DIY Subwoofer Risers

[phoenix74]

Hey Bid Daddy, I was doing some research on Subwoofer risers and came across your very informative post. Thanks for all the great info. I just have 1 question. What does the foam at the bottom of the riser do? Thanks again for your time.

[Big Daddy]

Originally Posted by phoenix74

Hey Bid Daddy, I was doing some research on Subwoofer risers and came across your very informative post. Thanks for all the great info. I just have 1 question. What does the foam at the bottom of the riser do? Thanks again for your time.

Basically, you do not want the riser to become part of the subwoofer cabinet. You would want the foam under the riser to act as a bass trap and reduce any reverberation. The thicker and denser the foam, the better it will dampen the low frequency sound. Of course, absorbing and getting rid off the low frequency reflections is not an easy job and in most case, it is not very effective at very low frequencies.

Read post #3 of this thread for explanation of the Subtrap.

[Sousa86]

Originally Posted by Big Daddy

Basically, you do not want the riser to become part of the subwoofer cabinet. You would want the foam under the riser to act as a bass trap and reduce any reverberation. The thicker and denser the foam, the better it will dampen the low frequency sound. Of course, absorbing and getting rid off the low frequency reflections is not an easy job and in most case, it is not very effective at very low frequencies.

Read post #3 of this thread for explanation of the Subtrap.

building my own sub-riser as i type lol kinda mooched off your original post with the design lol used 3/4" mdf and 2x4 wood. the riser will give me almost three inches of height and i can just add/build on that when i need to if necessary. thanks for the diy tips, this thing is looking awesome, almost! lol

[dancel]

Fiancee, did not like what I created so I end up buying the Auralex Subdude HD (Home Decor)

[Fors*]

Originally Posted by dancel

Fiancee, did not like what I created so I end up buying the Auralex Subdude HD (Home Decor)

Where are pics of what you built....I am curious to see what she didn't like?

[dancel]

Originally Posted by Fors*

Where are pics of what you built....I am curious to see what she didn't like?

when i added the foam on the bottom and the carpet on top she said its ugly aahahahahha

[Sousa86]

here are a few pics f the sub riser i made, lemme know what ya think.
mostly of the front just to show height and took a ruler to it in one pic. still gotta get some foam for the bottom but that should be easy rite lol. you can see some of the mess left on the carpet in the last few pics lol better clean that up before THE BOSS gets home

[Big Daddy]

Originally Posted by Sousa86

here are a few pics f the sub riser i made, lemme know what ya think.
mostly of the front just to show height and took a ruler to it in one pic. still gotta get some foam for the bottom but that should be easy rite lol. you can see some of the mess left on the carpet in the last few pics lol better clean that up before THE BOSS gets home

Congratulations. Your riser looks like a Gramma or Subdude. Have fun and enjoy your new creation.

[Sousa86]

Originally Posted by Big Daddy

Congratulations. Your riser looks like a Gramma or Subdude. Have fun and enjoy your new creation.

thanks! i'm about to put those guys out of business lol
i made three total, two smaller ones for my fronts, the sub riser turned out the best tho lol still gotta make two more for my polk tsi500s i'll be getting later in life lol

[crazyBLUE]

Originally Posted by Sousa86

thanks! i'm about to put those guys out of business lol
i made three total, two smaller ones for my fronts, the sub riser turned out the best tho lol still gotta make two more for my polk tsi500s i'll be getting later in life lol

Sousa , The Riser looks good !

[Fors*]

Originally Posted by dancel

when i added the foam on the bottom and the carpet on top she said its ugly aahahahahha

Too bad, you do great work. That looks very good!

[dancel]

Originally Posted by Fors*

Too bad, you do great work. That looks very good!

Thanks!

Yea the fiancee likes the Subdude (Home Decor) better, and honestly it did change the sound of my system dramatically.

[lamont360]

Just finished my riser as well. Built for an SVS PC12-NSD. Test drove some scenes from Finding Nemo. Not really sure if I can tell a huge difference. I'll play with it more tomorrow.

