Do amplifiers really sound the same?

[sq225917]

[/QUOTE]

Squad cars, the top of the pharmacy sign, the ricoh sign, two missing ball lights on the left hand side, text under the Yahoo sign and the bottom of the long strip sign on the right hand side.

You should see me do it with hifi. ;-)

 

[Cereal Killer]

Theres also people missing bottom right hand side and the traffic lights are a different colour!... Middle top, a round blob at building roof level also missing

 

[hammeredklavier]

This is an interesting read regarding the above topic (make sure you read it all):

http://www.hydrogenaudio.org/forums/index.php?showtopic=75195

Interesting! In a similar vein, I seem to recall reading somewhere that Sennheiser discovered that headphones with a flat frequency response sounded harsh.

Alex

 

[cooky1257]

I think there are two different things going on there.
They added drivers capable of extending past 14khz in order to highlight noise but that isn't related to the famous BBC dip.

The 'dip' is down in the presence range.
Interestingly it isn't present to the same degree on the earlier BBC designs other than the 3/5 and seems to have become a more prominent feature when companies started producing domestic versions of the BBC work.

My understanding is that the dip was introduced to mask the unruly behaviour of the bextrene bass/mid drivers, which due to resonance at the top of their working range could 'shout' and sound hard. So the dip was introduced as a compromise - non-flat response but better subjective result.
Of course the BBC used measurement and blind testing extensively to achieve this subjectively pleasing sound, which is exactly how it should work IMO.

I'd heard the dip was down to the bextrene quack too.

 

[cooky1257]

This is an interesting read regarding the above topic (make sure you read it all):

http://www.hydrogenaudio.org/forums/index.php?showtopic=75195

Thanks, very informative.

 

[cooky1257]

http://seanolive.blogspot.co.uk/2011/04/version-204-of-harman-how-to-listen-now.html
http://www.aes.org/tmpFiles/elib/20120705/5276.pdf

 

[Yank]

I agree about trained observers. A blind test for testing small sonic differences between amplifiers would be pretty pointless just pulling people off the street.

Then how is a customer to choose which amplifier to buy?

 

[sergeauckland]

Then how is a customer to choose which amplifier to buy?

If I were completely untrained, I would buy on looks, facilities and price. I would be unlikely to be buying anything out of the ordinary like a SET valve amplifier, so if I was sticking to "normal" modern SS, it doesn't matter, does it?

S.

 

[cooky1257]

Very interesting read, thanks for posting it. So really, we're no nearer to knowing why it evolved.



S.

Yes we are, it just doesn't include the explanation you gave

 

[Yank]

If I were completely untrained, I would buy on looks, facilities and price. I would be unlikely to be buying anything out of the ordinary like a SET valve amplifier, so if I was sticking to "normal" modern SS, it doesn't matter, does it?

S.

You're assuming that the dealer has already somehow proven to the customer that they all sound the same...

 

[sergeauckland]

You're assuming that the dealer has already somehow proven to the customer that they all sound the same...

Why would a Dealer do that? He would propose the one he had most stock of, or the one he got the most margin from.

S.

 

[James]

Squad cars, the top of the pharmacy sign, the ricoh sign, two missing ball lights on the left hand side, text under the Yahoo sign and the bottom of the long strip sign on the right hand side.

You should see me do it with hifi. ;-)

Miss a few more details?

 

[john & Jake]

Have we decided that they sound different yet

I am listening to my lk280, I decided to buy one of these after listening to an LK100 which was a revelation to me so I sold my Exposure.

Tim Rose has just sang Come away Melinda, sounds different and so much better to my ears.
Katie Melua is current persuading me that I have done the right thing as she is sounding fine, and different to her renditions through my two previous amps.

 

[James]

That's nothing like optical performance or audio presentation so now the analogy is getting completely strained. What we have here are two very busy images which are identical apart from a number of manipulated details. It would be like trying to distinguish between the same recording played twice on the same equipment except that in one case a few single notes were edited out or changed. In both cases, the photos above and the hypothetical recording, the differences are objectively present and perceptible.

Perhaps, but I was simply pointing out human acuity in spotting differences.

I do agree with your earlier post, though, that if we measure the things directly associated with perception, then identical measurements should yield identical perception.

Comparing two passages of audio by ear, even repeatedly, is unlikely to discern differences to the same extent a sophisticated audio-analyser could (e.g. one that differentiates frequency and amplitude separately over time). Most of the analysis I have seen in my limited experience show only amplitude, which could hide additions/omissions.

It is much easier with static pictures, of course.

 

[James]

Detail vs Transparency

Until we bought our first HDTV recently, I thought the 100Hz display of our Loewe CRT was the bee's knees. Does the HDTV make the Loewe less transparent?

