Superdave Posted June 7, 2015 Share Posted June 7, 2015 I have added more fill to (2) of the 4 18" sub boxes and now at high volume they move/ dance out of place intensely. Ever heard of this just from adding more poly fill? Quote Link to comment Share on other sites More sharing options...
derrickdj1 Posted June 8, 2015 Share Posted June 8, 2015 You have change the tuning to act like the driver is in a larger box and it will play lower. How do the subs weigh? I have heard of som commercial subs dancing around the room but, not many DIY sub. I guess you can find something heavy to place on the sub or use a rubber mat is the sub is on a wood floor. Quote Link to comment Share on other sites More sharing options...
mustang guy Posted June 8, 2015 Share Posted June 8, 2015 You didn't use that Mexican Jumping Bean polyfill did you? 3 Quote Link to comment Share on other sites More sharing options...
derrickdj1 Posted June 8, 2015 Share Posted June 8, 2015 (edited) Most of the DIY 18 in. boxes will weigh like 115 lbs. and shouldn't dance unless they are musical subs, lol. Edited June 8, 2015 by derrickdj1 Quote Link to comment Share on other sites More sharing options...
Scrappydue Posted June 8, 2015 Share Posted June 8, 2015 so how much total do you have in them now? Quote Link to comment Share on other sites More sharing options...
Superdave Posted June 8, 2015 Author Share Posted June 8, 2015 Most of the DIY 18 in. boxes will weigh like 115 lbs. and should dance unless they are musical subs, lol. They are heavy, right at 120lbs. so how much total do you have in them now? 6-7 lbs is my estimate. Last night I installed some eye-hooks and used a rachet strap on each to secure. They have stopped moving, but now the xpa-7, pre-pro and dvd player are all moving. I was surprised to see that heavy amp move like that! Quote Link to comment Share on other sites More sharing options...
Paducah Home Theater Posted June 8, 2015 Share Posted June 8, 2015 http://www.diversitech.com/Product-Sub-Category?id=a04C000000JpCrgIAF Quote Link to comment Share on other sites More sharing options...
Scrappydue Posted June 8, 2015 Share Posted June 8, 2015 4 lbs is recommended for the si drivers in the 4 ft flat packs. could possibly damage woofers? not sure on that would have to read on it. Quote Link to comment Share on other sites More sharing options...
Paducah Home Theater Posted June 8, 2015 Share Posted June 8, 2015 (edited) 6-7 lbs is my estimate. That's probably a bit too much. The goal is to dissipate the air being compressed from the back side of the cone as well as turn the internal sound waves into low level heat. Doing this makes the sub act like it is in a larger box. Adding too much stuffing makes it act like it is in a smaller box than it should be and is more or less defeating the purpose. Edited June 8, 2015 by MetropolisLakeOutfitters Quote Link to comment Share on other sites More sharing options...
Superdave Posted June 8, 2015 Author Share Posted June 8, 2015 I'll open one up and remove the stuffing to weigh it properly. The anti vibration pads are a good idea (Iso-Cube Economy Anti-Vibration Pad) Quote Link to comment Share on other sites More sharing options...
derrickdj1 Posted June 8, 2015 Share Posted June 8, 2015 (edited) The sub due and anti vibration pad will help a sub stop dancing as will a cheap mat from Homedepot for 1/3 of the cost. The other things shaking in the house are due to the long bass waves and not much can be done with that. A slightly over damp system can have tighter bass. It may also stop some resonance in the box. Most of these DYI designs have been looked and there is a recommended amount of polyfil per box. Edited June 8, 2015 by derrickdj1 Quote Link to comment Share on other sites More sharing options...
Superdave Posted June 8, 2015 Author Share Posted June 8, 2015 I have removed and weighed, it's only 3 lbs +/- an ounce or two. Quote Link to comment Share on other sites More sharing options...
Superdave Posted June 8, 2015 Author Share Posted June 8, 2015 I only turn it up to that level when testing and or demoing it. Quote Link to comment Share on other sites More sharing options...
Scrappydue Posted June 8, 2015 Share Posted June 8, 2015 I have exaxtly 4 lbs in each of mine and mine don't dance at all. And I get stupid with the volume frequently. Quote Link to comment Share on other sites More sharing options...
Superdave Posted June 8, 2015 Author Share Posted June 8, 2015 The more I think about it, I believe it's due to the fact that these 2 boxes are on 2x8 framed pedestals, wood on wood, not much friction compared to sitting on carpet? Quote Link to comment Share on other sites More sharing options...
Superdave Posted June 9, 2015 Author Share Posted June 9, 2015 One note: The rear 2 subs are stacked on top of each other and on carpet. This don't move at all. Quote Link to comment Share on other sites More sharing options...
Superdave Posted June 9, 2015 Author Share Posted June 9, 2015 The sub due and anti vibration pad will help a sub stop dancing as will a cheap mat from Homedepot for 1/3 of the cost. The other things shaking in the house are due to the long bass waves and not much can be done with that. A slightly over damp system can have tighter bass. It may also stop some resonance in the box. Most of these DYI designs have been looked and there is a recommended amount of polyfil per box. I'll get something from HD to put under the feet of the equipment to isolate them. I'd hate for that huge amp to fall off and crash to the floor! Ouch to the checkbook for sure. Quote Link to comment Share on other sites More sharing options...
Scrappydue Posted June 9, 2015 Share Posted June 9, 2015 what about some rubber feet on top of these pedestals you are talking about. like on all 4 corners on it? Quote Link to comment Share on other sites More sharing options...
Superdave Posted June 9, 2015 Author Share Posted June 9, 2015 what about some rubber feet on top of these pedestals you are talking about. like on all 4 corners on it? I now have the boxes strapped in and very tight to the front wall. But, the components are feeling the affects. Quote Link to comment Share on other sites More sharing options...
Paducah Home Theater Posted June 9, 2015 Share Posted June 9, 2015 (edited) The more I think about it, I believe it's due to the fact that these 2 boxes are on 2x8 framed pedestals, wood on wood, not much friction compared to sitting on carpet? My ultimax's flex more than your HT-18's and my baltic birch is lighter than your MDF and I have polyfill too yet they don't budget on carpet. Edited June 9, 2015 by MetropolisLakeOutfitters Quote Link to comment Share on other sites More sharing options...
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