Cobi
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http://chipmusic.org/forums/topic/6976/ … inversion/
(noise cancellation through stereo inversion)

I came across that thread a couple of months ago and I thought it could work on GBA with Nanoloop.
Unfortunately you can't pan the R and L channel in Nanoloop 2.7.x, otherwise I've also thought about that technique.

Have you tried any similar methods  ?

Also, does anyone know any guide for prosound modding the GBA ?
- I don't know if I'd go for it but I'm just curious!c

Last edited by Cobi (Jul 3, 2016 1:40 pm)

e.s.c.
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IL, US

that works the same way that software noise reduction works with the disadvantage of having to make your tracks mono.. useful if you find a device too noisy for even live use and don't have access to a noise gate

edit: could work around the mono limitation if you had two of them and access to a stereo looper (like the ones built into kaoss pad minis).. you'd have to loop just the line noise from before you start playback of the track and feed the looper's outputs into the input meant to receive the line noise

2nd edit: didn't see what you'd linked to, assumed it was the topic about PISSbox.. doing it manually in software is just making software noise reduction one step more difficult for no reason

sandneil
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the way the stereo inversion thing works is to invert the exact same signal to cancel itself out

let's say noise is a bunch of random numbers:

-3  -2   7   8  -4   6   2   3  -8  -9   1   0  -3   4

if you take that exact sequence and add it to the inverted version of itself, you get silence:

-3  -2   7   8  -4   6   2   3  -8  -9   1   0  -3   4

 +   +   +   +   +   +   +   +   +   +   +   +   +   +

 3   2  -7  -8   4  -6  -2  -3   8   9  -1   0   3  -4

 =   =   =   =   =   =   =   =   =   =   =   =   =   =

 0   0   0   0   0   0   0   0   0   0   0   0   0   0

however, if you take some pre-recorded noise, or noise from a different source, that'll be a different set of random numbers:

 8  -2   6  -4   1  -2  -1   4  -5   8  -3   7  -7   3

add them together and you just get even louder noise

-3  -2   7   8  -4   6   2   3  -8  -9   1   0  -3   4

 +   +   +   +   +   +   +   +   +   +   +   +   +   +

 8  -2   6  -4   1  -2  -1   4  -5   8  -3   7  -7   3

 =   =   =   =   =   =   =   =   =   =   =   =   =   =

 5  -4  13   4  -3   4   1   7 -13   1  -2   7 -10   7

this means it has to be done in realtime using the same device - you can't use recorded noise, you can't use noise from a different gba, basically if you can't get one channel with your song on it and a second channel with just noise, you're out of luck

software noise reduction is done with fft / eq / gating / expansion and is necessarily imperfect, depending on the quality of the software you use to do it, it can either sound good or terrible

the stereo inversion method doesn't work the same way at all and in theory itshould perfectly remove any noise without affecting your recording negatively in any way

herr_prof
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You guys ever listen to mulitrack band recordings? NOISY AS FUCK. Pristine silence is overrated.

4mat
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The other factor is it's $50 gaming hardware aimed at teenagers, if you want pristine output use a good emulator, export each channel singularly and do some post-processing to simulate the mix chain in the device if you really want to get into it.  (at a guess some summed busses with compressors influencing each other might get you someway there, with some over-saturation to make it a bit dirtier)

Cobi
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@sandell
Thanks so much for clarifying the theory behind noise cancellation and the difference between what's going on in the noise reduction through software.
I use chipmusic's forum a lot as a resource for when I make music and run into different kinds of obstacles or if I'm just looking for some tips/tricks. So I really appreciate making it very clear! Thanks!
If I get some more time this summer I'm definitely gonna sit down and experiment with noise cancellation.

@herr_prof
Unfortunately my home studio is very primitive so I haven't done a lot of crazy multitrack recording except the two stereo inputs on my EMU-0404 USB interface. But I've added separately recorded channels from LSDJ on top of each other that I used the "noise-as-synch-point" technique to get them fairly in synch.

@4mat
You're completely right, I've also used emulators before to record certain noise-free samples, like Snares or Kick Drums, that I wanted to process and combine with others sounds in Ableton. Since I'm new to music making on the GBA I thought I'd start a thread to see how other people dealt with this and gain some knowledge about it. I've been making chiptunes and chiptune inspired music for a long time but I've never really upgraded my home studio in any drastic 'hardware' way because I don't know in which direction to start. I also like the flexible/DIY way of making chiptunes where you can apply small mods and use certain techniques to get more juice out of your Gameboys, much more than they were intended to!
I have been listening to your music for years (I'm a big fan!) and I assume that you're mostly not using Game Boys for your arrangements(?), but I'm curious ; How do you deal with noisy outputs from synths/computers on recording ? I've heard that some are using Passive or Active DI-Boxes before plugging it into their sound card. Is that something you've also used ?
__

Since I never really dug deep into the theory or the 'under the hood' of noise reduction in music production I appreciate everything you share and just keep the tips coming! Sharing your experiences is really helping me a bunch! Also what's your typical use of the GBA with Nanoloop? I think I'll only use mine as an auxiliary instrument with sampler/synth.

Dolby-Z
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East Coast USA

The original DS has an almost completely clean signal and you can get them for dirt cheap. I use it for all my Nanoloop 2 recording

Dolby-Z
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East Coast USA

The original DS has an almost completely clean signal and you can get them for dirt cheap. I use it for all my Nanoloop 2 recording

pselodux
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Melbourne

Yeah, if only the DS had link cable support, then I'd use that instead of my micros. Having said that though, the tempo of nanoloop is pretty solid so it's probably not too bad to sync by ear as long as the tempo doesn't change..

Cobi
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@Dolby-Z @pselodux

Cool! Have you compared it to the DS Light, which is said to one of the best consoles for audio quality ?

pselodux
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Melbourne

DS Lite is pretty much the same as the original DS, from my experience (not much). The only minor issue with the DS Lite is that the GBA cart sticks out the bottom rather than sitting flush like on the original. It's a shame, because other than that (and the lack of a link port, of course), the Lite is perfect.

Dolby-Z
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East Coast USA
pselodux wrote:

Yeah, if only the DS had link cable support, then I'd use that instead of my micros. Having said that though, the tempo of nanoloop is pretty solid so it's probably not too bad to sync by ear as long as the tempo doesn't change..

I usually just record into Ableton Live and sync everything in a track that way. Of course that doesn't help in a live setting unless you're like me and you just load gameboy samples into an Electribe and leave the actual hardware at home. It might not look as cool  on stage but its a hell of a lot easier to work with (for me anyway).

pselodux
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Melbourne

Wellll, if I wanted to do something like that I'd just use my monomachine big_smile
The point of nanoloop for me is being able to tweak a sequence/sound design on the fly—chucking it into a sampler can have its own tweakability but not in the same way imo!

But yeah, this thread inspired me to get the DS out again and bust out some 1x nanoloop 2.7 jams big_smile