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 Post subject: Sound question
PostPosted: Mon Sep 28, 2009 7:32 am 
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Joined: Mon Sep 28, 2009 7:29 am
Posts: 2
Im reading the gameboy sound wiki and it says the following to do with the wave channel:

"The DAC receives the current value from the upper/lower nibble of the sample buffer, shifted right by the volume control. "

it says that if the shift value is 4 then it produces silence, which kind of makes sense becaues a nibble shifted right 4 bits produces 0.

However when looking at what it says on the DAC section it says:

"An input of 0 generates -1.0 and an input of 15 generates +1.0, using arbitrary voltage units. "

So how does a value of 0 produce silence when the dac will return -1 which isnt silent?

Thanks


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PostPosted: Tue Sep 29, 2009 8:41 am 
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Joined: Wed Apr 05, 2006 10:12 am
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Location: PA, USA
When channel 3 is turned off using the bit in the NR30 register, it outputs 0v.
If shift is set to 0% (>>4) it outputs -1v.
(at least I THINK this is right... blargg?)

LN

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 Post subject:
PostPosted: Thu Oct 01, 2009 12:00 am 
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Joined: Mon Sep 28, 2009 7:29 am
Posts: 2
Thanks for the reply :-)

As you said when the channel is turned off it outputs 0v (silence). So when its shift is set to 4 then then it passes 0 to the dac which is -1v. This isnt silence yet the gameboy snd wiki says that shifting 4 outputs silence.


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PostPosted: Thu Oct 01, 2009 4:55 pm 
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Joined: Sun Sep 19, 2004 11:12 pm
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Location: NE Indiana, USA (NTSC)
Any value held for a long time is called "direct current", or "DC" for short. You can't hear DC, and speakers can't reproduce it.


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