Ascilab C8C Active Speaker Review

[nbot]

Neumann is currently updating their KH310, KH420 with DSP functionality.

The Ascilab are in Europe only available in one online store. And before someone is buying anything there, I recommend to read their return policy carefully.

They are updating them for a very long time now and from the rumors it was supposed to be Q2 2026 but I still hear crickets from Neumann

 

[markstein]

They are updating them for a very long time now and from the rumors it was supposed to be Q2 2026 but I still hear crickets from Neumann

I just hope Neumann sorts out their DSP/digital amp issues with the new larger speaker models a number of KH80 and KH120 II seem to have.

 

[zonk]

Why is that (more expensive) combination better than the C8C? It's difficult to make direct max SPL comparisons, but the KH750s produce 90dB SPL at 3% THD, equivalent to roughly -30dB. The C8C, at 96dB output, produces -22dB or 8%. Assuming linear behaviour, reducing the playback level by 6dB to 90dB SPL nets you -28dB in distortion, nearly the same level of performance. In real terms, distortion tends to increase at a faster rate than level, so that number is conservative rather than optimistic.

• https://www.audiosciencereview.com/forum/index.php?threads/how-loud-genelec-vs-neumann.47820/
• https://www.audiosciencereview.com/...e-about-to-launch.54794/page-102#post-2466795

And this is setting aside the cardioid behavior, which is a key difference to how the speakers will sound in-room.

The prices that I mentioned were just taken randomly from the web.

The best prices I saw within the last year were 5200€ for 2 KH150 and 2 KH750. The biggest difference to the Ascilab is that if I want to buy Neumann, I go tomorrow to a store near by and take it to my home or let them deliver.

And I just wrote this because someone was asking for a comparison of the C8C and KH150. To compare this two speakers is just nonsense.

 

[nbot]

I just hope Neumann sorts out their DSP/digital amp issues with the new larger speaker models a number of KH80 and KH120 II seem to have.

I wasn't aware of those issues - do you have some more info on that? Thanks

 

[AudioJester]

The prices that I mentioned were just taken randomly from the web.

The best prices I saw within the last year were 5200€ for 2 KH150 and 2 KH750. The biggest difference to the Ascilab is that if I want to buy Neumann, I go tomorrow to a store near by and take it to my home or let them deliver.

And I just wrote this because someone was asking for a comparison of the C8C and KH150. To compare this two speakers is just nonsense.

I own Neumann speakers - for over 10yrs now. Brilliant speakers, really like them.

Its a bit like comparing KH150/subs to KH420. Both will have their own advantages/disafvantages.

If you really want to buy off the shelf and save money look at Kali IN8 plus sub, or even the Orbit11.

The C8C is more comparable to the D&D 8C in performance. The cardioid feature is a big differentiator in this callibre of speaker. But for many applications smaller, cheaper, less capable speakers and sub are more than enough.

Hopefully Ascilabs can boost production of their entire range - there is lots of demand!

 

[zonk]

I own Neumann speakers - for over 10yrs now. Brilliant speakers, really like them.

Its a bit like comparing KH150/subs to KH420. Both will have their own advantages/disafvantages.

If you really want to buy off the shelf and save money look at Kali IN8 plus sub, or even the Orbit11.

The C8C is more comparable to the D&D 8C in performance. The cardioid feature is a big differentiator in this callibre of speaker. But for many applications smaller, cheaper, less capable speakers and sub are more than enough.

Hopefully Ascilabs can boost production of their entire range - there is lots of demand!

The comparison was between KH150 without subs and C8C.

It's not that I have doubts about the technical quality of the C8C. The longetivity is unknown.

 

[Fletcher–Munson]

Did a quick dirty measurement of my C8C/BX8C combo, speakers basically plonked in corners, measurement at 3m. Still need to work out best positioning, very easy to move around on felt feet provided by Ascilabs - but have just been enjoying and not tweaking

View attachment 537146
C8C alone, this what I thought was optimal position in my room - 2m or measuring distance from memory

View attachment 537147
C8C and BX8C

AudioJester, can you say that there are less low frequency vibrations in the room with BX8C vs C8C alone, due to the cardioid extension?

