Why are lower frequencies(in sound)less directional than higher frequencies?

Answer 1

It's to do with signal / wavelength strength. The more energy a signal has - the further it can travel. Lower frequencies have longer wavelengths which loose their energy quicker than higher, shorter wavelength frequencies meaning they have a shorter range.

The directional ability is due to the same principal, as a signal looses strength it dissipates and looses direction.

Answer 2

the lower the frequency the the larger the wave length...

sound is made via wave passing through the air... if the waves are bigger they are going to disturb more air... thus they will have the tendency to spread out.

sound travels at 340 m/s (approx) if the frequency is, say, 1000 hz then the wave length is about 30 cm or 1 foot. So if it is a free area it will try to take up the space of atleast a cubic foot. that is a lot of air vibrating around, so the energy will disipate out quickly.

On the other hand if it is 10,000 hz then it is only a couple of centimeters or about an inch^3 space that it will take up so the energy is very focused and can be directed more easily.

Think about it this way. all sound has the tendency to double its area of influence. So for every (just a estiment) 1/10 of a second it double the ammount of space that it is in.

So in one sec it will double 10 times... 1unit then 2 then 4 then 8 then ... up to about 500 at one sec

So the sound wave that is 1000 hz is now 500 cubic feet, but the 10,000 hz wave is only 500 cubic inches

so the long wave spreads out very quickly

(the numbers i used are just examples the actual action of sound waves is much more complex, but i think this a decent description)

Answer 3

They aren't.

The issue is that a detector (your ears, say) are limited in their ability to resolve the direction a sound is coming from, and that resolution gets worse the longer the wavelength of the sound.

To improve it you have to increase the size of the detector.