB reduces acoustic energy, but that there's a high risk of losing subtle signals as well! Ask Chat GPT yourself. If you reduce 86.8dB to 82dB, is only acoustic energy lost? What else is lost? Ask them this question.

Thanks for the laugh
Surely you are joking, but I'll ask Chad GPT just in case!

 

[Frank Dernie]

I asked Chat GPT, and they said that lowering the dB reduces acoustic energy, but that there's a high risk of losing subtle signals as well! Ask Chat GPT yourself. If you reduce 86.8dB to 82dB, is only acoustic energy lost? What else is lost? Ask them this question.

Sadly on every subject where misinformation is rife AI is pretty well useless since reliable base data is rare. HiFi is such a subject...
AI is breathtakingly wrong in my speciality.

 

[MaxwellsEq]

I asked Chat GPT, and they said that lowering the dB reduces acoustic energy, but that there's a high risk of losing subtle signals as well! Ask Chat GPT yourself. If you reduce 86.8dB to 82dB, is only acoustic energy lost? What else is lost? Ask them this question.

DO NOT TRUST AI

Especially in areas where the Internet and printed literature is as full of nonsense as the HiFi world.

 

[AudioSceptic]

This is a review, listening tests and detailed measurements of the Ascilab A6B Stand-mount speaker with Purifi woofer and passive radiators. I purchased this from the company. The US cost is $1,955 each. Price varies in different countries due to tariff, local taxes, etc.
View attachment 515071
Please excuse the tapes. They are holding the magnetic rings in for shipping. I plan to sell these speakers after review so wanted to keep them in as new condition. On that front:

NOTE: My company, testedaudio.com, is the exclusive distributor for Ascilab products in North America. While objective tests remain the same as for any other speaker, subjective remarks may have business bias.

The A6B manages to act serious and stately at the same time. The rounded corners and invisible fasteners give it an elegant look. And the solid weight, an impression of quality.

I am not a fan of the wrinkles in the Purifi woofer surrounds. However, in the A6B when seen in normal lighting, they mostly disappear so were not an issue for me. The review picture however, highlights them to the max.

Speaker has dual Purifi passive radiators on opposing sides and are a nice indicator of when the speaker is being pushed by their excursion.

The bottom of the speaker is lined with some kind of neoprene which I much appreciate as it acts as some level of damping. To wit, I did not have to employ my elastic material for its measurements on top of Klippel Near-field scanner.

Ascilab A6B Speaker Measurements
As usual, we start with our all important, anechoic "CEA/CTA-2034" standardized frequency response and directivity measurements:
View attachment 515074
We have a very nice on-axis response (black). There is a bit of a drop in bass but then again, it extends way below to nearly 30 Hz with reasonable output!

The early window, and for that matter, sound power, track the on-axis extremely well indicating good directivity which we will examine more later.

We can see the bass extension comes from passive radiator tuning being on the low side:
View attachment 515075
The peak is around 40 Hz. As noted, resonances from the woofer is highly controlled. And given the fact that we don't have a port, there is not much to worry about with respect to enclosure resonances bleeding out. You pay a lot more for the radiator as opposed to just a port but this is the benefit it brings.

Early window sum looks very good, encouraging a room without much "treatment:"
View attachment 515076

With the resulting prediction of in-room response being what we look for:
View attachment 515077

Beamwidth is highly controlled, all the way to upper registers, courtesy of computer optimized waveguide:
View attachment 515078
The small penalty there is narrower beam width which translates into more focused imaging and less diffusion. Don't treat the side walls as to let that do its thing to widen the source image.

View attachment 515079

Vertical directivity is what it is for a 2-way speaker:
View attachment 515080

Stay at the tweeter axis.

Let me give you my usual distortion charts and then something new:
View attachment 515081
View attachment 515082

I have been on a mission to better correlate distortion measurements to audibility. Here, I could hear the start of very low frequency distortion at 96 dBSPL and heard the speaker nearly completely run out of excursion at 101 dBSPL. How can we better figure out from the graphs. Check this work in progress:
View attachment 515322
These are THD% levels charted below 200 Hz. That is where I heard the distortion. Above that, we are overdriving the speaker anyway relative to music.

We see a more or less plateau above 100 Hz indicating we have made the right choice regarding cut off at 200 Hz.

Below that we see different slopes in distortion. We see two distinct new distortion sources coming into play which I have marked as secondary and tertiary. I have placed a circle at the knee of those events. What this says is that you can play down to 42 Hz at 96 dBSPL whereas if you crank up to 101 dBSPL, you best stop at 65 Hz! This matches my hearing of the sweeps where I heard slight distortion at the very start of the 96 dBSPL sweeps. Whereas with 101 dBSPL, that lasted quite a lot longer and at much higher levels of audible distortion.

Going the other way, if you are playing at 81 dBSPL, you can essentially take advantage of the full response down to 30 Hz. We will see if this and the above prediction proves to be the case in listening test section.

Assuming above is correct, you don't need a subwoofer for 81 dBSPL and possibly 86 dBSPL. Above that, a subwoofer would be needed for those playback level and the frequency for that crossover is on the chart.

Finishing our measurements, we see some traces of resonances in waterfall graph:
View attachment 515084
Step response of the woofer is very smooth/clean:
View attachment 515085

Edit: impedance and phase:
View attachment 515092

Ascilab A6B Listening Tests
I paired the A6B with Topping LA90 amplifier which has modest amount of power. I did this to see how much power is needed given the fact that the sensitivity of A6B is a couple of dBs lower than average. I was pleasantly surprised that in near and mid-field listening, there was plenty of power available, albeit with one channel being driven.

