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Ascilab C6B Speaker Review
- Thread starter amirm
- Start date
We're pretty much on the same page as ErinGreat speakers.
The C6B models are essentially F6B units featuring aluminum-ceramic cone woofers with cast-aluminum chassis, offering lower distortion.
For the tweeters : the C6B features an aluminum-ceramic dome tweeter, whereas the F6B uses a standard aluminum dome tweeter
Spinorama :
Measurements for speaker AsciLab C6B
www.spinorama.org
Basically the same tweeter. Diy community has used these tweeters extensively and theyre pretty much interchangeable, t/s parameters nearly identical with the alu one being 1db louder.
Very good tweeters ime.
It's easy to underestimate how much displacement volume (Vd) a PR needs to operate smoothly. It should have twice—or better yet, three times—as much displacement volume as the active driver. In this speaker, it may be a bit too small.
holbob
Senior Member
I have 4 filters that correct on axis and lw and don't destroy the eir. They are also based upon mainly not correcting up to my Schroeder frequency, that should be done by measuring speaker in your room. All of these corrections correct differences shown in amir's data and erin's data.
frq gain Q
400 -1.5 3
720 -1.1 4.5
2460 +0.7 3
5240 -0.7 5
frq gain Q
400 -1.5 3
720 -1.1 4.5
2460 +0.7 3
5240 -0.7 5
OP
- Thread Starter
- #45
Thanks for catching that. I had fixed it in Photoshop but had forgotten to export it.
Fixed the other typo in the near field graph while I was at it.
OP
- Thread Starter
- #46
One comment on distortion: I do not expect a bookshelf speaker to pass 101 dBSPL. I ran it so that I have the data for that low frequency graph but it was unwise.
Distortion behavior is strange, it's considerably worse in the low end than the F6B - look how the higher order harmonics come up - but the mids are better. Usually LF distortion like that is indicative of running out of excursion. So it's almost as though the diaphragm is more linear given the lower higher frequency distortion but the motor is worse.
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phoenixdogfan
Major Contributor
Great review, Amir, thank you. I think even three years ago, this level of performance from a speaker costing l.t. $4000 pr would have been unthinkable. These guys will do everything above 100 hz pluperfectly, and would benefit from a sub crossed over around 80 hz. With that, you probably have performance at the level of a lot of $10-15 k speakers of five years ago. They are a long term solution to a high end speaker system that set you back $1400 and can be at the heart of a great system for years to come.
If you want more there is the A6b which will basically play most music without a sub in smaller rooms at volumes around 96 db with no audible distortion, and becomes an edge of the art system when used with subs and DSP.
If you want more there is the A6b which will basically play most music without a sub in smaller rooms at volumes around 96 db with no audible distortion, and becomes an edge of the art system when used with subs and DSP.
phoenixdogfan
Major Contributor
Amir, this is, I think, an opportunity to educate the non-technical among us as to what these acronyms mean. I do know what "ON" means but not "NBD", for instance. Is there a reference key for these acronyms somewhere on site, and an explanation on their significance?
This would be a great speaker to start with, then as your budget allows, add a LF bass unit with dsp and another two channels of amplification. You could have a very high end equivalent three way dsp/passive hybrid system for well under 5k. I think I would try to have two dedicated bass units and cross it at 100hz, if not higher.
For example, 2 Satori 9.5" woofers in a sealed box per side. (would give the narrow form factor that everyone loves, and the Sd of a ~12-13 inch woofer per side), 4 channels of Buckeye amplification and a MiniDSP flex. Could probably pull that off in the 4k ish range total for a genuinely full range high end system if you have a little DIY in your blood.
For example, 2 Satori 9.5" woofers in a sealed box per side. (would give the narrow form factor that everyone loves, and the Sd of a ~12-13 inch woofer per side), 4 channels of Buckeye amplification and a MiniDSP flex. Could probably pull that off in the 4k ish range total for a genuinely full range high end system if you have a little DIY in your blood.
