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Discussion Starter · #1 ·
I'm getting a Dayton 12 sometime today and I'm worried about how much it might shake things up in my house.


I live at home with my parents and brothers and my listening room is in the upstairs living room. The house isn't terribly old, but the floor boards definately squeak when you walk on them. My living room is fully carpeted, but I don't think that will really protect me from my floor-resonance woes. I formerly had an 8" Onkyo down-firing sub that came with my HTIB and it wasn't too troublesome in the shaking/rattling department. But with a huge upgrade to a 12" driver with 50+ more watts RMS, I have a feeling that I'll have to take some preventative measures.


At any rate, I have 2 questions:


1) I have read some other posts about decoupling and coupling speakers, and it is all rather confusing. It seems like half the people say "decouple for less vibration and better sound quality" and half say "don't decouple you moron - you'll just dampen the sound. instead, strongly couple for more tactile sensation through the floors." The new sub is a 12" down-firing. Do I decouple or couple?


2) If I should decouple, is there any ultra-easy DIY subwoofer platform that I can make (no woodworking, masonry, mettalurgy, rocket science design)? I took a stroll around Home Depot yesterday and (from what I've already read on these and other forums) made a rudimentary sub platform in my head. The shelf would be made as follows:


I found a huge 4 foot by 8 foot sheet of 1.5 inch thick pink insulation foam. I also found a roughly 18" by 18" patio tile that weighs about 25 lbs.


What I would do is just cut 2 18x18 squares from the pink insulation foam; Then spray paint the patio tile and the foam squares black. Once dry, I would just stack from bottom to top: foam, patio tile, foam, subwoofer


Would this work, or am I a flamin' retard? The only thing I was kinda unsure about was whether or not the top layer of foam would dampen the down-firing subwoofer's sound. In that case, I would just do foam, patio tile, subwoofer.


Any thoughts?


P.S. Oh, and if anyone feels like spending a few more minutes typing a reply, does polyfill tighten up a driver's response or loosen it? I've heard some people say that it tightens response while other's claim that it increases perceived volume of the box (which I would think would make response more slugish).


Thanks in advance for your replies!
 

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Quote:
Originally Posted by Chicago Dan
I'm getting a Dayton 12 sometime today and I'm worried about how much it might shake things up in my house.


I live at home with my parents and brothers and my listening room is in the upstairs living room.


Any thoughts?
Yes, If you don't want to royally P.O. your family downstairs, definately de-couple it! After trying it both ways, I think it sounds better decoupled also.

Quote:
Originally Posted by Chicago Dan
2) If I should decouple, is there any ultra-easy DIY subwoofer platform that I can make


Would this work, or am I a flamin' retard? The only thing I was kinda unsure about was whether or not the top layer of foam would dampen the down-firing subwoofer's sound. In that case, I would just do foam, patio tile, subwoofer.
Right, you don't want the top layer of foam. You want the sub to sit on a rigid platform which is isolated from the floor by a layer of foam. I have an Auralex Subdude, for $50 it's a decent bargain, and I recommend it since it fits my sub perfectly. If you want to DIY, take a look at it's design for inspiration. My sub is an Outlaw Audio LFM-1 (downfiring) and I have downstairs neighbors, a combination most would think is a recipe for disaster! Just recently, they mentioned how quiet we are :p , so that's a pretty good endorsement of it's effectiveness.
 

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I bought patio blocks, primed and painted them, no cutting involved. Cost about two bucks each (primer & paint not included). Cleaned up the sound, helped stop room resonance.


Click my sig to view, next to the cute dog.
 

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Decoupleing isnt going to do much, the sub is going to excite anything around it thats loose wither it's decoupled or not. Also sitting on top of another rigid surface wont do much either unless it has alot of mass (think concreet) or is absorvitive. Auralex Acoustics sells isolators called MoPAD's or there Gramma pad that could work well. You could also do some bass traps, wither store bought or DIY to help control bass.

Check out www.auralex.com or www.truesoundcontrol.com for some of the differnt things you can use.


That said let me get my flame suit on now, cause I'm sure it's commin;)
 

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Discussion Starter · #6 ·
Quote:
I bought patio blocks, primed and painted them, no cutting involved. Cost about two bucks each (primer & paint not included). Cleaned up the sound, helped stop room resonance.
So, you just have one layer of patio tile underneath the subwoofer...? No foam or rubber or anything? Does that do the job?
 

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No foam. The sub rests on its own 6 rubber feet. I really could tell the difference in SQ and it was easy to verify a lot less rattle in the room. It's my understanding the more weight the better. Patio blocks weigh 20 lbs. each. I've seen mention here of someone once using 700 lbs. of granite to resolve an old wooden floor.


