Creating WAVE sounds for HP48G(X)

With this html file, you'll find :

• Digiconv.exe : The PC program to convert 44100 Hz 16 bit PCM wave files to HP format.
• Digiconv.txt : Digiconv documentation
• opn.prg : HP48 program which plays the opening Star Wars music
• imp.prg : HP48 program which plays the Imperial March music
• dbv.cd : code which plays wave sounds on HP48
• appl.prg : HP48G(X) program that builds programs which play music using the output of digiconv

To create your own sounds on HP48, you need first to convert a wave or mp3 file into a 44100 Hz 16 bit mono wave file.
You can use Sound Forge to do that.

Then, use digiconv to convert the wave file into an HP file :
Example :       digiconv.exe Opening.wav Openinig.hp -f11242
That sequence will create an Opening.hp file from the Opening.wav file with a frequency of 11242 bits per second.
That frequency is needed by dbv.cd to play the sample at the same speed as the original wave file.

Digiconv creates an HP48 file with an HPHP48-W header. To play it, you need to extract the Library Data object from the string. This can be done with fixit, included in this package.

When you get the Library Data object, you can play it with Jean-Francois Morreuw's (aka DBV) program, which I called dbv.cd. That code needs two arguments :
2: Library Data
1:          #7h

You can change the speed by modifying the binary integer (it must be between #4 and #8, with #4 the faster and #8 the slower). However, if you choose to play it at a different speed from #7h, the sound will be quite strange. You can also change the frequency used by Digiconv and create sound files of different sizes.

Anyway, the other way is to create a program that plays the output of digiconv. This is allowed with appl.cd. Appl.cd take one argument, the "HPHP48-W..." string produced by Digiconv at stack level 1. It uses it to create a "Library Data #7h Code External" program that plays the original wave file you used with digiconv.

A major problem with this wave converting method is that much noise is generated while playing the sound.
This probably comes from the low efficient buzzer the HP calculators have. If anyone knows how to modify the original wave file to cut the noise off the sound, write to me.

Credits : I would like to thank Jean-Francois Morreuw for his music playing program, it is the best one of its category.

Yoann Désir

email : yoanndesir@yahoo.com
URL : ydesir.multimania.com/hp48gx/english.html

Liens :
Hp-Sources, a french web site about HP calculators which I maintain.
Hp-Network, another french web site about HP calculators.
HpCalc.org, the premier international database for programs and information about HP calculators.