I have a macro lens that can capture the same image and perspective as a standard lens, but upon close-up examination, it's evident that the macro lens produces a sharper image. Does that mean the macro lens is more transparent?

This is pertinent to me, because I'm still arguing the toss between a standard display vs Retina on a new MBP. I don't think I can see the difference (with presbyopia) but it'd make me feel sooo much better to have a more 'transparent' and higher 'spec' computer.

 

[hecd2]

Comparing two passages of audio by ear, even repeatedly, is unlikely to discern differences to the same extent a sophisticated audio-analyser could (e.g. one that differentiates frequency and amplitude separately over time). Most of the analysis I have seen in my limited experience show only amplitude, which could hide additions/omissions.

Not sure what you mean here - any meaningful assessment of amplifier performance will measure, in effect, amplitude as a function frequency over a range of gains into a realistic load.

 

[Arkless Electronics]

FOX. Unleash the herd!

 

[hecd2]

Detail vs Transparency

Until we bought our first HDTV recently, I thought the 100Hz display of our Loewe CRT was the bee's knees. Does the HDTV make the Loewe less transparent?

We have to be careful here not to confuse the metaphoric use of the term "transparent" in audio with the precise scientific use of the term in optics where transparency is defined as the ability of an optical medium to transmit light without scattering. A lens could be made of completely transparent material and stll have a poor transfer function owing to larger geometrical aberrations for example - a transparent but low resolution optical system. (By the way, this has reminded me that I forgot a fourth class of phenomenon that affects the transfer function of an optical lens in addition to the ones that I listed in the post above - viz non-image-forming light caused by scattering at the lens surfaces and the lens materials, multiple reflections from lens element surfaces and stray reflections from stops, vignetted rays, and reflctions from the internal surfaces of the barrell)

I have a macro lens that can capture the same image and perspective as a standard lens, but upon close-up examination, it's evident that the macro lens produces a sharper image. Does that mean the macro lens is more transparent?

Not necessarily according to the definition of transparency in optics - but it seems your macro lens has a higher resolution and a higher MTF at high spatial frequencies compared to your standard lens.

This is pertinent to me, because I'm still arguing the toss between a standard display vs Retina on a new MBP. I don't think I can see the difference (with presbyopia) but it'd make me feel sooo much better to have a more 'transparent' and higher 'spec' computer.

Presbyopia on its own is easily corrected with with correctly specified reading glasses so that you should be able to distinguish between one display and the other provided the improvement in resolution between them occurs at perceptible spatial resolutions (the limit of normal ocular resolution is generally taken to be of the order of one arc second - the benefit of greater display resolution is lost if the display is viewed from such a distance that the pixels are separated by less than that). On the other hand if you are suffering from cataract or macular degeneration you might not appreciate the benefits of the higher resolution display even if your nose is pressed against it.

 

[James]

Not sure what you mean here - any meaningful assessment of amplifier performance will measure, in effect, amplitude as a function frequency over a range of gains into a realistic load.

Sorry, I'm not explaining myself very well. Let me try again.

When using Audigy, for example, to compare input vs output or one except against another, you get a chart that looks like this.

Which shows amplitude plotted against a time scale. I was contending that it's more insightful if a third dimension is used to illustrate the spectral content (FR and amplitude) against time. Maybe such an analyser is already available; I'm just not that familiar with the technology.

 

[James]

We have to be careful here not to confuse the metaphoric use of the term "transparent" in audio with the precise scientific use of the term in optics where transparency is defined as the ability of an optical medium to transmit light without scattering. A lens could be made of completely transparent material and stll have a poor transfer function owing to larger geometrical aberrations for example - a transparent but low resolution optical system. (By the way, this has reminded me that I forgot a fourth class of phenomenon that affects the transfer function of an optical lens in addition to the ones that I listed in the post above - viz non-image-forming light caused by scattering at the lens surfaces and the lens materials, multiple reflections from lens element surfaces and stray reflections from stops, vignetted rays, and reflctions from the internal surfaces of the barrell)

Interesting, is it possible for amplifiers to be more or less resolving regardless of their transparency? What's the measure of resolution?

Presbyopia on its own is easily corrected with with correctly specified reading glasses so that you should be able to distinguish between one display and the other provided the improvement in resolution between them occurs at perceptible spatial resolutions (the limit of normal ocular resolution is generally taken to be of the order of one arc second - the benefit of greater display resolution is lost if the display is viewed from such a distance that the pixels are separated by less than that). On the other hand if you are suffering from cataract or macular degeneration you might not appreciate the benefits of the higher resolution display even if your nose is pressed against it.

Indeed, but the point I was trying to make is that a standard screen is *good enough* for my needs, and the higher resolution option appeals to ego or vanity.