Tone Generator

[Gigatron]

Hi

Last days i've sarted a project called Sin table generator
https://forum.lazarus.freepascal.org/index.php/topic,71121.0.html
This new projet is
based on generated sin wave to produce a simple sound (be carefull to play with parameters, sure bugged at now ).
It use mmsystem and fill buffer like players i converted. I will try to improve it to
make an interesting program (missing formula).

Regards GTR

[Thaddy]

Did it occur to you that for a pure sine in audio you just need half the wave and mirror that for the lower part? Or at most one complete sine cycle.
If it is sine, you can simply switch buffers two , not regenerate them.
That would greatly simplify the code and is less demanding on the CPU.
You should also generate the pre-compiled sine waves depending on the sample rate. Adjusting for note value can simply be done with the twelft root of two (~1.05 * note value)
This is how most synthesizers work.

[Gigatron]

Hi,

Thank you, I’ll study your recommendations and test the buffer mirroring approach. This could really optimize my code  ,  for now the latest version .

Regards Gtr

[JollyHong]

If you are writing or testing tone generation code in Lazarus, it’s really helpful to compare your output against a reference tone to verify frequencies, sample rates, and waveforms (sine, square, triangle).
When testing audio buffers or troubleshooting sound output, I usually drop a quick online generator like https://frequencylama.com/ into a browser tab to quickly double-check frequencies by ear alongside what the program is producing.
Are you generating PCM samples manually in code, or using an external library like BASS or PortAudio?

[CM630]

Did it occur to you that for a pure sine in audio you just need half the wave and mirror that for the lower part? Or at most one complete sine cycle.

Or maybe even quarter a wave ... though I wonder if the maximum of the sine will be fine.

You should also generate the pre-compiled sine waves depending on the sample rate. Adjusting for note value can simply be done with the twelft root of two (~1.05 * note value)

I have (always) thought it is 6 %, not 5 %, since my father told me so in the previous millennium. I think he did not lie.
2^(1/12) = 1,059463094


BTW, I also have played with these:
https://sourceforge.net/p/lazmer/code/HEAD/tree/trunk/misc/functiongenerator.pas (the package itself runs only in Lazarus Trunk).

[Thaddy]

Yes. Correct. I usually use the 12th root of two as a constant single.
This is fine in practice from middle C, although I sometimes code per two octaves to avoid any noticeable drift.

[Fred vS]

Hello.

There is also WavvieW, the signal producer and analyzer, included sine and white noise, with all pascal code.

It uses MSEgui widgetset.

[Bart]

Long, long time ago I programmed a piano like program (using Graph unit) that generated tones (using 12th root of 2 rule) using good old Sound() in TP.
This reminds me of that undertaking...

Bart