Tritone (GTIA beeper engine)

[+Stephen]

Sounds great on my 130XE - NTSC plays back at the proper speed too

[a8isa1]

> Could these sounds become a library for use in a tracker/player? I mean, is this for demonstration or low level programmers only, or could it be the basis for a user application?

 

e.g. MilkyTracker and xm2GTIAtr converter

 

 

> Still waiting for some real HW files to listen to it on an Atari 800.

 

not Atari 800 but Atari 800XL - XL/XE series (6502C)

 

try attachment - obx for atari and .xm for music editor

 

 

LAST version before converter

> Could these sounds become a library for use in a tracker/player? I mean, is this for demonstration or low level programmers only, or could it be the basis for a user application?

 

e.g. MilkyTracker and xm2GTIAtr converter

 

 

> Still waiting for some real HW files to listen to it on an Atari 800.

 

not Atari 800 but Atari 800XL - XL/XE series (6502C)

 

try attachment - obx for atari and .xm for music editor

 

 

LAST version before converter

Oops, didn't notice the bit about not for 800 until after I tried.

 

I do hear some of the rhythms.

Edited June 8, 2013 by a8isa1

[Fres]

Yeah, Steve. Guess I didn't notice that either.,

[+Philsan]

Is it possible to play POKEY and GTIA tunes together to have 5 audio channels?

[xxl]

hmmm, why not.

 

 

ok. small update. there is a possibility to adjust the base sound frequency for the player - synthesizer think that the CPU is running at 1.78 MHz, 2.5 MHz, 3.5 MHz

 

http://atari.pl/freqtest.mp3

Edited June 9, 2013 by xxl

[MovieMovies1]

I just want to say that you have done a fantastic job porting Tritone from the ZX to the Atari 8-bit. Keep up the good work, man!

[xxl]

MovieMovies1 makes great 1-bit music

 

http://chipmusic.org/moviemovies1/music/tritona-explodarium-1-bit

[snicklin]

Please excuse my ignorance here, I do not wish to sound disrespectful to this great bit of work. Something just occured to me after a few glasses of red wine...

 

What is the advantage of doing this with the GTIA over doing it with Pokey? Can the same not be achieved by a channel or two in Pokey?

 

What I have heard sounds great, better than Pokey in fact, but what is the difference... technically? Why does it sound better? Or is Pokey under-utilised?

 

... back to the glass...

[Synthpopalooza]

You can do the same with Pokey ... the GTIA adds a fifth channel though.

 

With pokey, you use an odd distortion value ($10-$1F for example) in AUDCx, AUDFx is not used at all, and by rapidly alternating the volume of the AUDCx registers in VBLANK, you get 4 channels of 4-bit samples. You could theoretically add the GTIA engine to this and get 5 channels of sampled sound.

[José Pereira]

But can't never be used for a in-game tune (because the use of GTIA in itself?)?

 

Something like this would never be possible:

ch0: GTIA music1

ch1: POKEY music2

ch2 and 3: 16bit POKEY music3

ch4: POKEY sound fx

(this or any other combinations...)

????

[Creature XL]

But can't never be used for a in-game tune (because the use of GTIA in itself?)?

 

Something like this would never be possible:

ch0: GTIA music1

ch1: POKEY music2

ch2 and 3: 16bit POKEY music3

ch4: POKEY sound fx

(this or any other combinations...)

????

 

AFAIK it doesn't disturb GTIA in any way.

The reason why it is (mostly) unusable in games is that it is CPU intensive.

Month ago, when this "NES-like pulse wave" thing came up here, I made some experiments and it should be usable in games, when you only use low notes, bass for example. However, doing it with GTIA wouldn't have gotten me an extra channel. The change of the pulse-wave frequency was done with a POKEY timer IRQ. So the channel is lost for music anyhow.

