In Reply to: OK, then this is possibly a really dumb observation....... posted by sober1 on May 27, 2015 at 14:59:16:
Think of it as a large chorus on a stage and you are sitting in the audience. There are bass singers, tenors, and altos all singing the same words at the same time. The sound of the chorus arrives at your seat at the same time so that you can understand the words of the song. The frequencies of the notes are all different, the bass is low frequency and the alto is high frequency. But is all arrives at the same time thanks to the constant speed of sound in air.
In an OB speaker the plus wave from the front of the driver and the minus wave from the rear of the driver also travel from the speaker to your listening position at the speed of sound. If there was no baffle (the driver's cone can be considered a small baffle) the plus and minus waves would arrive at the same time and cancel, no sound. The baffle adds an extra distance that the minus wave has to travel and the size determines at what frequency the cancellation will gradually cease to occur. Below this frequency the plus and minus waves add destructively and the output rolls off at 6 dB/octave, above this frequency the sound is almost the same as from an infinite baffle.
For an OB design the size and shape of the baffle, the driver's T/S parameters, and the crossover / EQ all need to be considered to determine over what frequency range the speaker will perform. It is all predictable using math and physics. Do the engineering up front to avoid a disappointment after you invest time, money, and effort building an OB / dipole speaker system that sucks.
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Follow Ups
- RE: OK, then this is possibly a really dumb observation....... - MJ King 16:02:49 05/27/15 (3)
- RE: OK, then this is possibly a really dumb observation....... - sober1 07:50:54 05/28/15 (1)
- RE: OK, then this is possibly a really dumb observation....... - MJ King 09:38:24 05/28/15 (0)
- RE: OK, then this is possibly a really dumb observation....... - MJ King 16:07:16 05/27/15 (0)