| As sound is produced by both the front and the back of a speaker, open backed cabs can suffer phase cancellation problems as the sound produced by the back of the speaker is naturally 180 degrees out of phase with the sound produced by the front of the speaker. This can result in an unnatural sounding midrange and absent low mids/bass frequencies. Of course the affects of this can be altered by room placement amongst other things. The advantage of open backed cabs, is that they are very dynamic and can reproduce fast transients accurately.
Closed back cabinets work on an adaptation of the infinite baffle theory which relies on the condition that the sound produced by the back of the speaker never reaches your ear. The method of doing this is by enclosing a sealed box around the back of the speaker. This does work to some extent, but as the back half of the speaker is in a partial vacuum, the speaker usually takes a little more 'motivation' to get moving, so fast initial transient peaks can seem a little muted.
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- Tommy
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