Noisy music

[Intellivision Brasil]

 

Hi friends.

 

I'm finishing up X-Rally but I've run into an intermittent issue with the main song (video attached).
At times, the music becomes noisy on channel 2 and only returns to normal when a sound is generated on that channel (using smoke or picking up a flag), although I used NO DRUMS.

 

What I have already identified (and tried) with no positive result:

 

1 - It occurs intermittently (when I use the control to change direction or even letting the car run freely and without generating any sound with a flag, smoke or collision).

 

2 - I isolated sound effects 1 by 1 and even disabled all sounds.

 

3 - All sounds are activated in ON FRAME GOSUB Sounds (with variables that indicate which sound should be played and when it ends).

 

4 - The menu music uses PLAY FULL and plays normally. At the start of each level, the main music is called this way:
     SOUND 4,,$38
     PLAY OFF
     PLAY SIMPLE NO DRUMS
     PLAY MainMusic

 

5 - This is the structure of the song:
MainMusic:
     DATA 5
     MUSIC GOSUB MainMusic1
     MUSIC GOSUB MainMusic2...

MainMusic1:
     MUSIC SPEED 5
     MUSIC A4Y,A2W
     MUSIC S,-
...

 

6 - The DATA commands of the song are allocated between 2C2B to 2E2E.

 

If anyone has an idea or suggestion, I would greatly appreciate it.

 

Edited February 1, 2023 by Intellivision Brasil

[carlsson]

I have found that setting instruments only affects the MUSIC GOSUB routine you're currently in, like a local setting. Once you exit back to the main list of music commands, you need to set it again. Usually I set instruments to desired default at the beginning of the song. Possibly that is what affects you.

 

Not sure if it is a bug or a feature.

[+DZ-Jay]

At first glance, it seems it could be a sound effect that uses noise, which either enables it on the wrong channel, or leaves it on.

 

I haven’t studied the IntyBASIC music player too thoroughly, but if it works like mine, once the channel tone/noise mixer is set, it doesn’t touch it until a new change is necessary.

 

So, if you are not using drums, the player does not have a need to enable and disable the noise channel at all.  Consequently, if you do so outside the player, and leave the noise enabled, it will persist.

 

Setting instruments won’t change this, since they are merely octave and volume envelopes controlled in software.

[+nanochess]

If you have any noise usage in your game.

 

For example, SOUND 4,,$18 then make sure it returns the mixer to SOUND 4,,$38 at the end.

 

In my own games, I tend to use only channel 2, and a statement ON sound_effect GOSUB sound_none, sound_explosion

 

This statement is invoked by ON FRAME GOSUB.

 

When sound_effect goes back to zero, then sound_none does this:

 

SOUND 2,,0

SOUND 4,,$38

 

Turning volume to zero and disabling the noise channel output.