DIY Subwoofer Risers

[Big Daddy]

Originally Posted by abc5

argh, big daddy strikes! i got a laborous wiring task to be able to set the sub to the back of the room, meaning the side of the room where my sofa is.

Two of my subwoofers are in the rear of the room. One of the coaxial sub cables is around 65ft long.

[crazyBLUE]

Originally Posted by abc5

argh, big daddy strikes! i got a laborous wiring task to be able to set the sub to the back of the room, meaning the side of the room where my sofa is.

Don't feel bad ~ I blame Big Daddy for everything Too

Just be glad it is 1 subwoofer.

I had to run wire for 3 tower speakers ~ 2 Front Height speakers a subwoofer & HDMI for the display to the other side of the room

[Saturnas]

What is the best length for DIY subwoofer riser?

[hamilton02]

Originally Posted by Saturnas

What is the best length for DIY subwoofer riser?

I really dont think there is a best length per se. (I could be totally wrong) but I made mine to the exact size as my subs. I was originally going to make them a few inches bigger all around until a friend suggested it. I think it makes the sub look a bit bigger

[Big Daddy]

Originally Posted by Saturnas

What is the best length for DIY subwoofer riser?

If you are asking about the height of a riser, you should read post number 2 of this thread. There is detailed information on how to calculate the optimum height of a riser.

[Saturnas]

Originally Posted by Big Daddy

If you are asking about the height of a riser, you should read post number 2 of this thread. There is detailed information on how to calculate the optimum height of a riser.

Yes I am asking about height of a riser. Thank you for advice but I already read all info on the 1st page, but still I am a bit confused. I have 8ft ceiling so theorically I can go up to 2 ft. However, the maximum height I can rise my sub is 7.1 inches, so should I go for the maximum or rise it for about 3 or 6 inches??

[Big Daddy]

Originally Posted by Saturnas

Yes I am asking about height of a riser. Thank you for advice but I already read all info on the 1st page, but still I am a bit confused. I have 8ft ceiling so theorically I can go up to 2 ft. However, the maximum height I can rise my sub is 7.1 inches, so should I go for the maximum or rise it for about 3 or 6 inches??

Build it as high as you can. If it is 2 feet, that will be great, but if you can only build it up to 6 inches, that will be ok too. Just make it as solid as you can. Remember that these numbers are based on approximation rules and they are not absolute laws.

[cyde]

Great information in this thread, and thanks for all the input. Earlier today I cut and screwed together my 24" riser (subtrap style). Only thing left is to stuff with foam, sand and stain. My order from Foamfactory is taking too long . I want to get this project finished and rock some clean bass.

[cyde]

The internal measurements of my riser is 13"x13"x20". How tight do I want to pack the foam? Do I want to eliminate most of the airspace or is it beneficial for a little air space?

[Big Daddy]

Originally Posted by cyde

The internal measurements of my riser is 13"x13"x20". How tight do I want to pack the foam? Do I want to eliminate most of the airspace or is it beneficial for a little air space?

Fill it up as much as you can. Ideally, cement would work the best.

[cyde]

Originally Posted by Big Daddy

Fill it up as much as you can. Ideally, cement would work the best.

Hmmm, to fill or not with cement. A 100+ pound riser does sound appealing (until it needs to be moved).

[Big Daddy]

Originally Posted by cyde

Hmmm, to fill or not with cement. A 100+ pound riser does sound appealing (until it needs to be moved).

That is the main reason why we have a wife or a girlfriend.

a_wife.jpg

[cyde]

Originally Posted by Big Daddy

That is the main reason why we have a wife or a girlfriend.

Attachment 31436

Hah we'll you've got me convinced. Thanks, BD, I'm going to fill it with concrete. My girl is always complaining she never sees any real life benefit to squats and dead lifts in the gym. Now she'll make use of them.

[cyde]

Stained and almost ready to fill with concrete. I'm not liking the way the stain turned out, but I guess that's my fault for using cheap Home Depot plywood. Scraps were sitting in my garage for a while, and there are a few spots that just won't soak up the stain properly. I may just cover the whole box with carpet to clean up the look if I can't fix the stain.

I used 2x2"s for the feet and glued some 1/2" thick strips of stall mat I had left over from a garage gym project.

[crazyBLUE]

Originally Posted by cyde

Stained and almost ready to fill with concrete. I'm not liking the way the stain turned out, but I guess that's my fault for using cheap Home Depot plywood. Scraps were sitting in my garage for a while, and there are a few spots that just won't soak up the stain properly. I may just cover the whole box with carpet to clean up the look if I can't fix the stain.