 

[AudioJester]

The comparison was between KH150 without subs and C8C.

It's not that I have doubts about the quality of the C8C. The longetivity is unknown.

Yeah, it was a bit of leap of faith. There previous products were well received, and they have a clear alignment with engineering/science and quality. Value for monet is incredible

One thing that helped me is the parts are easily available eg. Hypex plate amps, ie. I can maybe keep them running myself. Plus, takes a lot for Amir to back a brand...

AudioJester, can you say that there are less low frequency vibrations in the room with BX8C vs C8C alone, due to the cardioid extension?

Definitely more controlled bass and less boominess. Not sure I had noticeable room vibrations to begin with

 

[AsciLab]

Thankfully you are here to correct me.

For the same HD, IMD can be very different. This invalidates the complete paragraph above. The reason is that some nonlinearities in loudspeakers are frequency-dependent in their effect on sound produced by the speaker. So they can cause HD at one frequency while not causing IMD when adding a second frequency if the second frequency is not affected by the nonlinearity. Besides that, HD and IMD are different kinds of distortion that oviously also sound different. And for parts of IMD components, there is no masking signal. This means audibility can be very different. Correlation with perception depends on details of IMD measurement. Incompetent IMD measurements are the cause for low correlation often found in research.

While nonlinearities can be varied, this doesn't result in a specific percentage of HD or IMD for any given signal. If you introduce a nonlinear transfer function to a signal, the level of distortion depends on the signal level. When you apply a random signal, the level of distortion varies with the signal and is unknown. When combining sine waves, it's easy to precisely generate specific levels of (T)HD and IMD.

While some are interested in just noticeable difference (JND in scientific publications) others are interested in differences that make an average consumer pay higher prices due to obvious increase in sound quality. You may be happy to pay big money for theoretical improvements based on measurements or improvemens that only expert listeners hear. Normal consumers are not. In that regard, my testing is certainly useful to me.

THD as a test of known masking thresholds? Don't know what this means. Comparison to other devices is pointless if audibility is unknown. Due to details of auditory masking, the concept of THD is screwed. HD orders require weighting based on masking threshold before they can be combined into a single value.

I don't think you understood what I wrote in the post you replied to. Large parts were about making (T)HD more useful than it is today including quite detailed description how to get there and my own comparison of masking threshold models. Obviously, controlled listening tests are no standard for product evaluation. Measurements are the standard and they still require improvement to better correlate with perception.

(T)HD weighting against audibility thresholds is merely one step. One of the reasons is that lower is not always better. That's why most phones generate distortion in signal processing algorithms for support of bass output (virtual bass). This means audibility and preference may not be the same. Main reason is that IMD is more audible and always sounds bad. Correct IMD testing must be introduced to show audible differences between loudspeakers.

As you mentioned, good HD performance doesn’t necessarily translate to good IMD performance. This is because these characteristics can vary significantly depending on the speaker driver and crossover design.

Single-tone HD measurements are useful for observing a speaker’s signature and output limits, but to truly understand what kind of distortion is being generated, multi-tone measurements are necessary. In that regard, we frequently compare multi-tone measurements to assess distortion in a more practical sense. Of course, this measurement also cannot separate AM from FM — that requires a separate measurement — but it is well-suited for use as a comprehensive and easily comparable format.

We have compiled the MD measurements of the speakers we selected as comparison references. This list is excerpted from Erin’s Audio Corner, and to my understanding, Erin sets the final green line at around 97 dB. Since the weighting curve is the same as the one we use, the data is comparable when accounting for the slight level difference, so we are attaching it alongside our own data.

 

[markstein]

I wasn't aware of those issues - do you have some more info on that? Thanks

You may google "KH120 II tweeter crackling", look e.g. here:

Post in thread 'Neumann KH120 II Monitor Review'

Neumann KH120 II Monitor Review

Unfortunately, one of my KH120 II units developed tweeter noise after about a year of use. There were reports of the same issue earlier in this thread. It sounds like a quiet static noise even when no inputs are connected, regardless of the switch or knob positions. I tried a different power...

www.audiosciencereview.com

The KH80 amp died at a couple of ASR posters and produced blue smoke. Mostly after warranty expired.

