Can YOU hear the difference between amplifiers?? - Page 2  

Quote:

Originally Posted by mankite 

So by that logic two speakers that measure the same sound the same?

No. There's no comparison between speakers and an amp. Modern amplifiers, working within their design parameters - ie not being driven into clipping or other forms of distortion, will sound the same as each other. All an amp does is take an incoming signal and make it louder. If it is adding something, or taking something away, then it is not very well designed or has been specifically designed to add or remove something, such as, for example, designing an amp to make it sound 'warm'. But IMO that would be a terrible amp - what you really want is transparency to the source, not the amp adding something or removing something. All good modern amps can take the signal and pass it through, unchanged, other than in loudness. So it follow that all modern amps (with the caveat above of not being driven to clipping etc) will sound the same.

If you replace an amp with another one and it sounds better (and you can reliably determine this in a blind test) then the old amp was probably being driven too hard and its distortion levels were rising. So in that sense, all amps do NOT sound the same, period. But they do sound the same when they are being used as specced.

Speakers are totally different - they are analogue devices for one thing. And you don't actually hear the speakers (unless you play them outside or in an anechoic chamber). You hear the combination of the speakers and the room. All rooms will introduce distortion and all rooms are different, so the speaker-room combinations can sound very different to each other. You can minimise the effects of the room by using treatments and traps, but speakers will still have their own characteristics. It's not realistic to compare them with amps.

Quote:

Originally Posted by Theresa 

Good speakers have harmonic distortion below 1%. Its one of the reasons I use ScanSpeak midwoofers, their distortion is less than run of the mill speakers. Of course if they're driven past there linear range distortion will be present. Subwoofers on the other hand often have 10% distortion.

Thanks Theresa - you are of course correct - I am mixing up my woofs and my, er, non-woofs :)  I will correct my post.

Quote:

Originally Posted by Theresa 

No need to correct it. Miss you around here. Its said by some, and backed by blind listening tests, that we cannot hear distortion at the levels speakers produce it. I know I switched from Eton mid-woofers to ScanSpeak because the Etons have a very low xmax and distortion was audible to me with them. Large orchestral works were especially "muddy" and "congested" with the Etons even when crossed over at 80Hz.

I respect your ears, Theresa! Haven't been in these amp threads much lately - I got here this morning because I have recently discovered this "follow member" thing on AVS and I added Feri (mogorf) to my follow list and a post of his caught my eye and brought me to this thread. I must go and add you to the follow list as well - it's cool to see what AVS friends are up to :)

I have a pair of Seaton Submersive F2s waiting Customs clearance in the UK, so installing and setting up/integrating those will be my next project. I have also just recently added extensive treatments and bass traps to my little HT room, and the difference is amazing. Should have done this years ago. Even without XT32 the room sounds pretty good now - Audyssey is the icing on the cake.

Best wishes, Keith

Quote:

Originally Posted by mankite 

Quote:

Originally Posted by kbarnes701 

No. There's no comparison between speakers and an amp. Modern amplifiers, working within their design parameters - ie not being driven into clipping or other forms of distortion, will sound the same as each other. All an amp does is take an incoming signal and make it louder. If it is adding something, or taking something away, then it is not very well designed or has been specifically designed to add or remove something, such as, for example, designing an amp to make it sound 'warm'. But IMO that would be a terrible amp - what you really want is transparency to the source, not the amp adding something or removing something. All good modern amps can take the signal and pass it through, unchanged, other than in loudness. So it follow that all modern amps (with the caveat above of not being driven to clipping etc) will sound the same.

If you replace an amp with another one and it sounds better (and you can reliably determine this in a blind test) then the old amp was probably being driven too hard and its distortion levels were rising. So in that sense, all amps do NOT sound the same, period. But they do sound the same when they are being used as specced.

Speakers are totally different - they are analogue devices for one thing. And you don't actually hear the speakers (unless you play them outside or in an anechoic chamber). You hear the combination of the speakers and the room. All rooms will introduce distortion and all rooms are different, so the speaker-room combinations can sound very different to each other. You can minimise the effects of the room by using treatments and traps, but speakers will still have their own characteristics. It's not realistic to compare them with amps.

What is it that you believe a blind test doesn’t tell? It's not really a question of 'belief'. Sound reproduction is a science, so 'belief' isn't required. The purpose of a blind test is to enable comparison of two items while also removing any bias or prejudice the subject might have. In every properly-conducted blind test report I have seen, the subjects cannot reliably distinguish (more than chance alone would provide) between any two modern amps working within their design parameters. Of course, if nobody can hear a difference, then there can be no question of one sounding 'better' than the other. Sighted tests are meaningless because humans cannot eliminate expectation bias - and auditory memory is so short (a few seconds) that simply swapping amps, taking several minutes or even hours, or even days!, between the two amps also cannot provide meaningful results. Similarly, wide experience and testing shows that humans invariably perceive an amp playing louder as 'superior', so it is important to level match the amps under test to within 0.5dB, which is generally impossible in a normal listening environment. A blind test (preferably a double blind test) is the only reliable way to determine if amp A sounds different to amp B.