OP
- Thread Starter
- #51
They are in Olive's paper. But here is AI as a shorthand
.-----
Sure. In plain language, the Olive preference model is trying to answer one question: how likely is a typical listener to prefer this speaker, based on its measured frequency response and directivity?
The main components are:
- NBD On-Axis — how uneven the speaker sounds when measured straight in front of it. Lower is better. Peaks and dips in the direct sound increase this number. Think of it as a measure of tonal irregularity.
- NBD Listening Window — how uneven the response is over the small range of angles where a listener would normally sit. Lower is better. This is often more useful than a single on-axis trace because people do not keep their heads perfectly fixed.
- NBD Sound Power — how uneven the speaker’s total acoustic output is in all directions. Lower is better. This matters because the room receives sound from many angles, not just directly from the speaker.
- NBD Predicted In-Room, or NBD PIR — how uneven the estimated response will be at the listener after combining direct sound and room reflections. Lower is better. This is one of the most important terms in the actual Olive score because it tries to represent what you will hear in a normal room.
- Smoothness of Sound Power — how consistently the speaker’s total output changes with frequency. Higher is better. A speaker can have a tilted response and still score well here if the tilt is smooth rather than full of bumps and dips.
- Smoothness of PIR — how smoothly the predicted in-room response changes with frequency. Higher is better. The Olive model rewards a smooth overall trend because listeners generally prefer smooth spectral balance, even if the response is not perfectly flat.
- Low-Frequency Extension, LFX — how deep the speaker plays before bass output falls significantly. Lower frequency is better. A speaker reaching 35 Hz gets more credit than one reaching 60 Hz. This term has a fairly large influence on the final score, which is why adding a subwoofer can raise the preference score substantially.
- LFQ, Low-Frequency Quality — a measure of how well behaved the bass response is, not simply how deep it goes. Lower irregularity is better. It distinguishes smooth bass rolloff from bass with large humps or dips. Depending on the exact implementation, LFQ may be reported as a diagnostic component even when it is not one of the terms used directly in the final regression equation.
For the version of the Olive model we used on your speaker, the final score is driven most directly by On-Axis NBD, PIR NBD, PIR smoothness, and bass extension. So in very simple terms:
flat/smooth direct sound + smooth in-room behavior + deep bass = high preference score.
The directivity-related curves matter because they determine whether the reflected sound has a similar tonal balance to the direct sound. A speaker with a smooth on-axis response but erratic off-axis behavior can still end up with a poorer PIR and therefore a lower predicted preference.
The F6B uses a midwoofer from the budget line with a plastic basket. Those also don't have a copper cap though one can probably get one when ordering in OEM quantities. I suppose they didn't in this case.
phoenixdogfan
Major Contributor
Thanks, Amir. I think Olive's paper is behind a paywall.They are in Olive's paper. But here is AI as a shorthand
-----
Sure. In plain language, the Olive preference model is trying to answer one question: how likely is a typical listener to prefer this speaker, based on its measured frequency response and directivity?
The main components are:
- NBD On-Axis — how uneven the speaker sounds when measured straight in front of it. Lower is better. Peaks and dips in the direct sound increase this number. Think of it as a measure of tonal irregularity.
- NBD Listening Window — how uneven the response is over the small range of angles where a listener would normally sit. Lower is better. This is often more useful than a single on-axis trace because people do not keep their heads perfectly fixed.
- NBD Sound Power — how uneven the speaker’s total acoustic output is in all directions. Lower is better. This matters because the room receives sound from many angles, not just directly from the speaker.
- NBD Predicted In-Room, or NBD PIR — how uneven the estimated response will be at the listener after combining direct sound and room reflections. Lower is better. This is one of the most important terms in the actual Olive score because it tries to represent what you will hear in a normal room.
- Smoothness of Sound Power — how consistently the speaker’s total output changes with frequency. Higher is better. A speaker can have a tilted response and still score well here if the tilt is smooth rather than full of bumps and dips.
