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Actually using sine sweeps and graphs like it's done at r3mix.net doesn't prove much about psychoacoustic codecs.
Encoders are tweaked and properly tested using listening tests, not using sine sweep graphs...
Oh come on, John, *please* stop running down Roel and his site all the time. Since this signature thing happened and since this forum has been up, you have been doing that quite frequently.
This is from r3mix.net's "Critique" section:
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13. For the frequency sweeps, you're doing them all wrong!
For the frequency sweeps, you're doing them all wrong! You should use a logarithmic sweep, 20 seconds or longer. The problem with a 10 second linear sweep is that it zips through the ear's three most sensitive octaves in less than 1 second. A log sweep gives each octave equal time. Use logarithmic scale for displaying spectrum as it gives each octave equal length (on the graph's horizonal axis). Otherwise you will be guilty of grossly misrepresenting the data and contributing to the growing body of misinformation and disinformation on audio encoding.
Thank you for your honest and direct comments. You are obviously more educated about these issues then myself, but not once I use the sweeps to measure quality of an encoder. I only use them to show obvious flaws in, for example, the Xing encoder. I am aware that I could have taken the logarithmic rather than the linear basis to display to represent a more accurate model of hearing distribution, but this would still not make that sweep comparison a valid encoder-benchmark. With my method, all that are distorted sound and look distorted, and all that sound ok, look ok. I don't want to make a pseudo-valid scientific test, because strictly seen a more deviant graph does not necessarely mean a worse encoded piece. With mp3 you never know what frequencies are masked by others, so a sudden drop in a curve might not say all that much. Also take in account that mp3 encoding itself divides the frequency spectrum in equal shares rather than logarithmic.
The graphs are not to be measured, they're to be interpreted with plain and simple logic.
Sorry for coming off the topic, but I just think that remark wasn't right. And let's not start this Project Mayhem vs. r3mix discussion again here, that's certainly not my intention.
CU
Dominic