565 is half the speed of sound.

The formula is simplified to obtain the lowest frequency a given acoustic chamber (room) can accomodate. Therefore, dividing the longest dimension of a chamber into 1/2 the speed of sound gives that frequency.

BTW, it reflecting back completes its full wave length. You can see that a lower frequency reflecting back will not complete the length of its cycle, thereby causing acoustic anomolies in the space that distorts all other frequencies in the chamber.

So the worst thing you can for accuracy in playback is use speakers that extend bass frequencies beyond the room's capability to accomodate them. The resulting low frequency pressue zones are almost impossible to deal with without excessive room treatment devices that are very costly, and tend to deaden the room, as well as create distasteful aesthics.

See: 'Master Handbook of Acoustics' (Everet) available in paperback.

The formula is simplified to obtain the lowest frequency a given acoustic chamber (room) can accomodate. Therefore, dividing the longest dimension of a chamber into 1/2 the speed of sound gives that frequency.

BTW, it reflecting back completes its full wave length. You can see that a lower frequency reflecting back will not complete the length of its cycle, thereby causing acoustic anomolies in the space that distorts all other frequencies in the chamber.

So the worst thing you can for accuracy in playback is use speakers that extend bass frequencies beyond the room's capability to accomodate them. The resulting low frequency pressue zones are almost impossible to deal with without excessive room treatment devices that are very costly, and tend to deaden the room, as well as create distasteful aesthics.

See: 'Master Handbook of Acoustics' (Everet) available in paperback.