Support Report: Handling Plug-In Latency with the UAD-1 & Digital Performer
One of the great things about working at UA is the chance to get to know end users and find out how they are really using our products. Whether using our hardware or our plug-ins, I am often surprised by the ingenuity that our products inspire, and how people push their gear beyond the norm to get the results they want from their audio, and from their audio systems. While moving from our analog support department to supporting the UAD-1, I've tried to gather useful information to help improve the end-user experience and to help alleviate some of the misconceptions that seem to come up, while giving the people something new to try.
With this installment I will focus on the issues that come when using the UAD-1 with MAS/Digital Performer: specifically, how to deal with plug-in latency [Ed: otherwise known as plug-in "delay", not to be confused with a delay-effect plug-in.]. I happen to be a DP guy, and I use DP exclusively in my studio for multitracking and mixing. If you are a UAD-1/DP user, then you probably know that DP does not support automatic plug-in delay compensation at any level. You probably also know that the UAD-1 bundle comes with a plug-in called "Delay Compensator". But you might not know that there is more than one way to "skin a cat" when it comes to working around this issue.
Plain Vanilla Method
The Delay Comp plug works by moving tracks without PPI's (Powered Plug-Ins) back, to match the tracks using PPI's. The basic way of dealing with track delay is to put the Delay Comp plug-in on any track that does not have PPI's on them, effectively moving the non-PPI tracks to the delayed time position. It works, and many people use it this way. But once you have 24 tracks, you may have anywhere between zero and five PPI's on any channel. Then if you start adding in busses that also have PPI's on them, things can get a little overwhelming trying to juggle all of those Delay Comps.
The Group Method
A simple way to deal with delay is to have all of your audio tracks assigned to one bus or another. Group your guitar tracks to one bus, your vocals to another, drums to another, horns to yet another, you get the picture. Then assign all of your PPI’s to those groups. This simplifies the task of managing delay on an individual basis, by reducing your tracks to just a few busses. You can even create a bus for “non-UAD-1 tracks” so that the odd tracks with no PPI’s and which don’t contextually fit into a group can be manipulated as a whole regarding delay compensation.
The "Nudge" Method
Rather than use Delay Comp, another way to deal with delay is to use “Nudge” in DP. You just set your “Nudge” amount in DP to twice the exact host audio buffer, and move forward every track with a PPI inserted by 1 “nudge” for each PPI on any given track. For example, if you have a track with 1 PPI, nudge the track once. If you add another plug to the track, nudge the track again. The reason you need to set the Nudge amount in DP to double the audio buffer is because the buffer delay that the UAD-1 creates is the exactly double the host buffer size.
NOTE: This "nudge method" may not work properly when bouncing to disk. Since DP always uses a fixed buffer size of 500 samples when bouncing to disk (independent of your audio hardware buffer size), this will result in timing problems in the bounced track. If your audio hardware buffer size is 512 samples, the nudge method will still work even when bouncing to disk (internally the UAD-1 rounds up the "weird" mixdown buffer size from 500 to 512 samples). You can also record your mix to two track in realtime instead of using bounce to disk.
The Delay Comp Flush
This one I got directly from Danny Gold, a user of the UAD-1 and an employee MOTU. This is my preferred method. The trick is to put the Delay Comp Plug on EVERY insert on EVERY track; then, when you want to use the 1176, LA-2A, Nigel, etc., replace one of the Delay Comps on the inserts with the PPI of your choice. This alleviates a lot of having to "think about it". I rarely go beyond three plug-ins on any given track, so first I reduce my insert count in DP to four, three for audio plugs, and one for adjusting the sample slider when using the Pultec, or moving the Delay Comp slider if I happen to use a host based plug.
There's an easy way to set this up using Option, Command and Shift controls. With these you can select, then drag and drop groups of Delay Comp plug-ins to tracks quickly. Beware: The "Delay Comp Flush" trick is really only useable if you are totally done tracking, nothing left to record. If you go back and track after the fact, the audio will be out of sync on playback and you'll have to time align the tracks again.
Enjoy the plugs, and let us know you use the UAD-1!
--Will Shanks
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