On Monday 19 Oct 2009, Erik Hofman wrote: [snip...] > The odd part is, Doppler is working for the F-16 and Fokker-100 > for example. It's as if OpenAL is limiting the total pitch to 2.0 > which means that AL_PITCH and Doppler combined can not be higher > than 2 times the normal playback frequency. Or something like > that. > > Erik
I think the maximum drop of pitch is 0.5 of the emitted frequency, at least for a stationary receiver and a sub-sonic source. If... Fo= emitted frequency V= velocity of waves in the medium Vs= velocity of the source relative to the medium Vr= velocity of the receiver relative to the medium Fr= frequency observed by the receiver Then... Fr= Fo * ( (V + Vr) / (V + Vs) ) So when Vr= 0 and Vs= V (i.e. the speed of sound) V / (V + Vs) = 0.5 So Fr= Fo * 0.5 for something receding at V which means that for sound, the pitch can only drop to half of its original pitch while the source remains in the sub-sonic regime. This doesn't apply when the source is approaching though, and I wonder if the people writing the Open_AL code just thought the effect was symmetrical i.e. if the pitch halves for a retreating source then it should double for an approaching source. LeeE ------------------------------------------------------------------------------ Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel