Universal Audio Arrow Manual page 238

Console Latency
Arrow's Console mixer is used for low-latency input monitoring (cue mixing) of Arrow's
analog inputs. Using Console to monitor Arrow's inputs may or may not add to the
inherent analog I/O round-trip latency, depending on how it is configured, as described
below:
Console without UAD plug-ins – When Console is used without UAD plug-ins, monitoring
Arrow's inputs via Console does not add any latency. In this configuration, Arrow's analog
I/O round-trip latency is still 1.1 milliseconds at 96 kHz.
Console with Realtime UAD Processing – When Console is used for Realtime UAD
Processing with UAD plug-ins that are not upsampled, monitoring Arrow's inputs via
Console does not add any latency.
In this configuration, Arrow's analog I/O round-trip latency is still 1.1 milliseconds at 96
kHz, even if up to five UAD (non-upsampled) plug-ins are serially inserted (chained) on a
single Arrow input.
Multiple Arrow inputs can have up to five UAD (non-upsampled) plug-ins each (up to the
limit of available DSP resources), and this configuration also does not add any latency.
Note: Upsampled UAD plug-ins add latency when used in Console or a DAW. See
Upsampled UAD Plug-Ins
Console Auxiliary Buses – The outputs of the auxiliary buses in Console have 32 samples
of additional latency. This is necessary to maintain the lowest possible input latency.
DAW UAD-2 DSP Latency
When UAD plug-ins are used within a DAW (not Console), I/O buffering is used to shuttle
audio data back and forth between the UAD-2 inside Arrow and the DAW, which induces
additional latency.
UAD-2 DSP latency from UAD plug-ins within the DAW is determined by the DAW's
Buffer Size setting. This latency is unrelated to the (indiscernible) audio interface I/O
latency — they are separate processes.
DAW UAD-2 DSP latency makes tracking through UAD plug-ins in the DAW via
software monitoring problematic for the performer because an artist cannot hear their
performance in realtime.
The issue of UAD-2 DSP latency when recording with Arrow is eliminated by using
Console for live performance input monitoring with optional Realtime UAD Processing,
where buffering latency does not apply.
Does all this latency stuff matter?
With Arrow, not really. Performance input latency is not a factor because of Console's
low latency hardware input monitoring, and recording (track alignment) latency during
recording, overdubbing, and mixing is automatically compensated by Arrow's device
drivers and the DAW's automatic delay compensation engine.
Arrow Manual
for details.
238
I/O
Latency & Arrow