Downward firing Sub on suspended wood floors

Thinking of getting the new MJ Acoustics Ref 150. I heard it at a dealer and thought it sounded great.

(Mind you, the Primare A30.1/D30.2 -> Totem Model 1 setup was also spectacular!).

Do downward firing subs have problems on suspended wood floorboards? Don't most wood floors resonate around 50hz? Would using pavers/granite slabs help fix any problems?

I can't really loan the sub, since I auditioned them in a city other than where I live.

 

From my experience, a suspended wooden floor won't necessarily make a sub sound awful, though some floors may be worse than others. And if you can get the sub up onto a paving slab (or perhaps something like the Auralex Gramma isolation platform... though I feel a bit self-conscious mentioning it on here... ) it should sort out most of the problems.

Bottom line: it's hard to know for sure but you should be alright.

Dunc

 

With a downward firing sub there's no need to keep the enclosure from moving forward and backward so you don't need spikes which would couple to the floor, causing problems with floor vibration and resonances.

You could try something to isolate the speaker from the floor - rubbery things, squash balls, air supports (boards on top of inner tubes), etc.

 

I dont think a down firing sub will be any different than a front firing one in that regard, both will energise the floor the same way...

 

Agreed.

My point was a Newtonian action and reaction thing. Drive units moving front to back will tend to move the enclosure back to front. One of the functions of the spikes is to keep the enclosure still in this direction. With a down-firing sub the reaction forces on the enclosure are countered by gravity.

As far as energising the floor is concerned, it doesn't make any difference provided you're using the same floor coupling or decoupling devices (spikes or air-supports, etc.). However, if you don't need to maintain stillness in the front to back direction, you don't need spikes and the floor coupling that they cause.

Does that clarify my thinking on this?

 

One more thing, I have two Strata III, down-firing, on floating wood on concrete floor, I had them without spikes, just their rubber feet, than added the spikes and there was an huge improvement, bass is a lot more controlled...

 

Interesting. As spikes couple to the floor, the results will be dependent on the floor that you're coupling to.

I supply both solutions with my speakers (the spikes and decouplers are interchangeable) so customers can decide what works best in their room.

 

REL supplies fixed rubber feet + spikes, (to screw to the end of the rubber feet), to use with carpet, but me, and others, found they play better with spikes regardless of carpet or not...

 

My REL Storm III had considerably more impact and control after I placed it on a paving slab. Putting the spikes on improved this even more.

 

I guess that if the subwoofer "floats" a bit on the rubber feet, it will suck some of the work of the woofer...

I didn't try paving slabs, or whatever, because my floor is rigid enough, I hope...

 

It's about time I got a paving slab to go under my sub (I already have one under each speaker stand). An incredibly cheap upgrade potentially

Michael.

 

when I had my sub, the bass tightened up considerably with spikes fitted.

 

So, lowrider, technobear, michaelab and Robbo, were the subs (that were improved with spikes) floor-firing or forward firing?

Thanks. It would be useful to know.

 

Steve - mine hasn't improved, yet I have yet to use with spikes and/or a paving slab underneath it. But, for the record, it's downfiring.

Lowrider's subs are downfiring aswell. Don't know about technobear and Robbo's though.

Mike.

 

downward firing

 

Technobear's Storm is a REL, so also downfiring...

 

Interesting ... thanks guys.

 

Subs and wooden floors, the best one I've heard is Richards Kermit, twas on a home made seimic sink, with spikes and cups and decent power supply Wm

 

Thanks all.. I'll probably buy it and mess around with spikes vs rubber feet and mebbe add some pavers

 

Found this on the Rel website: