A.L. sound converter

[sometimes99er]

Frequencies listed in the Beginner's BASIC, Appendix A, page 124, and those listed in the Editor/Assembler Manual, 20.3, page 318, are slightly different in most cases. I'll concentrate on the first 4 notes.

 

BASIC

 

A  110
A# 117
B  123
C  131

EA

 

A  110.00
A# 116.54
B  123.47
C  130.81

I tried and enter these values in TI Basic and TI Extended Basic. And using the Debugger of Classic99, I got these values in the 9919 sound processor.

 

A  110    >3F9
A# 117    >3BC
A# 116,54 >3C0
B  123    >38D
B  123,47 >38A
C  130,81 >357
C  131    >356

So Basic actually does calculations on the decimal numbers.

 

Comparing with the frequency codes in the EA, we see that Basic does a fine job.

 

A  110    >3F9 >3F9
A# 117    >3BC
A# 116,54 >3C0 >3C0
B  123    >38D
B  123,47 >38A >38A
C  130,81 >357 >357
C  131    >356

Obviously, or at least I'm assuming that, the manual for BASIC simplified the frequency input by rounding to nearest whole number. Would this lead to music based on BASIC being more off/out of tune ?

 

Here's one to try out. I'll come up with something better to judge (don't know when).

 

100 CALL SOUND(500,117,0)
110 CALL SOUND(500,116.54,0)
120 GOTO 100

This might indicate that the differences are not significant. We'll see.

 

Edited November 8, 2010 by sometimes99er

[Opry99er]

So--- I would have loved to have seen Matthew's sound player for XB demo'd at the Faire... I used it in Honeycomb Rapture and I'm using it in Calimari Carl as well. I know Saturday can be very demo-heavy... But this player is pretty amazing... I think the guys would have been impressed to see XB doing that.

 

Matthew, the more I see of your work, the more I realize you're a true TI guru. It's a real pleasure getting to watch your work and getting to know you. Many people contribute a ton to the TI community, and there are those like you and Tursi who are taking the next steps. Jon and Marc have been quite influential as well. Too many to name....

 

I'm in the company of giants.