AsciLab F6B Bookshelf Speaker Review

[amirm]

This is a review, listening tests and detailed measurements of the AsciLab F6B stand mount speaker. It was sent to me by the company and costs US $835 for a pair (shipping included).

In black, the F6B seems formal with a very clean design. It feels solid with sense of precision. Compared to its F6Bs sibling which I just reviewed, we now have a passive radiator in the back which should extend the low frequency response:

Let's measure it with our Klippel Near-field Scanner and see what we get (company measurements correlate with mine).

AsciLab F6B Speaker Measurement
As usual, we start with our anechoic frequency response graph:

This is a type of result that puts a smile on this reviewer. On-axis response is a good studio monitor flat but with a slight downward slope. Early window and power response almost mirror the on-axis from 700 Hz or so, indicating excellent off-axis response and a room friendly speaker. Drilling down we get another good result:

Resulting in predicted in-room response that is just like on axis, but with more of a slope down:

Signature should be a warmer sound.

Near-field measurements show very well behaved elements:

Beamwidth measurements shows how well controlled the directivity is:

Like the F6Bs, its about 20 degrees narrower so would result in a more focused image. Directivity shows smooth transitions:

Even vertically we have more room than we typically do with 2-way, non-concentric speakers:

I heard no distortion at 86 or 91 dBSPL during the sweeps. But the 96 dB did start with some:

The F6Bs didn't have this issue because it a) had a high-pass filter and b) didn't play this low. But again, the response was very clean at 86 and 91 dBSPL.

Impedance is typical of modern speakers at 3.5 ohm:

Sensitivity is as low as F6Bs meaning you need 2 to 3 dB more power. I would try to get an amplifier that is above 100 watts, preferably more.

Waterfall plot shows a single resonance that is actually visible in the anechoic measurements as well at 700 Hz:

Step function is so smooth:

AsciLab F6B Speaker Listening Tests
Just like the F6Bs, the immediate impression was warm and ultra clean detail. Here, the F6B went lower, producing a full range response. It actually played my sub-bass track at low to almost medium level. Above that, distortion in bass sets in and gets out of control. Normal music doesn't have such content and there, you could blast the speaker pretty loud levels with almost no bass distortion. And this is with one speaker!

I felt no need to change anything with EQ. Every track in my reference library was produced with excellent fidelity, making me want to just sit there and listen. Alas, I had to stop and come and share the results with news with you!

Conclusions
Th level of refinement oozes from every aspect of the F6B from external design to objective measurements. It is nearly perfect given its physical size. Compared to F6Bs, it brings good level of bass response but with a loudness limit. You could dial in a high-pass filter and get more loudness out of the bass region especially if you have a sub.

When you include the price in the equation, I am at a loss to recommend alternatives to the F6B. It is that good!

I am happy to recommend the AsciLab F6B speaker.
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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/

 

[amirm]

 

[Maiky76]

Here is my take on the EQ.
Please report your findings, positive or negative!

For the score rational your journey starts here
Explanation for the sub score

The following EQs are “anechoic” EQs to get the speaker right before room integration.
If you able to implement these EQs you must add EQ at LF for room integration, that is usually not optional… see hints there.

The raw data with corrected ER and PIR:

Score no EQ: 6.5
With Sub: 8.5

Spinorama with no EQ:

• Great effort and engineering.
• Slight bump in the 700Hz region
• Tuned a bit dark?
• Great directivity
• Easy to EQ
• Great all around especially at this price.
• Competes with active designs
• Probably does not need EQing

Directivity:
Commendably benign, easy to find a good spot

Better stay at tweeter height but a bit above or under is still ok.
Horizontally, better toe-in the speakers by 10/15deg and have the axis crossing in front of the listening location, might help dosing the upper range.

EQ design:
I have generated two EQs. The APO config files are attached.

• The first one, labelled, LW is targeted at making the LW flat
• The second, labelled Score, starts with the first one and adds the score as an optimization variable.
• The EQs are designed in the context of regular stereo use i.e. domestic environment, no warranty is provided for a near field use in a studio environment although the LW might be better suited for this purpose.
• Very little difference between the EQs.

