ATK: FOA speed of sound

[joslloand]

ATK issue: ambisonictoolkit/atk-sc3#104

AtkFoa.speedOfSound = 333.0; // (m/s)

NOTE: this value is implied by the current setting of the cutoff
frequency (53 Hz) found in the sc3-plugins code for FoaProximity & FoaNFC

freq = speedOfSound / 2pi // wavenumber = 1
speedOfSound = 53 * 2pi // 333.0

this value is the speed of sound @ 3C
https://www.weather.gov/epz/wxcalc_speedofsound

TODO: consider updating sc3-plugins to align with
AtkHoa.speedOfSound = 343.0

The fix for this is simple. For FoaProximity and FoaNFC, replace the frequency setting of 53.0 Hz with 343.0 / 2pi -> 54.59014548052

There are four lines to be updated:

sc3-plugins/source/ATK/AtkUGens.cpp

Line 1949 in fa550fb

float freq = 53.0 / distanceStart;

sc3-plugins/source/ATK/AtkUGens.cpp

Line 1999 in fa550fb

float freq = 53.0 / distance[i];

sc3-plugins/source/ATK/AtkUGens.cpp

Line 2063 in fa550fb

float freq = 53.0 / distanceStart;

sc3-plugins/source/ATK/AtkUGens.cpp

Line 2113 in fa550fb

float freq = 53.0 / distance[i];

[joslloand]

Don't forget to update the README!

[joslloand]

@mossheim, @telephon, @joshpar

The question is one of etiquette. Is it preferred for me to directly make the above listed changes to the ATK's plugins, or would it be preferable for me to make a PR?

Do let me know, as I'd like to be sure play nicely!

[dyfer]

Hi @joslloand
I think anything that gets into the main branch needs to go through a PR anyway, so making one is probably the best way forward.

[joslloand]

Thanks @dyfer, I'll go ahead and prepare a PR.

It would be great to be able to have the update in to coincide with the upcoming SC 3.12 release.

[dyfer]

It would be great to be able to have the update in to coincide with the upcoming SC 3.12 release.

Noted.
I have a feeling the 3.12 release of sc3-plugins will be a bit behind the SC release, FYI.

[joslloand]

@dyfer, yes, I would expect so... but was hoping to be ready for it....