weeellll, I've already thought carefully about that idea but the Rparam variable already controls the playback Rate as appropriate on a range (say) +/- 10 (m/s) so the frequency of the sound changes from low (-10) to high (+10). If I set the Vparam to scale from zero to max (100?) over the same range, if I understand your suggestion correctly I'd could have quiet low frequencies and loud high frequencies, but it's not clear how I'd be able to modulate the sound over the full frequency range at a fixed volume, but also shift to lower or higher volume but still the full frequency range. The trick I mentioned above to turn the sound OFF was to extend the vparam table far outside the normal range of the controlling variable (normally +/- 10), and I set an area of rparam = 0 from -99 to -40. To turn the sound OFF I set the controlling variable to -70.
The idea is the volume would be controlled by a volume knob implemented on the gauge, but I *still* have to be able to swing the frequency of playback as normal.
I *could* compress the normal range of the controlling variable by a factor of 10, and offset it into the vparam/rparam range. The vparam would look like a series of steps going from zero volume to max, and the rparam would look like a sawtooth with the rate control being effective for each of the steps in vparam. Technically to implement that I'd need to use a series of vparam/rparam blocks linked together. *But* this doesn't work because I can't control the controlling parameter accurately enough due to internal FSX updates. The basic sound adjustment works ok over the normal range though.
I know the audio vario in a glider sounds like a niche hobby, but the challenge is it's an instrument that beeps higher as lift increases, and lower as you fly through sink (it doesn't get louder/quieter during normal usage). The default FSX variometer does this using the exact same modulation parameters as are used for prop and engine sounds, as the frequency modulation technique is identical using playback rate of the WAV. But I need a volume control.
I can think of a made-up example for a power-plane that would require a similar solution: if the pilot had a switch on his panel that turned his headphone noise-cancellation on and off, you would need to adjust the engine volume between two values (I don't mean engines versus silence which has possible work-arounds). I don't think you could do that with a combustion sound definition for one set of engines.
I've wondered about having multiple vario sound definitions and somehow only enabling one at a time but can't think how to do that. Defining linked sections to cover different non-overlapping ranges of the controlling variable sounded promising (the 'sawtooth' profile as mentioned above), but the 'offsetting' technique of the controlling variable is problematic, as it would also be for engine speed.
Si thanks for your comments - this is an interesting problem to think about if there's a trick I can use in FSX, but I won't be offended if you're bored of it - you've been very helpful.
Thanks
B21
