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#### theater_lover

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1) Are two drivers in an enclosure of 4 cubic feet sonically the same as dual enclosures of 2 cubic feet with single drivers? Would this difference be the same for vented as well as sealed?

2) Can more than one driver, each receiving independent (and different) input signals, share the same enclosure space? If driver "A" models well in a 4 cubic foot enclosure, and driver "B" models well in a 3 cubic foot enclosure, can they share a 7 cubic foot enclosure? What about sharing vents and passive radiators?

3) If you can share a passive radiator with drivers receiving more than one input signal, how do you calculate which PR to use?

4) If you are planning on equalizing a sub, do you simply want to get as much SPL as low as possible and not worry about a flat response (knowing that you can correct for this later)?

#### Jay1

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Quote:
Originally Posted by theater_lover /forum/post/16973318

1) Are two drivers in an enclosure of 4 cubic feet sonically the same as dual enclosures of 2 cubic feet with single drivers? Would this difference be the same for vented as well as sealed?

Yes, as long as the larger box is braced well enough. It's easier to make a small box inert

2) Can more than one driver, each receiving independent (and different) input signals, share the same enclosure space? If driver "A" models well in a 4 cubic foot enclosure, and driver "B" models well in a 3 cubic foot enclosure, can they share a 7 cubic foot enclosure? What about sharing vents and passive radiators?

If you are talking about two different drivers, then no.

3) If you can share a passive radiator with drivers receiving more than one input signal, how do you calculate which PR to use?

Not sure I get what you're asking?

4) If you are planning on equalizing a sub, do you simply want to get as much SPL as low as possible and not worry about a flat response (knowing that you can correct for this later)?

It depends on what your goals are.

.

#### brandonnash

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1. Yes. But you have advantages in placement if you have duals (separate enclosures).

2. No, don't do that.

3. No, still don't do that. It won't work and you will need a lot of PR's depending on your drivers.

4. Yes and no. If you frequency peaks you can tame them pretty easily, but increasing by three db at a certain frequency will need double amplifier power at that frequency. Also you run into harming your driver with too much power.

#### theater_lover

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1) When I model a single driver in half a half sized enclosure, compared to two drivers in a double the size enclosure, the single is 6 dB less. Is 6 dB gained by having two single driver subs, versus one single driver sub?

2) Why?

3) If you could have two different drivers, with different signals, share the same enclosure space, and you were able to determine what size/weight of the PR you would use with each if they were separate, what PR specifications would you add/subtract together to determine the PR size for both?

4) I am thinking that the EQ would only bring values down, none up, as the sloped response I am getting just rises until it plateaus.

#### Jay1

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Quote:
Originally Posted by theater_lover /forum/post/16974989

1) When I model a single driver in half a half sized enclosure, compared to two drivers in a double the size enclosure, the single is 6 dB less. Is 6 dB gained by having two single driver subs, versus one single driver sub?

yes

2) Why?

the model assumes you are wiring them in parallel, which halves the impedance and draws twice the current (theoretically), that gains 3db, doubling the surface area over the same frequencies gains the other 3db. two separate boxes placed next to each other would have the same effect.

3) If you could have two different drivers, with different signals, share the same enclosure space, and you were able to determine what size/weight of the PR you would use with each if they were separate, what PR specifications would you add/subtract together to determine the PR size for both?

This is not an option.

4) I am thinking that the EQ would only bring values down, none up, as the sloped response I am getting just rises until it plateaus.

.

#### LTD02

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Quote:
Originally Posted by theater_lover /forum/post/16973318

1) Are two drivers in an enclosure of 4 cubic feet sonically the same as dual enclosures of 2 cubic feet with single drivers?

more or less. if they are front-back loaded, you will have minor phase issues.

Quote:
Would this difference be the same for vented as well as sealed?

no. the port length will be much longer in each of two small enclosures than it will be in one larger enclosure.

Quote:
2) Can more than one driver, each receiving independent (and different) input signals, share the same enclosure space?

possibly yes, but be careful. see the jbl everest for an example. it is a .5 design. one woofer rolls off at a first order slope, while the other does not. they are receiving the same signal though. putting one signal (e.g. the lfe) to one driver, and another signal (e.g. the right channel) is heading for the cliff at high speed. however, combining both signals and sending the sum to each driver, but then crossing one driver at a lower cuttoff could work.

Quote:
If driver "A" models well in a 4 cubic foot enclosure, and driver "B" models well in a 3 cubic foot enclosure, can they share a 7 cubic foot enclosure? What about sharing vents and passive radiators?

this sounds like a disaster.

Quote:
3) If you can share a passive radiator with drivers receiving more than one input signal, how do you calculate which PR to use?

a qualified yes, but it's tricky.

Quote:
4) If you are planning on equalizing a sub, do you simply want to get as much SPL as low as possible and not worry about a flat response (knowing that you can correct for this later)?

it depends. if you have a smallish room, rolling off at 30hz or so second order will end up nearly flat in room. if you have a giant room, rolling off at 20hz or even lower will end up more flat in room. if you have a HUGE room, the modeled response in 2 pi space will be pretty close to what you get in room.

there are lots of other things to consider though. amp power vs. frequency. driver/enclosure efficiency vs. frequency.

hope this helps.

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