state of the art atari SNDH music?

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Re: state of the art atari SNDH music?

Postby lotek_style » Tue Nov 05, 2019 5:36 pm

He's doing live gigs and selling his stuff on platforms like bandcamp:

http://ultrasyd.free.fr/
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Re: state of the art atari SNDH music?

Postby leonard » Wed Nov 06, 2019 8:23 pm

I looked a bit at the 0913 music disk protection. That's quite funny actually. The protection is quite smart because it makes ripping hard even using emulator. However it "may" affect sound quality. Some part of the music driver are decoded/encoded real time using trace mode. During these parts, interrupt are disabled ( sr=$a700 ). It means that some SID voice timer could be slighty delayed. I don't think it could be noticed, but anyway it should be mentionned :)

Worst is the music driver tick system. Some musics are not exact 50Hz music. For instance some music are 52Hz. Instead of using a 52Hz timer, a fixed 200Hz timer is used, and time to time music driver is called or skipped. So the music tick is not called at 52hz exactly. But maybe original Maxymizer music driver is using the same behavior.
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Re: state of the art atari SNDH music?

Postby evil » Wed Nov 06, 2019 8:53 pm

leonard wrote:Worst is the music driver tick system. Some musics are not exact 50Hz music. For instance some music are 52Hz. Instead of using a 52Hz timer, a fixed 200Hz timer is used, and time to time music driver is called or skipped. So the music tick is not called at 52hz exactly. But maybe original Maxymizer music driver is using the same behavior.


This is normal as many trackers use three timers for effects (A/B/D) and the remaining timer is C. Timer C is also used by the OS (plus harddisk driver) for it's 200 Hz clock. If you want to play the songs without killing the OS the normal thing is to hook on to the OS 200Hz Timer-C and call the music there.

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Re: state of the art atari SNDH music?

Postby leonard » Wed Nov 06, 2019 10:00 pm

evil wrote:This is normal as many trackers use three timers for effects (A/B/D) and the remaining timer is C. Timer C is also used by the OS (plus harddisk driver) for it's 200 Hz clock. If you want to play the songs without killing the OS the normal thing is to hook on to the OS 200Hz Timer-C and call the music there.


Yeah I get that. But still the music driver is not called at 52hz then. it's 52hz'ish with at 200hz granularity. 52 is quite ok because it's very close to a 200 multiple. But if you use same technic for say a 73hz music, I'm sure you will "hear" the difference with a real 73hz timer
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Re: state of the art atari SNDH music?

Postby dma » Thu Nov 07, 2019 8:09 am

maxYmiser can adjust the replay "frequency" by a single digit, so you can have 50/51/52/53/54/.......

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Re: state of the art atari SNDH music?

Postby evil » Thu Nov 07, 2019 10:05 am

leonard wrote:
evil wrote:This is normal as many trackers use three timers for effects (A/B/D) and the remaining timer is C. Timer C is also used by the OS (plus harddisk driver) for it's 200 Hz clock. If you want to play the songs without killing the OS the normal thing is to hook on to the OS 200Hz Timer-C and call the music there.


Yeah I get that. But still the music driver is not called at 52hz then. it's 52hz'ish with at 200hz granularity. 52 is quite ok because it's very close to a 200 multiple. But if you use same technic for say a 73hz music, I'm sure you will "hear" the difference with a real 73hz timer


Well if you want to do a SNDH player that plays tripple timer music and keep the OS alive (for example SND Player) there isn't much choice other than try to play it on the OS 200 Hz interrupt. If you reprogram Timer C there's a risk of harddrive corruption.

I don't know how this particular demo does it, but SND Player is something in the line of;

Code: Select all

play:
   sub.w #replay_freq,counter
   bpl.s   .noplay
   
   add.w #200,counter
   bsr sndhfile+8

.noplay:
   rts

counter: dc.w 200



My ears (or rather timing) is perhaps too inaccurate, but it has seemed fine with the tracks I've tested, and there are quite many 60 Hz files in the archive.

Perhaps if I got time tonight I'll try find some 60+ Hz file that doesn't use all timers and setup a true interrupt and an approximated 200 Hz. It will be interesting to see if I can notice a difference :-)

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Re: state of the art atari SNDH music?

Postby evil » Thu Nov 07, 2019 3:49 pm

evil wrote:Perhaps if I got time tonight I'll try find some 60+ Hz file that doesn't use all timers and setup a true interrupt and an approximated 200 Hz. It will be interesting to see if I can notice a difference :-)


Ok, so I did a test between a true 70 Hz Timer A (ok, 69.8181 Hz) and a simulated 70 Hz from the OS 200 Hz Timer C.

Here are two recordings, please listen to them first before downloading the source with the spoiler :-)

Method 1: http://ae.dhs.nu/tmp/replay_1.mp3
Method 2: http://ae.dhs.nu/tmp/replay_2.mp3

Here are the test sources, hopefully I didn't make too many errors.
http://ae.dhs.nu/tmp/leosndh.zip


I can't tell which is which.

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Re: state of the art atari SNDH music?

Postby leonard » Thu Nov 07, 2019 4:07 pm

evil wrote:I can't tell which is which.


nice test! I have to admit it's same for me, I can't tell which is which. I'm surprised. I thought it will be more noticeable ( esp about some nasty jittering in the music tempo )
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Re: state of the art atari SNDH music?

Postby npomarede » Thu Nov 07, 2019 5:17 pm

Hi
a long time ago, when writing the YM2149 emulator for Amiga I was faced with the same issue : how to play 60 Hz musics when the Amiga was running at 50 Hz VBL.
I used a similar method (ie add 50 / sub 60) to simulate 60 Hz replay when VBL was 50 Hz and as with Evil's test it was also mostly not possible to tell the difference between the replay running at true 60 Hz on ST or the 50 Hz equivalent on Amiga.

Nicolas

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Re: state of the art atari SNDH music?

Postby Grazey / PHF » Thu Nov 07, 2019 5:23 pm

evil wrote:
evil wrote:Perhaps if I got time tonight I'll try find some 60+ Hz file that doesn't use all timers and setup a true interrupt and an approximated 200 Hz. It will be interesting to see if I can notice a difference :-)


Ok, so I did a test between a true 70 Hz Timer A (ok, 69.8181 Hz) and a simulated 70 Hz from the OS 200 Hz Timer C.

Here are two recordings, please listen to them first before downloading the source with the spoiler :-)

Method 1: http://ae.dhs.nu/tmp/replay_1.mp3
Method 2: http://ae.dhs.nu/tmp/replay_2.mp3

Here are the test sources, hopefully I didn't make too many errors.
http://ae.dhs.nu/tmp/leosndh.zip


I can't tell which is which.


Nice one Anders. You beat me to it!

To be honest I’ve never noticed a difference either. Even with 75hz + tunes like some of those by Chris Denman.

I always use the timer c method when converting tunes even for those which don’t use timers a/b/d for fx. There are even some SNDH’s which have different hz for different sub tunes! If you can find them :)

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