Score EQ LW: 6.3
with sub: 8.3

Score EQ Score: 6.8
with sub: 8.7

AscLab F6B APO EQ LW 96000Hz
June062025-124902

Preamp: -3.00 dB

Filter 1: ON HPQ Fc 48.6 Hz Gain 0.00 dB Q 1.67
Filter 2: ON PK Fc 81.7 Hz Gain -3.74 dB Q 1.06
Filter 3: ON PK Fc 258.9 Hz Gain 0.54 dB Q 3.63
Filter 4: ON PK Fc 694.2 Hz Gain -1.60 dB Q 5.99
Filter 5: ON PK Fc 4637.9 Hz Gain -1.18 dB Q 1.22
Filter 6: ON PK Fc 11445.2 Hz Gain 2.94 dB Q 0.17

AscLab F6B APO EQ Score 96000Hz
June062025-124902

Preamp: -3.00 dB

Filter 1: ON HPQ Fc 48.6 Hz Gain 0.00 dB Q 1.77
Filter 2: ON PK Fc 81.7 Hz Gain -3.74 dB Q 0.81
Filter 3: ON PK Fc 249.0 Hz Gain 0.66 dB Q 3.21
Filter 4: ON PK Fc 696.2 Hz Gain -1.74 dB Q 5.99
Filter 5: ON PK Fc 4618.9 Hz Gain -0.89 dB Q 0.94
Filter 6: ON PK Fc 8537.9 Hz Gain 1.83 dB Q 0.15

Spinorama EQ LW

Spinorama EQ Score

Zoom PIR-LW-ON

Regression - Tonal

Radar no EQ vs EQ score
No improvements?

The rest of the plots is attached.

 

[ranai]

The review I've been waiting for. Amazing stuff!

 

[Beave]

The review I've been waiting for. Amazing stuff!

P.s. isn't this the C6B?

No. The "C" in the series stands for ceramic, because it uses the SB Acoustics ceramic woofer and tweeter.

The "F" in the series probably stands for "fiber," because they use the SB Acoustics fiber cone woofer (ie, reed cone, or paper), and an aluminum tweeter.

So this is indeed the F6B model.

Erin reviewed the C6B model.

 

[ranai]

I just woke up and saw the review, should've drank coffee first

 

[JSmith]

This is a review, listening tests and detailed measurements of the AsciLab F6B stand mount speaker. It was sent to me by the company and costs US $835 for a pair (shipping included).

Excellent measured results and another stellar product from @AsciLab, thanks for testing.

No. The "C" in the series stands for ceramic, because it uses the SB Acoustics ceramic woofer and tweeter.

The "F" in the series probably stands for "fiber," because they use the SB Acoustics fiber cone woofer (ie, reed cone, or paper), and an aluminum tweeter.

Correct;

S = as Signature, model using the Purifi transducer assembly

A = as Aluminum, aluminum woofer and ceramic-aluminum tweeter

C = as Ceramic, ceramic-aluminum woofer and ceramic-aluminum tweeter

F = as Fibre woofer, woofer with (aramid) fibre and aluminium tweeter

B = as Bookshelf, as shelf / stand - opposite where it belongs

C = as Cardioid, cardioid radiation - also quartic, simply directional characteristic

¤ the middle number represents the Ø of the main converter in inches

¤ the last letter indicates the type of enclosure

JSmith

 

[SDC]

I'm just happy to see the compliments on C and F series.

Nobody believed it was this freaking good when there was no reviews but it's here and real


I'm thrilled this is just their first and conservative approach on loudspeaker.
There should be so much more exotic designs stuck in CAD files I can almost sense it.

 

[Beave]

Excellent measured results and another stellar product from @AsciLab, thanks for testing.

Correct;



JSmith

A speaker model naming convention that actually means something! Wow!

 

[pierre]

I dont think this speaker need an EQ. Here is what you get if you compute one: basically the EQ is trying to
extend the bass and make LW and PIR ruler flat.

Scores goes from 6.5 to 7.0 without a subwoofer and from 7.0 to 8.7 with a perfect subwoofer. That make it one
of the best measured speaker and the first one with a low price. Great work @AsciLab.

