AsciLab C5B Review.

[Old_School_Brad]

Blind also judging by that.

For those that insist on measurements.
The Hypex NC500 is current limited to 26amp and that's PEAK!!! Some old BJT output stage Rotels and NAD's are better than that.
The Gryphon can do 100amps continuous without breaking a sweat.

You’re right -there’s a difference in current capability and other factors. However, to make a convincing case, you’ll need to provide more details. For example, describe the setup and specify the SPL during the comparison, just to name a few key points. Based on the disclosed SPL at the listening position, I could probably evaluate whether your assessment is accurate. It’s also crucial that such tests are conducted blindly and with precise level matching to ensure valid results.

 

[kharan]

People, we're talking about a woofer with 50W capability wrt power handling, a lot of amps are going to be just fine, even if 2.2 ohm is very low.

 

[Old_School_Brad]

People, we're talking about a woofer with 50W capability wrt power handling, a lot of amps are going to be just fine, even if 2.2 ohm is very low.

Yes, as long as the protection circuit isn’t actively intervening. Some systems detect impedance and may shut down even if the current capability isn’t exceeded.

 

[georgehifi]

especially with the Wilson Alexia, which has a 90dB sensitivity..

And a .9ohm load in the bass which wants big current. Listen with measurement's and your ears.

 

[georgehifi]

But I also suspect that your hearing will be seriously damaged by trying to identify them with music, especially with the Wilson Alexia, which has a 90dB sensitivity..

So you think between 2 similar wattage amps driving the Wilson Alexia's which has a .9ohm low bass loading.
Fosi V3 and the Gryphon Antilleon, your going to be hard pressed to pick the differences between them even at medium listening level, good luck with that.
These C5B's have quite an nasty load, -phase angle & impedance between 80hz to 400hz
Cheers George

 

[georgehifi]

This, I agree with you. 2.2 ohms is not great design. XO needs reworking.

Then they could sound worsen (KISS). Better if it is driven by an amp that won't get asthmatic if pushed hard into those loads.
Also I still have doubts the tweeter getting down that low without doing harm to itself.
BTW the Purifi specs are not "rms wattage" or "continuous current", trust the manufacture not to mention this.

Cheers George

 

[boXem]

"rms wattage"

Wut?

 

[sigbergaudio]

Isn't there a separate thread for bashing class D already?

 

[DanielT]

Yes and that's from around 80hz (epdr) to 400hz, a good linear BJT amp with decent power supply and current drive will be fine with that.
Mosfets & Class-D's may get a bit asthmatic into it though, and start to strain in that region.

Cheers George

Okay but just to exemplify the problem, around what is a decent power supply and current drive regarding the AsciLab C5B speakers.

Let's say I'm a person who likes to listen to dynamic music at around 75 dB. I sit 2.5 meters/ 8 ft from the AsciLab C5B (from what I see ; they have 85 dB sensitivity, possibly 86 dB) when I listen to them.At least 30 minutes of continuous listening time at that sound level.
How do I know if, for example, if this class AB amplifier can handle the load it must work with?:

NAD C 316BEE V2 Integrated Amplifier Review

This is a review and detailed measurements of the NAD C 316BEE V2 integrated amplifier with phono stage and headphone jack. It is on kind loan from a member and costs US $399. The unit feels just heavy enough to not feel cheap. Controls have a nice feel and can be managed with a remote...

audiosciencereview.com

Just a theoretical example, for now I'm happy with the stuff I have.
Edit:
This is what NAD themselves state about the C 316BEE V2:

• Clipping power (at 1 kHz 0.1 % THD)
• >45 W in 8 ohms
  >60 W in 4 ohms
• IHF dynamic power
• 8 ohms: 90 W
  4 ohms: 120 W
  2 ohms: 170 W
• Damping factor
• >200 (ref. 8 ohms, 1 kHz)

C 316BEE V2 - NAD Electronics

For the C 316BEE V2, NAD’s Director of Advanced Development, Bjorn Erik Edvardsen, developed a clever new computation circuit requiring fewer parts at a much lower cost without any reduction in effectiveness.

nadelectronics.com

 

[fredoamigo]

Before knowing if a lambda amp will be capable for this load, it will be useful to have the Klippel EPDR data from Ascilab or Erin if it passes by him..
https://www.audiosciencereview.com/...ereophile-has-started-calculating-epdr.15497/

 

[AsciLab]

Hello guys. Thanks for watching our tiny son. and Thanks to @Nuyes.

I've seen some of you concern about very low impedance at midbass range and steep phase at bass range.
It was also my concern too while designing crossover. It is 2-way and has LR4 XO at 1.1kHz. To get exactly matched phase each drivers at XO point and not to suck out midbass, We had to use quite large cap and low DCR air core coil. That's the main factor for the C5B having that low impedance.

We had another way to use 8ohm version woofer.
But then it must has -3dB lowered sensitivity. It is 80dB/2.83V@1M. We didn't want to design that low sensitivity. It needs higher voltage for same level.
And also bass alignment of 8ohm version doesn't fit to our purpose size.

So we chose 4ohm version though it has quite low minimum impedance.
Actually we don't concern about that now. Because it is only 5", 50W Power handling driver.
Even though it has hard to drive impedance, you don't really need much power.
If your amp is lack of power to drive this speaker, Please. There are a lot of great amps these days.

I want to share a practical result by 2 different amps. One is Topping PA5ii, and the other one is NAD C298(Purifi amp).
I measured with STEP Sine Sweep from 1V to 20V, 1V step.
20V is 100W at 4 ohm. Yes, I didn't regard about crest factor. but with only 20V is pretty enough high level for this speaker, about 101dB @ 1M.