What makes it 'crazy'? All that an amp does is take a signal and make it louder. If the signal coming out is the same as the signal going in (other than its amplitude), where do you believe the  possibility of a difference in sound quality arises?  (If the signal coming out is NOT the same as the signal going in, then the amp is defective of course).

The different parts isn't relevant so long as the parts perform to spec. The goal of an amplifier designer is transparency to the source, but louder :) That is to say, to amplify without adding or taking away anything (ie without introducing distortion). Amps aren't like speakers or rooms - they are relatively easy to design and to get right, and the basics haven't changed much in decades.

Well I didn't express that notion, but I will comment on it. There's no question of wanting everything to sound 'in a predetermined way' - what the good amplifier designer wants to do is to create transparency to the source. Huge effort went into creating the source, using the creative talents of many people and the huge technical resources of the recording studio or mixing room. Surely what you want is for your equipment to reproduce that exactly as the creators intended it to be heard? With nothing added or taken away - that is to say, without audible distortion of their intent? I can't see why you would think that was 'hogwash' but you are, of course, entitled to believe anything you want ;) 

You misunderstand the purpose of room correction. It does not change the 'purity' of the sound. The room does that - with its huge peaks and nulls, flutter echo, comb filtering distortion and so on. Room correction, either by treatments or electronically or (preferably) both aims to bring the audible sound back to what was recorded in the first place. All rooms distort sound and what you call the 'purity' of it (by which I assume you mean accuracy) - room EQ gives you back the 'purity' not takes it away.

Expectation bias. "It costs 6 times more so sure as hell it is going to be better than that cheap lil'ole thing I had before!" The only way to know is to blind test both and see if you can reliably pick the VK-6200 from the other. Unless you were pushing the other amp beyond its design parameters (ie it may have had insufficient power and therefore being clipped) my money says you won't hear any difference at all. Sorry :) 

Everything you say there is subjective. Of course it is not possible (or desirable) to impose one person's preferences on another. I know people who prefer their $3000 TV in torch mode. But that doesn’t mean they are right, or that the recognised broadcast standards of REC 709 etc are pointless. The aim of a science forum is surely to introduce objectivity and science into matters, not to just accept that 'everyone is right'?

You are, of course, free to disagree with me and anyone else. But you haven’t provided any reasons on which to base your disagreement other than pure subjectivity and preference. 

Quote:

Originally Posted by Lepus 

 

Yes you can hear the difference between two different amps.

And you've proven this how?  In a double blind test?

Which parts contribute to what a person hears?

What if those parts have the same specifications?

If these parts change the sound from one amp to another, then by definition, one of the amps is not passing the signal without modification or distortion - IOW it's adding something or taking something away from the original signal, which a properly-designed amp shouldn't do. So what you are really saying there is that there will be a difference between two amps if one is not properly designed. Well, yeah, nobody's disputing that. We're saying there is no audible difference between properly-designed amps working within their design parameters.

Indeed. But the most significant component in any system is the room itself. It's vital to get the room right first - the best speakers in the world will still sound terrible if the room is plagued with reflections and nulls and peaks. It's totally pointless to worry about the minute differences electronics might or might not make, or even the big differences speakers can make, if the room itself is the main problem, which it is unless it has been treated, or unless some form of electronic EQ is being used (eg Audyssey).

Anyone who wants to improve the sound of an even half-decent system should forget about changing amps (and even speakers), and certainly forget about changing wires and interconnects and BD players etc, and instead spend a little money on the component that influences the sound dramatically - the room. A few bass traps and acoustic treatments can cost way less than a new amp or new speakers and make a massive difference to the sound. If WAF is the problem there, then an AVR with Audyssey XT32 is the next best thing.

Quote:

Originally Posted by KidHorn 

The double blind test results are always misinterpreted. The tests don't show that all amps sound the same. They were never intended to show that. They were intended to show that the differences between amps aren't obvious. The tests were designed to rebuff claims that there are dramatic sound quality improvements when switching between amp A and B. The idea is that if the improvements are as dramatic as advertised, then people should be able to consistently pick amp A over amp B. People can't always pick one amp over another.

If you pick amp A over amp B 80% of the time, it's a failed test. You have to pick amp A 100% of the time.

I have heard differences between amps. I have a NAD amp that sounds better than a crappy aiwa receiver/VHS player combo. I probably couldn't pick the NAD 100% of the time in a double blind test, but I would guess almost everyone would agree that, in general, the NAD amp sounds better.

