Hey gyus,
During the development of the DPC support for the new version of Javatari, I found an interesting fact.
For the DPC audio to work better, the game software should try to read the audio data from the DPC chip and update the TIA audio register (AUDV0) as frequently and regularly as possible. Regularity would be very important here, in order to produce smooth waveforms.
But I noticed that Pitfall 2 does not update the audio register regularly. It updates it several times per scanline durting VBLANK, but then only once per scanline during the display section, and at different intervals. This produces the somewhat noisy and hissing music we all know.
This happens because it does not generate a smooth sound wave. Instead, if the same amount of updates (maybe 2) were sent per scanline (and every scanline), the audio quality would have been much better.
So I decided to play around with this and created a special ROM format in the emulator, which I called DPCa.
Using this special Cartridge Format, the emulator sends updates to the TIA automatically at every DPC audio clock. The result is very interesting, as it produced a much better audio quality!
If you are interested, you can try it with Javatari 3.00 or later. http://javatari.org
The emulator should detect Pitfall2 automatically. If it fails to detect it, you can select between normal DPC and DPCa ROM formats in the Settings Dialog, or toggle the format in realtime with ALT + B. Try both formats and hear the difference!
Also, the DPC audio clock is adjustable with ALT + HOME/END. So you can simulate the clock variations/imperfections found in real carts.![:)]()
Regards,
Peccin
During the development of the DPC support for the new version of Javatari, I found an interesting fact.
For the DPC audio to work better, the game software should try to read the audio data from the DPC chip and update the TIA audio register (AUDV0) as frequently and regularly as possible. Regularity would be very important here, in order to produce smooth waveforms.
But I noticed that Pitfall 2 does not update the audio register regularly. It updates it several times per scanline durting VBLANK, but then only once per scanline during the display section, and at different intervals. This produces the somewhat noisy and hissing music we all know.
This happens because it does not generate a smooth sound wave. Instead, if the same amount of updates (maybe 2) were sent per scanline (and every scanline), the audio quality would have been much better.
So I decided to play around with this and created a special ROM format in the emulator, which I called DPCa.
Using this special Cartridge Format, the emulator sends updates to the TIA automatically at every DPC audio clock. The result is very interesting, as it produced a much better audio quality!
If you are interested, you can try it with Javatari 3.00 or later. http://javatari.org
The emulator should detect Pitfall2 automatically. If it fails to detect it, you can select between normal DPC and DPCa ROM formats in the Settings Dialog, or toggle the format in realtime with ALT + B. Try both formats and hear the difference!
Also, the DPC audio clock is adjustable with ALT + HOME/END. So you can simulate the clock variations/imperfections found in real carts.
Regards,
Peccin