LFO - Low Frequence Oscillator
LFO is a sound synthesis acronym that means "Low frequency oscillator". MOD means modulation. Rate is the frequency (how often the effect repeats itself).
So
lfomodpitch means that the low frequency oscillator is affecting the pitch of the sound. This effect is commonly called "vibrato". You're probably familiar with the difference between a singer singing with and without vibrato... That's what you would do if you set lfomodpitch. Higher numbers mean more change in the pitch -- singers use very little, whereas a police siren uses a lot.
lfomodvol means that the LFO is affecting the volume of the sound. This is sometimes referred to as "tremolo" although in some musical contexts tremolo and vibrato are synonymous. This is more of a "pulse" through the sound than a wavering of pitch as above. Hopefully you get the idea.
lfotype is the shape of the waveform that is used. I assume that
sqr is a square wave,
tri is a triangle (or maybe sawtooth) and
rnd is random. All of these have different characteristics as to how they affect the sound.
sqr will jump back and forth between low and high,
tri has sharp transitions, and
rnd has smooth transitions. It's difficult to explain in text, but easy to hear, just experiment with it.
Radius sizes
Roughly speaking, the maximum distance that a sound could be heard from at a particular radius is (provided it is playing at maximum volume)
- Small is 800
- Medium is 1250
- Large is 2000
Most sounds aren't being played at maximum volume, and they aren't recorded in the full dynamic range of the sample either, so the actual distance for hearing them is lower. There is no way to alter the attenuation values without writing code. You will be able to set the radius more precisely by writing entity code, but its not an exact science because of the variations in sound / sample volumes.