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AsciLab F6Bs Speaker Review

Rate this speaker:

  • 1. Poor (headless panther)

    Votes: 1 0.3%
  • 2. Not terrible (postman panther)

    Votes: 6 1.8%
  • 3. Fine (happy panther)

    Votes: 55 16.5%
  • 4. Great (golfing panther)

    Votes: 272 81.4%

  • Total voters
    334

amirm

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This is a review, detailed measurements, EQ and listening test of AsciLab F6Bs bookshelf/surround speaker. It was sent to me by the company and costs US $575 [now $725 with shipping included] for a pair.
AsciLab F6Bs Passive two-way speaker surround bookshelf review.jpg

This is an absolutely gorgeous design! It feels that way as well with a solid cabinet that is neither too light, nor too heavy. I didn't know if the grill over the woofer came off so left it alone. Back side shows that it is a sealed speaker:
AsciLab F6Bs Passive two-way speaker surround bookshelf back panel review.jpg


Company uses Klippel Near-field scanner for testing which as you all know, is the same system I use. I reviewed my measurements with them and they concur with those results.

AsciLab F6Bs Speaker Measurements
As usual, we start with our anechoic frequency response measurements:

AsciLab F6Bs Passive two-way speaker surround roon player anechoic frequency response cta-2034...png

Wow, that is one smooth response! Even when a speaker has a flat on axis response, Klippel NFS manages to tease out small variations. Here, there are not other than a gentle "bump" centered around 500 Hz. There is also a slight slope down to the on-axis response. Directivity is heavily managed/controlled as you will see in later graphs.

We can predict the early window reflections:
AsciLab F6Bs Passive two-way speaker surround roon player anechoic frequency response cta-2034...png


And as a result, predicted in-room:
AsciLab F6Bs Passive two-way speaker surround roon player anechoic frequency response cta-2034...png

Is that bump an issue or not? Will have to examine with listening tests. For now, the slope is somewhat aggressive which should result in a warmer tone.

Near-field measurements show that the woofer is responsible for that small bump:
AsciLab F6Bs Passive two-way speaker surround frequency response driver measurements.png

Horizontal tweeter is exceptionally well controlled, courtesy of good design and that wide waveguide:
AsciLab F6Bs Passive two-way speaker surround horizontal beam width measurements.png

It is a bit narrow though as is typically the case so more of a sharp focused soundstage. Directivity shows the same:
AsciLab F6Bs Passive two-way speaker surround horizontal directivity measurements.png

This is what we see in well designed professional monitors! Even the vertical is well mannered for a 2-way:
AsciLab F6Bs Passive two-way speaker surround vertical directivity measurements.png


I was worried that F6Bs wouldn't be able to handle the full 96 dBSLP. So went up to 91 initially. Hearing no distortion, I went to my standard 96 dBSPL and it still sounded clean!

AsciLab F6Bs Passive two-way speaker surround relative distortion measurements.png


AsciLab F6Bs Passive two-way speaker surround THD distortion measurements.png


Before I forget, sensitive is low as is the case for sealed enclosures. I estimate about 2 to 3 dB lower than average so better have good amplification.

Impedance shoots sky high as we get down to DC indicating a high pass filter:
AsciLab F6Bs Passive two-way speaker surround impedance and phase bookshelf measurements.png

So no worries about overdriving the speaker with too much bass.

Waterfall shows the expected time domain elongation due to 500 Hz bump:
AsciLab F6Bs Passive two-way speaker surround csd waterfall time measurements.png


Finally, here is the step response which is pretty clean:
AsciLab F6Bs Passive two-way speaker surround step time response measurements.png


AsciLab F6Bs Speaker Listening Tests and EQ:
Initial impression was super positive with a warm "glow" to the music that was a bit apparent. Otherwise, the impression was that of neutrality. I almost stopped there in my analysis but thought I should dial out the bump and see what happens:
AsciLab F6Bs Passive two-way speaker surround roon player equalization.png

I preferred the eq as it lightened up the tonality some, bringing extra clarity. To be sure, I switched to my Revel Salon 2 speakers and they definitely had less of a bass tilt. It is a small change though and preference will likely vary especially if you have some room modes piling on as well.

Sub-bass output was essentially zero. Go up a bit though where techno bass lives and this little speaker puts out solid tones, even causing physical sensation of bass! I did not hear distortion even as I cranked up the volume. And crank I had to do with my 400 watt amplifier. Didn't have to go near max output but did push the volume up. So definitely get a mid to higher power amplifier to drive them.

Closing my eyes and listening to one speaker as I always do, the spatial halo around the speaker was not very large. This was predicted from the directivity plot. So if you are a fan of wide dispersion, then this speaker may not be quite for you. But the reverse is also true of people who want a focused soundstage.

Overall, the response was delightful. Every reference track sounded wonderful and belied the size and cost of this speaker.

Conclusions
Amazing what happens when you follow audio science and engineering to the max: you get a very reasonably priced, gorgeous speaker that is near perfect objectively. It does things that speaker many multiples of its cost can't. I don't know how AsciLab has managed to optimize so many factors all at once without having to sell the F6Bs for thousands of dollars.

Not only is this speaker excellent for surround duty -- with its screw holes in the back for wall mounting -- but it also makes an excellent monitor or desktop speaker.

It is my pleasure to recommend the AsciLab F6Bs speaker. Don't walk, run to purchase a pair!
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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/
 

Attachments

  • Ascilab F6Bs Frequency Response.zip
    60.9 KB · Views: 118
Last edited:
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: 5.6
With Sub: 8.2

Spinorama with no EQ:
  • Great effort and engineering.
  • Slight bump in the 500Hz region
  • Tuned a bit dark?
  • Great directivity
  • Easy to EQ
  • Great all around especially at this price.
Ascilab F6Bs No EQ Spinorama.png




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.
Ascilab F6Bs 2D surface Directivity Contour Only Data.png

Ascilab F6Bs LW data.png


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.