I used 2x2"s for the feet and glued some 1/2" thick strips of stall mat I had left over from a garage gym project.

Riser looks great so far cyde That thing is going to way a ton filled with concrete

[Big Daddy]

Originally Posted by cyde

Stained and almost ready to fill with concrete. I'm not liking the way the stain turned out, but I guess that's my fault for using cheap Home Depot plywood. Scraps were sitting in my garage for a while, and there are a few spots that just won't soak up the stain properly. I may just cover the whole box with carpet to clean up the look if I can't fix the stain.

I used 2x2"s for the feet and glued some 1/2" thick strips of stall mat I had left over from a garage gym project.

It is looking good.

[MAL01]

I am about to build my own risers for my dual Rythmiks that are on the way. I was going to steal Kareface`s design, but after seeing this should i make the riser solid and heavy or open and filled with fiberglass? Come on BD or Kareface, let`s settle this once and for all!!!

[Big Daddy]

Originally Posted by MAL01

I am about to build my own risers for my dual Rythmiks that are on the way. I was going to steal Kareface`s design, but after seeing this should i make the riser solid and heavy or open and filled with fiberglass? Come on BD or Kareface, let`s settle this once and for all!!!

Take a look at these SubTraps from ASC.

SubTrap1.jpg

SubTrap2.jpg SubTrap3.jpg

http://www.asc-home-theater.com/subtrap.htm

Once you hear the difference, you’ll never go back. The SubTrap is more than a simple isolation stand. In addition to isolation, it absorbs excess bass and decouples your sub-woofer from room mode. The end result is a unique product available only from ASC. Raise your subwoofer up to its full performance potential. Just slip the ASC-SubTrap underneath your subwoofer and you’ll create the powerful “SubStack.” Instantly improve bass detail, changing “muddy” low frequency playback into a richly detailed picture. Not only does the SubTrap increase bass extension and punch, it also gets rid of "one note bass.

By raising the sub off the floor and putting a SubTrap under it, the subwoofer is effectively decoupled from the vertical room mode. Excess bass buildup is reduced and the playback volume of the subwoofer can be cranked up much higher than before.

The setup is almost too simple. Lift the subwoofer up and slip the SubTrap underneath.
1) This raises the subwoofer up off the floor, out of the vertical mode pressure zone and decouples the subwoofer from being able to contact a pressure mode and pump energy into the mode.
2) In addition, a bass trap has been located on the floor, right in the middle of the vertical mode pressure zone. Any vertical mode action that might be stimulated by the subwoofer is rapidly damped out.
3) Finally, the SubTrap acts as an iso-deck, a floating platform to mechanically decouple the subwoofer vibration from the floor, electronic gear, video equipment and the rest of the house.

The SubTraps from ASC act as a riser and a bass trap at the same time. If you are going to build a very short riser, fill it up with dense material and make it as steady as possible. If you are going to build a tall riser like the ones from ASC, assume the bottom part is a bass trap. Dense fiber glass inside the box can absorb some of the energy and may be beneficial. For more detail, read post #3 of this thread.

[MAL01]

Hi BD, i`ve gone through post #3 and other than decoupling and getting the sub out of the vertical mode, i still don`t get how it makes much of a difference if the riser is closed and solid or open and filled with fiberglass. If there is not much difference i might do the closed method, if open is significantly better i will do it that way. The open riser requires alot more work so i don`t want to waste time if it makes no difference. I plan on doing a 18"-24" H x 18"Wx24"L riser.

[de Rookie]

I had an old side table that has a metal frame with a wood top set inside the top of the frame. Very sturdy, but completely open (just think of L-shaped metal welded together to form a cube). I placed my sub on top of it and did some testing. The table is 1.75' tall, ceiling in that area is 10' tapering to 8'.

I didn't get an increase in db output according to my SPL meter. However, I did get an interesting effect. Felt like there was more pressure on my eardrums, but overall I wasn't hearing as much as when it was on the floor. Oh, and the couch vibrated more, haha.

I moved it around in the area it sits (have about a 4'L X 2'W of room, corner placement) and just couldn't seem to get it dialed in. I'm going to try putting some poly-fil sheets left over from my subwoofer project, and perhaps some towels to see if that helps out, then test different placements.

To me, it seemed like the bass was getting projected to the left of my right tower instead of the main listening position. But the sub sitting on the floor seems to hit the listening position decently for the most part.

Anybody have any similar experience with this or have any suggestions? Perhaps the table is too tall? The room has 3 walls and the back is completely open extending into a kitchen.

One more thing to note, I was just getting the general position set up to see where it sounded best, but I have not run Audyssey again. Should I do that first and foremost? Could be the issue