DIY Subwoofer Risers

[duder1234]

Originally Posted by Fors*

Anything that can help with decoupling the sub from the floor can't hurt. Give it a try and let us know.

Will do! I've actually got some speaker stands I've been working on for the better part of a week. I'm painting them right now, but its slow due to intermittent weather! I went with 3/4 inch plywood. The center of the stands with be filled with silica sand. The rubber feet are going on the bottom and I'll probably throw some rubber on the top corners of the stands to isolate the speakers a bit more.

This thread helped alot...so thanks everyone!

[kareface]

Ug, lol. I threw out my back last night moving those subs (~100lb each) all over the place trying to figure out this damn dip at 80hz. Part of the problem was some of the 2 channel listening modes on my receiver seem to ignore the crossover point I've set, which threw me off. However, it's clear that the dip is a result of the vertical node. I have to acoustically correct it with a riser so the project is back on! lol

I'll be going out today to pick up the materials I need to construct them. After testing it looks like I need about 20-22" from the floor to break up the node enough to correct the dip, which is great the 25% of the distance. I'll be building them with the intention of creating a LF bass trap underneath to help reduce the excess energy. I'll post updates once I'm finished.

Edit:
Shopped around today for ideas. I might go a different route to get to the same result.

[kareface]

Picked up the MDF and the materials. I had an idea I'm going to test to see if it pans out. I'll post images, most of today will be gathering the tools.

[crazyBLUE]

Originally Posted by kareface

Picked up the MDF and the materials. I had an idea I'm going to test to see if it pans out. I'll post images, most of today will be gathering the tools.

Well ~ Are you building A fancy one of A kind Riser

[kareface]

I'm just building a taller riser to get it high enough to decouple it from the node. The advantage of going this route is you have more room beneath the sub to play around with. There are 4 different ways I've found that would help reduce excess energy in the node. 3 of them are different forms of sympathetic resonators and the forth works on the principle of pressure equalization. I'm likely going to stick with the cheapest and easiest of the 4 options to start with. The other 3 require tuning to a specific frequency, and to do that I will have to consult with an acoustical engineer. What is nice, down the line I can easily change the dampening out to one of the better options once I have the details hammered out.

Today I spent most of my time gathering all the tools I needed. I still need the compressor, but with luck I'll get that back from the guy borrowing it tomorrow. I also need to pick up the acoustically transparent cloth tomorrow. I found a really neat idea for the top of the riser. As long as I can get the compressor back I should be able to start work tomorrow. My room calibration is stalled on this project, I'm hoping to finish both soon.

[kareface]

I picked up a new fiscally conservative (i.e. cheap ass) saw to use on the project, and I spend most of the night just putting the base of the saw together. Damn near threw the thing out the window trying to get the pieces of the base to come together. You literally had to force each piece together with the nuts and bolts. I finally got the compressor and just to make sure I was ready for tomorrow I picked up the cloth I intend to use on the subs. I don't think I've ever felt more out of place then I did wondering around Jo-Ann Fabrics. BTW, I was not aware of the fact they sold speaker grill cloth. I nice tip for the DIY'ers out there.





I finally have everything I need to start the project, so I'll actually be able to make some progress tomorrow.

[kareface]

Finished one of the risers. I'm not in love with the results of the fabric, I'm going to play around with the second riser to see if I can get something that might turn out a bit nicer. On the whole tho I like the looks. Once I finish the second riser I'll post the acoustic results.

I have the build process in my gallery.

[KingLeonidas300]

Originally Posted by kareface

Finished one of the risers. I'm not in love with the results of the fabric, I'm going to play around with the second riser to see if I can get something that might turn out a bit nicer. On the whole tho I like the looks. Once I finish the second riser I'll post the acoustic results.

I have the build process in my gallery.

Great job on the riser. This is something that I would like to put together I just don't have the tools to do so. I need to build a new riser for the sub I have since one of my English Mastiff puppies chewed the front corner off and a second for when my second a2-300 gets here.

[erict]

Originally Posted by kareface

I picked up a new fiscally conservative (i.e. cheap ass) saw to use on the project, and I spend most of the night just putting the base of the saw together. Damn near threw the thing out the window trying to get the pieces of the base to come together. You literally had to force each piece together with the nuts and bolts. I finally got the compressor and just to make sure I was ready for tomorrow I picked up the cloth I intend to use on the subs. I don't think I've ever felt more out of place then I did wondering around Jo-Ann Fabrics. BTW, I was not aware of the fact they sold speaker grill cloth. I nice tip for the DIY'ers out there.





I finally have everything I need to start the project, so I'll actually be able to make some progress tomorrow.

Come on over to my shop Post#316 & 318
https://forum.blu-ray.com/subwoofers...ml#post1834203

[Steve]

Originally Posted by kareface

Finished one of the risers. I'm not in love with the results of the fabric, I'm going to play around with the second riser to see if I can get something that might turn out a bit nicer. On the whole tho I like the looks. Once I finish the second riser I'll post the acoustic results.

I have the build process in my gallery.

Very nice job. What did that fiscally conservative saw cost you?

[kareface]

Originally Posted by erict

Come on over to my shop Post#316 & 318
https://forum.blu-ray.com/subwoofers...ml#post1834203

I wish I had a setup as elaborate as that. I'll need something alone those lines for building the next set of speakers. A shame you live so far

Originally Posted by Steve

Very nice job. What did that fiscally conservative saw cost you?

~60$ on sale. I don't remember the exact number, but it was less than 70 for sure. I just needed something that would cut straight.

