Bass/Panel/Membrane trap questions - Build a Better Bass Tra Aug 11, 2018 18:49:32 GMT
Post by ths61 on Aug 11, 2018 18:49:32 GMT
I have a few questions about the Bass/Panel/Membrane traps described in Ethan's article found here:
- What is the actual thickness of the 1/8" and 1/4" plywood ?
- Can these sealed traps be made free standing so they could be moved and hung on a wall ?
- Can these traps be made to extend the lower frequency coverage by using a thicker plywood (e.g. 3/8" plywood) ?
I noticed that Ethan's design goes from using fabric (virtually no membrane) to 1/8" to 1/4" (0, 1, 2 thickness progression) and wondered if continuing the progression to 3/8" (0, 1, 2, 3) would extend the frequency range coverage to lower frequencies ?
Note (added October 7, 1999): Although it is not stated in the article, the low-bass trap is effective at frequencies between about 80 Hz and 160 Hz, and the high-bass trap absorbs frequencies between 150 Hz and 300 Hz.
I have some uneven brick walls, thus using toggle bolts and straight boards would be problematic for this application. I was wondering if these traps could be made self contained by using 2 layers of plywood, one front and one back while maintaining the internal dimensions?
I have a few RealTraps in my room but still have issues below 100Hz that I would like to address, mainly centered @ 40Hz.
Since the free standing traps would have 2 layers of plywood, they could be made with 1 thickness of plywood on one side and another thickness of plywood on the other side (e.g. 1/4" and 3/8") so the front facing side would chose the frequency range (e.g. dual-range traps). I would assume that the unused side would have to be damped when hung to not encourage additional panel resonance by having both front and panels vibrating in tandem.
As for using 1x4's and 2x2's on the sides, top and bottom, 2x4's could be used with a 1" dado down the center to hold the rigid fiberglass like how floating panel doors are made (with the rigid fiberglass being the floating panel). This would maintain the air space between the rigid fiberglass and the front/back plywood panels as well as grip the entire edge of the ridge fiberglass in the dado groove. The 2x4's should be rigid enough for self-standing structural support as well as stout enough for hanging purposes.
Since the existing design use 3/4" edge to attach the plywood, a 3/4" rabbet cut could be made on the edges of the 2x4's to thin the plywood connecting edge from 1.5" to 3/4" like the existing design if the extra edge width is of concern. If it is not of concern, it will make a more secure gluing/calking/nailing surface at 1.5".
Thanks in advance for your help.