I mentioned in my first post that I have a large backlog of material that I want to go through and slowly add to this site. Here’s the first of that! In my previous post I wrote about contact microphones and using one to make feedback with my guitar amplifier. I love feedback. You could call me a feedback connoisseur, or an addict. Maybe it’s just an involuntary obsession. Anyhow, today I’m starting a series that i’ll continue sporadically on this blog, about different kinds of feedback.
While I focus on audio feedback, this phenomenon isn’t limited to audio. All kinds of biological, mathematical and other systems have feedback loops. Really, any system that is influenced by its own output is a feedback loop.
One could say that pop music culture has a sort of feedback loop, though not a particularly interesting one, that is delayed by a few decades, with the delay seemingly getting shorter each year. Frank Zappa once mused that this cycle will get shorter and shorter until time eventually comes to a complete halt. I think human behavior has some particularly stubborn feedback loops, where certain kinds of behavior become increasingly prone to repetition.
Ye olde familiar Feedback
Here’s the most familiar kind of feedback loop. Put that mic too close to, or point it towards a speaker, and nails-on-chalkboard screeching ensues. This same behavior is at the heart of all kinds of amazing processes, and has a sort of organic quality to it. Move the microphone around, and the speaker howls and wails at different pitches and volumes, sounding not unlike a wounded animal. This is the result of a complex feedback loop that involves the acoustics of the entire room, the frequency response of the speaker, the microphone, the mixer, the cables, and all kind of other details that often become even more interesting as they are compounded with each other in successive loopings as the sound goes out the speaker and into the microphone again.
Despite occasional blowings-out of eardrums, I find this process to be incredible. Once put into the proper conditions, the beast can be tamed, and exceptional beauty and complexity are waiting to be found.
Anyhow, this subject is far too complex to be covered in one post, so I’ll get to the music. Last year, I was doing a lot of experimenting with FM radios and those small FM transmitters you can use to play CD’s or MP3’s in your crappy car that doesn’t even have a tape deck or CD player. If you have a multi-output audio interface, some software you can hack, and a few transmitters and cheap radios, I believe you have all the materials you need for the world’s cheapest surround sound system.
My favorite old rug
This is the setup I was using one day to make some feedback loops. Yes, that’s my shoe. I wear it every day to work. Makes a decent mic stand ;). In this particular setup, I had audio running out to all of those radios wirelessly via FM transmitters, was mixing them in the mixer, sending that signal into the computer, processing it, and then sending it right back out to the radios. The sound here was particularly complex because of all the interference I was receiving from the various FM radio stations that were tuned to the same, or near the same, frequencies I was transmitting on. It’s a nice way to feel more in touch with the electromagnetic spectrum!
I love this setup, and writing this post just makes me want to hook it up again, with some modifications, and make some more sounds!
Here is the track. Be careful, this is a 20+ minute radio feedback odyssey. At the very end, if you listen close, you can hear my landlord ringing the doorbell, and me apologizing and turning everything off, :P.
Link to MP3 download of this track
