8.09.2006

Feedback Suppression Obsession

Let me add my name to the list of people who confirm that automatic feedback suppression doesn't work in the environments where it's needed most. It is better suited for speech only, so it seems, and not somewhere where the organ and drums play unbridled.

If you want to use one, and insist on the auto functions, then be sure to patch it into a vocal channel. Unfortunately for me, my little mixer doesn't have channel inserts (which only adds to my drive to replace it). Fortunately, however, those thingamabobs also usually work as a parametric EQ, and I have had some luck locating some of the hot frequencies and locking them down.

For my use, I have a pink-noise CD for signal generation (or alternately a couple of programs on my laptop that do the same;
Google to find one that suits you and your software setup. On my setup, the evaluation version of NCH Swift Sounds' Tone Generator is getting a test spin (license around $30, depending on your options), and the RTA is a little freeware suite, though I think I'll move to a low-cost alternative produced my Allen & Heath (around $10, with a free trial period). Get one of those calibration mics (Behringer and dbx, produce sub-$100 models, among others), run it through one of those little table mixers (see Behringer, Yamaha, Mackie, Peavey for options on the lower end of the cost spectrum) and then see what happens with pink noise, white noise, and various sweeps going through the system. It's not perfect, but I think it has helped me, so I'm sharing it.

A useful little tool to train your ears to detect where exactly on the spectrum feedback is occuring is the
Simple Feedback Trainer. The title is the best description, and, in the absence of an expensive setup at home, it had proven a good way for me to practice.

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