How do I filter a voice recording to sound like a NES game sample?

Question

The style that I am shooting for can be heard on this video: http://www.youtube.com/watch?v=nZlPiehYpVM at 2:18 ("Blades of Steel")

I have tried playing with equalization, hi-pass/low-pass, and various filters, but I can't seem to get anywhere close to this effect, where the "s" sounds come off as static, and the annunciation of consonants is muted (possibly an attack filter?). I can't find any documentation through Google search, either.

I know very little about the sound architecture of the NES, other than that music was composed with Square and Triangle waves, and the "samples" were presented through a separate sound channel. On NES sound emulators I use, this channel is usually labeled "PCM," (Pulse Code Modulation?) The NES system itself was 8-Bit, but I do not know if its sound system was.

Answer 1

I know that FamiTracker can import WAV samples and they will play back in any emulator that supports the DPCM channel. You can get FamiTracker at http://famitracker.shoodot.net

Answer 2

Its possible that the reason that you are having problems recreating the sound you want is that the samples you are trying to recreate might have been recorded/played back using the NES sample channel's DCPM (differential pulse-code modulation) capabilities

This is where instead storing each audio sample directly the chip stores the first sample and then the delta's (how much the signal goes up or down between samples). I read a blog somewhere (I'll try to find it and link) where somebody analysed the behavior of this channel and found that it introduced lots of strange artifacts into the sounds

Not sure how you might emulate that without the hardware

Answer 3

That sound is due to a combination of low sample rate and low bit depth. Those are the 2 parameters you can control to diminish the data size on PCM data, which they had to do for the old game consoles because of their limited storage and processing power. A very low sample rate without pre-filtering introduces strong aliasing, and a very low bit depth introduces distortion on the signal.

I was able to re-create that kind of effect using McDSP FutzBox LoFi module in Wwise.

• Downsample: 4000 Hz
• Bit depth: 4 bit

Answer 4

Like Shane said, use at most 8-bits resolution, but also [re-]sample it around 4kHz or less. No lowpass filter necessary as you want the higher frequencies to wrap "poorly" while sampling at the low sample rate. (Though, some re-sampling actions on audio editors may do that lowpass for you).

Answer 5

CMT Bitcrusher is a great tool for this. dBlue Glitch also has a bitcrusher module.

Answer 6

You wont get that effect with just an EQ. try using a bitcrusher effect to reduce the bit-depth to 8 or 16 bits, maybe some saturation and a lowpass at the end to tame some of the distortion.

The characteristics of these old game sounds come almost entirely from the crazy low resolution and data compression necessary at the time to get the samples onto the game cartridge.

good luck!