Would anyone know of a good reason to not install a partition between the left and right pairs, when using the cabinet for a stereo input?
As it is now, there is just open space inside the cabinet.
All four speakers are identical (16 ohm) and there is a switch at the rear to select mono (4 or 16 ohm) or stereo (2x8 ohm).
There aren't any baffles, ports or stuffing in the box, just bare inside.. and I was contemplating installing a wood or wood/foam separator.
-- Cheers, WB .............
r .
From fundamentals: A loudspeaker in a box is a spring-mass-damper situation. The mass is the mass of the diaphragms, voice coils, and part of the surround and spider. The spring is the air in the enclosure, which provides a restoring force to the diaphragms. This gives a certain fundamental resonance, which is the low frequency corner that the speaker can reproduce.
Now, if you put a partition in the middle, you halve the moving mass, but you also halve the air volume. Intuitively the fundamental resonance should not change, because the two factors cancel out. I would verify this by finding the resonance with and without the partition using an oscillator, AC voltmenter, and resistor.
Thanks, I appreciate the informtion. I had read that Crate specifically chose birch plywood for the cabinet due to it's particular resonance characteristics, but I admit that a tuned cabinet is way beyond what I know about acoustics or enclosures.
-- Cheers, WB .............
From fundamentals: A loudspeaker in a box is a spring-mass-damper situation. The mass is the mass of the diaphragms, voice coils, and part of the surround and spider. The spring is the air in the enclosure, which provides a restoring force to the diaphragms. This gives a certain fundamental resonance, which is the low frequency corner that the speaker can reproduce.
Now, if you put a partition in the middle, you halve the moving mass, but you also halve the air volume. Intuitively the fundamental resonance should not change, because the two factors cancel out. I would verify this by finding the resonance with and without the partition using an oscillator, AC voltmenter, and resistor.
It's not often you will get any stereo info in the bass, but it exists, and could cause a problem without partition.
If the box is low passed below a couple hundred hz, then stuffing is not needed, but mostly it's necessary to be anything hifi. Open back cabs are the ones often Stuffingless.
Oh come on, sounds like crazy stuff like we used to do with two ampeg boxes with 8 12 inch drivers, but those boxes were stuffed and vented, and had tweeters.
Greg
Thanks for the additional comments. I may install the partition, but won't go as far as sawing the cabinet in half vertically (installing 2 sides in the middle) and put hinges at the back for some channel separation. I'd be more inclined to buy a second 4x12 cabinet.
-- Cheers, WB .............
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