Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Default Crate 4x12 Speaker Cabinet Partition for Stereo Use Model BV412SB

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
..............

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Default Crate 4x12 Speaker Cabinet Partition for Stereo Use Model BV412SB

On Nov 2, 1:58*pm, "Wild_Bill" wrote:
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.


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.
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Default Crate 4x12 Speaker Cabinet Partition for Stereo Use Model BV412SB

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
..............


"spamtrap1888" wrote in message
...
On Nov 2, 1:58 pm, "Wild_Bill" wrote:
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.


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.

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Default Crate 4x12 Speaker Cabinet Partition for Stereo Use Model BV412SB

"Wild_Bill" wrote:
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
.............


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
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Default Crate 4x12 Speaker Cabinet Partition for Stereo Use Model BV412SB

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
..............


"gregz" wrote in message
...

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


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