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PostPosted: Mon Aug 19, 2013 12:21 am 
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Posts: 179
I'm using the formula in the APU mixer wiki page, how do I add the output of the additional channels to the formula?


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PostPosted: Mon Aug 19, 2013 7:05 am 
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There's no explicit formula for combining expansion audio with the APU audio. Each one is its own analog signal, and you need to find an appropriate mix level for each of them. On the various expansion audio pages on the wiki I've tried to make a recommendation as to how loud to make each expansion, if I can, usually in reference to the volume of the APU square.

I've made some recordings of my Famicom for reference: http://forums.nesdev.com/viewtopic.php?t=8639

You can listen to those reference recordings to get a ballpark idea of what the balance should be. Of course, from Famicom to Famicom, cartridge to cartridge, there is a fair bit of variation. I recommend letting the user mix the expansions and the two APU signals so that they can adjust to taste.


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PostPosted: Thu Aug 22, 2013 8:39 am 
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Thanks, I'll check them out.


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PostPosted: Thu Mar 27, 2014 9:43 am 
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Two more to add to the list:

City Fighter IV Sound -> http://cah4e3.shedevr.org.ru/dumping_2012.php

"At the second look, it's actually have a extra sound cirquit on the cart's PCB. A small PLC chip makes a simple 4-bit DAC (actually, it may be ADPCM, but as soon as resulting sound is close enough to the original, I don't care ;)), and programm feeding it with samples by IRQ timer. So we have twice reducing of the samples size against 8-bit (7) PCM, and much more quality than DMC for DMC channel."

Currently his emulator just reroutes ADPCM data to $4011 as a hack to play the audio. I don't have a cart scan for this currently.

Various keyboard software that teaches English using a voice decoder > http://cah4e3.shedevr.org.ru/dumping_2013.php (Look for "GLK" and "Magistr".)

Despite what CaH4e3 says on his website, this does not use ADPCM. It uses a voice decoder chip with the data burned-into the chip. More or less this appears to be similar to Family Aerobics. For the voice data to be recovered the chip would need to be decapped. CaH4e3 uploaded some cart scans of these as well.

Can't seem to upload a ~50MB file here for some reason.


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