Any suggestions as to why I wouldn't tell a difference. It sits bout 6 inches higher now with the riser.

[crazyBLUE]

Originally Posted by lamont360

Just finished my riser as well. Built for an SVS PC12-NSD. Test drove some scenes from Finding Nemo. Not really sure if I can tell a huge difference. I'll play with it more tomorrow.

Any suggestions as to why I wouldn't tell a difference. It sits bout 6 inches higher now with the riser.

Is there carpet on top & foam underneath it .

I found moving it around A little also helped improve how it sounded by where it was placed .

Pics so we could all see it would be cool

[Big Daddy]

Originally Posted by lamont360

Just finished my riser as well. Built for an SVS PC12-NSD. Test drove some scenes from Finding Nemo. Not really sure if I can tell a huge difference. I'll play with it more tomorrow.

Any suggestions as to why I wouldn't tell a difference. It sits bout 6 inches higher now with the riser.

You may have to run the calibration program again and adjust the level of the subwoofer as changing the vertical position of the subwoofer will have an effect on vertical room modes. Also, you may have to slighly adjust the horizonal position of the subwoofer.

Don't forget to post some pictures.

[lamont360]

I will post some today. Yea I have carpet on the stand and underneath as well as foam attached to the bottom of the stand. I'll play around and let you guys know. Thanks for the suggestion of recalibrating.

[kareface]

Originally Posted by lamont360

Just finished my riser as well. Built for an SVS PC12-NSD. Test drove some scenes from Finding Nemo. Not really sure if I can tell a huge difference. I'll play with it more tomorrow.

Any suggestions as to why I wouldn't tell a difference. It sits bout 6 inches higher now with the riser.

Honestly, there might not be any difference, or it could be worse. Acoustics has very few one size fits all solutions. Isolating the sub helps reduce it's untuned sympathetic resonance. If for some reason the materials were acting to reduce the energy in a peak then you might actually to more harm then good. It could also very well be the height of the sub isn't ideal for your room dimensions. In general you don't want the subs height off of the floor (from the center of the driver) to be a multiple of the distance to the ceiling. 17% of the distance would be better then 20% of the distance. The other possibility is it had a positive benefit, but not audible. When I ran sweeps testing the risers I could hear the difference when the sweep was run (there wasn't a dip where there was before) but I really didn't notice any difference with something like a movie or music. Human auditory perception of subsonic frequencies is very poor, even several DB differences is difficult to notice. What has a much greater impact on LF isn't a perfectly flat response, but a increase in the decay rate at the frequencies that produce a modal ringing in the room. If you can achieve that you will notice a huge difference in the quality of the sound.

[lamont360]

Very helpful information kareface... even if its not something I want to hear. I have vaulted ceilings that start around 8-9 feet and go to about 14-15... It is also an open floor plan with only two solid walls. So acoustic perfection is not possible. I'm waiting for the washing machine to turn off so I can recalibrate. Check my HT Gallery to see shots of the riser and to add any suggestions

[kareface]

That's rough. No one will be able to predict with great accuracy your room modes. With a room like that you don't have to worry as much about LF because you'll likely have a steep roll off thanks to the open spaces. You'd have to measure to get an idea of the LF modes. You ceilings are going to create a higher decay with shorter wave lengths tho. I would highly suggest investing in some dampening panels. You can build them pretty cheap, it's about 110$ for six 2" panels worth of OC-703, and you'll just need some thin wood and cloth that you can easily breathe through to cover them with. In your room you might consider getting the 705 instead simply because you'll see better high end performance, which you'll likely have more problems with in your room. As for the risers, no one here can tell you if they'll be better or worse then not having them. You might be able to find a sweet spot for the sub with the riser, but with out a mic to measure the best thing you can do is just find the place and configuration that you think sounds best.

[lamont360]

Thanks for the advice. I'm renting the house and my lease is up in a few months. Hopefully the new place will have a good room for a dedicated theatre space. Fingers crossed.

Until then I am happy with the response my system is providing, but I know with a different room it could be much better