(possible) technical drum riser question

liv_rong

Senior Member
I am planing on building a platform for my drums to keep them up off the ground in my basement. Occasionally if there is a ton of rain and flooding my basement will get some seepage, nothing crazy but I want my drums up out of that. I was planning on building a frame out of 2x4's and then using 1/2" plywood to cover it, all screwed and glued together. I was going to use small adjustable legs to level it. I wanted to do it in two sections so I can just take out a few screws to remove from the room easily so I can sweep and mop occasionally.

What I am wondering is how this could affect the sound of the drums, mainly the kick, if at all in recording situations, which I will be doing shortly. Do I need to do anything special or just proceed as described above?

Thanks for any help!
 

larryace

"Uncle Larry"
It should improve the sound of your drums. A riser is a natural subwoofer. I would seriously consider 3/4" or 1" decking though. With 1/2" decking your studs would have to be 6" apart or else stuff will shake. I used 3/4's on my riser and while sufficient, if I had it to do over again I'd use 1" decking. Mine is 5 deep by 7 wide. Plenty of room. Support the most under where you sit. Like Bo says, you yourself are the heaviest part of your kit.
 

barryabko

Senior Member
If the bottom section of the wood riser gets wet it will eventually get mold or rot and the fasteners will rust. It may also warp once it dries. Maybe paving stones between the floor and the riser would help.
 

liv_rong

Senior Member
Thanks for the feedback, especially on the spacing of the joists. I would have just done 16" on center and that would not have been adequate for a 2x4.

Another forum I posted this question at brings up a good point that making a box could be creating a resonant box underneath the kit thus possibly causing unwanted effects while recording. Someone suggested that I should leave the ends open but that doesnt make sense becasue you need that for support. Which brings me to what barryabko said:

If the bottom section of the wood riser gets wet it will eventually get mold or rot and the fasteners will rust. It may also warp once it dries. Maybe paving stones between the floor and the riser would help.
But I am going to do this:

I was going to use small adjustable legs to level it.
So when it is complete there would be at least a 1/2" gap between the floor and the 2x4's. Maybe this would negate the possible resonant box effect since there is somewhere for the air to escape?

Any thoughts?
 

Bretton

Silver Member
it won't negate the resonant box effect, just like a port hole in your bass drum head allows air to escape but the chamber (your bass drum) still resonates.
 

barryabko

Senior Member
If the adjustable legs are only around the perimeter the center will probably sag to some degree.

Any structure will have passive resonance (as Bretton implied). You can minimize that by damping the main upper and lower panels but that will significantly add to the amount of work/materials required and increase the overall weight. My suggestion for paving stones placed under the bottom panel does have the added benefit of providing some amount of damping to the bottom panel.

LarryAce's comment about the riser being a kind of "subwoofer" is true to some extent but the riser will not resonate evenly at all frequencies. Some frequencies will be more prominent than others and that sonic "personality" will color the overall sound of your kit. Damping the panels will reduce that problem.

An accurately designed subwoofer should reproduce all the frequencies in its bandwidth at the same amplitude or volume and not add or subtract at various frequencies along the way. Of course, the room's acoustics will also play a major role in the end result.
 
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larryace

"Uncle Larry"
IDK, the adjustable legs....You can't just have 4 perimeter legs for a drum riser made of framing. It won't be stable. You would need more legs and center legs for sure and how would you adjust them? Having to level the riser greatly complicates things. I have no idea the best way to do it other than to buy a commercial product already designed for that.
 

MrInsanePolack

Platinum Member
IDK, the adjustable legs....You can't just have 4 perimeter legs for a drum riser made of framing. It won't be stable. You would need more legs and center legs for sure and how would you adjust them? Having to level the riser greatly complicates things. I have no idea the best way to do it other than to buy a commercial product already designed for that.
Milk crates, cinder blocks, or concrete deck piers would work if the basement floor is level. I would use the deck piers myself, as the framing sits in a channel. It becomes part of the assembly, not just something the riser sits on. For an 8'x8' riser, 9 piers would do the whole thing, one at each corner, one in the middle of each side, and one in the center of the riser. If using 2x8 joists, 2x6 runners, and at least 3/4 decking, the thing should be built like a tank. It could even be strengthened more by using joist hangers.
 

liv_rong

Senior Member
I am about halfway done with this thing.