First impression was quite a surprise: there was impressively clean and deep bass even in tracks that don't sport that spectrum! Research indicates 30% of our enjoyment comes from bass and there is no better example of this. The extra warmth, especially when it is this clean, balances tonality and creates butterflies in your stomach. I am not used to such a compact speaker being able to deliver such a bass.

I quickly skipped to my reference track for deep bass. This sized speakers either faintly reproduce the sub-bass, or distort it at slightly higher levels. The A6B in sharp contrast, reproduced the low energy like it was a full range speaker!!! It is one thing to see frequency response down to nearly 30 Hz, it is another to experience it with real music.

Excited, I cranked up the volume and bam! Massive distortion set it, just like the 101 dBSPL. You hear a static and see the dual radiators try to detach themselves as the fly out left and right! Crank it down a bit and you get a bit of roughness in bass. A bit more and you are back in business.

Note that the above test track has some of the lowest frequency energy track I have. On music with milder version of it, the A6B produced clean and authoritative bass that I could feel in my stomach (from 2 meters/6 to 7 feet away) and feel the air brushing against my face! I could get to mild distortion with cranking up the volume up again but not as bad as my reference track.

With general music tracks, no worries where there whatsoever with bass distortion and frankly any distortion. The high frequency notes would stand out in the midst of bass notes like nobody's business. Even tracks I have that don't sound very good on speakers (I use them for headphone testing), sounded nearly excellent here! The rest, wow, I kept smiling in disbelief! This is the most perfect speaker I have heard in this size. It just can't blast out its beautiful very low frequency beyond medium levels of loudness.

I am stunned....

Of course, at no time did I feel the need to EQ anything.

Nicely so, very little vibration was coupled to my desk where I had it -- unlike many speakers that uncover all kind of resonances in this setup (my far field listening space is down).

Imaging is rather focused as predicted. You hear the sound come from a circle close to the speaker.

As a side effect of my testing in near and mid-field, these speakers will also make an excellent studio monitor. I checked for horizontal directivity and it is excellent across 2 to 3 chair widths. Even after that, the drop off in high frequencies is rather small.

Conclusions
What a shame that I have started to sell these speakers and hence, my personal experience may not be trusted much. If you at all value my ethics, I am telling you, this is a speaker you have to experience. It will easily blow away any expectations you have.

Going into this review, I was kind of depressed. I an not into, "more expensive parts mean more performance" as some of you no doubt know. Those parts have pushed the price of this speaker rather high. What Ascilab has done with its tuning to deliver very low bass response that is ultra clean, is what justifies its cost. Yes, laws of physics can't be broken. It can't shake the house but if you are just a hair less power hungry than I am, you will be fully satisfied without having to mess with subwoofers and such.

As noted, I would give the A6Bs a serious consideration for mixing and mastering in smaller rooms. Pair it up with an ultra quiet amplifier like I did and you don't have none of the hiss issues of active monitors.

Please note that as of this writing, there is no production available of the A6B. Earliest time is May which means we will get them in June. I am going to put up my pair on Tested Audio but I have to say, I am so tempted to just keep them for myself! They are that good.

Needless to say, I am going to recommend the Ascilab A6B speakers. Objectively and subjectively, they have left me without pants.
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As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

(Deleted as answered elsewhere.)

You say massive distortion but was this with a low power amp driven to clipping, or actually the speaker itself being overloaded?

 

[RexrothPigeon]

Sorry if you've told us elsewhere, but what is your deep bass reference track?

You say massive distortion but was this with a low power amp driven to clipping, or actually the speaker itself being overloaded?

The answers to both questions are in this thread

 

[MZKM]

how do you get -14.9dB for 20Hz?

+/-, not just -.

Highest SPL is ~85dB and lowest SPL is ~55dB, that’s a ~30dB window, aka roughly +/-15dB.

Another way to represent the frequency response linearity is to separate + & -, compared to the 83.8dB average:
• 20Hz-20kHz response: +1.4dB/-28.5dB
• 80Hz-20kHz response: +1.4dB/-7.0dB
• 300Hz-3kHz response (used to calculate the average SPL): +1.3dB/-1.5dB.

Compared to the average SPL:
• -3dB: 38Hz
• -6dB: 35Hz
• -10dB: 32Hz

 

[Bleib]

So, something like 40-20.000hz would be more honest

 

[AudioSceptic]

This made me giggle as in my part of the world, pants are known as Y fronts lol

Pants, underpants, or trousers? Divided by a common language.

 

[AudioSceptic]

The answers to both questions are in this thread

Thanks. Still catching up...

 

[Chromatischism]

Sadly on every subject where misinformation is rife AI is pretty well useless since reliable base data is rare. HiFi is such a subject...
AI is breathtakingly wrong in my speciality.

Right.

It's one thing to pull information from the New England Journal of Medicine or University of East Anglia.

But if an AI is trained on social media or hobby forum discussions, I don't think it possesses the intelligence at this stage to parse fact from fiction—so the answers you get will be polluted.

 

[END WAY]

Typically baffle step loses -6dB at the bass. So the midrange to high level has to be compensated to the bass level to make it have proper tone balance.
Additionally the series resistance through the crossover also loses a bit of SPL. So 82dB sensitivity from the 86.8dB sensitivity woofer makes sense.
If you have a 86dB sensitivity speaker, then the original sensitivity of the woofer must be around 92dB if the speaker has a flat response.

Hi, what type of purifi does the W or the X use, and if you don't mind me asking, why did you choose the current type (W or X)?

 

[AsciLab]

Hi, what type of purifi does the W or the X use, and if you don't mind me asking, why did you choose the current type (W or X)?

We use extended excursion version, X.
The reason is that we want more louder bass and lower distortion in a small form factor. Only needs a more current.

 

[Bland_username42069]

Lot of potential for veil lifting here.

I have a somewhat huge amp and was debating whether to go active instead but these seem to make a strong defense for staying passive