Ascilab C6B Speaker Review

[Ajax]

Hi Amir,

Thanks for the review.

I'd appreciate your thoughts on your listening tests on the value vs performance between the C6B and the recently reviewed Ascend Acoustics CBM-170SE2 for an extra US$900.

 

[Guddu]

Hi Amir,

Thanks for the review.

I'd appreciate your thoughts on your listening tests on the value vs performance between the C6B and the recently reviewed Ascend Acoustics CBM-170SE2 for an extra US$900.

Please help in understanding and choosing - CBM-170SE2 vs F6B vs C6B

Forum members, please help in choosing among these. Is there tangible benefit from going 500$ >> 1000$ >> 1450$ in the following speakers? Not worries about looks. I will pair these with a budget subwoofer (like Dayton cs1200 or RSL) crossing at 60 - 80 Hz. Your input will be super helpful.

www.audiosciencereview.com

 

[markk]

What is their point of reference then? Do people compare it to other speaker measurements regardless of price? Should it match a6b?

I think folks do whatever they want when they rate. Take the rating with a grain of salt. Some folks take cost into consideration, some don't. Look at the Cubilux. Granted, tests very medicore. But $32.

I mean, what can you buy for $32? This is the cover charge to get into a high end audio store these days! (Yea, OK, I made that up. But, it sounds true, right?)

The only real problem this speaker has is the same problem ALL two way loudspeakers with a 6-7" driver have (units with two 7" Purifi drivers exepted...). That is, they cannot, due to the pesky laws of physics, generate full range bass signals. Even it if had a Purifi driver, maybe that would add 3dB to the absolute output level below 100 hz and a grand to the MSRP!

I think this speaker, given it's specs should be at or near the top in it's price range. But I get some folks probably just can't give any 7" two way a 5 star rating, no matter how smooth the curves look.

 

[galego100]

Best passive speaker I've ever owned, eagerly awaiting their center channel offerings so I can complete my home theater setup. And the C8T towers too!

They can compete with the Arendal 1723 THX S ? Where you see the center channel information?

 

[dfuller]

@AsciLab can I ask what the reason for going with a PR instead of a port was on this speaker?

 

[YouDontHaveEnoughBass]

I can take a decent guess; you get to have a smaller box while still having a deep tuning frequency

Buchardt recently switched from PR to port in one of their speakers and they had to make the box something like 18% bigger

S400 MK3

S400 MKIII Passive Loudspeakers

buchardtaudio.com

 

[Emulator II]

They can compete with the Arendal 1723 THX S ? Where you see the center channel information?

AsciLab speakers are about to launch

www.audiosciencereview.com

 

[rebbiputzmaker]

This is a review, listening tests and detailed measurements of the Ascilab C6B bookshelf speaker. It costs USD $1,357 per pair inclusive of import fees. Pricing varies in other parts of the world:
View attachment 550638

Important note: my other company, TestedAudio, is the sole distributor for all of Ascilab products. Indeed, C6B is by far our most popular speaker. So feel free to read my subjective comments with extreme skepticism.

The C6B shares the same everything with F6B but with an upgraded woofer. I like the white look which reminds of the iconic Yamaha studio monitors (there is a grill if you want to hide it).

This is surprisingly compact speaker yet feels quite heavy and dense. You can better see its compact dimensions from this side profile:

View attachment 550646

As with F6B, we have a passive radiator.

Ascilab C6B Speaker Measurements
As usual, we start with our anechoic measurements:
View attachment 550647
We have slightly flatter response before the step function but otherwise, it is in the same ballpark as F6B.

Early window is good but shows a small dip:
View attachment 550650

We can see that is caused by vertical reflections:
View attachment 550651\
You can see how the vertical response is compressed in the 3-D balloon visualization. As with most speakers, absorbing floor reflections with a carpet is advised if you want more perfection.

Horizontal is perfect which is the important bit as it means side wall reflections which can be beneficial have similar tonality to on axis.

