Do the SN76489 and 2A03 have different ways of handling volume?

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drdevil
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Do the SN76489 and 2A03 have different ways of handling volume?

Postby drdevil » Mon Feb 08, 2016 1:00 pm

I hope this hasn't already been asked, but anyway. I've tried to recreate SMS music on Famitracker, however it does not sound faithful to the original tracks due to the volumes. Why is this? Is there a way to workaround it?

Attached is an example. It is an unfinished recreation of the main theme from Girl's Garden. If you compare it to the original, you'll notice it sounds different.
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girls garden.ftm
(1.25 KiB) Downloaded 50 times

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HertzDevil
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Re: Do the SN76489 and 2A03 have different ways of handling volume?

Postby HertzDevil » Mon Feb 08, 2016 1:03 pm

SN76489 volumes are exponential (like the AY-3-8910). Each volume step decreases the output by 2 dB.
refactoring 0cc-famitracker

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drdevil
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Re: Do the SN76489 and 2A03 have different ways of handling volume?

Postby drdevil » Mon Feb 08, 2016 1:09 pm

Ahh, I see. Never knew that.

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za909
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Re: Do the SN76489 and 2A03 have different ways of handling volume?

Postby za909 » Mon Feb 08, 2016 1:42 pm

Your best option is to use the 5B because it's got the same sort of volume curve as the SN76489. Or you could make the right combinations of waves and volume for the N163 to get something similar to that. The N163 would allow you to imitate the particular way of noise generation used by the SN as well.

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drdevil
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Re: Do the SN76489 and 2A03 have different ways of handling volume?

Postby drdevil » Mon Feb 08, 2016 2:05 pm

za909 wrote:Your best option is to use the 5B because it's got the same sort of volume curve as the SN76489.

Doesn't the 5B (YM2149) use logarithmic volumes, though?

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Mojitone
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Re: Do the SN76489 and 2A03 have different ways of handling volume?

Postby Mojitone » Mon Feb 08, 2016 8:09 pm

drdevil wrote:
za909 wrote:Your best option is to use the 5B because it's got the same sort of volume curve as the SN76489.

Doesn't the 5B (YM2149) use logarithmic volumes, though?

So does the SN76489.

Out of sheer curiosity, I rewrote this VGM from the SMS game The Flash into a 5B track, and because the track had to be transposed one octave higher fine tune pitching problems may appear.
The mixing is à peu près close to the original though segments are barely audible.
Attachments
The Flash 5B.ftm
fixed noise pitch
(80.86 KiB) Downloaded 52 times
The Flash.zip
Original VGM dump
(1.11 MiB) Downloaded 34 times
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za909
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Re: Do the SN76489 and 2A03 have different ways of handling volume?

Postby za909 » Wed Feb 10, 2016 4:44 pm

This really makes it seem like Jeroen Tel didn't know about the log curve of the chip.