Now, you can see almost no difference between the two results.
NAD C298 has much high headroom to drive 20V. and PA5ii has Maximum 120W output @ 1%.
Though PA5ii was driven almost max level. There is no significant compression.
Please note that PA5ii isn’t 2ohm rated and is a quite cheap one among power amps. But doesn’t have an issue.

And here is distortion at 20V.
It would be more important to concern speaker output capability before Amp output.

So, Yes. As said above I also concerned about low impedance to while designing.
But in practical situation, don't have to worry about that.
You only need to worry about something like 2ohm 1000W subwoofer. And yes again, We won't do that when we design subwoofer.


C5B is our entry model. There will be some reviews of our bigger models C6B and A6B using Purifi woofer.
Please stay tuned. Nuyes is preparing a lot of datas. Thanks for watching us again.

 

[JohnnyNG]

There will be some reviews of our bigger models C6B and A6B using Purifi woofer.
Please stay tuned. Nuyes is preparing a lot of datas.

 

[DanielT]

Actually we don't concern about that now. Because it is only 5", 50W Power handling driver.
Even though it has hard to drive impedance, you don't really need much power.
If your amp is lack of power to drive this speaker, Please. There are a lot of great amps these days.

I agree with that. Good amps with enough power and good current capabilities are easy to come by these days. That at a not too high cost.

Good passive speakers on the other hand, is not the easiest to find. So therefore thank AsciLab for these C5B.

 

[Andreas007]

I can only say that I once owned a speaker with impedance below 2 Ohm over most of the frequency range (with 98 dB sensitivity, though).
Setup was driven by a Bryston B60 for over 15 years (2x 60 Watts - speaker was able to handle much more power).
Never had an issue. Only one thermal shutdown in this period while pushing it really hard. A well designed amp can handle such situations without going into flames.
IMO this low impedance discussion is a bit exaggerated. If you really want to max. out this speaker continuously (most won't do) then just get an amp which can handle it.

 

[Matt_Holland]

Hello guys. Thanks for watching our tiny son. and Thanks to @Nuyes.

I've seen some of you concern about very low impedance at midbass range and steep phase at bass range.
It was also my concern too while designing crossover. It is 2-way and has LR4 XO at 1.1kHz. To get exactly matched phase each drivers at XO point and not to suck out midbass, We had to use quite large cap and low DCR air core coil. That's the main factor for the C5B having that low impedance.

We had another way to use 8ohm version woofer.
But then it must has -3dB lowered sensitivity. It is 80dB/2.83V@1M. We didn't want to design that low sensitivity.
And also bass alignment of 8ohm version doesn't fit to our purpose size.

So we chose 4ohm version though it has quite low minimum impedance.
Actually we don't concern about that now. Because it is only 5", 50W Power handling driver.
Even though it has hard to drive impedance, you don't really need much power.
If your amp is lack of power to drive this speaker, Please. There are a lot of great amps these days.

I want to share a practical result by 2 different amps. One is Topping PA5ii, and the other one is NAD C298(Purifi amp).
I measured with STEP Sine Sweep from 1V to 20V, 1V step.
20V is 100W at 4 ohm. Yes, I didn't regard about crest factor. but only 20V is pretty high level for this speaker, about 101dB @ 1M.



View attachment 409668View attachment 409669

Now, you can see almost no difference between the two results.
NAD C298 has much high headroom to drive 20V. and PA5ii has Maximum 120W output @ 1%.
Though PA5ii was driven almost max level. There is no significant compression.




View attachment 409670View attachment 409671


And here is distortion at 20V.
It would be more important to concern speaker output capability before Amp output.

So, Yes. I also concerned about low impedance to while designing.
But in practical situation, don't have to worry about that.
You only need to worry about something like 2ohm 1000W subwoofer. And yes again, We won't do that when we design subwoofer.


C5B is our entry model. There will be some reviews of our bigger models C6B and A6B using Purifi woofer.
Please stay tuned. Nuyes is preparing a lot of datas. Thanks for watching us again.

I just wanted to say I applaud your efforts in interacting with this community (and presumably the wider one). It’s a breath of fresh air, just like the other manufacturers who communicate in a similar, detailed and honest way on these forums.

You deserve much success.

 

[thewas]

The EPDR dips to 1 ohm and it spends a wide area below 2 ohms. A class AB amp will probably get very hot.

Seriously now, an EPDR lower than 2 Ohm between 80 and 800 Hz isn't really an easy load for many middle class amps.

 

[Chr1]

Apologies for my ignorance, but is it not just a case of over-specing on the amplifier power required? Or is there more to it?
Surely amp topology is irrelevant?

 

[Scgorg]

Apologies for my ignorance, but is it not just a case of over-specing on the amplifier power required? Or is there more to it?
Surely amp topology is irrelevant?

Amp topology is in fact relevant in this case. The calculation of EDPR is specifically one that applies to class AB and B amps. Jack Oclee-Brown of KEF shared a concise writeup of how it is derived on this forum. His comment and file in this link: https://audiosciencereview.com/foru...as-started-calculating-epdr.15497/post-584683

 

[AdamG]

Even Hypex NC500 monoblocks which I use with 80v rails, they don't like Wilson Alexia type of loads you loose a lot of bass grunt). I use a linear BJT amp on those and you can hear it even though it's less than half the 8ohm wattage than the Hypex's are. The linear BJT amps can just give more constant current drive into those low loadings. As @DanielT said that limits the type of amp to get the best out of them
https://www.audiosciencereview.com/forum/index.php?threads/ascilab-c5b-review.58753/post-2148188
Cheers George

Well that explains why almost the entire supply of Powered Subwoofers on the market employ “Class D” plate amps.

 

[Chr1]

Thanks. Begs the question : What about class G and H then?