Why do you some time only hear the bass when listening to music

[g.lemaitre]

Sometimes when music is playing next door you can only hear the bass. Why? This website likes people to make a guess so here's my shot. Perhaps the bass is on a wavelength that can penetrate walls better. I'm not sure why it is equally as loud as the treble or the other sounds when you're in the same room, though.

 

[OMGCarlos]

You know, I've always wondered this myself. Here's what I know:

Some of the deeper bass notes have wavelengths which are several feet long. I know, but can't tell you how I know, that wavelengths can pass through objects so long as the wavelength is longer than the object (I don't know if density matters).

In other words, the wavelengths of the deep bass sounds of a dubstep track, for example, could be say 30 feet. If your wall is 1 foot thick, the wavelength will easily pass through your walls yet reflect the treble notes which have wavelengths a foot or less.

Because sound is a pressure wave (air molecules experience compression and rarefaction), and because high frequency sounds carry more energy than low frequency sounds (the air particles "wobble" more) there is more friction experienced in the high frequency sound wave vs the low. Thus, the friction mutes treble notes considerably faster than it does bass notes.

In short, high frequency sounds travel shorter distances but reflect off surfaces, whereas low frequency sounds travel longer distances and pass through more objects.

This is why a bat will use high pitched squeeks to echolocate while a whale will sing ultra-low songs to communicate over hundreds of miles. If this was reversed, the bat would never catch anything smaller than a hippopotamus and the dense salt water would prevent a mother whale from communicating with her calf a few feet away.

 

[g.lemaitre]

great answer, I really appreciate it, thanks