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31

Players / Re: Tempo, Speed, Rows, etc.

« on: January 08, 2024, 16:52:37 »

As a reference if that might help: Most if not all C64 tunes were written on a PAL C64, meaning a 50hz refresh rate. In emulators, or even let's say "Furnace" (Another tracker) a SID will always be in 50hz mode. Hard to explain but if you line a SID playback with an another chip, you will notice that SID will sort of "lag" behind.

Thanks.  I was born back then, but unfortunately I was not tracking.  I was a Club DJ, so to me BPM is a very specific measurement of music tempo.  It is more "music-y," in that it is a more common term among musicians; whereas "ticks," "speed," and "rows" are purely technical things in trackers.

Intuitively (and naïvely), I feel that you either measure your track tempo by Ticks-Per-Row (Speed), or by Beats-Per-Minute (BPM), but not both.  To me, the former seems more natural in a tracker; while the latter is more natural in a higher-level production software, like Logic, etc.

As I see it, when using BPM, you would have to necessarily define how many rows fit in a "beat."  But then, there is nowhere to enter such a number in trackers, so it seems very arbitrary to me.  (I guess you can just keep it in your head, like a 4/4 signature = 4 rows per beat, 16 rows per pattern, etc.)

I think the only thing that doesn't rely on your refresh rate is BPM.

I suppose I could use BPM to compute a speed that is not a multiple of the refresh rate, like using fixed-point arithmetic to scale the refresh rate to any speed equal to, or lower.  But again, that requires you to figure out the relationship between rows and beats.

Then again, I could also be way off.  It does not help that I tend to over-think these things. 

Hopefully someone else can chime in with more insight.

     -dZ.

32

Players / Re: Understanding effects processing

« on: January 08, 2024, 16:26:02 »

Hi again. The note volume stays to whatever it is sled to after. The effect itself slides the volume of the note played and not the sample itself.

Hmm ... I think I understand.  In my case, I don't have samples -- just software instruments.  I suppose that for this, your comment above means that the base volume of the instrument (modulated by its envelope) is not affected, but the note in the channel is.

Is that right?

Keep in mind that "Volume slide" is not only an effect command but also a volume command. What do I mean? In XM and other later tracker formats you can do like so:

Yeah, I've seen that before.  My current data structure supports a single byte for the volume, so it has no way to encode those.  Therefore, I'm sort of ignoring them for the time-being.

Also keep in mind that there is an effect like "Kxx" which is a VolSide+Vibrato and "Lxx" which is VolSlide+NotePorta

Hmm ... I've seen those as "6xx" (Vibrato + Volume Slide) and "5xx" (Portamento To Note + Volume Slide), but I suppose it's the same thing.

Also, you can keep it in one thread. It's okay

Will do.

Hope this helps

Thank you, it does.

   -dZ.

33

Players / Tempo, Speed, Rows, etc.

« on: January 08, 2024, 16:11:08 »

I have what is probably a very silly question, but I will ask it anyway:  What is the actual relation of the BPM to the Speed of the song?

Here's what I know:

• Speed is the number of "ticks" representing the duration of a row.  So, a speed of 5 means that each row lasts for 5 "ticks."
• "Ticks" are the lowest unit of time in the tracker:  the state of effects, envelope, and other instrument synthesis is updated on each tick.
• BPM is another way of measuring the speed of a song, in beats-per-minute.

On my tracker (and I thought this was standard, but I'm not sure now), a "tick" is 1/60^th of a second, tied to the vertical refresh rate of the video signal (or 1/50^th of a second, on PAL/SECAM video).

So, my question is, where does the BPM fit in there if the tracker sequencing is controlled by the speed of the song, which is counted in 60Hz "ticks"?  It is not clear to me where in a pattern is a "beat," since it could be arbitrary depending on how you arrange it.

I suppose I could change the speed of "ticks" by scaling them down.  However, I wouldn't be able to make them go faster on my tracker, since the only source of timing I have is the vertical refresh signal at 60Hz.

Any insight in clearing my confusion will be greatly appreciated.

     -dZ.

34

Players / Re: Understanding effects processing

« on: January 08, 2024, 15:53:36 »

I have another question on effect functionality.  (Please let me know if you recommend I start a new topic for each individual question.)

For "volume slide," is the note volume itself altered or is it only modulated while the effect is given?

Here is an example.  Suppose I set a note with a volume slide downwards by one unit (the amplitude range on my sound chip is from 0-F).  The volume is decrement on each tick, only row #2.  Does the note continue at its regular volume, or does it stay at the last level modulated in row #1?

Code: [Select]

00 C-4 -1 F A01
01 --- -- - A01
02 --- -- - ---   <-- what happens to volume here?
03 --- -- - ---
04 --- -- - ---
05 --- -- - ---
06 --- -- - ---
07 --- -- - ---
08 --- -- - ---
09 --- -- - ---
10 --- -- - ---
11 --- -- - ---
12 --- -- - ---
13 --- -- - ---
14 --- -- - ---
15 --- -- - ---

   -dZ.

35

Players / Re: Understanding effects processing

« on: January 08, 2024, 14:29:20 »

https://modarchive.org/index.php?request=view_artist_modules&query=85716&page=2#mods

A good chunk of them is AHX. rest are MODs with chiptune samples in them
The difference here is that in AHX is not sample based

Thanks for that.  It seems MilkiTracker does not open AHX.

Sorry for the bother, I'm sort of new to the scene -- can you recommend an AHX tracker for Mac?

    -dZ.

36

Players / Re: Understanding effects processing

« on: January 08, 2024, 13:20:44 »

BTW, Dz, You can try to port Pink's chiptunes as a benchmark for your work. He has a lot of great chips out there. You can also take a look at AHX uploads, since they are SID-like tunes but made on Amiga.

