[sdiy] Hiss, Crackle, and Pop

[rsdio at audiobanshee.com]

Thanks for the write-up, Tom. I wouldn't have guessed that you bothered to write in PIC assembly!

I designed a DMX-512 light controller on the PIC16F87, which didn't have a C compiler at the time. The project definitely took longer than it would have if I could have written most of the code in C. More recently, I designed a Hammond drawbar-to-MIDI controller based on the PIC18F24K50, and that project went much faster.

Anyway, my point is this: Kudos to you for getting down into the low-level details and then writing up the project so that others might learn from your example.

Brian

p.s. I like the idea of noise passing through a Decay-controlled VCA, because that's very drum-machine. However, if you really want to simulate pops on vinyl then I think it would be more accurate to skip the noise source entirely, and just connect the DC Control Voltage from the Decay envelope to the audio. Maybe a little bit of Attack or slew limiting to tame things differently than a first-order low-pass might. I think this would simulate the way the needle is deflected on the vinyl surface when a damaged groove passes underneath. Since you're allowing the end user to "adjust to taste," maybe the option of skipping the noise would be useful.


On Apr 3, 2017, at 8:37 AM, Tom Wiltshire <tom at electricdruid.net> wrote:
> Thanks. It does have some high pass, but you might be right that more would be better. I've got it on the breadboard, so I'll give it a try.
> 
> It's an "adjust to taste" circuit really - you could do a lot of tweaking in terms of pop/crackle frequencies and tone.
> 
> Since I posted it here, I've written it up and put it online:
> 
> http://electricdruid.net/adding-vintage-hiss-crackle-and-pop/
> 
> Tom
>