nesdev.com
http://forums.nesdev.com/

Namco 163 audio levels
http://forums.nesdev.com/viewtopic.php?f=3&t=16469
Page 1 of 1

Author:  NewRisingSun [ Sat Sep 09, 2017 10:34 am ]
Post subject:  Namco 163 audio levels

The Wiki page on Namco 163 audio lists some very approximate relative volumes for several games. A different page lists the mixing resistors used in the various games. I know that APU<->expansion audio balance is a hopeless affair, since it differs between Famicom revisions. But surely it would be possible to calculate the Namco 163 sound volume at least for the 10kΩ/15kΩ/22kΩ mixing resistors relative to 4.7kΩ mixing resistor configuration with precision. Unfortunately, I cannot. Can someone else? :)

Author:  lidnariq [ Sat Sep 09, 2017 10:49 am ]
Post subject:  Re: Namco 163 audio levels

The topology on the 163-using boards looks like this:
Code:
famicom        :  cart  :  famicom
   +--100k--+  :    163 :
   |        |  :     |  :
C--+--|>o---+--:--R--+--:--RF modulator
            |  :        :
          DA15
(edit: added location of Famicom expansion connector sound)

It should be the case that any given size of resistor should make the NES audio quieter proportionate to its conductance (1/resistance).

Unfortunately, the resistor values we've observed don't correlate with the reported loudnesses. So either the reported resistors are incorrect, or something even weirder is happening.

Author:  NewRisingSun [ Sat Sep 09, 2017 11:12 am ]
Post subject:  Re: Namco 163 audio levels

I thought that one could identify the resistor values from looking at high-resolution images, but no. The people on that archived nifty forum page linked to in the wiki seemed to just have held an Ohmmeter to the cartridges' audio pins ([MEMO 45-46の抵抗をテスターで計った結果] ).

Author:  lidnariq [ Sat Sep 09, 2017 5:23 pm ]
Post subject:  Re: Namco 163 audio levels

One could, but the backs in NesCartDB don't match 1:1. The resistor is literally the only differnce between the different backs.

Page 1 of 1 All times are UTC - 7 hours
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/