AsciLab F6B Bookshelf Speaker Review

[Selkirks]

What did you replace them with?

Triangle Comete 40th Anniversary. In my situation a front ported speaker worked out better.

 

[Bwaslo]

An option I found in my previous Synergy-ish (constant directivity) diy horn speakers was to add "ceiling splash" speakers, ala Duke Lejeune, to add ambience without losing focus. Mine played only from about 2kHz and above, and about 10dB below the mains level so they didn't markedly affect the overall frequency response or make the system sound too bright. That house had low ceilings, so I played the "splash" speakers at an added delay of about 10msec. With higher ceilings and better directivity of the splashers I imagine the delay could be skipped and still make the room and soundstage seem bigger.

Unfortunately, that would probably have to be a diy effort, I don't know of a commercial offering. I bet an ASciLab waveguide and tweeter, placed behind speakers and aimed upward and back would work well for that kind of setup.

 

[MarkS]

Exactly , that's the upside to the trade off with losing the soundstage width and " air "... It's purely subjective preference... In certain ( mostly smaller ) rooms the narrow dispersion will be preferred by many

IMO, there are two different contributions to "soundstage width" in a stereo (two channel) system.

One is on the recording itself. Out-of-phase signals can sound like they are coming from outside the areea between the two speakers (eg, from the region to the left of left speaker). A good test of this effect is out-of-phase pink noise (equivalently, mono pink noise with one channel with reversed polarity). This effect is reduced by room reflections, because they do not have the correct phase relations. Therefore speakers with narrow dispersion are better at conveying this type of "soundstage width".

The second type of "soundstage width" is created by room reflections. This effect is not on the recording itself, and would not be present in an anechoic chamber. Broad dispersion speakers result in more of these reflections. For many types of music (in particular classical orchestral music), these reflections can create an illusion of greater concert-hall realism. Omni and similar speakers produce the extreme of this effect. Floyd Toole himself once had such a system in his own home, specifically for classical music. (He has since moved on to multichannel systems, which he believes give superior results.) I had bipolar speakers for many years, and was quite happy with them.

But now I am quite happy with my C6B speakers. They excel at the first type of soundstage width, and have enough of the second type to keep me happy.

 

[tw 2022]

IMO, there are two different contributions to "soundstage width" in a stereo (two channel) system.

One is on the recording itself. Out-of-phase signals can sound like they are coming from outside the areea between the two speakers (eg, from the region to the left of left speaker). A good test of this effect is out-of-phase pink noise (equivalently, mono pink noise with one channel with reversed polarity). This effect is reduced by room reflections, because they do not have the correct phase relations. Therefore speakers with narrow dispersion are better at conveying this type of "soundstage width".

The second type of "soundstage width" is created by room reflections. This effect is not on the recording itself, and would not be present in an anechoic chamber. Broad dispersion speakers result in more of these reflections. For many types of music (in particular classical orchestral music), these reflections can create an illusion of greater concert-hall realism. Omni and similar speakers produce the extreme of this effect. Floyd Toole himself once had such a system in his own home, specifically for classical music. (He has since moved on to multichannel systems, which he believes give superior results.) I had bipolar speakers for many years, and was quite happy with them.

But now I am quite happy with my C6B speakers. They excel at the first type of soundstage width, and have enough of the second type to keep me happy.

Yes , I've heard about the relationship with phase being a factor, never tried creating it though, reflections on the other hand: I experiment with placement and boundaries frequently ( or at least I used to, then I found my happy zone )...

 

[Karmacoma]

Triangle Comete 40th Anniversary. In my situation a front ported speaker worked out better.

Source: https://www.soundstagenetwork.com/i...th-anniversary-comete-loudspeakers&Itemid=153

 

[jEDGEc0m]

.personally I like wider dispersion

That's what I believed about my own preferences before buying a pair of C6Bs ...

It was interesting that Erin from the corner, who has many times said in his experience (and presumably also pertains to his rooms) that he prefers wider radiating speaker - Yet in his review of the C6B (Which we can fairly expect is effectively identical to the F6B), that despite the spin data indicating a fairly narrow radiation, he didn't get that impression from listening to them.

@ ~2:47...

(ps Thanks as always to Amir and Erin for these measurements and contributions)

 

[Selkirks]

View attachment 474202
Source: https://www.soundstagenetwork.com/i...th-anniversary-comete-loudspeakers&Itemid=153

If I was choosing strictly by measurements I'd have kept the C6B's. In this case I chose the speaker I'd rather listen to

 

[staticV3]

View attachment 474202
Source: https://www.soundstagenetwork.com/i...th-anniversary-comete-loudspeakers&Itemid=153

Whoever at SoundStage decided to make all graphs the same shade of black deserves a stern talking-to

 

[Karmacoma]

If I was choosing strictly by measurements I'd have kept the C6B's. In this case I chose the speaker I'd rather listen to.

