Benchmark AHB2 design

[jmdesignz2]

I have a big room, and it's well damped. Floor to floor carpet, 6 inch think absorbers. So I would even reduce the gain from room.

But anyway, as one can seen, the AHB2 at 100 Watts per channel into 8 Ohms, both channels driven is more than sufficient for my needs and most use cases.

Now Amir had once mentioned how his monoblocks would run out of juice on him, he also mentioned that he has a loft that is huge, his loft must be huge. Erin also gloats about his McIntosh monoblocks, but from his videos, that guy seems to listen at very high SPL, I wonder how long his hearing can last him.

92dB speakers at 8ohms is not "most use cases" that falls into 'unusally efficient' which is great for you if that is what they really measure

what speakers exactly do you have? How do they measure?

the most commonly seen efficiency levels of well measuring speakers are around 85 to 89dB (approx avg 87ish)
as many manufacturers constantly overstate efficiency

 

[jmdesignz2]

I have a big room, and it's well damped. Floor to floor carpet, 6 inch think absorbers. So I would even reduce the gain from room.

But anyway, as one can seen, the AHB2 at 100 Watts per channel into 8 Ohms, both channels driven is more than sufficient for my needs and most use cases.

Now Amir had once mentioned how his monoblocks would run out of juice on him, he also mentioned that he has a loft that is huge, his loft must be huge. Erin also gloats about his McIntosh monoblocks, but from his videos, that guy seems to listen at very high SPL, I wonder how long his hearing can last him.

so one vs two other use cases that would not be good for the AHB2 amp? Then add my use case and it is one vs three?

In the end the AHB2 is a nice amp but limited in power output compared to other lower cost offerings with equal sound quality class D amps which have greater power output and less likely to clip a much wider selection of speakers and user situations.

For users that have money to burn, smaller spaces, easy listening habits they are fantastic. I actually wish I could use them. But I don't relish the thought of running an amp that would run into clipping in my speakers.

 

[PristineSound]

92dB speakers at 8ohms is not "most use cases" that falls into 'unusally efficient' which is great for you if that is what they really measure

what speakers exactly do you have? How do they measure?

the most commonly seen efficiency levels of well measuring speakers are around 85 to 89dB (approx avg 87ish)
as many manufacturers constantly overstate efficiency

Using the Benchmark calculator that others have used. At 85dB efficiency, 3 meters away, 8ohms, a huge room, you are still getting 98dB with the AHB2. Honestly, I can't imagine anyone wanting to listen above 90dB for a prolong period of time; Personally, I physically wouldn't be able to handle more than 85dB. Am I the only one here?

What exactly is your use case? How big is your room, what is the nominal impedance of your speakers and it's anechoic sensitivity?

BTW, if you are using the Hypex NCx500, you are only getting 102dB with the same parameters.

 

[voodooless]

This isn’t about average SPL, it’s about the peaks. If you listen to 90 dB on average, you’ll probably have peaks above 100 dB. And yes, even 90 dB is pretty loud already.

 

[PristineSound]

This isn’t about average SPL, it’s about the peaks. If you listen to 90 dB on average, you’ll probably have peaks above 100 dB. And yes, even 90 dB is pretty loud already.

Frankly, I see a lot of people complaining about not having enough amplification power. It feels as if they are power FOMO. I don't know if this is a legacy result from the 60's and 70's when amplification power is scarce.

I have yet to go into anyone's home in the last 25 years, where someone complained that they do not have enough SPL from an "average" amp in an "average room" with an "average speaker" listening at an sane level; not once ever.

When Amir complained that his mono blocks running out of juice, I was honestly puzzled; his room must be ginormous with very inefficient speakers.

 

[jmdesignz2]

This isn’t about average SPL, it’s about the peaks. If you listen to 90 dB on average, you’ll probably have peaks above 100 dB. And yes, even 90 dB is pretty loud already.

Bingo

Mr pristine isn’t reading the entirety of our posts

 

[rdenney]

Ok. You’ve never been to many live orchestras

• Studies measuring sound levels experienced by symphony orchestra musicians confirm that peak levels of 115 dB (C-weighted) or higher are common during a performance, especially near brass and percussion sections.

I've measured tympani strikes from 24 inches, which was the distance from my head to the timp where I was sitting playing tuba, and I wanted to know what I was up against. A peak reading was 108 dB, unweighted (which would be very similar to C weighting for tympani). A good percussionist (and a better drum) might get a bit more.

