Ascilab C8C Active Speaker Review

[TimVG]

S400mkII is quite totally different case. It has 3-4 dB more relative power at 200-1400 Hz than C8C so it's definitely less thin with the same on-axis balancing.
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Makes for an interesting discussion. Most normal forward firing loudspeakers that feature some form of controlled directivity, do so only between the edge of the mid/woofer passband and the working range of the tweeter. The result is a polar which explodes in the midrange, and so the sidewall reflections, which I'd argue are the most important, always have a certain amount of coloration. In that respect I much prefer a much more constant directivity down to the modal range. I can't say thin sounding is how I would describe it, but I can only speak for myself in my own room which is small and on the damped side. It would be interesting to test a speaker which features a slightly downward tilt its horizontal behaviour but still in a linear fashion, without compromising the on-axis. I guess it could be done with either a well designed wide baffle or a variation of resistance slots.

 

[WillBrink]

If i was starting from scratch, I'd get the best actives I could afford, a streaming source, and be done with it. The c8c would have to be on a short list.

 

[AsciLab]

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I'd say we do. Having to cut it at 60Hz to have it play clean?

We have to divide H2 and H3. Of course all of distortion is eliminated that's the best but If we choose one of them, H2 is more benign. Because the high H3 means directly it hits the Xmax and also brings higher order distortions. That must be heard easier than H2. You can see the H3 is very low only rising below 40Hz. And actually that's quite low distortion as a sealed box design in the same sized speakers. Did you check the link?

 

[mj30250]

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I'd say we do. Having to cut it at 60Hz to have it play clean?

Okay, but what else in its size class will be appreciably better across this region? If you prefer foundation-rattling bass, you should be looking at 1) subwoofers 2) the companion bass module 3) large floor standers.

 

[kharan]

@AsciLab Something I didn't realize was the case, but the HD level on the tweeter seems to be very sensitive to a lot of things.

It almost doubles in % between the A6B and the C8C with Audio Science Review's measurements.

And your C8C's tweeter's HD levels are better than your C8T's tweeter HD levels.

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I'd say we do. Having to cut it at 60Hz to have it play clean?

A lot of it is size related. Having a bigger box allows you a different choice of drivers. See the C8T tower speaker prototype from Ascilab, it's very, very clean up to 30 Hz. The enclosure is also twice is large.

 

[pat355]

Okay, but what else in its size class will be appreciably better across this region? If you prefer foundation-rattling bass, you should be looking at 1) subwoofers 2) the companion bass module 3) large floor standers.

Exactly --> can't wait to get the BX8C bass extension...

 

[AsciLab]

@AsciLab Something I didn't realize was the case, but the HD level on the tweeter seems to be very sensitive to a lot of things.

It almost doubles in % between the A6B and the C8C with Audio Science Review's measurements.

And your C8C's tweeter's HD levels are better than your C8T's tweeter HD levels.


A lot of it is size related. Having a bigger box allows you a different choice of drivers. See the C8T tower speaker prototype from Ascilab, it's very, very clean up to 30 Hz. The enclosure is also twice is large.

Yes it is. 1-3kHz region is sensitive. It’s more like occurring cancellation in that region by several factors. We’ve seen it has different H2 notches by each samples. Fortunately, it keeps its upper limit(if it exceeds the threshold, we deny that sample at QC stage) and H3 is almost same by samples.

 

[ShadowFiend]

The precision of a cardioid pattern, especially in the midrange, depends on the driver placement, the width of the baffle, and the degree of forward directivity.

