Dizzy the Adventurer fixed NSF

Dwedit · Post by **Dwedit** » Wed Sep 21, 2011 2:18 am

Download the Fixed NSF for Dizzy the Adventurer. The original game is infamous for a sound bug, where it resets the phase of the square and noise channels every frame, causing a nasty scratching noise. I hacked the game to remove that problem.
This is the NSF of the hacked game. (I also fixed an initial noise problem too)

BMF54123 · Post by **BMF54123** » Thu Sep 22, 2011 2:00 am

Wow, I always wondered why that game sounded so awful. How could they have missed such a glaring bug? O_o

Post by **tepples** » Thu Sep 22, 2011 3:53 am

BMF54123 wrote:How could they have missed such a glaring bug? O_o

Probably for the same reason that early versions of the NerdTracker II replay code also reset phase every frame: incomplete knowledge of how the NES works. See note under Comic Bakery on the main page.

Dwedit · Post by **Dwedit** » Thu Sep 22, 2011 9:05 am

The game writes to every sound register every frame. When it writes to 4000/4004/400C, it sets the "disable envelope" bit, but does not set the "disable length counter" bit. So you need to hack that along with only writing to 4003/4007/400F if the value has changed.

BMF54123 · Post by **BMF54123** » Thu Sep 22, 2011 2:08 pm

tepples: I don't buy that. Codemasters made plenty of NES games prior to this one, and none of them sound this bad.

Drag · Post by **Drag** » Thu Sep 22, 2011 2:30 pm

One of the Dizzy games tried to do something completely whacko; they tried to give the triangle channel some kind of "volume envelope" by toggling it on and off very rapidly. If it's this game, maybe they caused this issue by adding that feature in?

Dwedit · Post by **Dwedit** » Sun Sep 25, 2011 12:54 am

I've never heard of any Dizzy game doing that, any idea what game might be doing that?

Drag · Post by **Drag** » Thu Oct 06, 2011 8:38 am

Funny, I thought it was Dizzy the Adventurer, but I just checked the three NES Dizzy games I know of and I can't hear it in any of them. I know there was a Codemasters game that did it though, but apparently I don't know which one.