Maybe a snare-drum rimshot is louder (but shorter).

But people in the audience aren't going to get anywhere near that. My own use case of wanting the orchestra to be at stage loudness is so that I can play tuba along with a recording without feeling the need to hold back. I have an NC502MP Buckeye amp and Revel speakers that are 91-dB sensitive, and my system can meet that use case, but, truth to tell, most recordings can't meet it fully because they are compressed to some degree (even classical music, and especially on percussive peaks) and so just don't have the same dynamics as one hears on stage.

And from where I sit, the screechy instruments up front are much less loud with respect to the back row compared to what the audience hears.

But it gets close and it's fun. Of course, I can't do it when my wife is on our end of the county, or she'll accuse me of murdering the cat. The cat, on the other hand, simply crawls into her usual hiding place under the heavy blanket on her favorite couch (which she does not allow us to use, of course).

All that said, I seriously doubt any audience member is subjected to SPL greater than about 95 dB for acoustic music, even from a large symphony orchestra. Amplified music is a whole other thing, of course. And I have been to hundreds of live orchestra performances.

Rick "doesn't sit in front of trumpets but has on occasion sat behind horns" Denney

 

[pablolie]

Bingo

Mr pristine isn’t reading the entirety of our posts

It's not a straigh forward thing- depends a lot on the dynamic range of the music you are listening too, as well as your listening habits (some actually choose those peaks as the very top SPL they want to hear (I know I do). So we move into the "relative" here. I don't think it's an inevitability that we end up listening to 106dB peaks when we listen to music. I for one am pretty aware of the DR of the tracks I listen to in 90% of cases, and the peaks don't catch me off guard.

 

[PristineSound]

Bingo

Mr pristine isn’t reading the entirety of our posts

You do realize that argument is saying the AHB2 is likely more than enough power for most use cases?

 

[rdenney]

And for the record, the Benchmark AHB2 is in a league of it's own. There was never ever any previous amp technology that ever came close to the AHB2 nor any older technologies that the AHB2 could of have leveraged.

The AHB2 uses the THX AAA patent of feed forward to reduce THD+N to a vanishingly low level. This technology was only really ever implemented on headphone amps prior, and never on any power amplifiers until the AHB2 came along. If I am not mistaken, the AHB2 is the only amplifier that successfully implemented the THX AAA technology.

To even say the AHB2 with any other amps in the same breath is an insult.

So, the AHB2 has 120 dB SINAD. I can't hear any better than 80 dB and I strongly doubt I could hear that reliably. Maybe some can hear as well as 90 dB, and maybe devices earlier in the amplification chain can expose flaws that small if we gain-ride the amplification in the quiet bits. But I doubt it.

I admire Benchmark as a company and I think the AHB2 is a standard-setter by any measure. I'd rather have a couple of them as bridged monoblocks than my Hypex amp simply because of that admiration and because the design is very likely more bulletproof. But I can't see under what circumstances I'd be able to actually hear a difference.

Rick "can't afford them, so it doesn't matter" Denney

 

[PristineSound]

So, the AHB2 has 120 dB SINAD. I can't hear any better than 80 dB and I strongly doubt I could hear that reliably. Maybe some can hear as well as 90 dB, and maybe devices earlier in the amplification chain can expose flaws that small if we gain-ride the amplification in the quiet bits. But I doubt it.

I admire Benchmark as a company and I think the AHB2 is a standard-setter by any measure. I'd rather have a couple of them as bridged monoblocks than my Hypex amp simply because of that admiration and because the design is very likely more bulletproof. But I can't see under what circumstances I'd be able to actually hear a difference.

Rick "can't afford them, so it doesn't matter" Denney

Agreed, as I stated as well in my previous posts on audibility.

It's an engineering feat, like a Ferrari that you can't drive more than 120MPH on an average street.

 

[rdenney]

What do you mean by "linear" the frequency response or the distortion profile is consistent?

Can you hear the distortion of a 15 KHz signal? The second harmonic is at 30 KHz. 15 KHz square waves sound indistinguishable from sine waves because our hearing filters out all the overtones. That is, for those of us who can still hear at 15 KHz, which isn't very many (including myself) who have sat in loud orchestras a lot without hearing protection.

That's true even if the distortion at 15 KHz is 100%, let alone the many orders of magnitude below the signal level as it is with the amps under discussion.