Of course you can try a layer of foam if you like and see what effect it has, if any.
 

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Decoupling only prevents transferring the enclosure's vibration from being transfered to the floor. It doesn't prevent the output from the driver and/or ports from transferring to the floor.


A VERY good enclosure has so little vibrations coming from the enclosure, that decoupling is a waste of time. And an enclosure that good will probably have such high quality driver(s)/amp that it will wreak havoc in the room.


So, the lesser the sub, the more (foam &/or weight) decoupling will help.
 

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Quote:
Originally Posted by JeffD2.
Uh, okay. How thick is that suit? Do you have a Sony sub? :eek:
It's ok I'm pretty thick skinned, minimal suit required. And Nope I'm pretty far from anything Sony could offer in the sub department just look at my homepage ;).
 

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x 2 on the G.R.A.M.M.A./Subdude...
 

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Quote:
Originally Posted by JeffD2.
Hey sony, my bad, just bustin' chops, havin' a little fun. ;)
No offence taken, I take most things pretty lightley anyhow.
 

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Discussion Starter · #13 ·
Yeah, I know about the Auralex Subdude and Gramma. I bougt a Dayton subwoofer that only cost me like $140 so I think that buying a $50 foam stool would be pretty rediculous for my particular needs.


My subwoofer is cheap, I want a fairly cheap solution. That's why I'm trying to find something DIY that I could drum together.


Any further suggestions along this line?
 

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How about a couple cheep 3x8x16 cinder block caps usually less than a buck each with a couple pieces of Homosote panel on top of them? That would give you both some mass & something that will asborbe vibration both. Just incase your not familiar with Homosote you can find it at most your home stores it's a dense panel (pretty much just compressed cellouse insulation in a board form) used for sound control. You should be able to get it in 4x4 or 2x4 by 1/2" thick panels for less than 10 bucks. Cheep effective & easy to find;)
 

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Ditto on the subdudes.


My HT is in my basement, which is what I would call semi-finished, carpet, drop ceiling and that nasty fake-wood/cardboard paneling eveyone loved so much in the 70's.


As soon as I get any decent SPL on my subs, the walls, floor, ceiling and everything else start to shake, rattle and roll. Count to five and my wife busts open the basement door and yells to turn it down because the plates and glasses in the kitchen cabinets are shaking.


I put each sub (LFM-1 and a JBL) on a Subdude and put a DIY bass trap in each corner behind the subs (perhaps not optimal, but thats how they fit right now).


The result is pretty impressive, greatly reduced booming and renonance of the structure, and cleaner bass at the listening position.
 

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Dan, since most don't understand your situation, I would go ahead with your original plan. I used something very similar to it back at college in my apartment and never once got a complaint from neighbors. Just change the order to sub, patio block, two layers of foam, then floor. Let us know what you think.


You should get slightly cleaner sound if you are using a downfiring sub. As opposed to firing into carpetted wood and losing some energy, it will now fire onto concrete and reflect. Also, the driver will be that much closer to your ears.
 

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I too use the SubDude under each LFM-1, and noticed a *significant* difference. Yours might not be quite so dramatic since the LFM-1 uses spiked feet and the Dayton (reportedly) uses rubber feet, which already decouple to some extent.


I disagree with Steve's second paragraph. Low frequencies won't respond with the absorption and reflection as you suggest. Only higher-frequency distortion components may. To that end, Dan might want to top the paver(s) with a layer of foam.
 

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As I understand it, you cannot get a reflection from a surface closer than 1/2 wavelength. (Or is it 1/4?) Yes, some energy will be transmitted from the acoustic wave to the floor (of whatever material), but not because the sub is close to the surface. (Mechanical coupling is a different matter.) The energy lost depends on the resonant frequency of the material. One of the worst surfaces for losing bass energy is the windows (they flex), and they're not usually close to the sub at all.


This is surely a misconception. Don't think of the sound moving out from the driver (in this case down) like a beam of light, then running into the floor and either bouncing off or being absorbed (or both). Think of it as a pressure front that escapes through whatever opening there is, in this case through the gap between the case and the floor.


If the distance is > 1/4(?) wavelength, then the sound acts more like a beam. If
 

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Ok but what if we took a bunch of really thick blankets and stacked them so that there is 24" worth of blaketing directly under and around a down firing sub. Then for the second setup, we stacked 24" worth of solid concrete directly under and around the same sub in the same position in the same room. If we ran some tests, are you saying we would get exactly the same response and output under both setups?
 
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