bitcrusher stompbox

[sovtek50]

Ladies and Gentlemen,

I'm looking for some sort of lofi-distortion-box for guitar which sounds similar to some sort of bitcrusher, like 8-bit-sampling. Does somebody know any schematics which could do that?

thanks alot

[aron]

Maybe this one?

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

[MarkB]

not a DIY solution, but how about one of Paul's boxes?

http://www.frostwave.com/sonicalienator/
"-)

[Paul Perry (Frostwave)]

The Alienator works, yes. But it uses surface mount chips (a lot of stuff is only made that way now..). Also there is a certain amount of programming in it
If you can find parallel in & out D to A & A to D, it is not too hard!
(the alienator uses serial chips, to interface with the PIC).

[travissk]

For a while I've wanted to mess around with lo-fi A/D and D/A conversions on the PIC chip (I'm no expert on the model lines, but I know for certain that the 40-pin PIC 18F's I have do at least a/d).

I know that the PICs are way too underpowered to do good-sounding DSP, but if the purpose is to mangle the sound anyway, perhaps one or two interesting noise effects could be generated.

If you don't have a programmer, it's probably better to use a different approach due to the cost of the PIC microcontroller, program, etc, not to mention the time involved in getting set up for one project.

[Peter Snowberg]

As Paul's work demonstrates, there is a whole world of bit crushing you can  do to a signal. Inversion of selected bits, swapping of selected bits, remapping the values via an EPROM..... many many options.

If you get a parallel A/D and D/A and use a 4046 PLL as the oscillator, you can manipulate the bits with simple logic chips and forget the microcontroller. This turns into a larger board but it is much easier to understand and play with if you don't already do PICs.

Consider using 12 bit converters. The prices are realistic now and you mahe better S/N ratio where you want it with more bits to play with. You can always crush the lower bits if you want less resolution.

I would suggest running the signal through a compander (NE571, etc) around the A/D/A just like BBD devices use.

I have such an effect in the wings and it is a new landscape for sure.


Hey Paul,
Your alienator looks (and sounds!) great!


Take care,
-Peter