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| | Previous Messages | Posted By
MMS
on 2014-08-04
17:20:42
 |  Re: Tracker instruments
Sound like that 
Editd above after rechecking my FB discussion. It was my fault to misunderstood some parts, blame it to the beer!
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Posted By
Csabo
on 2014-08-04
17:09:26
| Re: Tracker instruments
Surely you mean this: Digi Mixing Player. If you scroll down, you can see the instructions on how to load the Michael Jackson song (Smooth Criminal).
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Posted By
MMS
on 2014-08-04
17:19:31
| Re: Tracker instruments
I spoke with Copas on FB few months back. He was a friend or so of Pigmy, and they both lived in Zalaegerszeg. I recently worked there for 1 year too, and accidentally met with Copas.
He showed me the 3 channel digi player at the Univertsity (BME), we lived on the the same floor. At that time I made my "raytrace" gfx, and he programmed the digi player at the same time (full multimedia, yeah!)
EDIT: Pigmy and Copas discussed the details at Copas flat and both made parts in that.
Copas ripped a sample from Microdrums, defined it as "baseline" and wrote a BASIC program to resample the samples in advance. The sounds were not calculated "on the fly" , but stored in the memory. They made only channels and limited samples to fit into 16KB.
As Csabo highlighted below, it is that linked PRG. Time machine rulez! :-)
It run with a blank off screen, and played a Michael Jackson tune. The sound output was rather straighforward: added together the instruments current volume to each other then divied by 3, and transcoded to fit to the volume register.
So, it was a PWM, and a kind of tracker player without editor, even if very simple and very staighforward. As I remember it was pretty noisy (4 bit samples), and I think the 3 channel could produce worse result than the 4 due more complex maths. But it was a fantastic piece of code at it's time (1993) as multi track playback was as Amiga at that time, and my 286 16Mhz also badly performed later on tracker file playback on speaker(1bit) or Covox card (8bit) too. Not saying +4 is better
As visible on Youtube (and discussed also ), the 3.5Mhz ZX Spectrum could also do this, even with 4-6 channel. 1bit rulez! But 8 bits can be better
https://www.youtube.com/watch?v=QZnOd_f9YjQ
So the theory: very short 8 bit samples, add 4 channel current volume to each other, divide by 4, push to User Port Covox. I dropped Ferranti, as my simple ZN728E8 costs a lot now, maybe I can sell my Covox for >100USD now
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Posted By
Litwr
on 2014-03-25
13:51:53
| Re: Tracker instruments
to siz & MIK. Thank you very much! I am curious do you use Amiga OS? I used Amiga 500 during 2 years but completely forgot about these info-files. I thought they are alike GNU info. I was also confused by their relatively big sizes.
to Spektro. IMHO it will be worth to add samples with two sound generators simultaneous output. The samples with sound on and sound off toggles may show potential ability of C+4 to use PWM.
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Posted By
MIK
on 2014-03-25
05:41:24
 | Re: Tracker instruments
Indeed. (.info) is a bit like Windows when you look at the properties of a file. Sometimes it holds important options that can be turned on or off depending on machine type and spec such as screen modes, sound modes and many more but this side it linked to executable files in this regard on Amiga.
Along side this it contains the data of what the file icon will look like such as a Draw/Folder. If the (.info) is removed from a Draw/Folder it will not display on Workbench, it would then be like a Windows hidden file and if you do a Show All Files... you get the idea.
.info files can be ignored on anything other than a Amiga.
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Posted By
siz
on 2014-03-25
01:55:03
| Re: Tracker instruments
The AmigaOS .info file contains only launch information for the file with the same name. (What app should be used to open it, what icon should be displayed and so on). You can safely ignore them on any other OS.
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Posted By
Litwr
on 2014-03-24
14:03:07
| Re: Tracker instruments
Is there a way to read info-files without Amiga OS4? Why not to use more common TXT, HTML, PDF, ... format?
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Posted By
MMS
on 2014-03-23
09:25:02
| Re: Tracker instruments
Comment 1) 8bit HW output?
I recently had a discussion with TLC, if the SID card's improved 8bit digital output (called SID Digi-blaster) may improve the digi sound output?
The question is raised due to an idea to realize a 8bit Covox like sound card (with Ferranti ZN426E or equivalent) via the Plus/4 User Port: would it have any benefit on the quality of sound output? Modifiying existing programs would no be a big deal, as I see, but I am a lamer to do it myself, haha!
