Project Processes; Dither; Mixing Down Projects - Merging Pyramix 4.3 User Manual

Project Processes

Dither

Whenever changes are made to digital audio signals such as mixing, altering gain, eq or reverb, the
result is usually an increase in the number of bits. These extra bits have to be removed to suit the
requirements of delivery and interconnect standards. If the bit depth is reduced by simply ignoring the
extra bits (truncation) or even rounding the least significant bit up or down, the resulting error can give
rise to audible distortion of low signal levels. Obviously, there is also a permanent loss of resolution.
These effects are cumulative. I.e. If the signal is repeatedly processed and bit reduced to shorter word
lengths, there will be a significant and audible loss of accuracy in subtle, low level sounds. Human hear-
ing makes use of this low level information in imaging and unless something is done to avoid the prob-
lem, space and clarity will be adversely affected.
In Pyramix all processing takes place in 32 bit floating point so, if signals are kept within this environ-
ment, there is no need for bit depth reduction until the final stage before output. Truncation or rounding
are undesirable but a single 'dithering' stage can reduce bit depth whilst maintaining low level linearity.
This is achieved by adding a controlled amount of low level noise to the signal. Since there is no such
thing as a free lunch, the trade off is a slightly increased level of noise. However, the noise can be
'shaped' to reduce its perceived audibility.
See also: Dithering on page 76
It is important dithering is only applied once.

Mixing Down Projects

Exporting a Composition to a File
Once you have finished editing your Composition, the complete Composition or any selected area
can be exported to an audio file (or files). This is really the same as mixing down the Composition to a
file instead of to an audio output.
1. Choose Project > Mix Down to open the Mix Down dialog box.
2. In the Target Settings section, type in an appropriate file name under Record Name; choose the
folder to which the file will be saved from the Media Folder drop-down menu (only previously
mounted folders will be available as options); choose the bit depth /word length from the Resolu-
tion drop down; leave the One file per track box unchecked to make a single multi-track audio
file, or click it to generate separate audio files for each Track and choose the appropriate export file
type from the Format pop-up list.
3. In the Record section, choose to export the Whole composition, or the area between the In and
Out Markers with Between Marks or a previously made Region with Selection by clicking the
appropriate radio button.
4. Choose the appropriate output bus as the source for the exported file. All output busses configured
in your Mixer will be available in the Mix Source list box.
5. Click the Mix Down button to begin the process.
User Manual : Project Processes
User Manual
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