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Author Topic: How does I SID? Halp!  (Read 1715 times)

Offline LordHypnos

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How does I SID? Halp!
« on: March 31, 2016, 06:47:12 PM »
So, I'm trying to do a C64 cover of Spider Dance. I started out by condensing my YM2151 DMF into 3 channels, and then changing the system, and now I've been gradually changing octaves and designing instruments to get it to work. However, in pattern 10, row 16 channel 3 stops making sound. I can get it to work in that row by removing one of the other two notes that's playing simultaneously, but it really only delays the issue. Because I understand basically nothing about the SID, I'm not sure what I can do to fix the problem.

Additionally, if there's any resource that goes through what different filters and stuff actually do, that would be nice.

Offline Delek

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How does I SID? Halp!
« Reply #1 on: March 31, 2016, 09:07:51 PM »
This have to do with the filter.
The instrument 0 (Bass) in row 16 of pattern 10 is set to "Use filter values from instrument" (this will change THE FILTER state)
The instrument 3 (saw) in row 16 of pattern 10 is set to "Use filter values from instrument"  (this will change THE FILTER state at the same time)

The filter is only one and two channels are trying to use their own values at the same time (I should think a way to put this more clearly), if you un-set that checkbox for instrument saw, the notes will trigger.

However, I don't know WHY the SID decides to stop the sound of channel 3, maybe this does some "illegal" operation inside the soundchip. I will look around this.

The thing is that the filter in the SID was created originally to be controlled independently from instruments, I added filter controls per instrument so you will have some collision here and there if you don't know what you are doing. This makes using the SID with filters enabled in Defle even more complicated, because you should care about to use only 1 instrument that controls the filter state at a time.
« Last Edit: March 31, 2016, 09:12:01 PM by Delek »

Offline LordHypnos

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How does I SID? Halp!
« Reply #2 on: April 01, 2016, 01:41:21 AM »
 :) Thanks, Delek! I still don't think I actually understand, but getting rid of the "use filter from instrument" did the trick. What a confusing chip. ???

Offline LordHypnos

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How does I SID? Halp!
« Reply #3 on: April 01, 2016, 02:18:01 AM »
Any thoughts on keeping volume level. Example would be ch1 pattern 18 of this. It's not all that important elsewhere where it shows up, but triangles are incredibly quiet, and I want it to be audible. I suppose I could switch the bass to also a triangle there if necessary. IDK.

Offline tEFFx

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How does I SID? Halp!
« Reply #4 on: April 01, 2016, 01:00:35 PM »
The volume control is global on the SID-chip. It seems like there's still some volume changes going on here and there, and some lines has different values which behaves weird.
I usually have really long decay on my triangle instruments in order to make them more audible.

I hope that helps. :)

Offline LordHypnos

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How does I SID? Halp!
« Reply #5 on: April 01, 2016, 03:28:37 PM »
The volume control is global on the SID-chip. It seems like there's still some volume changes going on here and there, and some lines has different values which behaves weird.
I usually have really long decay on my triangle instruments in order to make them more audible.

I hope that helps. :)
Oh okay, that makes sense. Will try that when I get a chance. Thanks!