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Propeller Head Plaza Technical and scientific discussion of amps, cables and other topics. |
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Propeller Head Plaza Technical and scientific discussion of amps, cables and other topics. |
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In Reply to: Re: Same ol' house of cards posted by Mahatma Kane Jeeves on January 8, 2005 at 04:43:29:
“â€("well, if you do an incomplete measurement suite, it's... ummmm... incomplete!")â€â€â€œâ€...I've never met one who said that THD alone is a suffient measurement. Necessary, yes, but not sufficient.â€â€
THD is worthless in telling us how a part of equipment sounds.
I’ll repeat to clarify: WORTHLESS!!!!!!!!!!Let’s look at this in a historical perspective, with a twist:
It was not that many years ago when you so called objectivists did say that THD was the only thing needed to measure and if two amplifiers had the same THD reading they sounded the same…
But when we showed that the amplifiers had different IM readings, the objectivists first argued but did after a while agree that the IM readings made a difference when they where overwhelmed with evidence. But the order of harmonics did still not mater.
But after controlled listening tests that have shown that high-order harmonics are annoying to the listener, the objectivists did say that the order of harmonics made a difference, but only after first arguing against it for a long time. BUT only if the harmonics where high enough in level AND they did absolutely not have any effect at the low levels we were talking about. AND of course they only had effect in the audio band.
Then we showed that high frequency stress in an amplifier caused audible and measurable effects, the objectivists did say that SID made a difference, but again only after first arguing against it for a long time.
With that we are somewhere at present time and despite that we have shown that harmonics are more and more annoying as the order rises and that the number of IM products rises to enormous amounts when exposed to multitone test signals (Witch AGAIN for the record, resembles music much more than a single or dual tone) and the Total InterModulation Distortion (TIMD) rises to much higher levels than with a single tone.
You still argue that the levels are too low to be heard WITHOUT providing any proof, you just say it can’t be heard … … … Show me the evidence to that.
There is loot of more examples of this, with one of the more obvious being the loudspeaker connected to the amplifier, but you can check that out in another post in this tread.
I believe that education and EXPERIENCE combine to make the best estimations as to what is important to audio, and that you have to trust your ears when designing something that in the end is going to be evaluated by the listeners ears and hearing. And if that then includes partly to alter your design without be able to show measurable effects with the measuring tools we have today but only audible effects, may it be so then.
And I fully agree to what Jon Risch said:
“â€Good designers deal with the 'unmeasurable' in as scientific a manner as possible, using their experience, the experience of others they trust, and logical and controlled experimentation to achieve their goals.â€â€And I have to say a last thing about listening tests: It’s very difficult to hear differences when you have to make decisions at the moment. I have experience of that myself with one pre-amp prototype I made, at first I could not hear any difference between it and the earlier version (also my own design witch I had listened to for a month). But after two weeks of just listening without the need to make any decisions about the sound I realised that I preferred the earlier version, but I could still not pinpoint down what the differences was. So back to the drawing table again…
Enjoy Creating / Mad Man Harju
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- Re: Same ol' house of cards - MAD MAN HARJU 07:08:38 01/08/05 (0)
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