An old friend of mine wants me to build him a vocal effects unit and aside from delay and reverb he wants something akin to a megaphone sounding effect. It seems like that "megaphone" sound is a combination of a lot of treble, compression, and distortion, but i'm not yet sure how to tackle it. Any circuit suggestions or ideas?
would something like the LofoMofo or the Geofex low fidelity/telephone-noise-circuit fit the bill, no experience with either.
http://www.geofex.com/FX_images/lofi.gif
http://www.generalguitargadgets.com/effects-projects/filters-other/lofo/
Some info on the geofex here.
http://www.diystompboxes.com/smfforum/index.php?topic=81197.0
Some of it's not reproduceable, because it comes from the horn itself.
Tom Waits tried everything he could think of to find this sound, and he bought a megaphone in the end.
Anyway, the "megaphone" effect in Garageband does the following:
High pass at 76Hz.
Compressor with 10mS attack and 48mS release and a ratio of 5.8:1.
American (read "Fender") style amp simulation with the bass at 0 and the mids and treble halfway up.
Distortion with a 2900Hz treble cut
EQ with a +8dB peak boost centered at 3450Hz.
In that order.
That's actually quite a lot of circuitry, but it's a VERY close emulation. Still not quite the same, though.
Thanks guys. I'm a bit intrigued by the lofomofo actually. In our old band, we ran a few of his vocal parts through a proco rat and the guts of a snare, and it ended up sounding super cool. As long as I give him something that somewhat even remotely resembles the feel of a megaphone, he'll be right as rain.
IIRC, there's a vid of Tom Waits doing the same thing on some USAian show :)
When I build a megaphone sound in a post session, it is basically a honky thing with no bottom or top.....
Start with a high pass filter with a corner freq between 250-400.
Low pass filter set to 2-4 khz
Peak eq boost at about 1.8/2k, 5 or 6 dB
A dB or 2 of cut at 800hZ
Touch of distortion to give it a slightly metallic feel.
Compress the crap out of it....
Some slap back echo finishes the picture!
This is where the idea of a tiny speaker and a condenser microphone in an enclosure would get you hypothetically the sound you want. Instead of trying to mimic the sound of an AM transistor radio, just convert one into a circuit that takes an input. It's actually pretty easy to do on old radios because the input from the tuner is usually a connection on the volume pot itself. Then you just add in a condenser mic circuit to pick up the sounds inside the enclosure and viola, you have real soundwaves bouncing around in there that would already be very LoFi.
Lars, I actually thought about doing that! I'll keep you guys posted on what I end up doing. Thanks for all the input.
The funny thing is, an easy circuit that would probably work for this is the Dora the explorer sing along microphone. ;D My friend's bought one for their daughter, and if you sing loud through it with the microphone close up, it distorts and feeds back just like a bullhorn. Right there you have a battery-powered circuit with the speaker and mic all ready to go. Just put the guts in an enclosure and figure out a balanced line driver circuit for the XLR input and output, put a stompswitch in there, and then you could hook it up to any PA system.