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FM synth BRR sample generator
http://forums.nesdev.com/viewtopic.php?f=12&t=14727
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Author:  psycopathicteen [ Sat Mar 11, 2017 3:18 pm ]
Post subject:  Re: FM synth BRR sample generator

I implemented all 8 algorithms but I'm having a quantization noise problem with algorithm 7. In order find the BRR "range" I just added up the carrier volumes, and counted the number of 0 bits at the top. If you have several carriers that are slightly detuned they could cancel each other out, which would turn into a square wave with only 4 bit samples. I guess I just have to find the BRR range by checking each sample individually.

Author:  Augustus Blackheart [ Thu Mar 23, 2017 4:27 pm ]
Post subject:  Re: FM synth BRR sample generator

psycopathicteen wrote:
I implemented all 8 algorithms...


I'm looking forward to hearing what that sounds like.

I made this test awhile ago using the original code you posted... I just dropped your code into the middle of the SNESMod vibrato routine. 4xy: x = vibrato speed and carrier frequency, and y = vibrato depth and modulation frequency; but only when the vibrato waveform is $08-$0f. <$08 is just vibrato waveforms. Each time the song repeats the FM waveform is changed.

Channel 1: FM waveform echo

Channel 3+5 FM waveform
Channel 4+6 2nd waveform (pitch modulation enabled)

carrier frequency = #$02
modulation frequency = #$04

I was working on a ROM that would allow you to change various settings maybe I'll dig that up.

Also, it's weird that .spc extension is not allowed.

Attachments:
fmtest.bin [64.5 KiB]
Downloaded 49 times

Author:  psycopathicteen [ Sat Mar 25, 2017 11:01 am ]
Post subject:  Re: FM synth BRR sample generator

Can BIN be directly used as an SPC file?

Author:  93143 [ Sat Mar 25, 2017 9:52 pm ]
Post subject:  Re: FM synth BRR sample generator

I just saved it as an SPC file, and it worked.

Author:  Bregalad [ Sun Mar 26, 2017 1:34 am ]
Post subject:  Re: FM synth BRR sample generator

I tried to play it with both of my SPC players and it sounded awful in both. Is this due to an emulation inacuracy or is it supposed to sound like this ?

Author:  Augustus Blackheart [ Mon Mar 27, 2017 1:30 pm ]
Post subject:  Re: FM synth BRR sample generator

Bregalad wrote:
I tried to play it with both of my SPC players and it sounded awful in both. Is this due to an emulation inacuracy or is it supposed to sound like this ?


It doesn't sound great. I noticed playback varied a lot on each SPC player I tried. After real hardware it probably sounded the best on SPCPlay.

Due to limited RAM I'm only using two BRR blocks. How good it sounds depends on the waveform selected and settings used. The ramp up and ramp down waveforms probably sound the worst unless you are looking for a super glitch-y sound.

I've attached another test and a song, although they probably do not sound much better.

Attachments:
File comment: Channel 1 & 3 are a saw waveform
Channel 2 is the fm synth

other-test.spc.bin [64.5 KiB]
Downloaded 39 times
song.spc.bin [64.5 KiB]
Downloaded 43 times
song.mp3 [2.06 MiB]
Downloaded 75 times

Author:  psycopathicteen [ Mon Mar 27, 2017 6:20 pm ]
Post subject:  Re: FM synth BRR sample generator

The first half sounds awesome though

Author:  Espozo [ Mon Mar 27, 2017 8:36 pm ]
Post subject:  Re: FM synth BRR sample generator

Augustus Blackheart wrote:
It doesn't sound great.

What is causing this? It sounds like an electronic voice crack at 22 seconds in.

Author:  Optiroc [ Tue Mar 28, 2017 2:17 am ]
Post subject:  Re: FM synth BRR sample generator

Wow, this is awesome!

Author:  Augustus Blackheart [ Mon Aug 28, 2017 7:03 am ]
Post subject:  Re: FM synth BRR sample generator

Here's another example (made during a shocking international incident). There's one version with FM and pitch modulation, it's used starting one minute into the song, and one version with pitch modulation only.

Attachments:
File comment: with FM (change extension to spc)
Augustus Blackheart - Lengi lifi ananas-pizzan - Orsök.bin [64.5 KiB]
Downloaded 32 times
File comment: without FM (change extension to spc)
Augustus Blackheart - Lengi lifi ananas-pizzan - Orsök-no-fm.bin [64.5 KiB]
Downloaded 19 times

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