I know, just showing what you'd rather listen to

 

[antisuck]

It was interesting that Erin from the corner, who has many times said in his experience (and presumably also pertains to his rooms) that he prefers wider radiating speaker - Yet in his review of the C6B (Which we can fairly expect is effectively identical to the F6B), that despite the spin data indicating a fairly narrow radiation, he didn't get that impression from listening to them.

I don't recall if Erin ever commented on this, but I wouldn't be surprised if that relates to the custom phase plug on the tweeter that reduces the beaming you see on many directivity plots above 7 or 8 kHz.

 

[jEDGEc0m]

I don't recall if Erin ever commented on this, but I wouldn't be surprised if that relates to the custom phase plug on the tweeter that reduces the beaming you see on many directivity plots above 7 or 8 kHz.

Yeah, Erin from memory doesn't hypothesise the specific cause, but does mention the width it maintains and even expands a bit at higher frequency might be part of the reason he likes them so much and why perhaps why the impression of the width of sound didn't quite match up to expectations from the data.

From his video... ~3:12

 

[sceptical1]

Those reflections do not include the near sidewall. You have to keep those wide,constant,controlled directivity speakers at least 3 ft. away.

 

[AsciLab]

I’m so glad to see these active discussions about the directivity and beam width.

Yes. We focused to get constant yet wide top frequency dispersion.
Most of speaker has narrowing beam width above 8kHz. It leads to get dull top frequency or is easy to be rolled off when a listener trying to set the speaker toe out.

Our top frequency has very similar level around 0 to 30 deg. It can make magic.
Wide dispersion makes bigger ASW(apparent sound width, from Sound Reproduction). It is especially related with side wall reflection.
Regarding this effect, you can use our speaker more toe out, saying 10~15 deg out, without losing top frequency clarity.

This set up helps to get versatile soundstages keeping the sound “airy”.

 

[jEDGEc0m]

you can use our speaker more toe out, saying 10~15 deg out, without losing top frequency clarity.

I look forward to experimenting with crossing in front of listening position, and toe-ing out off-axis.

Do you suggest that they are best not aimed directly on-axis?

 

[MarkS]

I believe @AsciLab's point is that you can toe them out if you want to increase (slightly) the ratio of reflected sound to direct sound, without reducing the amount of direct high-frequency sound (as happens with many other speakers). This may or may not be to your liking, depending on many factors.

 

[tw 2022]

Yes. We focused to get constant yet wide top frequency dispersion.
Most of speaker has narrowing beam width above 8kHz. It leads to get dull top frequency or is easy to be rolled off when a listener trying to set the speaker toe out.

that's a big plus, being able to make 8k+ hz beamwidth a constant /even dispersion has many advantages.. most domes start beaming at 8k or somewhere just above ....that's one reason i'm partial to good ribbons (like raal)... you guys seem to have made some great adjustments...

 

[tw 2022]

I look forward to experimenting with crossing in front of listening position, and toe-ing out off-axis.

Do you suggest that they are best not aimed directly on-axis?

with that dispersion pattern the *theory*(afaik) is that it becomes more room dependent , and personal subjective taste...

 

[dalbert02]

I’m so glad to see these active discussions about the directivity and beam width.

Yes. We focused to get constant yet wide top frequency dispersion.
Most of speaker has narrowing beam width above 8kHz. It leads to get dull top frequency or is easy to be rolled off when a listener trying to set the speaker toe out.

Our top frequency has very similar level around 0 to 30 deg. It can make magic.
Wide dispersion makes bigger ASW(apparent sound width, from Sound Reproduction). It is especially related with side wall reflection.
Regarding this effect, you can use our speaker more toe out, saying 10~15 deg out, without losing top frequency clarity.

This set up helps to get versatile soundstages keeping the sound “airy”.

What can we expect in terms of the difference between ceramic, aluminum, and fiber drivers? Since they all measure extraordinarily well, I am curious about the differences between the various models. Thank you.

 

[traind]

I’m so glad to see these active discussions about the directivity and beam width.

Yes. We focused to get constant yet wide top frequency dispersion.
Most of speaker has narrowing beam width above 8kHz. It leads to get dull top frequency or is easy to be rolled off when a listener trying to set the speaker toe out.

Our top frequency has very similar level around 0 to 30 deg. It can make magic.
Wide dispersion makes bigger ASW(apparent sound width, from Sound Reproduction). It is especially related with side wall reflection.
Regarding this effect, you can use our speaker more toe out, saying 10~15 deg out, without losing top frequency clarity.

This set up helps to get versatile soundstages keeping the sound “airy”.

How is the progress with the C6C and S6C models?

 

[staticV3]

What can we expect in terms of the difference between ceramic, aluminum, and fiber drivers?

Ceramic vs Fiber you can see here:

Post in thread 'AsciLab F6B Bookshelf Speaker Review'

Jun 18, 2025

Here's the difference in distortion:






So the F6B does better <200Hz, C6B better above.

Edit:
I'd unironically decide based on aesthetics (black vs white tweeter dome, fixed vs removable woofer grille, plus optional gray cabinet on the C6B).

• staticV3

•