As forward directivity is narrowed, lobbing can become more pronounced, and as the distance between drivers increases, lobbing also becomes stronger. A wider forward radiation pattern could have reduced the lobbing pattern, but we considered control of the forward radiation to be more important than achieving somewhat reduced side and rear radiation, and accepted that trade-off.
If the drivers had been placed closer together, the lobbing would have been reduced, but it would have been difficult to achieve the level of low-frequency output we obtain with the current 8-inch subwoofers, and it also would have been harder to relieve the midrange from low-frequency duties. In fact, a prototype using only 6-inch woofers showed a cleaner lobbing pattern, but within a nearly similar size it left something to be desired in low-frequency output and required much more low-frequency contribution from the midrange.
In that respect, some lobbing in the midrange is in fact the result of a realistic compromise made in consideration of perceived performance, and the benefits gained from that compromise were substantial enough to justify tolerating the lobbing in that band.
Of course we also considering smaller model which have cleaner midrange directivity pattern. That might satisfy your requirement.

Thanks for provide the details answer. I understand your trade off in principle but I still can not agree with you on some point below

For the Kii Three, it has wider forward beam width than C8C, and though D&D has the finest directivity pattern among three of them cause it has closest placement between front driver and the side slots, but it compromised the distortion around mid-bass which is inevitable of passive cardioid design.

Yes a passive cardioid design can have higher distortion but it is not because of the slot IMHO. The distortion is due to the increased excursion of speaker driver, similar to the effect of driver in dipole configuration. So, if the driver has low distortion, high excursion capabilities and/or high Sd then the increase of distortion due to passive cardioid configuration is not an issue. Too bad D&D uses a driver with unimpressive motor from SEAS, if it is PTT8.0, WO24P-4 or 22W/8857 or big 12" BMS like in Sigberg Manta then this problem will not be called up.

To analyze the actual behavior in more detail, the energy radiated from the sides to the rear is already 9 dB lower on average that means there will be only about -3dB dip when the reflection adding to the direct sound as an out of phase timing. Furthermore, this falls within roughly the 400–800 Hz range, which is relatively easy to absorb. By contrast, the 100–300 Hz range, which tends to have a much more significant negative impact in real rooms, clearly exhibits a cardioid pattern. For this reason, it would be difficult to say that it should not be called cardioid. To mention a specific example, Genelec claims that the W371A has a cardioid pattern up to 500 Hz, but in reality it crosses over around 150–250 Hz, which means the cardioid effect can only be seen below roughly 200 Hz at most. In that sense, such criticism is somewhat unfair.

Yes, absorption at 800Hz is easy but 400Hz is not IMHO. Wave length of 400Hz is 85cm so 1/4 wave length is 21cm. The absorption layer of that thickness is IMHO not easy or light especially when the amplitude is relatively high. 150-350Hz is definitely cardioid but calling it is cardioid is just like calling a Linkwitz Pluto omnidirectional just because it has omnidirectional upto 2500Hz. Don't get me wrong, your speaker is still a great speaker in my opinion. I just cannot agree with the marketing that this is an cardioid speaker based on the measurement shown here. And I agree with you about W371A, it is a cardiod woofer box from 80Hz-200Hz, and I have no problem to call out those as marketing blurb.

 

[Matias]

Exactly --> can't wait to get the BX8C bass extension...

From their own measurements, in 96 dB, HD relative, from best to worst between these 4.

IMO the A6B is the overachiever.

C8C + BX8C crosses -50 dB around 80 Hz.

A6B crosses -50 dB around 100 Hz.

C8C crosses -50 dB around 150 Hz

C8T crosses -50 dB around 180 Hz.

 

[dcolak]

Do we know what is the compression behavior of these speakers? I'd like to compare them to JBL 4367's

 

[F1308]

I was literally in the final seconds of committing to a full Neumann setup — KH310 with the KH750DSP — after a long evaluation process and with the order practically ready to go. But after seeing the measurements and technical analysis of the Ascilab system, everything changed. The engineering approach, the cardioid behavior, and the performance of the tower system convinced me that this is the direction I should take instead. So I’ve decided to go for the Ascilab system, the full tower configuration, as it clearly aligns better with what I’m aiming for.
Thank you very much...

