Review and Measurements of Benchmark AHB2 Amp

[Blumlein 88]

Maybe, but these amps sound too different to me even at moderate volumes. I will try to borrow my friends spl meter soon and check though.

Don't do this with an SPL meter. I wish people would stop suggesting this. Much like matching volume by ear they are just enough off to fool you.

Get a multimeter, run a tone thru once you have set a comfortable listening volume, and match output with a 1 khz or so test tone so the readings are within 2% of each other or less.

 

[SIY]

Let us focus on one aspect.

Of the AHB2 measurements, which infer depth? Or the existence of sound planes.

OK, so you don't have a single example.

 

[Blumlein 88]

orangejello, do not listen to SIY, I suspect he compares expensive audio systems using Metallica - Death Magnetic

http://dr.loudness-war.info/album/view/104343 DR3

Please don't be ridiculous. Do you think non-level matched listening tells you anything comparing amps for sound? Let me answer that: no. If you disagree, express your reasoning and you can learn from this.

As SIY says it is the methodology most likely to mislead. It can give you a deep gut felt sense you've done the right thing. If that is the main point, then I suggest orangejello just call it a day, send the Benchmark back and be happy. This talk of dull, but more detailed is contradictory.

I can't tell you if the two amps orangejello are considering should sound the same or if they sound different. I can tell you with long term non-level matched listening comparisons you'll never know the truth.

 

[zalive]

I can't tell you if the two amps orangejello are considering should sound the same or if they sound different. I can tell you with long term non-level matched listening comparisons you'll never know the truth.

Long term non-blind non-level matched comparisons are pretty good to find your preference.
You'll be listening to pretty various levels and content and you'll get a picture which makes you more satisfied.
So, what is the truth here? Something other than personal satisfaction, preference, taste?

 

[SIY]

Long term non-blind non-level matched comparisons are pretty good to find your preference.

If "preference" is qualified to mean "regardless of whether you actually hear a difference or not," sure. As far as sonics, there's absolutely no evidence to support that notion, and several experiments with results contrary to that.

 

[Blumlein 88]

Long term non-blind non-level matched comparisons are pretty good to find your preference.
You'll be listening to pretty various levels and content and you'll get a picture which makes you more satisfied.
So, what is the truth here? Something other than personal satisfaction, preference, taste?

Why? Why would your statement be true?

It will give you confidence in your preference yes. If you need it to reinforce your decisions it will work fine. It won't get you close to any other truth. Not even what your preference really is except as informed by biases. The picture you are getting will be built by your confirming things you think you experience whether you are or not.

SIY beat me to it. Your proposition has been tested, and found wanting in terms of how good a job that methodology is with determining differences. If you follow this faulty methodology that can't discern large differences then how accurate can the results be vs reality. Results vs fantasy can come out fine. As long as you know that then it is okay. It won't lead to any reality based quality results however.

 

[zalive]

If "preference" is qualified to mean "regardless of whether you actually hear a difference or not," sure. As far as sonics, there's absolutely no evidence to support that notion, and several experiments with results contrary to that.

Why? Why would your statement be true?

It will give you confidence in your preference yes. If you need it to reinforce your decisions it will work fine. It won't get you close to any other truth. Not even what your preference really is except as informed by biases. The picture you are getting will be built by your confirming things you think you experience whether you are or not.

SIY beat me to it. Your proposition has been tested, and found wanting in terms of how good a job that methodology is with determining differences. If you follow this faulty methodology that can't discern large differences then how accurate can the results be vs reality. Results vs fantasy can come out fine. As long as you know that then it is okay. It won't lead to any reality based quality results however.

You can't qualify me whether I hear a real difference or not, because none of DBT science discoveries says anything about me particularly.
In other words, you don't know anything about me. Eventual implying that you do know what I will hear or not even if it's not level matched and blind, is foolish.
Now just replace -me- with -any particular person-.

 

[SIY]

You can't qualify me whether I hear a real difference or not, because none of DBT science discoveries says anything about me particularly.
In other words, you don't know anything about me. Eventual implying that you do know what I will hear or not even if it's not level matched and blind, is foolish.

If you tell me you can standing jump 4 meters high and lift 500 kg, I can be pretty safe in assuming you're mistaken.

 

[zalive]

If you tell me you can standing jump 4 meters high and lift 500 kg, I can be pretty safe in assuming you're mistaken.

Were talking about hearing a difference between two amps. This was a childish comment, you know.

 

[SIY]

Yes, we are. And you seem enamored of peeking and not trusting your ears, which you have every right to do. But don't claim that your conclusions arrived at without even the most rudimentary controls have any value exceeding the claims of those who say they have been kidnapped and anally probed by space aliens.