Rick "difference between measurable and important" Denney

 

[pablolie]

Agreed, as I stated as well in my previous posts on audibility.

It's an engineering feat, like a Ferrari that you can't drive more than 120MPH on an average street.

I would contend that all of the architectures discussed in this thread (AHB2 Class H, Ncore or Purifi Class D) represent phenomenal engineering. Measurement-wise the AHB2 is of course phenomenal... but not the best that's ever been measured here. Not that is matters. I think any amp with a SINAD of above 90dB sounds phenomenal, however you may get the itch for "better" when you look at those delivering over 110dB...

 

[PristineSound]

Can you hear the distortion of a 15 KHz signal? The second harmonic is at 30 KHz. 15 KHz square waves sound indistinguishable from sine waves because our hearing filters out all the overtones. That is, for those of us who can still hear at 15 KHz, which isn't very many (including myself) who have sat in loud orchestras a lot without hearing protection.

That's true even if the distortion at 15 KHz is 100%, let alone the many orders of magnitude below the signal level as it is with the amps under discussion.

Rick "difference between measurable and important" Denney

Read my other posts on this thread about audibility.

 

[rdenney]

Here is the audibly challenge once again, where did I say it was audible? I challenge anyone here to take a screenshot of my saying such switching noise is audible and show it to me.

"Then why the hell are you bringing it up?" My answer: Why the hell not? It's a matter of engineering discussion, if it's not audible and therefore we don't bring it up, then why the hell do we even have ASR? Why are we even measuring after 100dB SINAD when common cited level of distortion audibility in music is .5%?

The reason is the claim you are so assiduously challenging was about differences in the result, not in the design.

Rick "late hits but can't help it" Denney

 

[mdunjic]

This isn’t about average SPL, it’s about the peaks. If you listen to 90 dB on average, you’ll probably have peaks above 100 dB. And yes, even 90 dB is pretty loud already.

He already said that he is listening at 75db spl most of the time ... so for him 95db is probably and very likely peak

 

[PristineSound]

I would contend that all of the architectures discussed in this thread (AHB2 Class H, Ncore or Purifi Class D) represent phenomenal engineering. Measurement-wise the AHB2 is of course phenomenal... but not the best that's ever been measured here. Not that is matters. I think any amp with a SINAD of above 90dB sounds phenomenal, however you may get the itch for "better" when you look at those delivering over 110dB...

The only other two amps that have better measurements are the Topping B100 and B200. I argue that the Benchmark is overall still better.

 

[PristineSound]

The reason is the claim you are so assiduously challenging was about differences in the result, not in the design.

Rick "late hits but can't help it" Denney

Rick, what is my claim exactly?

That the Benchmark AHB2 is an engineering marvel?

It is in a league of it's own?

Or that it is not a class D topology?

Which one of these claims is questionable based on objective data?

 

[rdenney]

Rick, what is my claim exactly?

That the Benchmark AHB2 is an engineering marvel?

It is in a league of it's own?

Or that it is not a class D topology?

Which one of these claims is questionable based on objective data?

Okay, maybe I was reading too quickly, trying to catch up. But it sure seemed to me that our friend Pablolie was claiming only that all of the amps in the excellent category (at least) would be indistinguishable from one another (audibly, which is all that matters to such a claim) if operated in their linear envelope, and you were sounding like such a claim was a disparagement to Benchmark, which it was not. His claim was based on audibility, and yours was based on design and execution. I had already responded to a couple of those posts by the time you stipulated that it made no audible difference, though when I saw that I wondered why all the heat.

But now I'm adding heat and don't mean to. We are all friends here.

Rick "whose left ear noticeably distorts at probably 95 dB SPL, which seems to go along with the tinnitus, but still listens to loud music on occasion" Denney

 

[NTK]

We have this thread. It is not too difficult to push the AHB-2 into clipping.

E

'AHB2 real world power output - enough?'

Feb 10, 2021

I have a number of these little devils and love them. Even if they weren't so well engineered I appreciate them for the size/weight factor. Like many of us I've wondered if 100 watts/channel is sufficient for my particular applications. Rory Rall at Benchmark told me i'd get about 20 db above the speaker sensitivity rating so for an 88 speaker the amp could produce roughly 108 db without clipping. For my particular setup I felt this would be "more than enough". The setup is a Node2i digital out/STR preamp/AHB2 in stereo(hi gain)/Revel 106be speakers supported by a pair of JLA f112v2...

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