Is Subwoofer Elevation a Viable Option?

@artemus_5 REL's are made to be stacked (if desired). That's why they come with those brackets and screws. I attended REL's subwoofer seminar at Upscale audio and specifically asked REL rep about this.

Elevated on of my REL S/510's by stacking one on top of the other and it was a game-changer. Ended all my moving around silliness.

I have run multiple subs for a number of years in different rooms. Good news,  furniture has minimal impact on sub. That said, elevating subs does change how they interact in the room so it is worth experimenting with. You'll lose some reinforcement from the floor but you may like how the sound changes. Like all things in the hobby, let your ears decide what you like best.

 Since subs produce low frequency audio which is Omni directional there is no need to elevate.  In bottom firing subs elevation would be counter productive. 

So, why do we even want the bass to be "reinforced"?

If the low frequencies aren't reinforced in a uniform way, that might be of some benefit, but I very much doubt that's the case. Even if it does, why not just increase the loudness instead adding room boom?

Maybe if we have less reinforcing we can save some dollars on bass traps.

The reason to use multiple subs isn't reinforcement so much as it is to break up standing waves- that 'room boom' you mentioned, or it can manifest as a lack of bass at the listening position while there is good bass elsewhere in the room.

Furniture is always included as a way of mitigating bass frequencies and serves the same purpose as a bass trap. 

It would have to be specially designed to actually be a bass trap. Its much better at absorbing higher frequencies. Wherever you got that idea about furniture being an effective bass trap is erroneous and might be part of why this thread exists.

Another thought to keep in mind is your floor type. Mine is a wood floor over a basement, and the floor would sing along with the sub a bit. I elevated the sub just enough using these- 

Aperta SUB Series - Subwoofer Isolation | IsoAcoustics

They cleaned things up a bit in my case. 

There are other options for doing this- but it's worth a try in some cases.

" am very pleased with the results, but some questions keep nagging me."

Audio Nervosa alive and well in 2025.

Instead, sit back and enjoy the music.

@tony1954 Wrote:

Is Subwoofer Elevation a Viable Option?

See here, here and here

Mike

@atmasphere 

How would furniture be "acoustically transparent" to low frequencies?

Furniture is always included as a way of mitigating bass frequencies and serves the same purpose as a bass trap. 

When I built my acoustic panels, they required the cloth wrapping fabric to be acoustically transparent. If you couldn't see light through it or breath through easily, then it wasn't considered to be transparent, so I am guessed a sofa or a sideboard wouldn't be either.

@artemus_5 

Yes, the REL's feet are the proper height, but the sub wouldn't be floating or have a hole under it. It would be on a table, plinth or pedestal so it would still radiate the same way. Just not at floor height.

@clio09 

REL is all aboard with their line arrays. Unfortunately my REL's have a bottom loaded radiator. Although, maybe the radiator would function the same for the most part?

@soix 

So, why do we even want the bass to be "reinforced"?

If the low frequencies aren't reinforced in a uniform way, that might be of some benefit, but I very much doubt that's the case. Even if it does, why not just increase the loudness instead adding room boom?

Maybe if we have less reinforcing we can save some dollars on bass traps.

In a multi sub system Earl Geddes recommended placement of one of the subs so that it is closer to the ceiling than the floor. The point made regarding not doing this with REL subs should be considered, but it looks like you have an SVS sub as well and maybe you could try getting that up off the floor and hear how it sounds.

According to Rel, the answer is NO! The feet are at the proper height for the down firing speaker. Raising or lowering them is not advisable. I suspect its because it interferes with the subs proper interaction with the floor.

There is a good couple of hours worth of reading if you google the term stacking subwoofers. 

Because the sub is typically on the floor, along with all the furniture in the room, wouldn't low frequency waves be blocked/diffused a lot. Wouldn't the sound from a subwoofer benefit from an unencumbered dispersion of energy into the room?

@tony1954 No. At those frequencies the furniture is acoustically transparent.

One thought is that the subs get some help from the floor in reinforcing bass output, which would require them to work less hard and with lower distortion so there may be trade offs in raising them off the floor.  That’s all I got, but it’s an interesting question.