Predicted in-room response shows more of a tilted down response indicating a warm sound signature:
View attachment 550652

Woofer response is a bit more refined compared to F6B:
View attachment 550815

Let's jump into distortion because that is what is unique here with respect to woofer upgrade. I will start with a comparison against F6B:

View attachment 550653

We see substantial reduction of distortion in upper bass and midrange relative to lower cost woofer used in F6B. However, there is an increase in distortion at very low bass frequencies. I don't know why that is the case but overall, this is an excellent improvement over F6B.

Here is our standard graphs:
View attachment 550655
View attachment 550812

And our bass response in both linear and log scales:
View attachment 550657

You can see how the 101 dBSPL is not usable given its massive distortion. Woofer distorted some but it was the passive radiator that bitterly complained. I heard a bit of distortion at the start of the sweep at 96 dBSPL and we see the reason for that: non-linear rise in distortion below 42 Hz. This is very typical even in larger speakers.

Directivity is highly controlled and beautifully smooth once it takes hold:
View attachment 550658
View attachment 550659

Vertical directivity allows a bit of freedom to sit above tweeter axis:
View attachment 550660

Someone asked for Group Delay:
View attachment 550664

And rest of the bits (yes, I am tired at 1:42am):
View attachment 550666
View attachment 550667

Ascilab C6B Speaker Listening Tests
The first impression is that of warmth: there is enough bass there that you don't wish you had a subwoofer. High frequencies are clear but not piercing/standing out. Sibilance, unless in the source, is not in the C6B's vocabulary.

Throwing my torture deep-bass track at the C6B, there was distortion at anything above modest levels in that region. For all of my other bass heavy tracks though, reproduction was superb. Ton of clean bass accompanying delight notes above it. Every track in my library sounded excellent.

Spatial image is limited to halo a foot or two round the speaker. This is of course due to controlled and slightly narrower than normal beam width. I listened in mono but in stereo, it is likely to have more focused imaging.

Unfortunately I don't have an F6B in stock to compare, nor is my memory of that with me. So rely on the measurements for that.

Conclusions
One of the best driving experiences I have is that of a Honda Accord circa early 1980s. That thing had such a smooth engine and low effort stick shift that put a smile on my face that you could not wipe out. It was no sports car but it was so competent for everyday driving. Such is the story with C6B. It is just full range enough, and accurate enough to just do the job. That is, do justice to your music making you want to delight in what you are hearing. If you don't want to go all out and spend a lot more money, then the C6B is a wonderful answer. Pair with a few hundred dollar amp and some EQ and you are good to go.

I am going to recommend the Ascilab C6B speaker.
------------
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/

Luckily, it’s only the white woofer and not the sound that reminds you of Yamaha NS10’s!

 

[dfuller]

I can take a decent guess; you get to have a smaller box while still having a deep tuning frequency

Buchardt recently switched from PR to port in one of their speakers and they had to make the box something like 18% bigger

S400 MK3

S400 MKIII Passive Loudspeakers

buchardtaudio.com

I don't know; a very quick-and-dirty WinISD modeling only need about 13L for an F3 of 45hz with the SB17CAC35, though it would involve using a bendy port design to make it fit in the box (as we know this is far from impossible to do).

 

[a4eaudio]

I can take a decent guess; you get to have a smaller box while still having a deep tuning frequency...

The box modelling based on TS parameters will require the same net volume for a port or passive radiator. The gross volume can be less for PR because a port will take up more volume.

 

[Matt_Holland]

I don't know; a very quick-and-dirty WinISD modeling only need about 13L for an F3 of 45hz with the SB17CAC35, though it would involve using a bendy port design to make it fit in the box (as we know this is far from impossible to do).

Small boxes need a long port for a low tuning frequency. Long ports have worse pipe resonances. Long ports sometimes don’t even fit in small boxes. A PR solves that issue, but might introduce other issues if it doesn’t have enough excursion at high SPL.

 

[rebbiputzmaker]

Small boxes need a long port for a low tuning frequency. Long ports have worse pipe resonances. Long ports sometimes don’t even fit in small boxes. A PR solves that issue, but might introduce other issues if it doesn’t have enough excursion at high SPL.

