[sdiy] Hiss, Crackle, and Pop

[Neil Johnson]

Hi Tom,

> Yeah, I was probably aiming for something about 30 years earlier than vinyl! But I know what you mean, that "old 78s" noise would be lovely. You could probably get closer with a bit of fine tuning of the circuit.
>
> The mains hum…I dunno. I think it might be from recording the sample on the laptop with an unshielded cable. I should really have added a mains hum generator into the mix too, with a EU/US 50/60Hz selector!
>
> And no, I definitely didn't think of using a dsPIC! A 16-bit processor to make the noise of old wax cylinders going round?! Are you crazy, man?!
> No, I used a simple *8* bit processor for a job like that!! I even stayed away from op-amps because that just seemed too modern for the job. Maybe a 741 would be allowable.
>
> But you're dead right - it's one place the background hiss on the internal DAC might even be a benefit…

A few years ago a friend of mine (top-notch DSP engineer with an
interest in audio) developed a DSP system for recreating the sound of
78s (I gather it was a homer project in between designing DSP code for
satellite comms).  It had everything you could imagine - wow&flutter,
scratches, hiss, and so on.  It was very convincing.  Not sure where
it went, but suffice it to say that doing it right is a lot lot lot
harder than it seems...

Neil
-- 
http://www.njohnson.co.uk