Theoretically the 8 bit instead of 4 bit may result more noise-less output, not to mention that some CPU power could be saved, as you can pass the raw 8bit data (mixed from 3-4 paralelle samples) to user port output, no need to reconvert it to 4 bit. --> higher sampling rate can be reached. --> upper frequencies could be converted too eg in SID emu. By this the tracker like playback would be possible, in a better quality than on C64 (8bit VS 4 bit).
Covox card is easy, I made one for my PC 16 years ago.
Interestingly switching on and off the Digi blaster in Plus4emu did not cause any noticeable difference.
anyone has any idea, why?
Comment 2)
Increasing the spped also possible if you do not switch off completely the screen (Pigmy did it in the past witha 3-channel playback, was something from Michael Jackson in 1995 or so), but to switch off partially the screen (eg. leave only 100 rasterlines visible) and switch the Plussy to NTSC mode in the non visible area. That may provide extra 20% CPU power, as I calculated, though with half screen visible, but still much nicer than a completely blank screen.
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Posted By
Spektro
on 2014-03-20
16:41:56
 | Re: Tracker instruments
Thanks for the noise generator link Csabo!
I tried the C program. The program seems to have typing error in line 8. Instead of %i there should be %c.
So the pseudorandom sequence is used for producing noise by creating a pulse waveform with randomly alternating pulse width?
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Posted By
Csabo
on 2014-03-19
12:09:59
| Re: Tracker instruments
I think you're confused there, that digi is not 16 bits. It could be (unlikely), but they don't say that anywhere. (In fact, if I'm understanding correctly, it's 4 bits as usual.) What they are saying is that the playback speed is 16Khz. My part in CD4 has 19Khz digi playback, and that's from 2005 Increasing the speed is possible, and not even that hard, but the screen would have to be closed, and honestly there's not much audible difference.
Edit: here is the stuff about the TED noise generator.
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Posted By
Litwr
on 2014-03-19
11:47:45
| Re: Tracker instruments
[Csabo] 16-bits at C64 is at https://www.youtube.com/watch?v=O0t9mTNbQco
PWM with IBM PC speaker uses exact time interval to set up the volume of sound - http://en.wikipedia.org/wiki/PC_speaker#Pulse-width_modulation. Thank you for the reference to TLC results but I could only find information about 4-bits sound. TLC wrote about PWM too...
[Spektro]The algorithm of these "random" waves was published somewhere.
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Posted By
Spektro
on 2014-03-19
11:10:47
| Re: Tracker instruments
I noticed something interesting about the noise waveform regarding the pulse width. When you look at a low frequency noise sample (for example "TED_noise_lowest.wav") with an audio editor, you can see that the noise waveform is actually a pulse waveform whose pulse width changes semi-randomly.
My guess is that TED is not altering pulse width but the noise waveform is produced by using a square waveform and altering the sound frequency semi-randomly very quickly.
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Posted By
Csabo
on 2014-03-18
17:36:07
| Re: Tracker instruments
Well, no, there's no TED register for PWM (the SID does have those). All you have is the 2 frequency registers and the volume/noise bit.
Digi playback is just changing the volume register quickly, so with that, it's possible to do "PWM" (as it is possible to play pretty much any waveform).
As far as bits: TLC maestro measured all the volume levels and made a nice table out of it, it's here in our mail archive somewhere. Using those produces the highest possible quality digis, I call it "quasi-8-bit". I think the hidden part of Vancouver 2010 is the first and so far the only demo that actually uses this (quite unceremoniously it seems, there's no mention of it anywhere). So, can you name a C64 demo that can play 16-bit samples? I haven't heard of that yet.
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Posted By
Litwr
on 2014-03-18
07:03:41
| Re: Tracker instruments
It is curios is it possible to use PWM (pulse width modulation) with TED? C64 newest demos show 16-bits sound...
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Posted By
Spektro
on 2014-03-17
13:44:49
| Tracker instruments
Hello,
I've uploaded TED sound sample pack to OS4Depot to be used with music editors (trackers): http://os4depot.net/?function=showfile&file=audio/tracker/tedsounds.lha
The samples are in WAV format. They are packed into an LhA archive, so you need a tool which can unpack LhA archives. The archive contains some AmigaOS 4 icon files (.info). Just ignore those files if you are not an AmigaOS 4 user.
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