For the legs I used two adjustable ones and the rest are just rubber feet. It worked out pretty well that the floor was only out of level about 1/2" in the back corner and maybe 1/4" in one corner. At the lowest point the 2x4's are about 3/8" above the floor, good enough for my needs - as I said earlier I am just getting out of some minor seepage that occurs from time to time. There are rubber feet along the edges and in the middle as well, some are not quite touching but there doesnt seem to be any and/or much flex. Im thinking the ones that arent touching the ground touch when weight is added to the riser(me). I built the frame first with each joist at 10" on center using 2 1/2" screws. After the frame was built I put the rubber feet and adjustable legs on and then was easily able to adjust the legs to the height needed. Once it was leveled I installed the 3/4" tongue and groove plywood using liquid nails and 1 1/2" screws. It is very solid and is pretty heavy. Dimensions are 84"x64"

I didnt think to take pictures until after I started installing the plywood but I will post what pics I have when I am done, hopefully today.
 

liv_rong

Senior Member
Finished. This is the beginning of upgrading a few things in this room in the coming months. Next is building a new smaller desk followed by treatment.





 

liv_rong

Senior Member
Good news is the drums sound good and the riser is solid. The bad news is when I keep tempo with my foot on the high hat I am getting undesirable effects. Its not a huge deal just not ideal. I wont know for sure how it really is until I record someting which wont be for a while since I am not set up to record now. If that's the case I may try adding another layer of plywood.
 

larryace

"Uncle Larry"
Nice job. I didn't think it would be stable not having the 2x4's on the floor. I was wrong. First time that's happened, not lol.
 

barryabko

Senior Member
Good news is the drums sound good and the riser is solid. The bad news is when I keep tempo with my foot on the high hat I am getting undesirable effects. Its not a huge deal just not ideal. I wont know for sure how it really is until I record someting which wont be for a while since I am not set up to record now. If that's the case I may try adding another layer of plywood.
Hi Liv_rong, The riser looks very good and well built. What are the "undesirable effects" you mentioned?
 

liv_rong

Senior Member
Hi Liv_rong, The riser looks very good and well built. What are the "undesirable effects" you mentioned?
Thanks.

Basically when I keep tempo with my foot it is like I am tapping my foot on top of a big resonant box, lol. The pedal is right in the middle of two joists so the first thing I am going to do is shift the drums over about 6" so the high hat pedal is right above a joist and see if that helps at all. Its really not that bad but I cna hear it and if I can hear it then mics are going to pick it up too. Maybe Im being too hyper sensitive to changes though and it wont be bad at all once I record.
 

barryabko

Senior Member
I do have a few suggestions that will probably help the situation but they would require some disassembly and modifications. Some of the modifications would be relatively simple and some more extensive depending on how much reduction of the problem(s) you'd like to achieve. Is that something you'd be willing to do? If so, please let me know and I'll explain further.

Barry
 

liv_rong

Senior Member
I do have a few suggestions that will probably help the situation but they would require some disassembly and modifications. Some of the modifications would be relatively simple and some more extensive depending on how much reduction of the problem(s) you'd like to achieve. Is that something you'd be willing to do? If so, please let me know and I'll explain further.

Barry
Id definitely be grateful to read some possible solutions. Thanks!
 

barryabko

Senior Member
Hi Liv_rong,

If you will be doing any type of serious recording in this room the more attention you pay to reducing potential problems with the riser the better the final recordings will be.

Right now you are concerned with the resonance of the structure in reaction to the mechanical action of your foot stomping on the hi hat stand footboard. You will probably find, however, that once that problem is reduced or eliminated, other issues will become apparent.

