What To Listen For
Needless to say, different types of signal processors will affect overall gain structure differently, and some are easier to work with than others.
Digital reverbs are particularly hazardous – the “soft” nature of some reverb algorithms, combined with reverb’s typical in-the-background role, can mask other artifacts, including noise resulting from too low an input level.
Multiband EQ can be particularly nefarious, especially when it comes to peaks and transients.
With modern multiband EQ plug-ins, it’s not hard to inadvertently overlap a range of frequencies in two different bands, and the cumulative boost can result in clipping.
Compression and dynamics processors, being gain-based concepts, present a whole different set of challenges, and deserve a column of their own (maybe next month).
Briefly, though, it’s important to pay attention to a compressor’s attack and gain settings, as these can have a major impact on gain structure of the signal coming out of your compressor.
Get To Know Your Plug-Ins
Just as every guitar, keyboard, and vintage amp has its own sonic character, so too does every signal processor. This is no less true for software plug-ins than it is for hardware units. Different devices have different ways in which they handle gain and clipping. And getting a good sense of how each of your plug-ins performs in different situations is as important as knowing any other instrument in your arsenal.
In the analog era, engineers would test each new box by running a sine wave through it and looking at the signal on an oscilloscope. They could see where each device would clip at specific frequencies, what kind of distortion would occur, and other characteristics that helped to map out the device’s optimal gain settings and place in the chain.
You can easily do the same thing with your frequently used plug-ins. Open an oscilloscope or frequency display in your DAW, set the plug-in’s input (and output, if it has one) level to unity gain, and send a sine wave through the device. Watch the output as you gradually raise the send level.
Not Exciting, But It’s Real
Of course, the geek factor of testing with sine waves is no substitute for listening. Many tracks in a mix will have multiple plug-ins inserted in their signal path, and it’s important to check each individual track, inserting each plug-in one at a time, and then all together. Things may sound find in the overall mix, but only critical listening will tell you if something’s not quite right.
In the busy hubbub of live recording, particularly if you’re tracking a whole band, picky details like gain structure can be easy to overlook. But it’s a necessary fact of life, and ignoring it is not an option.
The more familiar you are with gain structure in general and your equipment in particular, the less time you’ll have to spend optimizing levels when you’ve got a room full of antsy musicians waiting to lay down tracks.
Daniel Keller, a.k.a., the Studio Curmudgeon, is a musician, engineer and producer. Since 2002 he has been president and CEO of Get It In Writing, a public relations and marketing firm focused on audio and multimedia professionals and their toys. Despite being immersed in professional audio his entire adult life, he still refuses to grow up.