6 driver cube, locked at centre.

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Circlotron

Circlotron

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Joined 2002
#1
Iwas just musing over the idea of a cube-shaped sub with a driver at each face of the cube. More importantly, I had seen somewhere drawings of a 2 driver setup that had the drivers back to back and facing out each side of the box and a steel rod between them bracing them together so that any antiphase vibration would be cancelled.

What I am thinking of though is a system where the backs of the magnets of all 6 speakers are joined to a single metal cube. Actually as long as it was some kind of thing with 6 projections to anchor the driver backplates to, then it would be suitable. The idea is that as all the cones move inward or outward at the same time, the vibration of the speaker magnet and frame (equal and opposite reaction, remember) would be =completely= eliminated, but even more importantly, because each driver was attached to the centre of a box panel it would also brace that panel from any vibration as well as eliminated the centremost (most vibration-prone) area of the panel. The remaining panel area seeing it is closer to the edge would be way less likely to flex.

Anyone seen/played with one of these??
 
#2
Circlotron said:
Iwas just musing over the idea of a cube-shaped sub with a driver at each face of the cube. More importantly, I had seen somewhere drawings of a 2 driver setup that had the drivers back to back and facing out each side of the box and a steel rod between them bracing them together so that any antiphase vibration would be cancelled.

What I am thinking of though is a system where the backs of the magnets of all 6 speakers are joined to a single metal cube. Actually as long as it was some kind of thing with 6 projections to anchor the driver backplates to, then it would be suitable. The idea is that as all the cones move inward or outward at the same time, the vibration of the speaker magnet and frame (equal and opposite reaction, remember) would be =completely= eliminated, but even more importantly, because each driver was attached to the centre of a box panel it would also brace that panel from any vibration as well as eliminated the centremost (most vibration-prone) area of the panel. The remaining panel area seeing it is closer to the edge would be way less likely to flex.

Anyone seen/played with one of these??
Click to expand...

I had this idea before, and i wanted to use 15" drivers, but i could not, and still cannot afford to make a prototype. :bawling:
 
#3
I had this idea before, and i wanted to use 15" drivers, but i could not, and still cannot afford to make a prototype. :bawling:
Click to expand...
you could always give it a go using some smaller drivers. It'd still work ok and in fact the transient response would be better to. I'm thinking of using 12" drivers. If your gonna stuff 6 speakers in the 1 box then don't make them too big!
 
#6
Your idea would certainly look cool but I'm not sure it would have a performance advantage over other simpler configurations

It sounds like you are expecting to make a small box in which the 6 magnets are in close proximity. If this is the case you are going to need small drivers with small VAS. Most 12" drivers require at least 1 cubic foot for a sealed enclosure and many need 2 or 3 cubic feet for one driver. Your box would then have to be 6 times that or 6 to 12 (or 18) cubic feet. Your magnets would not be so close to each other.

If you use smaller drivers(say six 8"drivers) to get around that problem, you would probably have about the same performance as two 12" drivers. The six 8"'s have greater SD but probably less XMax. This is assuming an equivalent QTs and Resonant Frequency (although you can more easily buy 12" drivers with low Fs than 8" drivers)
 
#7
dhenryp said:
Your idea would certainly look cool but I'm not sure it would have a performance advantage over other simpler configurations

It sounds like you are expecting to make a small box in which the 6 magnets are in close proximity. If this is the case you are going to need small drivers with small VAS. Most 12" drivers require at least 1 cubic foot for a sealed enclosure and many need 2 or 3 cubic feet for one driver. Your box would then have to be 6 times that or 6 to 12 (or 18) cubic feet. Your magnets would not be so close to each other.

If you use smaller drivers(say six 8"drivers) to get around that problem, you would probably have about the same performance as two 12" drivers. The six 8"'s have greater SD but probably less XMax. This is assuming an equivalent QTs and Resonant Frequency (although you can more easily buy 12" drivers with low Fs than 8" drivers)
Click to expand...

The idea is not great performance, but to cancel all antiphase vibration. The box size could be increased, as I do not think the close proximity of the magnets is essential.
 
#9
Matttcattt said:


The idea is not great performance, but to cancel all antiphase vibration. The box size could be increased, as I do not think the close proximity of the magnets is essential.
Click to expand...

You don't need six drivers opposing each other to cancel out vibration. Two opposing drivers will cancel out out all the vibrations due to the cones moving in and out. There should be no vibrations in any other plane.
 
#11
Slightly OT, but I hope not too annoying:

What type of sub would this (six-driver cube) be called? Would it still be a monopole because the drivers move in and out at the same time? Would there be strange or unpredictable cancellation effects drom the different positions of the drivers?
I've been wondering about how the M&K two-driver push-pull designs behave. They have one driver on the front and one driver on the bottom face, out of phase with each other so that the pressure inside the enclosure never changes. Are these classed as dipoles? Do they have any of the advantages of an isobarik config? I suppose the box would present no load to the drivers and so you would have to use IB-suitable drivers in this sort of sub. Is that right?
I was wondering because I would think that a lot of the output would cancel due to the proximity of the two drivers. Can anyone point me to an online explanation of what advantages this configuraition gives?
 
#14
dhenryp said:


It sounds like you are expecting to make a small box in which the 6 magnets are in close proximity. If this is the case you are going to need small drivers with small VAS. Most 12" drivers require at least 1 cubic foot for a sealed enclosure and many need 2 or 3 cubic feet for one driver. Your box would then have to be 6 times that or 6 to 12 (or 18) cubic feet. Your magnets would not be so close to each other.
Click to expand...


Can you not Linkwitz transform the sub to any Q you want ?

Rob
 
#17
Hi Dave, Charles,

wrt efficiency, with 6 drivers (suggested 12") would this be a problem ?

Dave - what is the subset ? (laws as to what can and can't be done)- I've read through the Linkwitz site etc, and I've (personally) always thought you could stick pretty much any driver with enough x-max into a box and transform it.. ??

Cheers

Rob
 
#18
Hmm, all these posts since mine, but didn't get any notices (yes, the box is checked).

Anyway, what subsets won't work? I was under the impression that you could use this on any sealed box/driver combo, just that there was a gain limitation, and of course how much of a hit in power handling could be tolerated.

GM
 
#19
GM said:
Anyway, what subsets won't work? I was under the impression that you could use this on any sealed box/driver combo, just that there was a gain limitation, and of course how much of a hit in power handling could be tolerated.
Click to expand...

All i can say is that when the LT was 1st discussed on the BassList i came up with a driver, box combo that wouldn't work.

dave
 
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