Music with DAC??

[magoseitor]

hi guys.. i had this idea,

if possible, could it be factible instead of trying to ouput nice music trough the I/O port using pwm, use an external digital to analog converter?

i am just frustrated in playing MOD, (or S3M, IT, whatever tracker format) format music on the ti.

i tried out pplayer and midi68k, and some external tunes, but none of them had even 100% near to MIDI quality...

is it possible to encode MOD format to whatever format the TI calc understands, and then decoding it to digital audio and output it through the I/O port and then to the external DAC?

cheers.

please don't abuse of me, i am a noob, but i have this idea, i just want to know.

[DigiTan]

Yep. It's possible to come up with a new sound program and use an R-2R Digital/Analog converter. With the two link wires, that would give you 4 possible output levels. Then a capacitor on the output would provide filtering of high-pitched noise. This has been done for video, but not sound that I know of.

Also Jim e came out with the RealSound program that plays MP3-quality audio. Again, you can filter out the upper harmonics for even crisper sound. Jim e uses PWM.

In the Sonic thread we were once considering recording real instrument samples to get a MIDI-like system. It was based on the idea that:
Frequency = Original Frequency ( Sample Rate / Playback Rate )

We abandoned the idea after a while.

[magoseitor]

Thanks for the answer DigiTan...

I tried to check out RealSound, but i have a 89Ti, also i wanted to see the code, and see it didn't came with the zipped file :-(

I have another question, is it possible an usb driver for the ti-89 like the 84 has?
Because if we have a nice quality sound with small files (MOD, 100%-alike MIDI), then is good for us; the realsound is a nice idea and app, but you can fit less than 2 min of sound. So, if we could have external storage this would be no problem.

Another question: is it possible to read/write from the multiple ports in the 89Ti at the same time (I/O and mini-USB)

Now about the R-2R DAC, i would like to play with that.
Look, i am a student of electrical engineering, and in 3/5 of the carreer, this semester i am cursing digital electronic and microcontrollers. So, besides what i may learn and apply it to this stuff; i am willing to crunch whatever texts/information/knowledge is necessary to somehow make my ti-89 a factible music player.

Could you please, or somebody, give me the light so i can walk the path?

Thanks.

[TheStorm]

Well for the usb stuff no-one has yet to figure out how the usb hardware one the 89t's work hence the lack of msd driver. if you want to look into it go ahead. as for the read and write to two ports at the same time, I'm pretty sure you can but I do not own a 89t so don't take my word for it.

[Liazon]

I suspect no one has bothered to write an MSD driver. iirc, I remember that TIGCC was updated some time ago by Kevin Kofler to support the USB on a high level. As to why it's not used much idk, maybe programmers feel not many people have 89tis or something. Kevin mentioned that the USB is not really that much better than the link port, it's just different, but I'm not sure about that. Also, I think since the 89s have a lot of flash space, and perhaps out of lack of interest, there aren't that many sound programs/USB programs for it.

[DigiTan]

[magoseitor]

Many thanks for the answer guys!! :biggrin: i guess i'll be playing and playing until i figure out how the f**k i can play mod with quality or make usb storage while taking my courses... (so so far...) but at least i'll have fun

cheers, and again, seriously thank you.

[DigiTan]

Yep. TI-89 has a serious amount of memory, so it kind of makes sense that there should be more sound progs for it. A midi system would be really useful for games too.

[CoBB]

I don’t think playing existing module music on the Z80-based calculators is feasible, there’s simply not enough raw power to perform the mixing at any sensible quality (just consider for starters that you need at least one multiplication per channel per sample to handle volume). If all the samples fit in 16k (which basically leaves us with chip music) and we leave the amplitudes alone, then a few channels might be possible. However, that would leave little time for everything else, so using such a player in the background is out of the question.

[Jacoby]

[magoseitor]

I came up with more stuff in class today, i am just writting what i thought, i haven't yet read any information about it, so i'm open to flames hehehe

Ok, the MOD file is supposed to be samples+structure... we take the samples, and the structure, rearrange it to whatever the 89Ti likes, making a new ti-readable file. We make a new player that do the same as the mod players: throw out the samples according to the structure, plus, some effects. That supposed sampled music goes out in series through the I/O port. We put in the middle a series to parallel converter and finally that R-2R DAC (or other better [or comercial]).

Using 8 or 16 bit.

so the newbie has made its humbble aport :-P

cheers
and thanks for the posts...

[CoBB]

[magoseitor]

Well,.. after reading the mod format and the midi format i guess i still need plenty more C/asm knowledge. I'll first try to output a simple 12k WAV PCM enconded file to test the possible hardware i might build. If the simple data stream plays with aceptable quality (at least form my point of view) with the external hardware, the i get into the software part.

thanks for the answers...

[CoBB]

[magoseitor]

Thanks for pointing that out, i like more mod than midi.. just spoke about mod for saying another pre-sampled file format.

About the hardware, i think something about this..

89Ti I/O port (series data stream) -> 74HC164N (8-Bit Serial-to-Parallel Shift Register) -> 8 AND gates -> 8-bit DAC

Know... i still have doubts about DAC's. What kind of binary number are these devices used to operate with? (signed, unsigned, ones or twos complement??)

[Jim e]

Just for your info, the 89 has Ti-vibe. Pretty much realsound for the 89. To bad they can't make their own flash apps.

http://www.ticalc.org/archives/files/fileinfo/386/38629.html

[magicdanw]

[Jim e]

[Jacoby]