 

[Sokel]

Do we know what is the compression behavior of these speakers? I'd like to compare them to JBL 4367's

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You really want to compare a 200 liter cabinet speaker with C8C ?
You can fit four (4) C8C in it.

I can only see it as you're joking or something.

 

[dcolak]

Why not?! They both play the same frequency range. If it's going to be used for monitoring, it should be able to withstand high SPL's. Since when high SPL is not part of required studio monitor specifications?

 

[AsciLab]

Yes a passive cardioid design can have higher distortion but it is not because of the slot IMHO. The distortion is due to the increased excursion of speaker driver, similar to the effect of driver in dipole configuration. So, if the driver has low distortion, high excursion capabilities and/or high Sd then the increase of distortion due to passive cardioid configuration is not an issue. Too bad D&D uses a driver with unimpressive motor from SEAS, if it is PTT8.0, WO24P-4 or 22W/8857 or big 12" BMS like in Sigberg Manta then this problem will not be called up.

No. It is came from the side slot. Of course it would be better to have lower distortion motor design woofer. Then it has lower distortion at the midrange. But at the mid bass region, the distortion is came from the resistance slot, the side hole, cause it is basically occurred by mechanical loss. If you have a chance to measure the 8C, try to near-field measurement of the front woofer and the side hole. They show different distortion shape. So different with the intuition, it isn’t fully related with excursion, it means the different woofers will have the same issues.

Yes, absorption at 800Hz is easy but 400Hz is not IMHO. Wave length of 400Hz is 85cm so 1/4 wave length is 21cm. The absorption layer of that thickness is IMHO not easy or light especially when the amplitude is relatively high.

To absorb 400Hz you don’t need 8” absorber.
Quarter wavelength theory is widely known but it is not essential in real. The velocity is maximum at the quarter wavelength, but absorption doesn’t happen only at the maximum range. And in the porous absorber the sound speed gets lower than in the air. For these reasons typically 4” absorber can absorb 400Hz well. Even already getting 9dB reducing, if there is additional -6dB attenuation it makes very little affection to the direct sound.

 

[Sokel]

Why not?! They both play the same frequency range. If it's going to be used for monitoring, it should be able to withstand high SPL's. Since when high SPL is not part of required studio monitor specifications?

Have you ever dealt with speakers, at all?
Different speakers serve different tasks.

If you're confusing mixing room, mastering room, and control room, etc there's not much to talk about.

 

[dcolak]

Have you ever dealt with speakers, at all?
Different speakers serve different tasks.

If you're confusing mixing room, mastering room, and control room, etc there's not much to talk about.

I am tired of speakers that disarm themselves when you play them a bit louder. Since when it was OK to not be able to play loud, specially for that money?

 

[AsciLab]

You really want to compare a 200 liter cabinet speaker with C8C ?
You can fit four (4) C8C in it.

I can only see it as you're joking or something.

It must the same performance or better indeed with -12dB (4 times more speakers).

If we have a chance to design like that big ones, we’ll try to challenge.

 

[dcolak]

It must the same performance or better indeed with -12dB (4 times more speakers).

If we have a chance to design like that big ones, we’ll try to challenge.

That would be awesome! Too many speaker producers forgot that many of us have no problem what so ever with having big speakers!

 

[AsciLab]

I am tired of speakers that disarm themselves when you play them a bit louder. Since when it was OK to not be able to play loud, specially for that money?!

Not all of people have a space to place that speaker and need that loud one.

There are several applications and proper designs for each environments.

Additionally if you saying the price point, there are bunch of products that should be criticized before us.

 

[anlin]

I am tired of speakers that disarm themselves when you play them a bit louder. Since when it was OK to not be able to play loud, specially for that money?

You clearly need to look at larger speakers then. The fact that you like and can accommodate large high SPL speakers doesn't mean smaller speakers shouldn't exist. Comparing these to JBL 4367s is completely absurd, they are 4x larger and cost 5x as much.