[kareface]

I'm waiting on the primer to dry, so I decided to do some testing of the finished riser. This is with 1 sub, 0 digital correction (so no EQ's or PEQ's), crossover @80hz & the position of the sub is about the same (I eyeballed it). The dip at 65 is likely the vertical node, and the overall DB increase is likely because the couch isn't blocking as much of the sub (thinking about it, I might of increased the gain by mistake when placing the sub on the riser, I'll have to check). Blue is before, red is after.

[MAL01]

Originally Posted by kareface

I'm waiting on the primer to dry, so I decided to do some testing of the finished riser. This is with 1 sub, 0 digital correction (so no EQ's or PEQ's), crossover @80hz & the position of the sub is about the same (I eyeballed it). The dip at 65 is likely the vertical node, and the overall DB increase is likely because the couch isn't blocking as much of the sub (thinking about it, I might of increased the gain by mistake when placing the sub on the riser, I'll have to check). Blue is before, red is after.

Wow, that`s some improvement. Alot of guys here ( including myself ) have made these simple 3 or 4" peg leg risers. It seems your riser has made quite a difference in your graph. Could you explain this without being too technical
I might have to rethink this whole riser business.

[kareface]

Originally Posted by MAL01

Wow, that`s some improvement. Alot of guys here ( including myself ) have made these simple 3 or 4" peg leg risers. It seems your riser has made quite a difference in your graph. Could you explain this without being too technical
I might have to rethink this whole riser business.

You should shave off about 3-5db off the red results, I'm pretty sure the difference is bumping the gain. However from 50-70hz, that is all riser, lol. The dip there was created by the vertical node, which means that between the floor and ceiling in my room a wave was creating a null at that frequency.



Nulls are created naturally at points where sound waves of the same frequency collide. In my case I needed to a) raise the sub to reduce the energy given to the standing wave and b) absorb the excess energy of the wave. The reason why I specifically say that you shouldn't use foam or high density fiber in a larger riser like this is because it isn't as effective. By making it easier for air to pass threw a lighter material you allow the material to move with the pressure wave. Even if it's very minor, by moving the material some of the energy is taken away from the wave. This is important for waves below 150hz, as normal panels and foam have little effect on them.

[erict]

Originally Posted by kareface

I wish I had a setup as elaborate as that. I'll need something alone those lines for building the next set of speakers. A shame you live so far

~60$ on sale. I don't remember the exact number, but it was less than 70 for sure. I just needed something that would cut straight.

I love the speakers you built as they look awesome If you don't mind me asking, how much did it cost per speaker?

[MAL01]

Originally Posted by kareface

You should shave off about 3-5db off the red results, I'm pretty sure the difference is bumping the gain. However from 50-70hz, that is all riser, lol. The dip there was created by the vertical node, which means that between the floor and ceiling in my room a wave was creating a null at that frequency.



Nulls are created naturally at points where sound waves of the same frequency collide. In my case I needed to a) raise the sub to reduce the energy given to the standing wave and b) absorb the excess energy of the wave. The reason why I specifically say that you shouldn't use foam or high density fiber in a larger riser like this is because it isn't as effective. By making it easier for air to pass threw a lighter material you allow the material to move with the pressure wave. Even if it's very minor, by moving the material some of the energy is taken away from the wave. This is important for waves below 150hz, as normal panels and foam have little effect on them.

I have null at 50hz at the listening position. I did a little experiment, while running my sms, i took my 2x4x4" acoustical panels that were behind my subs and put them in front of me as i was standing at the lp. The null flattened out some, not all the way. Do you think any kind of treatment on the wall opposite the speakers would help at all? Short of holding a bunch of panels in front of me while watching movies, i may not have many options

[kareface]

Originally Posted by MAL01

I have null at 50hz at the listening position. I did a little experiment, while running my sms, i took my 2x4x4" acoustical panels that were behind my subs and put them in front of me as i was standing at the lp. The null flattened out some, not all the way. Do you think any kind of treatment on the wall opposite the speakers would help at all? Short of holding a bunch of panels in front of me while watching movies, i may not have many options

Panels are pretty ineffective in the bass region. It would be hard to properly correct a dip at that frequency with panels alone.

Originally Posted by erict

I love the speakers you built as they look awesome If you don't mind me asking, how much did it cost per speaker?

With out the finish, so no paint or stain it runs around 350 per speaker in parts and materials.

[kareface]

I've been thinking about what I want to do with the second riser. I wasn't happy with the appearance of the first one, the fabric alone wasn't that great. I was thinking of sanding down the legs and top, finishing it a little better with the black and then getting some speaker grill cloth to run on the inside of the legs (instead of the outside like the last one). The other option is instead of black I could apply a veneer and stain that, but I haven't decided yet. I can also apply a layer of carpeting over the foam as well. Right now the second riser is still in coffee table mode, so I can play around with it a little. Any suggestions?

[crazyBLUE]

Originally Posted by kareface

I've been thinking about what I want to do with the second riser. I wasn't happy with the appearance of the first one, the fabric alone wasn't that great. I was thinking of sanding down the legs and top, finishing it a little better with the black and then getting some speaker grill cloth to run on the inside of the legs (instead of the outside like the last one). The other option is instead of black I could apply a veneer and stain that, but I haven't decided yet. I can also apply a layer of carpeting over the foam as well. Right now the second riser is still in coffee table mode, so I can play around with it a little. Any suggestions?

Just A suggestion if you are looking to improve the way it looks , You could always find some Molding to miter & apply to the outside of it .

This is the last one I made for my monster Dayton 15" .

[TCR Alliance]

Originally Posted by crazyBLUE

Just A suggestion if you are looking to improve the way it looks , You could always find some Molding to miter & apply to the outside of it .

This is the last one I made for my monster Dayton 15" .

Crazy, nice sub riser.