Universal Audio Realtime Rack - Manual (Page 76)

Realtime Rack Manual Chapter 4: Realtime Rack Application 76
Delay Groups Overview
Upsampled UAD plug-ins
Some UAD plug-ins are upsampled, meaning their internal sample rate is increased to
achieve sonic design goals. When upsampled UAD plug-ins are loaded in Realtime Rack,
additional latency delay is induced in the channel(s) using the plug-in(s).
Although the delay added by each upsampled UAD plug-in is negligible (typically be-
tween 0-140 samples, depending on the plug-in and sample rate), this extra delay can
affect output phase coherency.
For example, if two microphones are used on an acoustic source (such as a drum kit) and
an upsampled plug-in is used on one of the mic channels but not the other, the phase of
the two mic channels will no longer be aligned.
Note: For the list of upsampled UAD plug-ins and their specific latency values,
see the
“Upsampling Values Table” on page 81 .
How Delay Groups work
Delay Groups automatically add small amounts of delay to each channel in the group
that are not delayed by upsampled plug-ins, so all channels in the group are still phase
aligned. In other words, all channels in the Delay Group are delayed by the same
amount.
Note that the amount of delay added by the Delay Group engine is automatic. Only the
minimum amount of delay actually required to compensate the channel(s) is dynami-
cally applied, maintaining the lowest possible latency required for phase alignment at all
times.
Up to 16 unique Delay Groups can be configured. For specific instructions, see
“Config-
uring Delay Groups” on page 79 .
When To Use Delay Groups
Delay Groups are required to maintain channel phase alignment only when both of these
conditions are met:
1. Multiple Realtime Rack channels are used for a single source (such as a drum kit
using multiple microphones), and
2. Any of those source channels contain upsampled UAD plug-ins.
Latency compensation using Delay Groups is not needed for any these conditions (when
phase coherency is not imperative):
• When upsampled plug-ins are not used on the same source
• When upsampled plug-ins are used on different sources
System Latency
Overall system throughput latency with Realtime Rack is 73 samples when no plug-ins
are assigned (and also through non-upsampled plug-ins).