Originally Posted by Martycool007
With regards to the DIY bass traps made from the pink fluffy stuff stacked in the corners, does it matter what kind of fabric you cover it with? Will any of the standard fabrics from some place like Hobby Lobby work? I have read that it is a good idea to put some type of plastic sheeting over the front to help not absorb too much of the high frequencies. Is that a real concern, and if so, what type of plastic should be used?
For starters, many prefer to face the trapping/fiberglass with covering for either aesthetic or environmental reasons. One can also place polyfill in front of the fluffy stuff to help contain the fibers if you want to, then fabric in front of that.
Now, nearly all HTs need more damping/bass trapping in the LF, to lower the LF decay times. Essentially, as much as you can fit into your room is welcome to address the decay throughout the bass range. However, you may get to a point where you're over-deadening the MF and HF, diminishing liveliness .. but it's subjective, as many prefer it. But, if you want selective absorption, you can face the trap in a variety of methods; Paper facing, like a thicker craft paper, ... will start to reflect around 1khz. Next up one could use pool liner type product, which begins returning around 500hz. Even lower one could use 1/2lb mass loaded vinyl (MVL), which returns beginning around 250hz.
In most instances, I'd suggest full spectrum, broadband absorption from the listener forward. Behind the listener, perhaps one may pursue some more selective absorption, to retain the MF/HF, yet damp as much LF as possible. Typically, from the listening position, to the front wall, if you absorb, you absorb it all. Otherwise, you're merely EQ'ing the reflection. So, if you wish to address the sidewall lateral reflected energy with absorption, you employ thick and effective panels.
One great aspect about room treatment, diy solutions can often be extraordinarily inexpensive, relative to the commercial solutions out there.
Bass traps and thicknesses aren't as intuitive as one may think. Too thick and one begins to enter into an area of diminishing returns. So, I often suggest a rule of thumb relative to how much space you can forfeit to the treatment. If you have around 4" of space to use, use rigid 703 or equivalent product. From around 6"-9", I suggest Safe-N-Sound Rockwool product. If you have more space than that, I suggest going with fluffy stuff.
Now, that said, the fluffy does require being mindful of not over-compressing. Some plastic bird netting, or similar .. every so often will help it not to compress too much.
Some use rigid, superchunk style, stacking triangles of rigid in the corners .. floor to ceiling. This works fine, albeit more expensive. There's so many approaches to bass trapping, some more effective than others. But a quick search would turn up countless examples. The Safe-N-sound stuff is a great compromise, as it's stays together self supporting etc, stack it up and make it thick.
I've no experience with the newer cotton or denim material, recycled stuff. Nor am I aware of how effective it is, beyond the potentially dubious mfr claims, just don't know.
We're discussing bass traps, but for treatments for reflections, I'd likely utilize 4" minimum
rigid, spaced 4" off the boundary be it the wall or ceiling.
Treatments have the capability to absolutely transform the sound of the room. The bang for the buck is off the chart.
I hope this helps