BUILDING A BASS TRAP
This week’s blog is all about Building Bass Traps.
A bass trap is a control measure for the dreaded “standing waves.” a build up of pressure in a room caused by low frequencies. This is a standard problem face by people who’s room wall are parallel. The “trap” is use to reduce the over abundance of 80-300Hz frequency sound waves (the bass range). They are most effective, when they are placed in corners of the room, which is where sound wave pressure is the highest .
There are 3 main types of bass traps are: The “cylinder,” the “panel” and the “corner” bass trap. In this article you will learn how to make the “cylinder” and “panel” types of bass traps.
The key filler ingredient is fiberglass or rock wool, use only materials rated with high R-values.
Materials for the trap’s frame can be made out of wood, metal and even chicken wire! The frame covering can be made from plywood, plastic or burlap.
THE CIRCULAR BASS TRAP
The easiest of all the trap to design is the circular bass trap. What you will need as far was materials is rock wool or fiberglass; chicken wire; burlap; 3/4 inch plywood, adhesive and staples.
Tools needed for this project: jig or skill saw, wire cutter, heavy duty scissors or sharp knife, staple gun, a roll of string, safety goggles and gloves.
First Step: Place on your safety glasses/gloves/mask (Note: Remember to wear safety gear throughout the whole process!), then roll the filler material(rock wool or fiberglass) tightly, the roll should be no smaller than 4 inches in diameter and I would suggest as a maximum no more then 12 inches, cut the remainder of the filler away with either a pair of heavy duty scissors or sharp knife.
Now Second Step: take the chicken wire and wrap it around the filler use the wire cutters to snip the wire to desired length and then firmly fasten the chicken wire unto itself.
The Third Step: cut the 3/4 inch plywood in to two circular disc to the same diameter as the top and bottom of the trap and attach the chicken wire with staples to the plywood discs.
Step Four: wrap the cylinder tightly with burlap (FYI- you can spray paint the burlap any desired color prior to added it to the cylinder) and fix the burlap to itself with adhesive.
The Final Step: take the roll of string and cut it at the minimum of 4 sections and tie them around the cylinder in several places to secure the burlap in place until the adhesive has a chance to cure (approx. 24 hrs). Once the adhesive is dried remove the string. Congratulations, you now the owner of your own cylinder bass trap.
You can now place the cylinders in the corners which will reduce the low-end wave pressure in the effected room.
THE PANEL BASS TRAP
The materials you will need as a filler is rock wool or fiberglass. You will need pine studs (2″-4″ in width) to build your frame, you will also need a sheet of 1/4 inch plywood, burlap, 2″ & 1″ nails, adhesive and staples.
The equipment you will need for this project are safety gloves & glasses, a saw, hammer, staple gun, heavy duty scissors or sharp knife.
The First Step: is to decide and design a plan as to how wide and long you would like the frame of the panel trap to be.
Step 2. place on your safety glasses/gloves/mask (Note:Remember to wear safety gear throughout the whole process!), before using a saw to cut the studs to desired sizes for your panel trap’s frame, then use a hammer (or optional nail gun) to fasten the frame together with 2″ nails.
Step 3. Use a saw to cut the 1/4″plywood to fit the frame you have made, then tack the plywood to the frame with the 1″ nails.
Step 4. Now cut the filler to a size where it fit snuggly inside the frame, and cover the plywood bottom located inside the frame with a strong adhesive. Then press and place the filler inside the structure.
Step 5.Take the burlap and use the heavy duty scissors to cut it, make sure you cut it large enough to overlap the frame of the panel trap. Overlap the top of the frame for the panel trap with the burlap, then stretch and tack it to the sides of the trap with staples and staple gun.
You now have the option: to add coasters or wheels to the bottom of the panel trap to make it easy to move or re-position; or to use toggle bolts to permanently fix the panel trap in position on a wall or covering a corner. For those of you that would like to build a trap for underneath your speaker or sub woofer. make sure to build the trap a little larger than the base of the speaker or sub-woofer you are going to rest on the trap. Make sure to flip the trap over and use the plywood side to rest your speaker on.
Please note, that using the plywood side of the trap will work to effectively to reduce the the low end frequencies of 80Hz-140Hz (by facing out the burlap side you help reduce low frequencies from above 140Hz to 300Hz). By placing a panel traps on the wall behind where you have your speakers (plywood side facing out), you can reduce a lot of the “low-end frequency bleed through” to the neighbors living directly below you and behind the wall where your speakers are set.
For the non-do-it-yourself-types, (who have the budget) you will be able to find manufacturer’s produced Bass traps, the most popular design being the corner units. Be a smart consumer and shop around for the best prices.
Now you know what measures to use to reduce “standing waves” in poorly acoustically designed rooms. If you don’t already know how, you will want to know a few ways to tests and figure out what and where the problem areas might be in your room, next week’s blog will cover that issue.
Next week’s blog’s tittle: “How to test for acoustic problems in your room.”