Dither

Purpose

Dither is a low level noise signal that, when added to an audio signal, can reduce or even eliminate quantization distortion. The signal processing in the MediaMatrix system is performed with 24 or 48 bit resolution. When the signal is sent to the D/A converters the resolution is reduced to the resolution of the converters. This reduction in resolution results in quantization distortion. This distortion is most noticeable on low level signals. The result of adding dither is a slightly noisier but much lower distortion signal out of the system. To use the dither device, wire it in to the second input of the output device primitives. These are found in the BoB and AES output devices (make the windows sizeable and scroll down to find them). One dither device may be used to feed as many output devices as necessary.

Controls

Mute

Disables the noise source (turning off dither).

PDF

Selects between rectangular, triangular and shaped triangular probability density function. Both rectangular and triangular dither increase the output noise level. Shaped triangular dither cuts the noise level at low frequencies while boosting it a high frequencies. This results in the noise being less audible. With rectangular dither the increase in noise varies with the signal. With (shaped) triangular dither, the added noise level is constant and slightly higher. In general, (shaped) triangular PDF dither is preferable. Note that with either type of dither, the added noise is small, on the order of 3 to 6 dB.

Word Size

Use this to select the resulting word size after truncation.