That's not true - 80% would have massive statistical significance.

Quote:

Originally Posted by gurkey 

Quote:

Originally Posted by Lepus 

Yes you can hear the difference between two different amps. Even though some amps may have the same specs in regards to wattage, they could also have different parts on the inside, which would contribute to what a person hears. Mind you speakers have a larger aspect to play when it comes what you hear.

It is one thing to post such a statement and another to proof it objectively.

Obvious design differences like differences between Class B and Class A amps etc. can be identified under certain circumstances, because the deficiencies of a Class B amp will show itself by discernible crossover distortion at lower volume in comparison.
All differences between the input and (amplified) output signal can be described by various means of distortion, either dynamic, intermodulation, slew rate, crossover, harmonic, frequency response, level etc. distortion and signal to noise levels.
The human ear is only able to resolve to a certain minimum, beyond those minimum specs data become rather meaningless, but still usable in terms of marketing.
The human hearing is - naturally - very subjective in terms of frequency response, perceived loudness levels etc. because of its very nature and interpretation of the brain.
A major part of human perception is the correlation between several senses and the corresponding individual interpretation by the (always involved) human brain, which interferes on purpose with the raw data received and interprets them in a very subjective and situation dependent manner.

Unfortunately we can't isolate the raw data from its interpretation, thus making subjective "objective" statements or the other way around in this respect very unreliable.
If all stated distortions stay below a certain and somewhat individual level, we won't be able to "hear/perceive" them anymore.
Thus our brain tries to derive additional "clues" from all sorts of other information not really connected to the original data / event.
Double blind testing environments try to eliminate the later from the individual experience by eliminating certain clues (expectations), which might (and do) mislead individual judgement.

To make "experiences" comparable to each other, objectively measured data using all sorts of calibrated measurement gear come into play.
Those measurements (unfortunately ?) have to be evaluated and interpreted (again) by individuals against certain criteria or hypothesis / theories, thus introducing another sort of subjectivism called conclusions into the equation.
Different persons thus might come to different conclusions looking at the same set of "raw" data, which actually happens not so seldom, because of different interpretations, sometimes even on purpose, wanting to make the raw data "fit" to their own theories.

Different components used within a design plus the individual design concept (feedback used etc.) might "favor" some distortions and might "diminish" others.
Additionally output stages might be (overly) "sensitive" to certain complex loads or load combinations or even become unstable at certain volume levels, thus causing (eventually) "audible" differences in some instances, but not in general.
Even minimal differences in head positioning might lead to different individual impressions due to room acoustics and speaker design criteria within a given room and set of speakers.
Don't forget illnesses, hearing deficiencies, psychic state of mind, concentration, emotions, expectations ... you name it.

But these all fall under the general term of "distortions" meaning deviation from the original characteristics of source (input signal) as perceived or experienced by an individual.
Again the limits of the human hearing have to be applied, to decide, if those distortions are relevant and meaningful.
Now the prior notes about additional "clues" etc. come into play, again.

Great post! +1 +1 +1

Quote:

Originally Posted by MUDCAT45 

Quote:

Originally Posted by kbarnes701 

No. There's no comparison between speakers and an amp.

Speakers are totally different - they are analogue devices for one thing. And you don't actually hear the speakers (unless you play them outside or in an anechoic chamber). You hear the combination of the speakers and the room. All rooms will introduce distortion and all rooms are different, so the speaker-room combinations can sound very different to each other. You can minimise the effects of the room by using treatments and traps, but speakers will still have their own characteristics. It's not realistic to compare them with amps.

When did ALL amplifiers become digital? If speakers A and B measure the same in an anechoic then the same room characteristic should effect both A and B speakers. Or is the frequency distributed differently because the room can distinguish which speakers are playing?

Sorry, I wasn't clear. I meant that speakers are true analogue devices (obviously) and wasn't referring to the so-called 'digital' amps, just the fact that you do not directly listen to an amp.

Quote:

Originally Posted by mankite 

Just because I can't pick out which amp is which in a blind test 100% of the time doesn't mean they don't sound different. 

What percentage of the time can you pick out which amp is which in a blind test?

Quote:

Originally Posted by holt7153 

Quote:

Originally Posted by kbarnes701 

All that an amp does is take a signal and make it louder. If the signal coming out is the same as the signal going in (other than its amplitude), where do you believe the  possibility of a difference in sound quality arises?  (If the signal coming out is NOT the same as the signal going in, then the amp is defective of course).

You make it sound so simple, Keith .

Well it isn’t hard, which is why even budget amps work so well these days :)  Remember it doesn’t have to achieve zero distortion (as my over-simplification implies) - it just has to achieve zero audible distortion. Most half-decent amps these days can do this - even those in modestly priced AVRs ;)