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Discussion Starter · #1 ·
I haven't ever seen anybody discuss this but I was wondering about something. I have a HSU vtf-2 sub (down firing) and my room is a pretty shaggy rugged room. Is there a difference between using a sub in rugged setting vs a hard wood floor (I might move the whole setup to a different room).


Also what about if i put say a wooden board down below the sub (on the rug) would I hear anything different?


Just curious!


Thanks,


-Jeff
 

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jeff,

I have the same layout you do, and I ended up with a piece of stained plywood under my sub. I think it tightens up the bass a little.
 

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In theory carpet should be "invisible" to the wavelengths coming out of the sub, but I too wonder if my down-firing sub sitting on a 0.5" thick pad with 1" thick carpet on top is being all that it can be.


Spikes tend to be a bad idea with downward firing subs because these subs are designed with a specific woofer to floor distance in mind. Spiking moves the woofer further away from the floor and prevents the woofer from achieving the desired pressure zone between the sub and the floor.


I can assure you that putting a board underneath your sub will make it sound like crap. The board combined with the carpet will act like a damper.


There are a couple things you can do try to tighten up your bass. Easiest one is putting a 25 lb weight on top of your sub. Second, you can get a granite slab (approx 16" x 20" x as thick and heavy as possible) and put it under your sub. Third, do #1 and #2.


I've done #1 with and audible improvement, but haven't shelled out the money yet to try #2.
 

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Quote:
Originally posted by greggz
Second, you can get a granite slab (approx 16" x 20" x as thick and heavy as possible) and put it under your sub. Third, do #1 and #2.


I've done #1 with and audible improvement, but haven't shelled out the money yet to try #2.
I went a building supply company and picked up a concrete paving stone that was sized suitable to accept the overall footprint of my sub.

It was approx. 2 1/2" thick and weighted about 35lb's.

I painted it the same color as the sub.

Cheap!!!!!! $7 bucks

Big improvement !!!!!!
 

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Granite is around $50/sq ft, so I guess you'd be looking at $100-$120.
 

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Quote:
Originally posted by greggz
In theory carpet should be "invisible" to the wavelengths coming out of the sub
You are absolutely correct, but it is not just theory...it is physics. the long wavelength of the low bass will not be affected by a rug or padding.
 

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Quote:
Originally posted by ve4can
I went a building supply company and picked up a concrete paving stone that was sized suitable to accept the overall footprint of my sub.

It was approx. 2 1/2" thick and weighted about 35lb's.

I painted it the same color as the sub.

Cheap!!!!!! $7 bucks

Big improvement !!!!!!
For every audiophile $100-$1000 tweak, there's a Home Depot equivalent for $1-$25!


If the sub is spiked, the carpet won't hurt the sub and will only absorb high frequency distortions and help keep the floor from resonating as much. If it's a front-firing sub, definitely spike it.
 

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I have my Rel Strata III on a 3/4" granite slab (on top of carpet & padding). It was a broken counter top that I had cut to fit. The cutting cost about $10, the slab was free. It works great.


Look at how SV subs are made...
 

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Wouldn't you be better off putting that granite slab on TOP of the sub. I would think this would do more to tighten up the bass.
 

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"Wouldn't you be better off putting that granite slab on TOP of the sub. I would think this would do more to tighten up the bass."


Good suggestion. I thought of that. You see, that chunk of broken counter top was long enough to make two pieces, 12.5" x 16.75". I tried 3 combinations:


1. One piece under the Strata III


2. One piece on top of the Strata III


3. The Strata III sitting directly on the carpeted floor


The Strata III sounded best with the granite slab under it. Some subs, my old Sunfire True Sub MkII for instance, sounded MUCH better with weight on top. That sub moves a lot, however. The Strata II doesn't vibrate, much less move very much at all.
 

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Quote:
For every audiophile $100-$1000 tweak, there's a Home Depot equivalent for $1-$25!
I can't agree more, John! LOL
 

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I just mindlessly threw a concrete slab under my sub after I built it. Then several months later some new speakers forced me to remove it. Didn't notice any difference.


Unless the legs on your down firing sub are short (less than 2"), increasing the distance to the floor more than likely won't affect anything.


Not convinced spikes do that much either. The only explanation I will partially buy is they couple the sub to the floor better preventing the driver from moving the cabinet back and forth. So with that explanation they are useless for downfiring subs and may be of benefit for front firing. Weight on top of the sub should have the same effect, but in both directions. And if your sub is heavy enough niether will make a difference.
 
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