- Smoothness of PIR — how smoothly the predicted in-room response changes with frequency. Higher is better. The Olive model rewards a smooth overall trend because listeners generally prefer smooth spectral balance, even if the response is not perfectly flat.
- Low-Frequency Extension, LFX — how deep the speaker plays before bass output falls significantly. Lower frequency is better. A speaker reaching 35 Hz gets more credit than one reaching 60 Hz. This term has a fairly large influence on the final score, which is why adding a subwoofer can raise the preference score substantially.
- LFQ, Low-Frequency Quality — a measure of how well behaved the bass response is, not simply how deep it goes. Lower irregularity is better. It distinguishes smooth bass rolloff from bass with large humps or dips. Depending on the exact implementation, LFQ may be reported as a diagnostic component even when it is not one of the terms used directly in the final regression equation.
For the version of the Olive model we used on your speaker, the final score is driven most directly by On-Axis NBD, PIR NBD, PIR smoothness, and bass extension. So in very simple terms:
flat/smooth direct sound + smooth in-room behavior + deep bass = high preference score.
The directivity-related curves matter because they determine whether the reflected sound has a similar tonal balance to the direct sound. A speaker with a smooth on-axis response but erratic off-axis behavior can still end up with a poorer PIR and therefore a lower predicted preference.
OP
- Thread Starter
- #54
It is unfortunately.
Ah, right, forgot about shorting rings and their midrange distortion improvement.
Anyway... Looks like this is the base for the midwoofer for the C6B:
SB Acoustics SB17CAC35-4 6 Inch Ceramic Midwoofer Review
SB Acoustics SB17CAC35-4 6 Inch Ceramic Midwoofer Review
www.erinsaudiocorner.com
Looks like its distortion limited xmax is more like 2.8mm and is suspension limited, which might explain it falling apart so badly at LF at higher levels... Not that I expect a 6.5" midwoofer to do particularly well at 96dB/1m.
By comparison the one I think they're using in the F6B - the SB16PFCR25 - has 1mm less calculated xmax, but I haven't found anybody doing large signal measurements of one like Erin did, so can't comment on that.
I am curious, though, about the choice to use a passive radiator over a port, given Amir's note here:
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It is at high SPL and it is a bookshelf. The laws of physics shall not be defeated.
But nothing a sub or two and having xover capability in the DAC or Amp can't fix.
Absolutely unbeatable performance at the price. If I wasn't happy performance- and look-wise with my LS50 in racing red I'd snap me up some Ascilab in a second.
I also use them in a desktop setup, but they are on stands beside my desk
I upgraded from Elac DBR62, and while tonally it was not a major shift, initially the treble had drawn a bit more attention than I was used to. But that impression went away after a week or so, I attribute that to constant directivity and more locked-in imaging. (https://www.audiosciencereview.com/...k-questions-share-feedback.62397/post-2390908)
Midrange and treble clarity were noticeable step up from DBR62, bass not as much, but I believe in case of bass it is more a room/placing problem. I use height-adjustable desk and the improved vertical directivity does make a difference too.
Is C6B worth 3.5x of DBR62? Honestly I do not think so, and I would advise budget buyers to pick DBR62 on sale
But I am happy with them, the reason of upgrade was that my second system was inferior, now I use C6B as primary and DBR62 as secondary and it works great for me.I mean, yes, but at the same time, you can very clearly see it run out of excursion with the way all the higher order harmonics come up with it. I'm not sure if it's the PR or the woofer.
I have slightly different eq filters for my C6B's, but my room is odd-shaped, carpeted, etc. and, no doubt, everybody' eq's will vary a bit with their particular room. Though, that said, my eq filters are definitely in the same general neighborhood as these. Along the PEQ slots and both a bass and treble adjustment, my RME ADI-2 DAC has seven possible PEQ adjustments. That, coupled with the three PEQ slots on my dual SVS subs (low passed at 50hz), and lots of room measurement hours, has resulted in---at least to me---is a significant step up in sound from the Revel F208's I had, previously (and they were very nice!).
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