CHAPTER 30. AUDIO FACT SHEET
492
30.2.4
Summing at Single Mix Points
Since version 7, Live uses double precision (64-bit) summing at all points where signals are
mixed, including Clip and return track inputs, the Master track and Racks. Mixing in Live is
thus a neutral operation for signals mixed at any single summing point. This is tested by
loading pairs of 24-bit les (white noise and xed-frequency sine waves and their phase-
inverted complements), adding the pairs together eight times and rendering the output as
32-bit les. All tests result in perfect phase cancellation.
Please note that, while 64-bit summing is applied to each
single
mix point, Live's internal
processing is still done at 32-bit. Thus, signals that are mixed across multiple summing
points may still result in an extremely small amount of signal degradation. This combination
of 64-bit summing within a 32-bit architecture strikes an ideal balance between audio quality
and CPU/memory consumption.
30.2.5
Recording external signals (bit depth >/= A/D converter)
Recording audio signals into Live is a neutral operation, provided that the bit depth set in
Live's Preferences window is the same or higher than that of the A/D converters used for
the recording. In this context, neutral means identical to the audio as it was delivered to
Live by the A/D converters.
30.2.6
Recording internal sources at 32 bit
Audio that is recorded via internal routing will be identical to the source audio, provided
that the recording was made at 32 bits. To ensure neutral recordings of plug-in instruments
and any audio signals that are being processed by effects plug-ins, internal recording at 32
bits is recommended. Please note, however, that if the source audio is already at a lower
bit depth, internal recording at that bit depth will also be neutral (assuming that no effects
are used); internally recording an unprocessed 16 bit audio le at 32 bits will not increase
the sound quality.
The neutrality of internal recording is veri ed using cancellation tests.