Cracks in the sound (YM+DMA)

[dma]

Hi,

Here attached is a .zip archive containing a test .snd file (along with .ttp player for it) which gives cracks in the sound on Hatari when all 3 voices are played along DMA mono beat.
It only occurs when the bassdrum is playing.

You can hear it at 17 seconds when playing the .snd file.
I also included a recording (as .ogg) from Hatari where you can also hear this problem.

Maybe it only occurs on my Hatari setup ? I cannot test it on another computer here.
So it would be nice if someone else could check this.

[Hippy Dave]

I think the LMC1992 volume or bass or treble register is turned up too high and causing distortion.
This can happen on a real STe too. Real STe distortion is caused by clipping; Hatari distortion is
caused by overflow because saturation mathematics is not used. Hatari should distort at about the
same point as a real STe, but may sound different.

[dma]

Actually, the test .snd file i provided sounds correct my STe.
Sorry that i forgot to mention that.

[Hippy Dave]

EDIT:
I found and solved the problem. YM + DMA sound samples exceeded 16 bits at one point in the code.
I also made a patch to do clipping instead of overflow for LMC1992 distortion.

-Following experiment cancelled.
Try this experiment:
Turn down the volume to see if the noise goes away on Hatari.
Maybe turn up volume on Real STe to find where it gets worse.
I'll think about the results, if you can tell me some levels.

[dma]

Ah that's marvellous. Is there any chance i could get a windows (32bits xp) build binary with this patch somewhere?

[Hippy Dave]

Ah that's marvellous. Is there any chance i could get a windows (32bits xp) build binary with this patch somewhere?

Check this link to see when the patch is applied.
http://hg.tuxfamily.org/mercurialroot/hatari/hatari

Download from CHS' automated Windows Hatari build link
the next day (first link on page).
http://hatari.tuxfamily.org/links.html

[dma]

Oh i didn't knew about the automated build, great!

I can't wait for the patch (literally, as it blocks my "out of the house" work on some tunes ).
Thanks again for such a fast job.

[npomarede]

Hello,
I applied the ym+dma patch made by David to the dev version, so it should appear soon in the windows' daily builds.

Nicolas

[dma]

Ah that's great, thanks, no more problem on my track(s).