So far we’ve talked about using busses to minimize the number of plug-ins you use and also committing to your plug-in settings by recording them to another track.
Well I have one more tip for you in this “Preserve Processing” series – offline processing.
If you’re using any computer-based recording system other than Pro Tools HD, you are using a native system, meaning your plug-ins are processed by the computer’s processor.
The number of plug-ins you can run simultaneously depends on how much your CPU can handle. Once you hit the limit, you get something like the error message above.
Pro Tools LE uses RTAS plug-ins (Real-Time AudioSuite). All other DAWs use something similar (VST, AU, etc.). These process the audio in real time, hence the drain on your CPU when you throw a ton of them on a song.
What is offline processing?
Not too long ago, when computers were too slow to even think about doing real-time audio processing, offline processing was the only way to affect a digitally recorded signal.
The way these older systems handled processing was to actually change the audio file itself. You would pick a setting, then apply it to the audio file. The computer would take a second to process the file, then you would listen to the result.
My first experience with recording was on a cheap version of Cakewalk. If I wanted a delay on the vocal, I had to process the vocal offline.
This was a destructive process, meaning it changed the audio file itself. You could hit “undo,” but once you saved and closed that session, your changes were final. Scary stuff.
Offline Processing Today
Fast-forward to today, you can just use real-time plug-ins without destructively changing the underlying file.
Of course, there’s always a limit, and we eventually max out our available CPU power.
In the previous two articles, I gave you two ways to address this, but what if you don’t need to bus the tracks through a single plug-in? Or what if you really don’t have the time (or the patience) to route each track to another track, record the effected signal, then inactivate the first track?
That’s where offline processing can help. In Pro Tools, these are called AudioSuite plug-ins. You can find them in the (shocking) AudioSuite menu.
Most plug-ins that you own will have an AudioSuite version. This simply let’s you select a region, open up an AudioSuite plug-in, dial in your settings, then commit those settings to the audio file itself.
This is a one-time process, and once it’s done, it’s done. You don’t have to worry about wasting CPU power on that process ever again.
The downside, of course, is that you can’t undo the process easily. Here’s what I suggest. Create a copy of the original track (I do this in Pro Tools by duplicating the playlist). Then you can use an offline plug-in, process it, and go on your merry way, but you’ll always be able to get back to the original audio file if you need to (by switching back to the original playlist).
How to do it
When you’re messing around with AudioSuite plug-ins, you’ll want to hear the changes you make before processing the audio. An easy way to do this is to open an RTAS version of the same plug-in on the track, dial in the setting you want, then use the “Copy Settings” feature to copy the settings. (Click the Picture to enlarge.)
Paste those settings into the AudioSuite plug-in and process away!
There are other ways to offload your processing and free up your CPU load. There are a number of DSP devices designed to do just this. I’ll let you check them out for yourself. They can be pricey, but they’ll give you more DSP headroom to open more plug-ins…and eventually rule the world.
- Focusrite LiquidMix – These are a few different firewire-based processors.
- Universal Audio UAD cards – These install in your computer and process some STELLAR plug-ins.
What offline processing tips do YOU have?