Mixing signals with a white noise generator

[aaronkessman]

I'm thinking about making a pedal to mix white noise with clean guitar signal. The white noise needn't be perfect, as it's for an effects box, not for, say, tone conrol designing.

Anyway, i was thinking of using brett's design http://diystompboxes.com/sboxforum/viewtopic.php?t=16571&highlight=white+noise because it's so simple. If anyone has any other simple analog suggestions or sound samples, i'd love to hear them.

I'm guessing that in order to do this i'd have to mix the white noise signal with a buffered guitar signal? Is it really as simple as that?

thanks for advice,

Aaron

[Paul Perry (Frostwave)]

The simplest thing to do, is to as you say just run the guitar & noise into a simple 2 input mixer.
But, this means the noise is there at a constant level whether you are playing or not.
The next level of complexity is to have an envelope detector (like in an Doctor Quack or similar) and use the envelope signal to modulate the noise level before mixing it in, so it follows the level of the guitar signal.
Or, most sophisticated, would be a vocoder type of system.
Easiest, but not DIY, would be to run the guitar & noise source into a multieffect unit that allows vocoder inputs.
What I would like, is a pan control so you could sweep between clean guitar, and vocoded (or just level controlled) noise.
I think this could be the next 5 minute wonder... The "WHITE-OUT" :wink:

[aaronkessman]

in the first suggestion, why would the white noise signal be there the whole time? If it's a mixer, can't I just stick a volume control right after the noise output to adjust the volume?

what i was thinking of was using a single pot to pan between guitar and noise. the guitar signal would be buffered before the pot.

[Chris R]

geofex has a 'Low Fidelity Pedal'

click http://www.geofex.com/FX_images/lofi.gif

c

[Chris R]

geofex has a 'Low Fidelity Pedal'

click http://www.geofex.com/FX_images/lofi.gif

c

[aaronkessman]

that might work. if i leave out the filters it simply pans between the two. wonderful.

thanks for the link. I'd thought RG had done something like this, but i did a search and didnt find it.

Aaron

[Paul Perry (Frostwave)]

in the first suggestion, why would the white noise signal be there the whole time? If it's a mixer, can't I just stick a volume control right after the noise output to adjust the volume?

You are right, but I thought you would want to be able to control the noise level with the guitar. I know I would.. if I played guitar!

[aaronkessman]

ah! ok. actually the application is a bit different. Someone i know wants a pedal to mix clean and white noise in a wah pedal enclosure. The mixing pot would be foot controlled as opposed to hand or envelope controlled. Thanks for the help...

btw, what opamps are those in RG's schematic?

Aaron