A passive radiator will have less distortion until, like you mentioned it reaches its limit.

 

[dfuller]

Small boxes need a long port for a low tuning frequency. Long ports have worse pipe resonances. Long ports sometimes don’t even fit in small boxes. A PR solves that issue, but might introduce other issues if it doesn’t have enough excursion at high SPL.

It can be worked around - see the stuff coming out of Neumann and Genelec, for example.

 

[AsciLab]

@AsciLab can I ask what the reason for going with a PR instead of a port was on this speaker?

In small box, PR has an advantage to make the enclosure smaller cause the port volume isn’t included to the required internal volume while PR doesn’t have a lot volume itself. So total internal volume as ported type enclosure must be larger than PR equipped box.

Additionally, in a small 2way bookshelf like C6B, the typical required port length can make pipe resonance that usually ruins midrange smoothness.

 

[NanoGuidingStar]

I have always wanted to build a home theater system based on Ascilab speakers. At the moment, I'm still missing the LCR speakers. The A6B and S6B are simply too expensive, and their sensitivity is quite low, so I have ruled them out.

The reason I've been hesitant about the C6B is that its (bass) distortion and SPL compression appear to be inferior to the KEF R3 Meta. Because of this, I've been hoping that Ascilab would release a model positioned between the C6B and A6B in terms of price and performance, one that could compete directly with the R3 Meta.

Ascilab's new center speaker comes in two versions. Given my setup, I would probably choose the MTM version. However, the MTM model uses dual 5-inch woofers and a sealed enclosure design. This suggests that bass and directivity performance may not be as good as the C6B, in exchange for the benefits of higher sensitivity and lower distortion/compression, especially when used as an LCR speaker.

 

[muad]

I have always wanted to build a home theater system based on Ascilab speakers. At the moment, I'm still missing the LCR speakers. The A6B and S6B are simply too expensive, and their sensitivity is quite low, so I have ruled them out.

The reason I've been hesitant about the C6B is that its (bass) distortion and SPL compression appear to be inferior to the KEF R3 Meta. Because of this, I've been hoping that Ascilab would release a model positioned between the C6B and A6B in terms of price and performance, one that could compete directly with the R3 Meta.

Ascilab's new center speaker comes in two versions. Given my setup, I would probably choose the MTM version. However, the MTM model uses dual 5-inch woofers and a sealed enclosure design. This suggests that bass and directivity performance may not be as good as the C6B, in exchange for the benefits of higher sensitivity and lower distortion/compression, especially when used as an LCR speaker.

I don't think the distortion graphs are directly comparable as the R3s have a bass shelf while the ascilab do not.

 

[Bwaslo]

A port can also leak midrange sound generated at the back of the woofer, a PR is a barrier to the leakage.

 

[ShadowFiend]

I think folks do whatever they want when they rate. Take the rating with a grain of salt. Some folks take cost into consideration, some don't. Look at the Cubilux. Granted, tests very medicore. But $32.

I mean, what can you buy for $32? This is the cover charge to get into a high end audio store these days! (Yea, OK, I made that up. But, it sounds true, right?)

The only real problem this speaker has is the same problem ALL two way loudspeakers with a 6-7" driver have (units with two 7" Purifi drivers exepted...). That is, they cannot, due to the pesky laws of physics, generate full range bass signals. Even it if had a Purifi driver, maybe that would add 3dB to the absolute output level below 100 hz and a grand to the MSRP!

I think this speaker, given it's specs should be at or near the top in it's price range. But I get some folks probably just can't give any 7" two way a 5 star rating, no matter how smooth the curves look.

Problem is not only the maximum SPL in bass, but also harmonic distortion and intermodulation distortion. The woofer in C6B, while having great midrange performance (when isolated), have weak mechanical compliance. Therefore the distortion in bass frequency and go to roof below 100Hz. Don't be fooled by great midrange distortion on the frequency sweep test. This test is done by plays a continuous, sliding tone from low to high frequencies to speaker and measure the distortion at one frequency at a moment only. So it is a indicator about distortion performance but not a represent of what happens in real speaker. When playing real music with both bass and midrange frequency signals at the same time, the weak compliance will make intermodulated distortion high too and affect the midrange performance.

