Tuning issues present in some ditties

[kieranhj]

The vgm conversion script has struggled to cope with a couple of the death ditties that use multi-channel FX.

See these clues.

[inversephase]

@simondotm thinks this is primarily due to the 3.58 vs 4mhz clock. I'm inclined to agree. One thing makes me wonder if there's an issue from where the bass (noise) channel is being tapped. On SMS noise is tapped from the third square wave channel and on one of the tunes (I'll have to find out which) it sounds like it might be coming from square 2 instead?

[simondotm]

Turned out to be a Quad-Tone issue. BBC Micro does not support harmonized tuned periodic noise at the same time as audible channel 2 tone due to its piddly 15-bit LFSR (whereas SMS has 16-bit).

[mattgodbolt]

So interested to discover why IP was having so much trouble with this :-) Thanks for all these bug reports and responses, as a vicarious passer-by, it's fascinating to hear all about it!

…

On Sat, 24 Mar 2018, 06:50 Simon M, ***@***.***> wrote: Turned out to be a Quad-Tone issue. BBC Micro does not support harmonized tuned periodic noise at the same time as audible channel 2 tone due to its piddly 15-bit LFSR (whereas SMS has 16-bit). — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#170 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAmsdSVRT0y67wUREKpwuGPa1XFxBqvFks5thk80gaJpZM4S2w1y> .

[inversephase]

Uh oh, looks like we might have a stalker gents 😉 (or perhaps: a "beebing" tom?)

[mattgodbolt]

Hahahahah!

…

On Sat, 24 Mar 2018, 07:19 Inverse Phase, ***@***.***> wrote: Uh oh, looks like we might have a stalker gents 😉 (or perhaps: a "beebing" tom?) — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#170 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAmsdRfKWL8CxtR2v8flXVSHfIm94HkWks5thlXbgaJpZM4S2w1y> .

[simondotm]

Ok more detailed explanation for interested passers by. :)
https://gist.github.com/simondotm/84a08066469866d7f2e6aad875e598be