Ascilab C6B Speaker Review

[trevor_bartram]

Superb measurements & VFM for the size. I believe I would like the sound produced by these speakers!

 

[DanielT]

Thanks for the review, Amir. Superb speakers, at an attractive price for hi-fi enthusiasts.

What else is there to mention? Rather low sensitivity and an impedance dip down to 2.6 ohms (iirc). So they need a bit more power and an amp that is comfortable going a bit lower.

I don't see an impedance and phase measurement/graph in Amir's test of this Ascilab C6B. Or did I miss it?

I wish there was a sealed version of this speaker.

Why?

 

[Emulator II]

Why?

Perhaps because you don't need deep bass extension when using subwoofers, and a sealed speaker is easier to integrate with sealed subwoofers? Maybe the flatter profile for wall mounting?

 

[daniboun]

I wish there was a sealed version of this speaker.

Get the F6Bs in the meanwhile )

 

[capslock]

Thanks for the review, Amir. Superb speakers, at an attractive price for hi-fi enthusiasts.

I don't see an impedance and phase measurement/graph in Amir's test of this Ascilab C6B. Or did I miss it?

Why?

Because LF distortion performance is poor anyway, and why pay extra for the passive radiator?

 

[daniboun]

I have the feeling that this might be a stupid question, but what do the "C" and "F" stand for?

To go further...

The first letter of the model name indicates the product category, classified by the following tiers:-

* S = Signature model, consisting exclusively of Purifi drivers.

* A = Purifi Aluminium woofer and a ceramic-aluminium tweeter.

* C = Ceramic Aluminium woofer and a ceramic-aluminium tweeter.

* F = Fibre woofer and an aluminium tweeter.

The middle number represents the diameter of the main driver in inches.

The final letter denotes the type of enclosure,

* B = Bookshelf

* C = Cardioid

 

[yo!]

For a 6" woofer not a bad compromise @ 85 dB/2.83V (4Ohm). A sub is mandatory for bass heavy material or EQ 45 Hz + 4-6 dB for near field.

Nice gems specially for the US market, tempting. Very good impulse response, masters most disciplines excellent, no major flaws.
Design and quality should still evoke a sense of satisfaction even 10 years from now.

 

[daniboun]

For me, the alternative to the C6B and F6B is the C5B. I say this because I have always found that bookshelf speakers with a 5-inch woofer are easier to integrate into more confined spaces.

AsciLab C5B Review.

Today, I’ll be reviewing the AsciLab C5B, which features a 5.25-inch woofer along with two passive radiators. For this review, I measured one official sample provided by the manufacturer and another pair owned by an individual who had purchased the product personally. Impedance The...

www.audiosciencereview.com

 

[DanielT]

Perhaps because you don't need deep bass extension when using subwoofers, and a sealed speaker is easier to integrate with sealed subwoofers? Maybe the flatter profile for wall mounting?

Because LF distortion performance is poor anyway, and why pay extra for the passive radiator?

Reasonable arguments.

A ported design—provided the port is well-engineered—usually delivers better bass output, but if a subwoofer is added to the mix, I agree that a sealed design makes more sense for bookshelf speakers.

 

[AM88]

I heard these speakers at the Singapore dealer earlier this year. They sounded too bass heavy for my taste but not exactly. Seeing the EIR now I think it was the tilt that I was hearing. Otherwise a fine looking and sounding speaker.

 

[Matt_Holland]

I find it odd how the -2.5dB shelf above 7KHz in the on-axis disappears in the PIR.

For nearfield use (or even in damped rooms for mid/far-field use), might the speaker benefit from anechoic EQ for this shelf?

Apart from this, the data looks great.

 

[Guddu]

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 (should say F6B)
View attachment 550663

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 550656

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.

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.
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As always, questions, comments, recommendations, etc. are welcome.

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Thank you @amirm as always.
Did you try any EQ for your listening tests?

 

[Marc v E]

I may be the only one here that owned them and didn't like them. I sold them after a few months.

Imo they are to big to be used as desktop speakers and their sound is very intense ime in desktop setup; don't know why. In my living room measuring 5.5 m by 10 m they lacked bass imo. Imaging is very good though and they sound very clean.

Summarising I would sooner recommend the smaller F6 as desktop but personally prefer Genelec and Neumann for this application. Ymmv and would love to hear if someone did like them in that setup.

 

[yo!]

Speakers in nerfield desktop setup, at least mine, need a couple of notch filters around 80-400 Hz and for the hights, the tweeters, specially with waveguides, often some degrease in power too.
And yes, you need a big desk for such blocks, got my old school 6.5"1" around 50 cm behind the desk.
Neumann and Genelec offers auto EQ, don't they?

 

[Marc v E]

Speakers in nerfield desktop setup, at least mine, need a couple of notch filters around 80-400 Hz and for the hights, the tweeters, specially with waveguides, often some degrease in power too.
And yes, you need a big desk for such cloppers
Neumann and Genelec offers auto EQ, don't they?

Some do, like the 83xx serie. The 8030 doesn't. I used rew and wiim ultra to dial in eq for the 8030 and the C6B in the sub 750 hz region.

I never corrected the treble region, though, which in hindsight may have solved it.

 

[AudioSceptic]

Fabric
Ceramic

It's the woofer cone material

Thanks. Should've guessed!

 

[AudioSceptic]

To go further...

The first letter of the model name indicates the product category, classified by the following tiers:-

* S = Signature model, consisting exclusively of Purifi drivers.

* A = Purifi Aluminium woofer and a ceramic-aluminium tweeter.

* C = Ceramic Aluminium woofer and a ceramic-aluminium tweeter.

* F = Fibre woofer and an aluminium tweeter.

The middle number represents the diameter of the main driver in inches.

The final letter denotes the type of enclosure,

* B = Bookshelf

* C = Cardioid

Thanks, saves me asking the next Q!

 

[VVR]

Great speaker for the price, but these SB Acoustics passive radiators are absolute cheap junk. I'm glad to see it confirmed with measurements. The frame couldn't be more flimsy and leaky, and the membrane morre under-damped.

 

[welwynnick]

Thanks Amir. Nice speaker. Nice test.
In particular thanks for the group delay plot. I usually look out for GD<0.5ms from 200Hz upwards.
You seem to have backed the right horse, there.

 

[dtaylo1066]

That's a hell of a well-designed and performing speaker for 1.3K per pair. I am not sure you will find a passive speaker to beat that in that price range. Aesthetically pleasing as well.

You pair a WiiM Amp Ultra with that and for less than 2K you have terrific sound and still some money for a streaming subscription.