Let's start with the footboard problem. It's hard to tell from the photo but I would assume that the top panels are screwed down firmly to the 2x4s. The seam between the panels is right under the footboard so the panel is unsupported and under damped in that area so it resonates loudly. The easiest fix is to place short 2x4 cross braces directly under the seam. That should be done across the entire riser. You will need eight of them. Doing that will eliminate a lot of the problem but a lot of the panel's underside is still unsupported where there are not cross braces. A much more effective fix would be to place cross braces at a number of points down each channel between the long 2x4s. You should stagger them between each channel for best results. That will have multiple benefits: much better damping and support of the top panels as well as making the channels underneath smaller. As it is now, each open channel underneath acts as a Hemholtz resonator which adds to overall amount of resonance - the air itself which occupies the space within each chamber resonates. If you will be having a bass player or keyboard in this room those low frequencies will aggravate the situation even more.

Even putting in all those cross braces won't cure all the potential problems because the top panels are relatively thin and light. It looks like they are floor underlayment which is made of big chunks of lowish quality wood held together with a resin glue. It is a relatively resonant panel compared to other materials. The carpet on top probably helps somewhat. If the carpet has a rubber bottom it would help even more. These suggestions will reduce your problem without a lot of extra labor or materials.

All physical materials resonate in response to a source of energy or mechanical vibration. The specific "resonance frequency" of an object, the specific frequency where the amount of resonance is at maximum amplitude or volume, will depend on the size and shape of the material. There may also be overtones or undertones from the primary resonance frequency but at lower amplitudes.

The most effective method of damping (which reduces resonances) is applying mass and/or bonding dissimilar materials together which which can reduce or minimize the amplitude of each other's resonance frequencies. If you want to significantly reduce the resonance of the top panel you can use a much more dense (higher mass) panel on top of the floor underlayment panel. A good choice might be marine grade plywood or MDF (multi density fiberboard). It would be even more effective with a layer of vinyl or dense foam matting in between. If you don't have this extra layer in between a liberal amount of adhesive (such as construction adhesive or a polyvinyl adhesive) should be used so that the two panels will be well bonded to each other to maximize the effectiveness. Keep in mind that once they are bonded they will not be able to be separated later. Adhesive between the bottom panel and 2x4s would also help. You should stagger the seam of the second layer of top panels towards the rear so it will make everything as stiff as possible. Use lots of screws to hold it all together. I would use drywall screws since they grab man made panel material better. Carpeting can then be put on top of that for good cosmetics.
 
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Razbo

Member
How about filling the cavities with styrofoam? One sheet cut in blocks to fit should eliminate the air space, and thus, the resonance. ...?
 

barryabko

Senior Member
How about filling the cavities with styrofoam? One sheet cut in blocks to fit should eliminate the air space, and thus, the resonance. ...?
Yes, Razor, that would take care of the air resonance issue but styrofoam is pretty rigid so it may vibrate against the wood frame and it will deteriorate over time which means lots of little pieces of foam everywhere. Also, finding long-term adhesive that will hold the foam suspended against the wood may be difficult.

The air resonance in the open cavity is a relatively minor problem compared to the mechanical resonance of the wood panels and frame.
 

loki03xlh

Senior Member
Many years ago (1995), my beloved 9pc. Ludwig kit became a victim of a leaky basement. The bass drums spent several hours in 6 inches of backed up storm water. When they dries, the shells delaminated.
I was determined for my new kit to not suffer the same fate. I was in college and lived in a variety of run down houses where my drums were relegated to the basement. My dad built a riser that saved them from many floods over the years.
It was 8'x6'x9", divided into two 4"x6" sections bolted together. 1/2" osb board on top and bottom and had a frame built of 2"x2"s. The thing was built like a brick shithouse. No wobbles or creaks at all. I used standard shims to level it out whenever the floor wasn't even. I got a piece of remnant carpet to cover the top and would spray a 50/50 bleach water solution on the bottom after any big floods or extended leaks. I never saw any mold on it. The riser survived dozens of moves and was dropped down more than a couple stairwells without any damage.
 
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