I did not read any issues about the KH150 yet, but the KH750 subwoofer had some quality issues with a cracking housing and rubbing bass driver

 

[illusonic]

As you mentioned, good HD performance doesn’t necessarily translate to good IMD performance. This is because these characteristics can vary significantly depending on the speaker driver and crossover design.

Single-tone HD measurements are useful for observing a speaker’s signature and output limits, but to truly understand what kind of distortion is being generated, multi-tone measurements are necessary. In that regard, we frequently compare multi-tone measurements to assess distortion in a more practical sense. Of course, this measurement also cannot separate AM from FM — that requires a separate measurement — but it is well-suited for use as a comprehensive and easily comparable format.

We have compiled the MD measurements of the speakers we selected as comparison references. This list is excerpted from Erin’s Audio Corner, and to my understanding, Erin sets the final green line at around 97 dB. Since the weighting curve is the same as the one we use, the data is comparable when accounting for the slight level difference, so we are attaching it alongside our own data.

View attachment 537638View attachment 537639View attachment 537640View attachment 537641View attachment 537642View attachment 537643View attachment 537644

Thanks for your confirmation that IMD is an important measurement. I did not have any doubt that IMD of the C8C would be good. IMD can mainly become an issue in 2-way and fullrange speakers.

For a more realistic test, multitone IMD has to be 1/f shaped (pink noise) to better resemble music spectra tha equal level muilti-tone stimuli. IEC268-1 defines additional HP/LP filters to get even closer to music.

As really revealing test, I use 2-tone measurements with f2 = 8.5*f1 and level of f2 20dB below f1. Than sweep or step through frequency (f1 = 20Hz - 2.5kHz) and levels to get a set of IMD curves. From these curves maximum SPL can be determined for a certain IMD limit (e.g. 1/3/10%). The limit applies to f1 and is most interesting in the bass because it shows the level that the speaker can play before excessively modulating f2, which is in the midrange for f1 below 100Hz.

Speakers with higher maximum SPL in this test sound much cleaner at high SPL than speakers with lower limit. It's a clear performance indicator and basically an indirect measurement of BL linearity, which is the primary cause for IMD in the midrange. Purify drivers will be very good in this test.

 

[Fletcher–Munson]

AsciLab,​

do you recommend acoustic treatment (thick absorption panels and bass traps) on the wall right behind the C8C+BX8C combo or between them?
Or absorption will not make any difference and bare concrete wall behind the floorstanders is better?

Thanks

 

[AsciLab]

Treating SBIR also can affect to Room Mode but following the main purpose the placement might be difference. If there is a limitation of product qty, I’d rather recommend to absorber the back wall(behind the listener). Strong back wall reflection can affect the response from the deepest range cause it has the longest path.

Treating the front wall can help to reduce SBIR in midrange(when the speaker is close to the wall) but treating the back wall can help to reduce LBIR over the full range.
Both can help to reduce Room Mode.

Choose right one followed by your environment.

 

[phoenixdogfan]

Thanks for your confirmation that IMD is an important measurement. I did not have any doubt that IMD of the C8C would be good. IMD can mainly become an issue in 2-way and fullrange speakers.

For a more realistic test, multitone IMD has to be 1/f shaped (pink noise) to better resemble music spectra tha equal level muilti-tone stimuli. IEC268-1 defines additional HP/LP filters to get even closer to music.

As really revealing test, I use 2-tone measurements with f2 = 8.5*f1 and level of f2 20dB below f1. Than sweep or step through frequency (f1 = 20Hz - 2.5kHz) and levels to get a set of IMD curves. From these curves maximum SPL can be determined for a certain IMD limit (e.g. 1/3/10%). The limit applies to f1 and is most interesting in the bass because it shows the level that the speaker can play before excessively modulating f2, which is in the midrange for f1 below 100Hz.