 

Here is hoping to find more time after the 31. of August to go back to that topic

[+skr]

Here is hoping to find more time after the 31. of August to go back to that topic

 

:thumbsup:

[utz]

Great stuff. And now that I finally have a working 800xl, I'm especially looking forward to xm2gtia converter (and secretly hoping for ZX-10 gtia port)

Btw some interesting distortion going on at bass frequencies. A bit different from how it sounds on Spectrum, but not really in a bad way. Overall great sound quality, actually sounds like it's running more stable than the ZX version.

[xxl]

ZX-10 on the Atari is available since "Beep'em all 3" - http://www.youtube.com/watch?v=_Jz_wObhyi8

 

 

xm2GTIAtr (Tritone) converter will be ready soon. I had to change more than I intended, what is released does not play some notes.

 

 

---

see post #28, utz uses Tritone engine:

Edited June 16, 2013 by xxl

[utz]

I don't see any ZX-10 tracks in Beep'em All 3?!?

[xxl]

I thought of the ZX-7 / Octode family. You're right, in Beep'em all 3 there is no music on ZX-10 engine. I'll try use it in "4"

[ZylonBane]

With pokey, you use an odd distortion value ($10-$1F for example) in AUDCx

 

Stop saying that. The documented way to activate POKEY's volume-only mode is to set bit 4 of AUDCx.

[Xuel]

Stop saying that. The documented way to activate POKEY's volume-only mode is to set bit 4 of AUDCx.

 

Technically the volume-only bit is a separate component but there is ample precedent for referring to the entire high nybble of AUDCx as the "distortion". Both RMT and TMC refer to it and make you enter it that way.

 

Quote from RMT documentation:

 

DISTORTION - Sound type from $0 to $E, even values only.

 

Quote from TMC2 documentation:

 

- Distortions (usually the A value is used for clear sound, C for basses and 8
for drums, odd values (e.g. F) turns the generator off and allow to directly
operate the membrane of speaker).

Edited June 17, 2013 by Xuel

[ZylonBane]

Then shame on the RMT and TMC2 documentation. That type of "I dunno know why this works" explanation isn't good for anyone.

[Creature XL]

Technically the volume-only bit is a separate component but there is ample precedent for referring to the entire high nybble of AUDCx as the "distortion". Both RMT and TMC refer to it and make you enter it that way.

 

Quote from RMT documentation:

 

DISTORTION - Sound type from $0 to $E, even values only.

 

 

Just for the fun of knit-picking:

The "even values only" kinda is contrairy to your statement "RMT manual calls it distortion"

[foft]

Is gtia vs pokey relative volume known? Is the mixing non-linear in the same way as combining pokey channels?

[Aking]

Is gtia vs pokey relative volume known? Is the mixing non-linear in the same way as combining pokey channels?

 

i think so

[xxl]

small progress. music data are not compatible anymore with the zx player.

 

http://atari.pl/huvva.mp3

[Faicuai]

WOW!

 

Since like good news are pouring lately (while I keep missing them...)

 

Tried this on my (affectionately) "JM"-800, loaded with Incognito and booting Q-Meg OS.

 

COULD NOT F-BELIEVE what was coming out of that little / old speaker... In fact, it is time for an UPGRADE. I need to upgrade the internal speaker to something that has a similar form-factor but much better bandwidth (there is MORE juice on Tritone's output, than what the internal speaker can deliver!)

 

I researched on the A800's internal speaker and this is the closest I've found, so far:

 

http://www.parts-express.com/pe/showdetl.cfm?partnumber=289-110

 

A800 Service Manual indicates impedance >60Ohm, though... it would be great to find something with a similar form-factor (drop-in replacement) with synthetic/longer-lasting cone material and spectral response of 250 Hz to 15Khz, at least...

 

Any ideas / suggestions, more than welcome!

[R4ngerM4n]

small progress. music data are not compatible anymore with the zx player.

 

http://atari.pl/huvva.mp3

 

Sounds a bit emkay-ish

 

You are a true Atari-Wizard, XXL!

 

Looking forward to the Last Ninja 2 tunes on Atari graphics chip