Posted: Tue Sep 20, 2011 7:34 pm Post subject:
using an audio input to gate an oscillator
I've been working on a circuit for a friend of mine. He wants to run vocals into it, and have it mix with an oscillator. I came up with this circuit, which is pretty interesting.
Here's an overview of the circuit and some samples
So far so good. But what I really want is to add a gate effect, so that when he sings into the mic, the oscillator switches on, and when the input drops below a certain level, it switches off.
I'm going round in circles here, so any suggestions welcome. Cheers!
rectify and filter the incoming audio so that when he sings the schmitt trigger simply turns on for the duration that the signal is there... you can have a volume control before the schmitt trigger to sort of control the threshold. that signal to an AND gate with the oscillator will gate it. get what i mean? i dont really have a schem handy, maybe someone can grab one?
Thanks Psyingo, I knew there was an easy solution. Funny how one capacitor can spell the difference between success and outright frustration. Here's what I've got at the moment.
The 386 gets the audio signal up to logic levels, C1 (1u) and R1 (10k) filter the signal, inverters A and B create the gate, which is NAND'd (using the two diodes and R2) with the oscillating output of inverter D.
Now all I need to figure out is how to replicate the 'blend' function of my original circuit. I know there's a simple solution, but I'm stuck once again. I just want to take the output of the 386 and the output of inverter C and use a pot to select the ratio of each on the final output.
Cool stuff. I recently did something similar mixing two oscillators into one new waveform through a 40106 schmidt trigger and then actively mixing back with the original.
Using a voice as the source must sound cool. Can you record a sample?
Joined: May 18, 2010 Posts: 308 Location: Oak Park, IL
Audio files: 5
Posted: Fri Nov 11, 2011 6:47 am Post subject:
Excellent stuff bud ! I have a similar device built into my lunetta. It's basically Tim Escbedo's PWM and works very well in adding voice, guitar, keyboards, etc. into the lunetta mix. In some of the samples below, I use either a guitar or my voice to trigger various sources on the lunetta. I like to run the PWM output into the IN of the 4040. The outs of the 4040 then go to gates or provide clock sources for other modules. I have a cv input on my variant of the PWM, which only adds to the lo fi experience.
It's one of my favorite modules in my lunetta and adds a ton of vibe.
GuTari2600 by Draal
And as far as its use in an actual "track", check out "Earth". It's not used entirely through the track but you'll know when it's on.
" Earth by Draal _________________ Zontar Prevails!
Joined: Nov 10, 2011 Posts: 878 Location: Lancashire, England
Audio files: 14
Posted: Fri Nov 11, 2011 8:48 am Post subject:
they sound really interesting, thankyou for the demonstrations, I love vocoders and things that basically make you sound like a robot So I'll definately be researching this and building one of these doohickeys (do they have a name?)
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