Different Amplifier Qualities? Same actual RMS power but different sound?

[msimon 10+ year member]

What I'm about to say is just my take on the situation... I could be wrong. I don't have any references for it, and if someone can jump in and confirm or disprove any of it that is welcome.
I would assume that BIG differences would be much easier to recall. For instance, I can recall that the only MB Quart tweeters I have ever heard really hurt my ears. Speakers have such a big difference between them that it should be retainable, the main points about them at least (eg: bright, dull, boomy, etc). For instance I can recall that the system in my old car had great bass up front and a high sound stage... these aren't really complex things about the system, but are critical parts of an SQ system.

I also doubt that even the most golden earned judge out there can recall ALL the subtle details of a system he heard long ago or even an hour ago. For that matter, SQ competitions are so subjective it's pretty much pointless as it is, maybe the judge liked it today but he wouldn't tomorrow. That is an ongoing debate in competition circuits... SPL is you and the meter, SQ adds the human element that can easily be wrong.

But then wouldn't a "SQ" amplifier be pointless for not only SQ competitors but also consumers? I mean, if someone couldn't remember hearing a difference, what would be the point of paying for it? I am not try to piss you off or anything, I am just trying to grasp what you are saying.

 

[sundownz Pro Seller]

But then wouldn't a "SQ" amplifier be pointless for not only SQ competitors but also consumers? I mean, if someone couldn't remember hearing a difference, what would be the point of paying for it? I am not try to piss you off or anything, I am just trying to grasp what you are saying.

No problem, it's all discussion //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

The point of what I said earlier is not that you can't remember that you heard a difference, it's just that you wouldn't be able to recall exactly what it was or be able to describe it in anything more than generic terms like, "airy, bright, dull, etc." This may be where all kinds of audio voodoo comes from... just the lack of ability to really pinpoint that THIS or THAT is the difference. And since you can't pinpoint exactly what it was you would be unable to pass RCs test.

I would be interested to see what differences could be measured between amplifiers. Not just the percentage of THD like we get as is, but what SORT of waveform deformation is happening. Also... I'd like to know if there is a way to measure exactly what goes on when an amplifier interacts with a load that has an extremely variable inductance and resistance like a real speaker. I also wonder how different amplifiers respond to sudden peaks of input and sudden bursts towards their limits like can be found in real music at high to loud levels. I'm sure much of this could be obtained using an O-Scope, but how would one interpret the results as far as audibility goes?

I think the sub-conscious perception of very small difference may be underplayed by some of the more hardcore guys like RC. His test is solid within it's own rules, nobody can pass it. All I'm saying is that it doesn't prove that a difference doesn't exist. It just proves that someone can't pinpoint that difference time and time again due to contraints of memory and perception.

Again, any further input on anything I'm addressing would be great. If I'm wrong, then I'm wrong. I don't claim to have all the information about this so I'm pretty much thinking out loud looking for more information.

 

[helotaxi 5,000+ posts]

The way SQ comps work are that since it is a subjective "quantity" being graded, the systems are not directly compared to one another. They are each graded on their own merits based on set criteria laid out by the competition sanctioning organization.

Because sensory memory is so short, they basically start with a clean slate and a new scorecard when the judges step to a new car. They score the car and once the cars are all scored the cards are added up.

 

[msimon 10+ year member]

The way SQ comps work are that since it is a subjective "quantity" being graded, the systems are not directly compared to one another. They are each graded on their own merits based on set criteria laid out by the competition sanctioning organization.
Because sensory memory is so short, they basically start with a clean slate and a new scorecard when the judges step to a new car. They score the car and once the cars are all scored the cards are added up.

Just playing devil's advocate here, but then couldn't you use this same method to pass a test like RC's? If you had a system, and then judged it by the set criteria and then changed only the amplifier and properly set it up in terms of the same output, wouldn't you be able to detect a change in the set criteria?

 

[helotaxi 5,000+ posts]

Probably you could tell a difference, but you still wouldn't be able to reliably tell the difference between the two amps. Truth is, the speakers introduce so much distortion that unless the amp severely colors the sound (i.e. a tube amp) the speakers (even the best audiophile component speakers) will mask most any difference in amps. The key to the RC challenge is that the power outputs are exactly matched and neither amp is being pushed hard so distortion from the amp is kept to a bare minimum and because the amps aren't being pushed, they both will have plenty of headroom so neither will have a dynamic advantage over the other.

The sonic qualities of an amp only really become apparent when you drive the crap out of the amp. Some amps have severe distortion problems when driven hard (still before clipping). Some amps are also poorly designed and/or built and crossover distortion is a problem. This isn't harmonic distortion and won't show up in a measurement of it, but it is audible and sounds like poo. You can only really detect it with an o-scope. It really amounts to a broken amp IMO but it can be chased to poor design and/or cheap construction.

I used to frequent a shop that swore by the old Targa and Sentrek amps. As long as you were judicious with the volume and bought more power than you needed and turned the gain down, they were great bang for the buck amps. Take it easy on them and you couldn't tell the difference between them and the Hafler amps that the shop owner had in his car. Try to get max unclipped power out of them, nevermind rated power, and they sounded like garbage.