"acoustic" circuit bent instument!

sk-1 · January 01, 2010, 02:41:08 AM

Quote from: Remork on December 31, 2009, 01:44:14 PM
by the way, a vocoder or talk box uses the SHAPE of your mouth as a sound transformer - you get sound shot into your mouth through the tube, and that gets picked up by a mic going to an amp/PA. by changing the shape of your mouth you get different overtones - you're not even supposed to make sound w/ your voice.

Exactly as I said... a fake talk box, only with a real talk box your mouth becomes an additional sound chamber. The Velleman kit in question has been set up to work in a similarly perceived fashion, but you are right... it is not the same principle at all. In the case of the Velleman kit, it appears that the tube is being used as the sound chamber to direct the sound to a small space surrounding the microphone. All microphones respond to air pressure, so even just blowing air silently through the tube would trigger the Velleman and cause it to make sound.

I can see how these kits would look very similar to a talk box or vocoder, to the untrained eye.

jamiewoody · January 05, 2010, 02:07:29 AM

how many varriable resistors are there? there are potentiometers. there are photo resistors.

could there be a resistor (or is there) which could respond to breath or wind?

wouldn't this be a cool control on a circuit bent synth?!

Gordonjcp · January 05, 2010, 08:48:49 AM

Actually, a vocoder doesn't really directly have much to do with the shape of your mouth - it's entirely electronic. What you have is a pair of filter banks, a bit like a graphic equaliser. One is fed with the modulator input (usually from a mike, but other sounds work well - use drums to get an effect like the chords at the start of Royksopp - "Remind Me (Geico Mix)"). This gives a bunch of control voltages, one for each channel, which feed the VCAs on the output of the other filter bank effectively turning the "graphic equaliser" up and down really quickly. Feed a harmonically rich (big fat pads are good) signal through the carrier filter bank, and it will give that classic "talking" vocoder effect.

The upshot of all this is that you are shaping the spectral content of the carrier with the spectrum of the modulator. Another way to think about it is if you took a snapshot of the spectrum from the modulator, and used it to "mask off" the bits in the spectrum of the carrier.

Bah, I'm not explaining this terribly well. Have a sample:

The bright, broad-spectrum Solina pad provides a lot of harmonics (but not quite enough really high ones, which is why the sibilants are a bit "thick"). The vocal has rapidly varying harmonic content, which is fed into the vocoder and gives that talking effect.

Shameless self-promotion - I wrote the synth plugins and extensively hacked on the vocoder plugin used on that track ;-)
http://www.gjcp.net/~gordonjcp/mp3s/kelly.mp3

Remork · January 05, 2010, 10:13:59 AM

my mistake - bit overenthousiastic there. make that 'talk box' exclusively

so these kits we're looking at here are doing exactly what a 'regular' vocoder does, only worse?

Gordonjcp · January 05, 2010, 06:53:20 PM

The voice changer seems to be more like a pitch shifter than a vocoder. I went to get one, but Maplin didn't have any. I'll let you know what it does once I get my hands on one...

jamiewoody · January 05, 2010, 08:17:08 PM

i like what this guy is doing! he is pretty proliffic!

this is hardly acoustic, but still very mechanical:

http://www.adachitomomi.com/a/sminst.html

check out the instrument named "tomoring"!

pure genious!

SineHacker · January 05, 2010, 11:46:32 PM

funnily enough, I came across that dude yesterday, I'm actually designing some simple synthesizers at the moment using similar methods (he's using the 40106 I think, I'm using the 4093) I was pretty impressed by the range of sounds he gets out of a hex schmitt trigger!

Remork · January 06, 2010, 01:29:05 AM

i was pretty impressed by the range of sounds he gets out of a zucchini.

jamiewoody · January 06, 2010, 05:16:55 PM

i looked at the first page...i'll look deeper a little later.

jamiewoody · January 06, 2010, 05:34:31 PM

i just had a though....

what about some things, non-electronic, totally organic, which would actually be ACOUSTIC?!

remember that toy called "THE FORCE LIGHT SABER"? it was a molded plastic tube, which looked like luke skywalker's light saber? when you wave it, it made a deep "woosh" sound?

other tube (not-vaccum) based instruments: the digeridoo, pcv tubing, etc. (similar to BLUEMAN GROUP, or much earlier EINSTURZENDE NEUBATEN!).

what about bluegrass instruments? a flimsy saw? a washboard? (off the subject a bit, but what if one were to connect piezos to a washboard?!!

other things, sheet metal, etc make cool sounds too!

SineHacker · January 06, 2010, 06:37:00 PM

Quote from: jamiewoody on January 06, 2010, 05:34:31 PM

what about bluegrass instruments? a flimsy saw? a washboard? (off the subject a bit, but what if one were to connect piezos to a washboard?!!

easily done... it would probably sound cool, leafcutter john has done some cool Piezo stuff: http://leafcutterjohn.com/?p=894

I'm a big fan of leafy J, you should definitely check out his site, software and music!

jamiewoody · January 07, 2010, 01:02:45 AM

Quote from: Gordonjcp on January 05, 2010, 06:53:20 PM
The voice changer seems to be more like a pitch shifter than a vocoder. I went to get one, but Maplin didn't have any. I'll let you know what it does once I get my hands on one...

they are out there. i think B&G electronics has them, at least they did a couple of months ago.

the voice changer does a pitch shift, reverb, modulation, and some other things.

they are not all that great...i mean the veleman one isnt. supposedly they are cheap, and there are others who make better quality voice changers.

i have thought about getting one, building it, then trying to make my own later without the kit and just the components. i am sure there are some groovy bends on it!