XNA - SoundEffect with SpeedOfSound

SoundEffect has SpeedOfSound property. I'm trying to use it, but it doesn't work:

SoundEffect.SpeedOfSound = 600.0f;
SoundEffectInstance soundEffectInstance = stepsSound.CreateInstance();
soundEffectInstance.Volume *= 0.5f;
soundEffectInstance.Play();


How to use it? How to set speed of sound?

SpeedOfSound is the value for the speed of sound... that is, how fast sound waves propagate. It does not control the playback speed (or thus, effective duration) of an individual sound. Instead, it alters how the Doppler effect of 3D sounds is perceived.
What you probably want is to change the sound's Pitch property, although this has a limited range.