Hi all. As you know, I am building a dual opposed 11” subwoofer using Scan-Speak 4-ohm (nominal) drivers. I use a MiniDSP plate amp in bridge mode. How do I wire this sub? Series? Parallel?
The drivers are mounted facing each other and the cones need to move in the same relative direction. Both series and parallel are possible here.??
There's really only one way to wire that setup.
Drivers in series and so the cones move opposite from each for force cancellation.
??
This seems correct to me. What if I unbridge using the original 2-channel jumper config? The amp has a thermal protection circuit, so maybe a 2 ohm load could be okay?No, I'm afraid not. Since the drivers are mounted opposed the cones need to move in opposite directions to achieve the force-cancellation objective.
And, since he's using the amplifier in bridged mode, a parallel connection would yield an approximate 1-ohm load on each amplifier channel. Not good.
Series is the only wiring method.
I also need a lot of power. I could just use the second plate amp too. Two of those amps, each in bridge mode, is a lot of power.If you operate the amplifier in the normal (non-bridged) mode, each channel will see a 4-ohm load. I see no issue with that. It's preferable, actually. However, slight differences in the amplifier channels/DSP-setup could cause some non-symmetrical operation.
I don't know why you started another, separate, thread???????
Here's how I'd wire dual opposed subs in parallel:No, I'm afraid not. Since the drivers are mounted opposed the cones need to move in opposite directions to achieve the force-cancellation objective.
I would do series, most amps really don't like low Ohm impendance.Here's how I'd wire dual opposed subs in parallel:
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The cones would move in the same relative direction, so both "out" at the same time and "in" at the same time.
If you flipped the polarity on one driver, then you'd get basically no sound, and a violently shaking enclosure.
Whether OP's Plate Amp can handle the 2Ω inpedance of a parallel config is another matter of course.
You'd get a dipole with the wrong EQ, rather than the intended monopole. There will be sound, but not the sound intended.If you flipped the polarity on one driver, then you'd get basically no sound, and a violently shaking enclosure.
thanks. yes, i am getting the larger minidsp plate amp, with double the power over the smaller minidsp amp. i have learned the minidsp software and would rather stick with those plate amps for now.I‘m not sure the ICEpower 250asx2 is a great choice for this application. You can either run each driver off a single channel so each channel drives a nominal 4ohm load, or put the drivers in series and run the amp bridged. Either way you only have 500w available, which is marginal based on what I recall of your plans. I would be aiming more toward 500w per driver if I were you, to allow some decent headroom instead of maxing out the amps. You can sim it all out in VituixCAD or similar to get a more precise answer.
thanks. do you have the same concern if the drivers are identical, bought at the same time and newly manufactured?Generally speaking, serial connection is not advisable, as minor differences in the drivers could lead to them not receiving the same amount of power.
The best solution due to the low impedance of the drivers is perhaps one channel per driver instead of bridging.
i agree. bridged mode causes this problem. easy to solve by abandoning bridge mode, but i still end up at 2 ohms.That would be the "opposite" relative direction, not the same relative direction.
And for the reason I mentioned above, the effective load on the bridged-configuration amplifier channels would be 1 ohms, not 2 ohms. So, not an appropriate hookup.
thanks. do you have the same concern if the drivers are identical, bought at the same time and newly manufactured?
awesome! i have the larger minidsp plate amp on its way, and it’s 250w into each 4 ohm channel. thank you for this info.@suttondesign I did a quick sim of a pair of 28W/4878T00 drivers in a 1.26cu.ft (35.7L) enclosure. 250W per driver actually seems pretty much OK. It can't quite drive them to xMax but you get 99dB at 20Hz, so 105dB with the pair of enclosures, plus room gain. Basically at least you can't mess up and blow up the drivers or tear them apart with that power.
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