Buttkicker LFE on my small riser underwhelming - AVS Forum
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post #1 of 3 Old 01-21-2013, 06:48 AM - Thread Starter
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I mounted a buttkicker LFE Transducer (from a Buttkicker LFE kit) beneath a 4’ x 5.5’ riser. The riser is constructed of ¾” plywood glued and screwed to a base constructed from 2”x8” lumber. Because of seat mounting requirements, there are 8 2x8s in 4 feet so the riser is very stiff. The transducer is bolted directly thru the ¾” plywood (and thru a piece of 2x8 to stiffen the floor) about 1.5 feet from the rear of the riser, beneath the 2 old style folding theater seats. I used 4 of the rubber isolaters from the kit as feet for the riser. I estimate that the risers and seats weigh around 170 pounds. Pictures:




I have a similar transducer mounted to a loveseat of about the same weight as the riser with 6 K28 isolators. At first, I wired the 2 transducers in parallel to the bk amplifier. When I played a bass heavy movie scene (beginning of Serenity), I noticed that the transducer on the riser overloaded almost immediately and continuously (started rattling – hammering noise), while the one in the couch only rattled once (as it normally does during that scene).

My first thought was to replace the LFE kit isolators with 4 of the heavier K28s that I have. This made it quite a lot better, but it still goes from no shake to overload very quickly. In order to stop the rattling, the amp must be turned down so that I can feel very little shake for most of the movie – kind of defeats the purpose. Removing the feet completely (carpet) reduces shake but not overload.

Anyone have any recommendations that might help? Is it possible that the unit is defective? My next project will be to switch the transducers between the couch and riser to see if they behave similarly, but this requires two people and some effort. Would more power help? I am powering it with a crown 1500 amp. It is rated at 1050 watts at 8 ohms (bridged) – has to be higher for 4. I can switch to a buttkicker 1000, but the amps are difficult to reach at the moment. Would going with the much more expensive large isolaters ($15 each) help? I suppose that it would be possible to cut out parts of the 2x8s to lessen the stiffness of the riser, but that would be a last resort and rather permanent...

Thanks in advance!

bill
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post #2 of 3 Old 01-21-2013, 07:58 AM
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My gut is that you are asking a lot from one unit. To test the theory that the new one is defective you could swap the two you have and see if your old unit can move the platform.
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post #3 of 3 Old 01-21-2013, 08:12 AM - Thread Starter
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Thanks. I'm a little worried about the capabilities of a single unit as well. Was planning to test the riser with an existing transducer, but a deal came up that I couldn't resist and I ran out of time. Switching the trasducers is coming - its a little down on my list due to the effort required. I have contacted Guitammer support and they are working with me - verifying wiring first. Then I will switch the amps driving the transducers to see if there are power or other issues.. I will update when I know more.
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