Monday, November 06, 2006

Observation regarding sound recordings

Something I noticed when cleaning up audio recordings is that, usually when they are recorded by a computer, there are noise spikes at frequencies like 60hz, 120hz, 180hz, etc. One could say well, all multiples of the base 60hz AC current frequency, so there is some sort of leakage.

But when I analyzed mastered CD tracks with the same mechanism, I also found such spikes. What's going on here? Why should there be frequency spikes like that coming from professional equipment?

Incidentally, the CD I looked at was Behavior, by Pet Shop Boys. Besides the spikes at multiples of 60hz, I had always (although barely) noticed a very high frequency hiss in the background of the tracks of this CD. Indeed, analyzing it found the spike showing very clearly, at about 20-22khz. Slowing down the music only made it much more obvious.

Grrrr... why are there such defects in CDs?!?! As if they weren't expensive enough already!!!!

Update: ah, now I see what the hiss could be... perhaps the tracks were mastered with a resolution higher than 16 bits, and the hiss is the noise dithering that was done when converting the originals to 16 bits. Grrr!!! I just learned what not to do.

1 comment:

Nate DeStefano said...

Love your blog man, very inspirational and thought provoking.