Commit Graph

18 Commits

Author SHA1 Message Date
Jeff Epler 1d1907b98b
synthio: Generalize vibrato into bend
bend can be static, sweep, or vibrato
2023-05-11 09:31:07 -05:00
Jeff Epler c031bda5dd
synthio: implement a range compressor with hard knee
This really improves the loudness of the output with multiple notes
while being a nice simple algorithm to implement.
2023-05-08 09:22:42 -05:00
Jeff Epler a53c0ed066
synthio: add onevo_to_hz, implement midi_to_hz in terms of it
this has the side effect of making some notes more accurate, the new
frequency= value in the test is closer to the true midi frequency of
830.609...Hz.
2023-05-06 21:35:19 -05:00
Jeff Epler d2aca7eba0
synthio: fix per-note envelope & envelope modification
.. and simplify the envelope advance logic by handling
'instant' values more intelligently.
2023-05-04 12:23:45 -05:00
Jeff Epler 2b0231e9d3
synthio: re-striking a note should re-enter attack
.. without changing the current note amplitude
2023-05-04 07:23:50 -05:00
Jeff Epler 1701552dec
synthio: make sustain level relative to attack level
and re-vamp overall envelope calculation again.

Now, if you set a low overall attack level like 0.2 this avoids the
"diminishing volume" effect when many notes sound at once. You need
simply choose a maximum attack level that is appropriate for the max
number of voices that will actually be played.
2023-05-04 07:23:50 -05:00
Jeff Epler c06597c07a
synthio: replace the quietest releasing note when over-writing 2023-05-04 07:23:49 -05:00
Jeff Epler 4f56b7646e
synthio: slow ramp overall envelope back up
.. and account releasing notes at their sustain level until they're
done.

this ameliorates the effect where multiple releasing notes
don't seem to actually be releasing, but stay at a constant volume.
2023-05-04 07:23:49 -05:00
Jeff Epler a7da245ad0
synthio: Add synthio.Note
This class allows much more expressive sound synthesis:
 * tremolo & vibrato
 * arbitrary frequency
 * different evelope & waveform per note
 * all properties dynamically settable from Python code
2023-05-04 07:23:49 -05:00
Jeff Epler 5514e3065d
synthio: add midi_to_hz
to convert notes in the MIDI 1-127 note scale to floating point Hz
2023-05-04 07:23:48 -05:00
Jeff Epler d8550f4e7c
synthio: fix offset in default square waveform 2023-05-03 09:37:02 -05:00
Jeff Epler 12c1a72f03
synthio: implement envelope
This works for me (tested playing midi to raw files on host computer, as
well as a variant of the nunchuk instrument on pygamer)

it has to re-factor how/when MIDI reading occurs, because reasons.

endorse new test results

.. and allow `-1` to specify a note with no sustain (plucked)
2023-04-25 12:05:53 -05:00
Jeff Epler 79d093d957
tweak max envelope calculation vs number of active notes 2023-04-05 17:43:03 -05:00
Jeff Epler 9993b4b01c
Prevent playing the same note on 2 channels 2023-04-05 16:53:08 -05:00
Jeff Epler 04f4092e11
synthio: support audio outputs that need double buffering
closes #7837

tested on rp2040 pico w on pico dv shield
2023-04-05 11:57:13 -05:00
Jeff Epler b011468251
Add synthio.Synthesizer
In contrast to MidiTrack, this can be controlled from Python code,
turning notes on/off as desired.

Not tested on real HW yet, just the acceptance test based on checking
which notes it thinks are held internally.
2023-04-02 20:37:23 -05:00
Jeff Epler e0984fa195
Factor out the synthesizer from midi track 2023-04-02 18:54:07 -05:00
Artyom Skrobov 8056af8648 [synthio] add a simple MidiTrack implementation 2021-03-26 16:38:10 -04:00