 

[daniboun]

Some pics and many other measuements here

어사일랩 (Ascilab) 스피커에 대한 이야기

트위터와 우퍼는 재질이 뭔가요? 종이? 알루미늄? 웨이브가드는 동일한가요? 사이즈는 어떻게 되나요?

audiolabinsight.com

 

[OnAir]

I really love this

 

[dogmamann]

Some pics and many other measuements here

어사일랩 (Ascilab) 스피커에 대한 이야기

트위터와 우퍼는 재질이 뭔가요? 종이? 알루미늄? 웨이브가드는 동일한가요? 사이즈는 어떻게 되나요?

audiolabinsight.com

View attachment 455793
View attachment 455787

View attachment 455792

See the internal cable size. Inside the amps, the story is more or less the same in most case. Yet people would use snakes to connect from the speaker to the amp funny thing is the actual voice coil itself and the leads to the crossover components are always around 1 mm. Yet the some snakes are even 10mm think!

 

[dogmamann]

I really love this
View attachment 455802

This looks more like a pro speaker than a consumer speaker. However in a good way

 

[OnAir]

This looks more like a pro speaker than a consumer speaker. However in a good way

I was really surprised to see that the paint finish was of a pretty decent quality for a speaker at this price point.

 

[Thomas Savage]

I feel like I should buy a pair purely out of respect for how great they've been shown to be.

I look forward to seeing their next effort put under the scrutiny of our Audio sage , thanks for showing these off in your review Amirm .

Congratulations and thanks to all at AsciLab. Buying in the UK being super simple as Keith of Purite is keeping these in house too !

Thats the only decent thing about the UK at the moment, finally some national competitive advantage ( beyond our common tongue) , how truly novel ha ha

 

[Videoteque73]

Wow! Dac, amps and players are solved with human prices. Is this loudspeaker the solution for home speakers??

 

[Waxx]

I would expect a bit more bass with a passive radiator, but what is there is very clean neutral (and you can add a sub if needed). I'm still not a fan of the styling, just like the other one. I would not put it in my home for that.

But it's great that speakers of that priceclass also are getting that neutral. This could be a good budget studio monitor, better than most in that priceclass. And that without esotheric or proprietary parts, the drivers are off the shelf (at least it looks like that) and the waveguide is very much like many diy-ers already make and use. I could make it myself if i had the plans because it's not that complicated. But on ASR merits, it plays with the big boys; just by good engineering based on science. And that is a very good evolution.

 

[thewas]

As always with this brand very fine performance for the money, also interesting to see the similar tuning to current KEF designs where the on-axis / listening window response has been tuned to be a bit dropping to high frequencies and less flat than possible to prioritize a smoother predicted in room response.

 

[AsciLab]

I would expect a bit more bass with a passive radiator, but what is there is very clean neutral (and you can add a sub if needed). I'm still not a fan of the styling, just like the other one. I would not put it in my home for that.

But it's great that speakers of that priceclass also are getting that neutral. This could be a good budget studio monitor, better than most in that priceclass. And that without esotheric or proprietary parts, the drivers are off the shelf (at least it looks like that) and the waveguide is very much like many diy-ers already make and use. I could make it myself if i had the plans because it's not that complicated. But on ASR merits, it plays with the big boys; just by good engineering based on science. And that is a very good evolution.

Thanks for your kind words.
Yes. Thanks to ASR we can compete with big brands.

But there is an opinion that I don’t agree.
The waveguide we designed is not like usual waveguides. Usually most of waveguide is axis symmetry circle waveguide while we use different shapes by angles. You can see the different curves in the surface.

The main purpose of that shape is to put square in circle. The different curve at 45 deg can hides the corner edge diffraction. This is important to get smooth and constant directivity around 2~4kHz. If you use simple circle waveguide with same dimension, you can see easily diffraction around 2~4kHz.

Additionally, deep waveguide like ours usually makes throat diffraction occurring messy high frequency above 8kHz. The throat design with optimized phase plug makes wide dispersion without messy error in top frequency.

As the waveguide is top notch design that we put a lot of efforts, I wanted to explain what is different and better.