Good luck with your project!

Hello,

Thanks for the support and encouragement.  Once I get a few effects more, I'll try porting some tunes.

I don't really compose music myself, but I like tracking.  I sort of treat it as "remixing" like back in my DJ days.

BTW, where do I find Pink's chiptunes?

     -dZ.

37

Players / Re: Understanding effects processing

« on: January 07, 2024, 23:37:49 »

HAPPY NEW YEAR!!!

I have some good news to share about my progress ...  I have managed to implement the first three effects:

• Arpeggio
• Portamento Up
• Portamento Down
• Portamento To Note

I have tested and debugged these first effects and they appear to work as expected.
Attached are three wave files generated from the emulator.  I created a simple one-track pattern for each to test the data encoding, the music player, and the effect processing.

For reference, below are the test patterns I used:
Arpeggio:

Code: [Select]

; 0xx: Arpeggio
00 C-4 -1 F 037
01 --- -- - 037
02 --- -- - 037
03 --- -- - 037
04 --- -- - 037
05 --- -- - 037
06 --- -- - 037
07 --- -- - 037
08 --- -- - 037
09 --- -- - 037
10 --- -- - 037
11 --- -- - 037
12 --- -- - 037
13 --- -- - 037
14 --- -- - 037
15 --- -- - 037

16 D-4 -- F 037
17 --- -- - 037
18 --- -- - 037
19 --- -- - 037
20 --- -- - 037
21 --- -- - 037
22 --- -- - 037
23 --- -- - 037
24 E-4 -- - 037
25 --- -- - 037
26 --- -- - 037
27 --- -- - 037
28 F-4 -- - 037
29 --- -- - 037
30 --- -- - 037
31 --- -- - 037

Portamento (Up/Down)

Code: [Select]

; 1xy: Portamento Up
; 2xy: portamento Down
00 C-4 -2 F 208
01 --- -- - 208
02 --- -- - 208
03 --- -- - 208
04 --- -- - 208
05 --- -- - 208
06 --- -- - 208
07 --- -- - 208
08 --- -- - 208
09 --- -- - 208
10 --- -- - 208
11 --- -- - 208
12 --- -- 0 ---
13 --- -- - ---
14 --- -- - ---
15 --- -- - ---

16 C-3 -- F 108
17 --- -- - 108
18 --- -- - 108
19 --- -- - 108
20 --- -- - 108
21 --- -- - 108
22 --- -- - 108
23 --- -- - 108
24 --- -- - 108
25 --- -- - 108
26 --- -- - 108
27 --- -- - 108
28 --- -- 0 ---
29 --- -- - ---
30 --- -- - ---
31 --- -- - ---

Portamento To Note

Code: [Select]

; 3xx: Portamento To Note
00 C-4 -2 F ---
01 E-4 -2 F 304
02 --- -- - 304
03 --- -- - 310
04 --- -- - ---
05 --- -- - ---
06 --- -- - ---
07 --- -- - ---
08 E-4 -1 - ---
09 --- -- - ---
10 --- -- - ---
11 --- -- - ---
12 --- -- - ---
13 --- -- - ---
14 --- -- - ---
15 --- -- - ---

16 E-4 -2 F ---
17 C-4 -2 F 304
18 --- -- - 304
19 --- -- - 310
20 --- -- - ---
21 --- -- - ---
22 --- -- - ---
23 --- -- - ---
24 C-4 -1 - ---
25 --- -- - ---
26 --- -- - ---
27 --- -- - ---
28 --- -- - ---
29 --- -- - ---
30 --- -- - ---
31 --- -- - ---

I am quite happy with the results and this success gives me confidence to proceed with the rest of the effects.

I have yet to implement "effects memory," but I suppose it shouldn't be a big deal.

Anyway, I just wanted to share some progress.  This is a major milestone in my project, for it included re-factoring and enhancing the music tracker, expanding the encoding structure, and implementing the effects. 

Thank you to looper231 for your patience.

     Cheers!
     dZ.

38

Players / Re: Understanding effects processing

« on: January 03, 2024, 18:08:32 »

50 years! Bloody heck! :O

I know!  Sounds crazy when I say it that way, but the truth is that the Intellivision is a games console released in 1980.  It has a CP-1610 processor -- one of the very firsts 16-bit microprocessors -- running at 1MHz, designed sometime in the 1970s!!! :O

The console has an on-board AY-8914 sound processor (a very early one!), and offers an expansion module that adds an extra sound chip.  Each AY has 3 square wave voices and a single noise generator which can be mixed with any of the voices.

That's it.  No filters.  No selectable waveforms.  No ring modulator.  All modulation is done in software, old school.

My goal is to make the Intellivision sing glorious chip-tunes like the best of the crop.

     -dZ.

39

Players / Re: Understanding effects processing

« on: January 03, 2024, 17:08:21 »

Interested to see progress from you!

Thanks for the interest.  I'll post a WAV or MP3 file as soon as I have something to show.

Right now, I have just completed the initial infrastructure changes to my music player that will allow it to support effects -- not a trivial thing for a tracker driving an AY-8914 on a 50 year old CPU with severe RAM limitations.

I will start implementing what look to be the easiest ones this week -- arpeggio, portamento up/down, volume slide, and tremolo -- so stay tuned!

    -dZ.


P.S., You may want to temper your expectations ... The Intellivision hardware is not powerful enough to play PCM samples, so all instruments are square waves with software envelopes.

40

Players / Re: Understanding effects processing

« on: January 03, 2024, 00:14:44 »

Thanks.  I have figured out my algorithm now.  I'm confident I can implement the effects. 

    -dZ.