| Posted By
Mike
on 2002-08-30
|  Sound emulation....
Okay... here we go...
I have added some "delays" to Minus4 sound, and its smoothed it out quite a bit.... However... the clicks now showing themselves are when sound is started and stopped.
If you imagine a sine wave(-1 to 1), and I stop it at "1".... I then get a vertival break in the sample... I can then either restart it at 0, or carry on from 1...
This is my problem... I have decided to restart my samples, which gives cleaner starts, but when I stop a sample.... I get that DROP to 0....
Any ideas....does the Plus4 hardware finish its current tone cycle?
Or does the speaker just finish and smooth it?
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Posted By
Gaia
on 2002-08-30
| Sound
I think the speakers are muted before any further processing would have taken place. But I'm really just guessing here....
Are you using original digital samples, or generate the waveforms at runtime? I mean, it's still just a squarewave, isn't it? Maybe it would be less troublesome to just render the waveforms yourself???
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Posted By
Mike
on 2002-08-30
| Samples...
No, I sample a tone from the plus/4... then I dynamically resample it every 1/2 a scanline..
Its not a "Square" as such... more of an ADSR looking wave... odd...
If you use minus4 -R then use SOUND1,MIDDLEC,1000 (whatever middleC is) you should get to see the sample 
I build the whole audio every "tick" One of my (many) audio buggets, is that BASIC (along with some other code) disables sound (FF11) and re-enables it quickly. The Plus/4 and TV speakers don't notice... My sample does... so I've added a 1/2 frame delay on all Audio changes (Not samples) this stops these "quick" changes being recorded - pain in the bum really...
I still get some "clicks" but not nearly as many as before...
Since ALL my audio is dynamically built, I have to know exactly how the plus/4 gets away with it....
Do you still use your windows play sample, then just change frequancy on it? Or do you build/mix samples now?
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Posted By
MIK
on 2002-08-31
 | Working with samples.
I've always found there is no escape from the click of death when trying to loop the smallest of samples (gonig back to my tracker days). More a replay fault from the computer...
Some how I would of thought the sound needs to be generated in the same way as Plus4 pulls it off. Much easyer for a C64 emu as they emulate SID and take it from there.
Both CP4 and Flamingo use the playsid.library (SID emualtion) to create awesome Plus4 sound. I don't have a clue how they managed to do it, no clicks at all. How ever they both suffer for not being able to play sample suff such as Ace and Terra Nova speech. Could be lack of updating who knows  Or just a fault from using SID in the first place?
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Posted By
Mike
on 2002-08-31
| (no topic)
The Clicks now only happen when stopping a sound... Looped sounds are perfect, "Lord Voldemort" sent a little program to demo it quite well...
10 for s=800 to 500 step -25
20 sound2,s,1: next s
30 goto 10
Lots of clicks in the current version with this. I've now smoothed them out... a combination of small bugs and extra fetures were fixed & added.
The problem is, even on a SQUARE wave (which the plus4 isnt....exactly...) you may still get a "click".. The drop off of the last edge -> __|--| gives a "click"...
It could just be my samples, as the SID emulation doesnt do it... Or perhaps with the extra channel in SID emulation, its never quiet enough to notice!!!
I did look at the resid LIB... its C++ so I may add it into the new one... I prefer mine, small and I did it () but I may add it...
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