Posted By
Fuzzweed
on 2024-10-21
19:14:00
|  Sample Playback - any tips and tricks?
I've got my basic sample engine working, varying volume output as per usual. The sound quality is fairly low which I kind of expect really. No worse than some demos I've been comparing it too, but I notice among them this One Love Demo by Chronos which is pretty good
One Love
Are there any tricks to improving playback? One thing in particular I find is the +4 lowest $01 note to provide the 'base' sound is actually pretty high frequency compared to e.g. AY chip so it tends to bleed through. Are there any hacks around this?
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Posted By
Csabo
on 2024-10-21
19:50:26
| Re: Sample Playback - any tips and tricks?
The quality of the playback depends on 2 things: speed (or sampling rate) and resolution (number of bits).
A few rules of thumb: Speed is more important than resolution. The higher the speed, the more memory the samples take and therefore the less audio you will be able to play back. For resolution, 4 bits is good enough: going higher than does improve quality, but not as much as increasing the sample rate. Finally, the louder the better - softer audio tends to be more noisy.
Couple of things you might find interesting:
- If you open Csabo's Wave Converter, you can just drop any 8 bit sample in it and get a working program out.
- The hidden part of 2020 By The Numbers has 27.7 Khz playback with 42 distinct values - near the best possible quality, but obviously it's very short.
- A.M.C Gotham: pretty standard, but I did a little write up with (hopefully) all the details one needs. This one is nearly 2 minutes long (with obviously a lot of repetition).
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Posted By
Fuzzweed
on 2024-10-21
20:13:40
| Re: Sample Playback - any tips and tricks?
thanks. the chopping up the tune in audacity is clever and useful. do you do any band limiting there, or just initial downsample?
My other question is in choosing $01 as the base output note for the ted. Is this the best choice?
(I think) in a SID you can lock (or trick) the output to always be high so your sample volume is always modulating an 'on' voltage.
Of course with the TED sometimes your square wave might be high, or might be low when your sample volume is applied to it......
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Posted By
Csabo
on 2024-10-21
23:12:21
| Re: Sample Playback - any tips and tricks?
I've done some experiments with filters, but none of them helped. If you use the "traditional" digi values ($90-$98,$B5-$B8) then the TED frequency values will have no effect, the square wave is not audible at all. (As an aside - you can play digi with TED, I have many tunes that do so: CD4 - TED + drums, Defiance - "DigiSaw", which is a 3rd melodic channel using saw-wave, Big Bass Cracktro - my first and so far only tune with full melodic samples + TED.)
The trick you're referring to is detailed here (by TLC maestro). Also, $01 is not the lowest frequency, and neither is $00, it's actually $3FF (explanation here).
Hope this helps 
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Posted By
Fuzzweed
on 2024-10-22
09:30:06
| Re: Sample Playback - any tips and tricks?
Thanks. I like a nice hardware expansion so I'll definitely look at that.
I'd like this to work on stock machines, but if anything I may use my Hannes memory as at least 256k is emulated in vice
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Posted By
siz
on 2024-10-22
10:18:46
| Re: Sample Playback - any tips and tricks?
emulated in vice
Ouch! Please use another emulator if You can (YaPE, plus4emu or YaPE SDL). The emulation in VICE xplus4 is far worse than those. Especially TED feature emulation has its flows.
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Posted By
Haegar
on 2024-10-22
10:25:48
| Re: Sample Playback - any tips and tricks?
I haven't sampled anything for ages, but I always used the Digital Composing Kit V2.0 from Apos. If I remember correctly, you could adjust a few things while sampling and then edit the samples later.
Unfortunately, I never used any of it in my programs in the end 
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Posted By
SukkoPera
on 2024-10-22
10:57:43
| Re: Sample Playback - any tips and tricks?
But you would need a DigiBlaster for that...
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(A little more patience, please! :8)
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Posted By
Haegar
on 2024-10-22
14:28:16
| Re: Sample Playback - any tips and tricks?
Yes, it should also work with 4-bit digits if I remember correctly. But....
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the wait will definitely be worth it.
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