Sound Quality Vs. Measurements

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I don't really know. But it might be worthwhile too look. Some days the system sounds better than others. I just ascribe that to my ears, but maybe there is an RF element?

Yes, it's a bigger problem in long run pro systems. Often a very big problem.
 
4) Do the AP2 Measurements as given above inform us if the DUT when inserted into a HiFi Audio System will produce what is perceived by the majority of the potential customers "good sound" and would lead to a purchase of the DUT?

Since "good sound" is subjective you can replace it with "good song" in that sentence, and it makes about as much sense. If you want to design amps based on popular opinion go a head, but dont try to tell us it will be a better (more transparent) amp.
 
@Pano: Unless you're sitting next to something with a continual carrier, it would seem unlikely. RF breakthrough is usually transitory. I'd more likely ascribe the differences from day to day (and I experience the same thing!) to brain, not ears.

It's funny about senses and our gray, squishy CPU- you've been to my place, you know I have my lab at 58°F because I store my wine in there. It's thermostatically controlled and monitored with two thermometers. Yet sometimes I go in there and it feels chillier than that, other times it feels warmer. Intellectually I know that it's still 58°, but I have to check the thermometers anyway, just to be sure!
 
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Most of my CDs have that as well. Yet my home-made recordings don't. Same playback system. Hmmm.
You have far fewer opamps or other active components in your recoding signal path than almost all commerical recordings. No big surprise. (I've heard SY's recordings, no sibilance). You also don't have the mic 3" from the singer's mouth.

Getting back to measurements and SQ, here are two test that have been discussed before on this forum. They are multi-tone tests of amps, cables and such. They may reveal audible differences that other tests don't. Sorry the Jensen paper isn't online, I have a hard copy of it here somewhere.

AES E-Library Spectral Contamination Measurement
http://eetimes.com/design/audio-design/4015821/Loudspeakers-Effects-of-amplifiers-and-cables--Part-5

The Cerwinski test does seem to show some significant RF influence, IIRC.
 
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Is it the lack of opamps or the lack of manipulation?
I think both. However, I'm able to manipulate the file in the digital domain with out picking up much, if any, sibilance or other nasties. A good, clean mic preamp is a great start.

Images are similar. Start with a high quality photo and you can do a lot to it before it falls apart. No so with a poor quality beginning.
 
Very cool! I'd love to see and hear one. I once tried to build something similar based on a CD pickup, but it didn't work well at all. Nice to see the principle in action.

They did their prototypes quite a while ago, now were bought by some bag with money, so started offering some production. I am thinking currently about some vacuum tube front-end for them...
 
The Crystal mike might be immune to RF, but its box of electronics will need to take all the usual precautions. Mikes of any type rarely pick up RF, but their cables do.

They go with 100 meter optical cables. Box of electronics has digital optical outs, internal DAW on a flash drive, and +4 dB balanced analog outs.

However, no sinatras/armstrongs were recorded by such mikes, so it would be hard to convince modern singers to sing in something invisible and unknown. ;)
 
And when any DUT sounds very good, subjectively, even more "transparent" than many others, yet it measures poorly in traditional measurements, what may we conclude?

That people may find slightly distorted sounds as more pleasant
than the same non corrupted sound.

Any other conclusion will inherently lead to pseudo scientifical
explanations such as the so called "bad sound of GNFB"....
 
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[snip]
So this Amp is at least as good as the AP2 or better. If you make a better amplifier how will you know?
[snip]Ciao T

Funny ennough, the answer is right in the next section you quoted.

Hmm, so you position COULD be rendered as: "The listed measurements are insufficient, but I do not know in what way and what needs to be measured in addition to them"?Ciao T

Yes it could, and it would be wrong. I still am amazed how easily you are able to turn things around to your liking. Is it automatic or do you have to think about it?

Jan, I included this question on purpose and I would suggest it actually bears some import and is worth reconsidering your answer. To focus this a little, sure, the amplifier does not change, but could it be perchance that it's environment change in ways that would influence the measured performance of the amplifier?

Yes but that is not what you asked. You asked whether the measurement result has an impact on the performance in a system, which of course it has. Amps that measure differently will perform differently.

Okay, let us de-link "good sound" and "purchase decision", though I had good reasons to include it, as it in many ways at least in the audiophile context the ultimate arbiter, "will I trade what I have for this new gizmo at a financial loss to me".

In that case, however, let us remove the purchase decision and focus on "will it sound good?"

Ciao T

If you want to decouple 'good sound' and 'purchase decision', I am all in agreement, because in actual real life they are only loosely coupled at best. Even a very cursory view of the market will confirm that.

If, after seeing the answer, you prefer to re-phrase your question to 'will the amp that measures good on the AP2 sounds good', I can only say, depends. We all know that 'sounds good' is a highly subjective judgement varying from person to person, with location, conditions, physical appeearance of the amp, reputation, price, peer opinion and probably a few dozen other conditions. Some swear by Halcro, some by Parasound, some by Bose.

Anyway, I thought I'd answer your questions because they are interesting and relevant, but I have no intention to engage in a protracted discussion with my answers being twisted and the questions being modified until the answer suites you.

I'll see you around,

jan
 
Ah! I can't claim credit for that. The nearest I got to learning Greek is the alphabet - between maths and physics I had to use most of it. A friend of mine was doing cosmology and ran out of letters to use for indices so he started using one of the indian languages too - I forget which one.

Of course, "taxi" is one of those words which seems to occur in lots of languages although with variant spellings e.g. tacsi in Welsh.
 
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