What is a dither CD anyway?

[BevvyB]

http://www.cranesong.com/analogdither.html

[tonedaddy]

I'm assuming it's recorded tape hiss to give it that analog smell...


Seriously. From http://www.digitalprosound.com/Htm/A..._vs_Dither.htm :

"Quantization error is a digital reality, and also applies to the analog to digital conversion of audio. Since the answer to "what came first, the A/D or the D/D?" is "A/D," dither was initially an analog white noise that was added to the signal to displace the audio signal level above the least significant bit. So we're actually adding analog noise to prevent digital noise? Yup, that's right.

The Fletcher-Munson curves show higher responsiveness to sounds in the 3 kHz to 4 kHz area. Intensity in level varies while the ear perceives equal volume at all frequencies (Click image for closer view). As insane as that might sound, you might consider this analog noise to be a more known quantity that those nasty random artifacts, and in that sense more desirable. A little system noise or tape hiss is something that our ears have been used to for years, and perhaps far more digestible than the unknown. Also, quantization error is considered distortion, whereas a noise is just a noise."


More info at: http://www.isip.msstate.edu/publicat...4773/lectures/

"ANALOG DITHER
Some types of quantization noise can be perceptually annoying (jagged, or "aliased" lines in computer graphics, LSB toggling that is correlated with the signal). Dither is a low-level white noise signal added to the input before quantization for the purpose of eliminating granulation or quantization distortions.

Analog dither is added to the signal before A/D conversion, often as a result of real artifacts in the recording process (microphones, mixers, cables). "

[RKrizman]

Originally posted by BevvyB
http://www.cranesong.com/analogdither.html

It's a CD of frequency shaped noise that you add to your DAW session--it functions as dither. I just listened back to a comparison CD I made and preferred it to UV22 and truncation. Lately I've been using a recording of air and distant streams I made several years ago in King's Canyon. I think the occasional bird popping through adds a sort of analog vibe.

-R