 

[restorer-john]

When I measured using a dummy load rather than an Activeload box to demonstrate a measurement lecture using AHB2.
AHB2 entered protection mode at significantly lower output than when connected to active load box.

So, you've also confirmed the AHB-2 when measured on a continuous basis (as opposed to the CEA-2006 burst test) shut-down prematurely and did not reach spec? What loads (8/4) were you using and was the testing single or both channels driven? How long did you run your continuous tests?

And in AHB2's torture test, there was a case of entering protection mode at a lower level than indicated in the spec sheet.
Later I asked John Siau. The APx 555 operates the relay when changing the output level, which creates a transient and inputs a level higher than + 22dBu.

If every professional sound reinforcement amplifier shut-down every time someone bumped a mic or unplugged a guitar, they'd be a lot of unhappy concert goers around the world. A transient input overload is hardly an uncommon situation and most amplifiers can handle that without feeling the need to shut-down.

 

[Hugo9000]

What if he has a combination of perfect pitch (absolute pitch, not just relative), phonographic memory (like Sgt Orville Stanley Sacker played by Marty Feldman in The Adventure of Sherlock Holmes' Smarter Brother), and is a human SPL meter? What would it take to be exempt from the normal human frailties involved in sighted listening comparisons?

 

[Blumlein 88]

What if he has a combination of perfect pitch (absolute pitch, not just relative), phonographic memory (like Sgt Orville Stanley Sacker played by Marty Feldman in The Adventure of Sherlock Holmes' Smarter Brother), and is a human SPL meter? What would it take to be exempt from the normal human frailties involved in sighted listening comparisons?

Not being human might do it. Otherwise he could meet all your above extraordinary characteristics and still not be exempt.

 

[Hugo9000]

Not being human might do it. Otherwise he could meet all your above extraordinary characteristics and still not be exempt.

In other words, it's not something anyone should get upset over or otherwise impact one's ego. Pity that so many take it as an insult when it's suggested that certain things might be beyond the objective and verifiable abilities of the human brain/perception.

 

[zalive]

I really can't believe few of you (possibly more than few) still don't understand.
I wasn't talking at all about me. I was talking about confusing reliability with the ability. Which is what you, gents, do. And you still don't understand the difference.

 

[Blumlein 88]

You can't qualify me whether I hear a real difference or not, because none of DBT science discoveries says anything about me particularly.
In other words, you don't know anything about me. Eventual implying that you do know what I will hear or not even if it's not level matched and blind, is foolish.
Now just replace -me- with -any particular person-.

So our understandings of the human organism are very extensive and well tested. Yet you are saying you are very far from the norm, and we don't have anything we can say about you. A claim like that becomes basically up to you to prove it. It also means if you are that most highly unusual and gifted a person you no longer can claim your experiences have any relationship to what other's hear.

In SIY's example of jumping 4 meters etc. if you can do it then you've proved it. You can't accurately say, "it is easy, anyone can do it".

 

[Blumlein 88]

I really can't believe few of you (possibly more than few) still don't understand.
I wasn't talking at all about me. I was talking about confusing reliability with the ability. Which is what you, gents, do. And you still don't understand the difference.

Okay then explain the difference between reliability and ability. If you lack an ability, then you have no reliability possible. You can have reliability in certain constraints of your abilities. Are you sure it is us who misunderstand?

 

[zalive]

View attachment 28184

So our understandings of the human organism are very extensive and well tested. Yet you are saying you are very far from the norm, and we don't have anything we can say about you. A claim like that becomes basically up to you to prove it. It also means if you are that most highly unusual and gifted a person you no longer can claim your experiences have any relationship to what other's hear.

In SIY's example of jumping 4 meters etc. if you can do it then you've proved it. You can't accurately say, "it is easy, anyone can do it".

What's far from the norm?
How it was proven that in conditions comparable to what you do at your home, you can't hear a difference between two amps?

 

[SIY]

How it was proven that in conditions comparable to what you do at your home, you can't hear a difference between two amps?

No one claimed that. It's just that if you say Amp A sounds different than Amp B, when both amps have flat response, aren't clipping, and aren't pathologically noisy or distorted, you need to demonstrate this is the case using basic controls. That's what science is about and what separates it from superstition.

To date, no one has done so, so an audibility claim is extraordinary and needs evidence in support.

 

[Hugo9000]

I don't think anyone discounts the idea of being able to tell poorly made and badly-operating junk apart from perfectly engineered and manufactured with great QA equipment without perfect level matching and blinding with difficult speaker loads and challenging program material. But most of the time, people are talking about comparing competent equipment, or state of the art to other state of the art gear.