Of course, this speaker is near the top in it's price range if you accept their design choice of narrower directivity, since better woofers cost much more. But it is fine (good) only in grand scheme of speaker, even when limiting to a two-way speaker category.

 

[Shoba]

The C6B is, in my opinion, an interesting loudspeaker to look at from two different perspectives.
On its own, it is an excellent example of what can be achieved with a well-engineered passive two-way loudspeaker. The engineering, driver integration, crossover design and measurements are already there, packaged into a relatively small enclosure. There is no need to reinvent something that has already been done properly.
But I think the C6B becomes even more interesting when you stop thinking of it simply as a complete full-range loudspeaker.
The first approach is to use it exactly as it is: a conventional two-way loudspeaker. This gives you a relatively compact, simple and very capable system.
The second approach, and the one I find particularly interesting, is to add two subwoofers underneath the main loudspeakers and allow the C6B to concentrate more on the midrange and treble.
This is not necessarily about trying to get more bass. The real advantage is to remove some of the low-frequency workload from the mid-woofer. Once the subwoofers take over the lower frequencies, the main driver no longer has to simultaneously operate as a woofer and a midrange driver over such a wide bandwidth.
That gives you a much more flexible system.
The important part is that the crossover between the C6B and the subwoofers does not have to be treated as an arbitrary fixed point. Depending on the room, listening distance, subwoofer capability and personal preference, you can experiment with the crossover frequency and level and find the combination that works best in the particular system.
You can also adjust the subwoofer output independently, rather than trying to make the main loudspeaker do everything. In other words, the C6B can remain the carefully engineered, measured part of the system, while the subwoofers give you another degree of freedom in dealing with the room and the lowest octaves.
And this leads to the second important point: multiple subwoofers.
Rather than relying on a single subwoofer and trying to place it at the "perfect" position, I would use the general approach advocated by Dr. Geddes regarding multiple-subwoofer systems. The idea is not simply to produce more bass, but to use multiple low-frequency sources to excite the room differently and reduce the severity of the inevitable room-related peaks and nulls.
This is, for me, one of the biggest advantages of the concept.
The lowest frequencies are where the room becomes a major part of the loudspeaker system. Below the transition region, what we measure at the listening position is influenced heavily by room modes, boundaries and the interaction between the loudspeakers and the room. A conventional stereo pair trying to reproduce the entire bass range can therefore leave us fighting the room rather than simply listening to the loudspeaker.
With two properly positioned and integrated subwoofers, we have another tool for dealing with this problem.
So, for me, the most interesting way of looking at the C6B is not necessarily as "a small two-way loudspeaker that needs subwoofers." I see it almost the opposite way:
It is an exceptionally well-engineered compact two-way loudspeaker that can form the upper part of a much more sophisticated modular system.
You get the benefits of the existing engineering and measurements in a small package, while the low-frequency section can be separated from it and optimized independently.
That gives you a system with considerably more flexibility than a conventional full-range loudspeaker. You can experiment with the subwoofer crossover, level and placement, while the C6B continues to do what it was designed to do.
For me, that combination — a high-quality compact two-way plus two properly integrated subwoofers — is potentially the sweet spot between simplicity, performance and flexibility.
It also follows a principle that I think is often overlooked in high-end audio: there is no particular virtue in forcing one loudspeaker driver or enclosure to reproduce everything from the lowest bass to the highest treble if the system can be divided into more manageable tasks.
Let the C6B do the part where its engineering is strongest, and let the subwoofers deal with the part of the spectrum where the room becomes the dominant problem.
That, in my opinion, is a very compelling way to build a system around the C6B

 

[Hansebio]

I can take a decent guess; you get to have a smaller box while still having a deep tuning frequency

Buchardt recently switched from PR to port in one of their speakers and they had to make the box something like 18% bigger

S400 MK3

S400 MKIII Passive Loudspeakers

buchardtaudio.com

The mk3 features a 7.5" satori woofer.