Speakers with higher maximum SPL in this test sound much cleaner at high SPL than speakers with lower limit. It's a clear performance indicator and basically an indirect measurement of BL linearity, which is the primary cause for IMD in the midrange. Purify drivers will be very good in this test.

I know you're a big advocate of the Palmers, Might be interesting for you to run that test of maximum SPL with them and publish it in that thread.

 

[Fletcher–Munson]

Treating SBIR also can affect to Room Mode but following the main purpose the placement might be difference. If there is a limitation of product qty, I’d rather recommend to absorber the back wall(behind the listener). Strong back wall reflection can affect the response from the deepest range cause it has the longest path.

Treating the front wall can help to reduce SBIR in midrange(when the speaker is close to the wall) but treating the back wall can help to reduce LBIR over the full range.
Both can help to reduce Room Mode.

Choose right one followed by your environment.

Thanks for the reply!

I am asking, because for the Dutch & Dutch 8C speakers it is not recommended to have absorption right behind them, because it might ruin the Boundary Coupled Bass effect, because rear-facing woofers and the front wall act as a single sound source.

 

[Satanica]

Thanks for the reply!

I am asking, because for the Dutch & Dutch 8C speakers it is not recommended to have absorption right behind them, because it might ruin the Boundary Coupled Bass effect, because rear-facing woofers and the front wall act as a single sound source.

Most treatments are not going to do much if anything to the 100Hz and less rearward output of the 8C.
I think almost all normal treatments are fine with the 8C, although because of the cardioid dispersion there's not much point to treat the rear wall anyway.

 

[dfuller]

Most treatments are not going to do much if anything to the 100Hz and less rearward output of the 8C.
I think almost all normal treatments are fine with the 8C, although because of the cardioid dispersion there's not much point to treat the rear wall anyway.

Even with decently sized monopoles, the front wall is by far the least important to treat. Doubly so for cardioids.

 

[illusonic]

I know you're a big advocate of the Palmers, Might be interesting for you to run that test of maximum SPL with them and publish it in that thread.

The Orbit's crossover frequencies are 250/1800Hz. This means the frequency ranges for f1 that will result in both tones played on the same driver are 20-30Hz and 2350-2500Hz. So there won't be much to see in terms of IMD - that's the advantage of 3-way systems. Now take a 2-way speaker with 1800Hz crossover and the complete f1 range from 20-210Hz will also have f2 playing on the mid-woofer. That's when you get IMD.
Whatever non standard measurements I could do with the Orbits, would at least require some other speakers to be tested the same way for comparison. The other speakers must have high reputation like Genelec/Neumann offers. Otherwise, the same people that construct issues from questionable noise measurements, no matter how many actual users of the speaker report otherwise, would do the same for IMD results they can't interprete correctly.

 

[illusonic]

Even with decently sized monopoles, the front wall is by far the least important to treat. Doubly so for cardioids.

That's true if cardioid dispersion is effective in the midrange. It's indeed very good for 8C. The front wall is the only wall that is getting much lower direct sound from cardioid speakers. So audible effects will be related to front wall reflections. Big speakers are not as effective in reducing rear sound as cardioids. See 8361 comparison further up in this thread.

 

[Fletcher–Munson]

Most treatments are not going to do much if anything to the 100Hz and less rearward output of the 8C.
I think almost all normal treatments are fine with the 8C, although because of the cardioid dispersion there's not much point to treat the rear wall anyway.

Yeah, there is no absorption on the front wall behind the 8C, but in the corners on the sides of the speakers i have stacked bass traps floor to ceiling (80x80cm diametre) to catch the low frequencies in the room (especially the sub region), because they are cardioid only down to 100hz.
And on the back wall corners i have 50x50cm bass traps floor to ceiling + 10cm thick panels all over the room to control the reverbation.
Soon i am planning to put 20cm thick cloud over my head.

Wondering if C8C + BX8C need that much treatment for optimal performance in a room.. but as far as I know acoustic absorption is never too much in a medium sized room of 18 sq/m like mine.