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SIDWAVE
Account closed
Registered: Apr 2002
Posts: 2238 |
How many BPM is a C64 or HardSID ?
[03:19] <rambones> any geniousses ?
[03:19] <rambones> how many bpm is a C64 raster irq ?
[03:20] <rambones> or as i this case. the music is at 51 hz... so i wanna find the sync to the beat
See. i wanna sync a sampled sid to the tracker..
So... it was sampled with HardSID which is 51 hz..
It must be around 120-130... but i am uncertain..
No clue what to google for |
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Frantic
Registered: Mar 2003
Posts: 1648 |
Sorry.. I didn't read the initial post properly. I missed the 51hz (is that exact?) part and the sample being from hardsid... 51hz gives you 127.5 beats per minute instead. |
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goto80
Registered: Jan 2002
Posts: 138 |
i get perfect sync when running a C64-tracker (on a PAL C64) with a tempo in ableton live set to 2 decimals, ie 125.31. it seems as if it is not always right though, which could be just my brain imagining, or could it have something to do with, uhm, electricity? --- (but yeah, i guess this a bit OT aswell) |
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Frantic
Registered: Mar 2003
Posts: 1648 |
It is kinda funny that there is something like a "standard song speed" on the C64. :)
(...even though of course not ALL tunes use this speed.) |
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Mace
Registered: May 2002
Posts: 1799 |
Quote:I was just trying to avoid the work of chopping PC audio programs like Sony Acid can do that work for you. I believe there are more tools (Recycle?).
Also there's the method of timestretching, available in Cubase SX 3 IIRC.
Quote:It is kinda funny that there is something like a "standard song speed" on the C64. Well, there are various speeds, of course. It depends on per how many rastercycles you cycle the music.
And then there's of course music that doesn't run on Raster IRQ. I believe Soundmonitor can be one of those... |
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(451)
Account closed
Registered: Mar 2012
Posts: 3 |
Quote: This is a function, of course, of the speed in your editor, and a function of how many lines you consider to be a beat :)
So if you multiple editorSpeed x lines-per-beat, you'll get a number out that is frames per beat.
Multiply 51(50) x 60 to convert to frames per minute (3060/3000), then divide by frames per beat.
I'm attempting to work this out, but I'm obviously no math genius. If anyone could tell me what I'm doing wrong alternatively posting EVERY possible SID (PAL) speeds in BPM I would be well happy!
My song tempo is 07 (in SID Wizard) and my beat is 6 lines.
7*6=42 (frames per beat)
3060/42=72,8571 BPM
Right?
When I play it back in Ableton Live with 72.86 it's not quite right, it plays a bit too slow, and it's more than just that 0.0029 difference. So I tried recalculating it with 3000 instead (71.43 BPM) and it gets better (the sync gets disturbing after about 3 bars 4/4 time instead of half a bar).
This was done with emulation (Vice) since I'm home for christmas and can't try it on the real thing, so maybe the emulation is the issue, but I can't figure out how to get the 187.967033, 125.3113553, 93.98351648 values either, so I'm thinking I'm doing something wrong in the calculation process.
Thanks in advance! |
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wacek
Registered: Nov 2007
Posts: 513 |
I had similar problems when porting music from other non-standard tools (jeskola buzz) into Ableton Live. The best way IMHO is setting the BPM value as a rough estimate, and then syncing manually the beat at the end of your sequence, using Live's very friendly user interface :) If you keep looking for a perfect value to enter in the clip properties, you'll never find it to my experience.
This method is much faster works best for me so far, like I said not only with 64 recordings, but also whenever you're doing a mix from different sources (analog/digital, vinyl, live music etc). |
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Graham
Account closed
Registered: Dec 2002
Posts: 990 |
Quoting (451)
My song tempo is 07 (in SID Wizard) and my beat is 6 lines.
7*6=42 (frames per beat)
3060/42=72,8571 BPM
Right?
PAL C64 has a base clock of 17734475 Hz, system clock is 1/18th of that. Clock cycles per frame are 312*63.
Framerate of the C64:
17734475 / (312*63*18) = 50.125 Hz
Quoting (451)When I play it back in Ableton Live with 72.86 it's not quite right, it plays a bit too slow, and it's more than just that 0.0029 difference. So I tried recalculating it with 3000 instead (71.43 BPM) and it gets better (the sync gets disturbing after about 3 bars 4/4 time instead of half a bar).
Per minute:
(17734475*60) / (312*63*18) = 3007.474 Hz
Divided by 7*6 = 42:
(17734475*60) / (312*63*18*42) = 71.607 Hz
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(451)
Account closed
Registered: Mar 2012
Posts: 3 |
Graham:
71.61 BPM (since I only can set two decimals) works REALLY well, thanks for explaining!
wackee:
Since I use Live mainly as sequencer I think I'll just fine-adjust the clips manually where needed, but that method might come in handy for future projects, thanks! |
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ChristopherJam
Registered: Aug 2004
Posts: 1409 |
Perhaps run off CIA instead of VIC?
Given that the system clock is (17734475/18)Hz, one fiftieth of a second passes every (17734475/18/50)=19704.972 cycles.
If you run the music routine off a CIA interrupt set for 19705 cycles, that'll get you a play rate of (17734475/18/19705) = 49.9999Hz, or 2999.996 ticks per minute.
At 24ppq, that's a speed of 124.9998bpm - that should drift by less than half a millisecond over the course of a five minute 125bpm track. |
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Mace
Registered: May 2002
Posts: 1799 |
Why sync the PC to the C64 and not the other way around? |
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