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Buffer size, I/o buffer size, Setting, which determines the overall – Universal Audio Apollo Software User Manual

Page 115: S analog and digital inputs when, Upsampled uad plug-ins, Are used in

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Apollo Software Manual

Chapter 8: Latency & Apollo

115

Upsampled UAD Plug-Ins

Some UAD Powered Plug-Ins are upsampled, meaning their internal sample rate is in-
creased to achieve sonic design goals. Depending on the session sample rate, upsampled
UAD plug-ins can add additional latency when used in the Console Mixer and/or a DAW.

Although the latency added by upsampled UAD plug-ins is negligible (typically between
0-300 samples, depending on the plug-in and sample rate), this extra latency can affect
phase coherency in a session. However, phase is managed automatically by

Input Delay

Compensation in Console

and

Automatic Delay Compensation in the DAW

.

Note: For specific values, see

“Upsampled UAD Plug-Ins Table” on page 113

.

DAW Latency

Most DAWs use I/O buffering to shuttle audio data back and forth between the audio in-
terface and the DAW. This I/O buffering induces additional latency with any audio inter-
face (not just Apollo).
I/O Buffer Size
The amount of DAW latency is usually determined by the DAW’s I/O interface buffer size
setting. Low buffer sizes reduce latency, but increase the host computer’s CPU loading.
If the buffer size is set too low, host CPU overloads and/or audio artifacts such as clicks,
distortion, or dropouts can occur.
Monitoring Live Performance During Recording
DAW latency can be a problem during recording when “software monitoring” via the
DAW’s mixer, because the buffering delay is a distraction; an artist cannot hear their per-
formance in realtime. DAW latency when recording with Apollo is mitigated by using the
Console Mixer for live performance monitoring, where buffering latency does not apply.
Time-Alignment Of Newly-Recorded Tracks With Previously-Recorded Tracks
Dealing with latency is also important with DAWs for time-alignment of newly-recorded
tracks and previously-recorded tracks which are inevitably shifted from the I/O buffering
process.
The solution is to use the automatic delay compensation (“ADC”) feature of the DAW.

Most modern DAWs, including Console, have automatic delay compensation. For more
information about system latency and its compensation, see

“Delay Compensation with

Apollo” on page 110

.