MODs for the IIe (!)

[irsman@iastate.edu (Ian Schmidt)]

This came in the mail; I'm posting it since it was inteded to go public.

Bug him, not ME!

--- begin quoted message ---

Hmm. I hope this message is actually going public. Anyway this
seemed like a good time to correct you on the above point. I have actually
written a .mod player for my apple 2e and though it admittedly needs quite a
bit on the hardware side of things it does sound quite reasonable on my
system. (IMHO) 

Specs: 

Hardware required - Some sort of DAC (digital to analog converter). I use a
                 SAM (software automated mouth) card but I suspect almost any
                 sound card will do. Eight resistors on the parallel port
                 does the trick also.
                 - A ramworks card is very useful. You can play very small
                 modules in 128k. If I cut out every second byte of the samples
                 modules up to about 70k can be played. With a 512k ramworks
                 card I have played a 320k module at full quality.

Speed - I have an 8mhz zip chip but its caching plays havoc with sound
        and I have to disable it for a significant portion of the main loop.
        On a 1mhz machine I will normally get 7.5 khz which is not very good
        obviously but as long as the module doesn't have voice in it it is
        bareable. With the zip chip I can get 17 khz playback which is 
        very good. Most samples in modules are sampled at less than this
        anyway. The quality at this stage is rarely dependent on the neat
        filtering and quality of your amp etc. The other reason GS's and 
        amigas will sound better is because they play back the full 8bit of
        the samples but due to only having on DAC I have to mix the samples
        which reduces it to 6bit.

Oscilliscope - With the 8mhz zip chip version I also have a double-hi-res 
         oscilliscope of the output waveform playing which is very pretty.
         This reduces sound quality to 12khz but the zip chip can be enabled
         through all of the oscilliscope routine. 

The reason I am writing this now is that I am thinking of posting the player
comp.binaries in the next few weeks if people out there actually have the 
hardware to use it and are interested. I have to make the interface a little 
more friendly and put in some code to select which slot the sound card is in
so if it is going to be worth my time to do this please mail me to let me
know.

-- 
| Damon J. Rand                        Thought for the day:                |
| Christchurch (The garden city)             If the shoe looks good        |
| New Zealand                                it doesn't fit                |
| Internet: D.Rand@cantva.canterbury.ac.nz                                 |
-- 
                                          Ian Schmidt: irsman@iastate.edu
"I will choose a path that's     |  /~~~\              irsman@aol.com
 clear: I will choose free will" | |    < o  o  o  o  o  o  o  o  o  o  o
 - N. Peart, 1980                |  \___/              twbv4@isuvax.bitnet