Score EQ LW: 5.9
with sub: 8.5

Score EQ Score: 6.4
with sub: 8.9

Code:
Ascilab F6Bs APO EQ LW 96000Hz
June032025-145251

Preamp: -3.00 dB

Filter 1: ON HPQ Fc 57.6 Hz Gain 0.00 dB Q 1.24
Filter 2: ON PK Fc 162.1 Hz Gain -1.75 dB Q 2.02
Filter 3: ON PK Fc 344.0 Hz Gain 0.58 dB Q 1.60
Filter 4: ON PK Fc 486.9 Hz Gain -2.67 dB Q 2.07
Filter 5: ON PK Fc 5025.6 Hz Gain -1.07 dB Q 2.43
Filter 6: ON PK Fc 9766.8 Hz Gain 2.55 dB Q 0.23

Ascilab F6Bs APO EQ Score 96000Hz
June032025-145251

Preamp: -3.00 dB

Filter 1: ON HPQ Fc 57.5 Hz Gain 0.00 dB Q 1.38
Filter 2: ON PK Fc 154.0 Hz Gain -1.66 dB Q 1.57
Filter 3: ON PK Fc 311.7 Hz Gain 0.75 dB Q 1.34
Filter 4: ON PK Fc 487.9 Hz Gain -2.54 dB Q 2.30
Filter 5: ON PK Fc 918.8 Hz Gain 0.83 dB Q 1.78
Filter 6: ON PK Fc 5149.5 Hz Gain -0.93 dB Q 4.47
Filter 7: ON PK Fc 9015.8 Hz Gain 1.98 dB Q 0.12


Ascilab F6Bs EQ Design.png

Spinorama EQ LW
Ascilab F6Bs LW EQ Spinorama.png


Spinorama EQ Score
Ascilab F6Bs Score EQ Spinorama.png


Zoom PIR-LW-ON
Ascilab F6Bs Zoom.png


Regression - Tonal
Ascilab F6Bs Regression.png


Radar no EQ vs EQ score
No improvements?
Ascilab F6Bs Radar.png








The rest of the plots is attached.
 

Attachments

  • Ascilab F6Bs APO EQ Score 96000Hz.txt
    412 bytes · Views: 87
  • Ascilab F6Bs APO EQ LW 96000Hz.txt
    361 bytes · Views: 84
  • Ascilab F6Bs 2D surface Directivity Contour Data.png
    Ascilab F6Bs 2D surface Directivity Contour Data.png
    397.2 KB · Views: 124
  • Ascilab F6Bs 3D surface Vertical Directivity Data.png
    Ascilab F6Bs 3D surface Vertical Directivity Data.png
    477.9 KB · Views: 114
  • Ascilab F6Bs 3D surface Horizontal Directivity Data.png
    Ascilab F6Bs 3D surface Horizontal Directivity Data.png
    457.5 KB · Views: 123
  • Ascilab F6Bs Normalized Directivity data.png
    Ascilab F6Bs Normalized Directivity data.png
    367 KB · Views: 120
  • Ascilab F6Bs Raw Directivity data.png
    Ascilab F6Bs Raw Directivity data.png
    499.7 KB · Views: 122
  • Ascilab F6Bs Reflexion data.png
    Ascilab F6Bs Reflexion data.png
    189.5 KB · Views: 123
Last edited:
Shipping cost to Europe is quite steep though :/
 
Grill can be removed for maintenance.

But it was never meant to be removed so paint job beneath it is not going be pretty when one decides to use it without one!
 
Speaker that looks nice and measures well. Why no company name or details on the enclosure ?
Thanks for the measurements
regds.
 
AsciLab F6Bs
Nice, thanks for the testing and for @AsciLab for sending in.

The F6BS is the sealed enclosure version and the F6B is the passive radiator version.
The posted measurements appear very similar to what @AsciLab posted here;

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

Great company, they post/publish Klippel NFS measurements and clearly make excellent speakers.


JSmith
 
Speaker that looks nice and measures well. Why no company name or details on the enclosure ?
Thanks for the measurements
regds.
Because Ascilabs has class. No need to plaster ugly logos all over our furniture :) I’m planning a trip to Seoul to see their higher end models in person to choose from the variety of colours. Love this company’s approach to things.
 
Thank you for reviewing these Amir.
Keith
 
Amazing speakers. Do you know who imports them to Europe (Italy) ?
No, so far I've only checked https://ascilab.com/ directly
$197.00 shipping to Sweden for the non s version, which btw has been tested and measured by Erins Audio Corner, the video has been posted online on youtube
 
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Thanks for the review, I've been looking forward to seeing AsciLabs on your bench. I know they're measured elsewhere but this helps with direct comparison to other ASR reviews.

Cracking speakers, and (personal choice) love the look. Fantastic value.
Slight caveat on the low sensitivity, but this would give me the excuse I'm looking for to upgrade amplifier ... Watts are cheap these days too.

What surprised me (must have missed this before) was the little mid-freq bump and the steepness of the general slope - and the resulting "warmth". Doubt that it's an issue though.

Nice.
 
Because Ascilabs has class. No need to plaster ugly logos all over our furniture :) I’m planning a trip to Seoul to see their higher end models in person to choose from the variety of colours. Love this company’s approach to things.
Nominal impedance and broad power input gives average customers basic general guidance to choose amplifier or speaker model.
A company name and model no is helpful in distinguishing speakers from others.

Small size basic info on back panel is helpful.
Regds
 
I agree that the speaker cup should have branding/model/manufacturing location. It did confuse me at first as to which speaker it was.
 
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