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Problem with my force canceling 12" or 15" sub design?

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Tim Weaver:

--- Quote from: Herman Chigrin on May 02, 2023, 12:49:19 PM ---Yes, I have done similar when there was a possibility such as an outdoor stage or a building with concrete slab.

HOWEVER, in Chicago, this is often not a possibility because there is either a basement below or just all wood joist contruction. So no slab that is available to connect with.

Still I will have to come up with something reasonable. Perhaps I start with selecting 15" or 12" sub drivers that are optimized for a compact box.

Any suggestions for such a driver?

--- End quote ---

Couple hundred pounds of concrete sitting on the pier and beam floor makes an effective mass tho.

For driver's I'd look at B&C first. Then maybe 18sound. Or if you just want to experiment to prove out the concept the cheaper Eminence drivers are actually great performers, but don't expect to get very deep with them. I'd probably buy some Delta-LF series from Eminence and build 3 separate cabinets that could be stacked in different ways to experiment with to see if the concept even works. Delta series are cheap, stamped frame drivers, but they punch well above their weight. They've been used for decades in music store subs and bass cabinets as far as I can remember. Remember, these would be for proof-of-concept. No the end product.

Tim Weaver:
By the way, we've given you all the ways to research cardioid subs. If you are planning on just sticking two drivers in opposite ends of a cab it won't work. You can try that right now by stacking one sub on top of another and spin one around backwards.

The concept can work, but it requires processing in the form of a delay applied to one or both subs.


If you are looking for subs that jiggle less you can also look at push-pull designs. There are some of these that use driver orientation to cancel out some harmonic resonances in the cabinet itself. EAW made a bunch of designs with that idea.

Tim McCulloch:

--- Quote from: Tim Weaver on May 02, 2023, 01:08:20 PM ---By the way, we've given you all the ways to research cardioid subs. If you are planning on just sticking two drivers in opposite ends of a cab it won't work. You can try that right now by stacking one sub on top of another and spin one around backwards.

The concept can work, but it requires processing in the form of a delay applied to one or both subs.


If you are looking for subs that jiggle less you can also look at push-pull designs. There are some of these that use driver orientation to cancel out some harmonic resonances in the cabinet itself. EAW made a bunch of designs with that idea.

--- End quote ---

One can experiment with "polarity flipped, cabinet reversed, delayed driver" cardioid by simply moving the "reverse" sub further up stage if no electronic delay is available.  If one has a Smaart rig, this can be an excellent teaching tool as it "opens the eyes to time, which is not seen."

Steve-White:

--- Quote from: Herman Chigrin on May 02, 2023, 12:49:19 PM ---Yes, I have done similar when there was a possibility such as an outdoor stage or a building with concrete slab.

HOWEVER, in Chicago, this is often not a possibility because there is either a basement below or just all wood joist contruction. So no slab that is available to connect with.

Still I will have to come up with something reasonable. Perhaps I start with selecting 15" or 12" sub drivers that are optimized for a compact box.

Any suggestions for such a driver?

--- End quote ---

One of the club installs I did back in the mid 80's was upstairs in an old ice packing plant.  When the dance floor was packed the whole floor moved around.  What we did was build a heavy console for the turntables and mixer and suspended it from the ceiling joists with all-thread.

Successfully using turntables many times takes some creative out of the box thinking for sure.

We used isolation damping on the turntables as well for the sonic feedback once things were decoupled from the building sway.  We used layers of 1" MDF sitting on latex foam pads which worked well.

Decoupling and mass are your friend.

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