Have fun doing some listening - no matter what the outcome of the testing, it should be enjoyable...

Thank You.

By the way, below is a photo of the distortion spectra I recently took of my turntable / moving coil cartridge while reproducing a 1kHz sine wave from a test LP.

Look familiar? It is almost identical to the ideal distortion spectra of a tube amplifier! I think this goes a long way toward explaining why vinyl generally sounds more musical / natural than purely digital recordings and media.

Altec, you are to be commended! This is one of the first rational/technical discussions of the whole analog/digital divide I have seen. Though there is a similar discussion going on at "Secrets" now too, with very similar results to Altec's in the latest round.

My question is, how do you know where the harmonic distortion components are actually added? It seems they could already have been put down on the vinyl itself in the recording or master-cutting process as easily as being added during the turntable playback. Or perhaps some of both?

My guess would be that the majority is added in playback, but there is almost certainly going to be some added in the original cutting process.

By the way, did you notice that the signal to noise ratio above the 1kHz test tone is about 80dB? So much for the criticism of vinyl being "noisy". 80dB is approaching the theoretical 96dB signal to noise ratio of digital.

Yes, it is at 80 dB from about 500 Hz and up, but is that turntable rumble at 65-70dB from 30-500 Hz, which is usually where decent turntables are spec'ed?

Also, that test disk is probably comparable to the best vinyl pressings available, and you probably haven't played 200 times either. Or maybe you have! ;-)

What is in the graph is what is generally normal for vinyl on a good turntable.

The ear is not very sensitive to low frequency noise as documented in the Fletcher-Munson curves, especially when it is so far down in level. It is the noise in the band above 1kHz where noise, as such, is audible, so that 80dB signal to noise ratio would be what you would hear subjectively.

The test disk I used was new. I only buy "premium" 180 or 200 gram remasterings, and these are extremely quiet and stay that way with repeated playings. Also, the mastering and cutting engineers know that these pressings will be played back on good equipment. Therefore, they do not use any of the limiting or low frequency rolloff that used to be used when it was assumed that records would be played on lowest-common-denominator quality turntables. These pressings sound far better than the original releases of the albums did, having a much wider dynamic range and extended frequency response.