[squeak-dev] Mac midi sound weirdness - it gets louder for first few notes.

tim Rowledge tim at rowledge.org
Thu Nov 6 01:22:52 UTC 2014


Dear Abby,
I’ve been dealing with some ‘fun’ Pi scratch sound related issues and a weird one has come up on the Mac. Oddly enough the problem was reported on the Pi but I can’t replicate it and whilst trying to work out what on earth is happening I discovered the Mac issue.

When a scratch script has a loop that looks like this

do forever
wait 0.5 secs
play midi note 60 for 0.5 beats

we hear the first few notes get louder and then stabilise at noticeably louder. If the wait time is longer - say 1 sec - it doesn’t seem to happen. The same effect happens with drum ‘notes’ via MIDI too.

The really odd part is that on the Pi there is *no* MIDI system making the noise - it is faked from an FMSound organ1 or SampledSound coffeeCupClink. And yet the user heard the effect; and I don’t.

I’ve checked the actual MIDI control byte value being sent to set the volume and it doesn’t vary. On the Pi the volume value sent to to the sound player system doesn’t vary either. I even checked that I wasn’t going insane by getting my wife to listen and she heard it get louder.

So my question is - is it wrong to take all the milk chocolate biscuits?

tim
--
tim Rowledge; tim at rowledge.org; http://www.rowledge.org/tim
Klingon Code Warrior:- 7) "You question the worthiness of my Code?! I should kill you where you stand!"




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