So you’re making square panels like in the diagram you posted?
Yes almost exactly like those, have done this before some years back when I had no idea about the lack of efficiency rockwool has at low frequencies.
I was never really happy with those traps and want to do it properly this time around.
Just a word of caution regarding DIY acoustic treatment:
Always research thorroughly in order to feel comfortable in knowing that what you’re doing will actually improve your acoustics. There are alot of myths and strange opinions wrt what works and what doesn’t… And when in doubt, only apply as little damping as needed, don’t overdo it.
I am to scared to go DIY myself so have been buying commercial acoustic products, but obviously YMWV
Well, some research has been done in the articles linked above.
How thick are those? What I have read about wedge style traps is that they do not really absorb much of the lower frequencies… for super low freq absorption, you need volume (thickness/surface area) and lots of it.
Dimensions:370 x 370 x 600 mm
I’m guessing more than two will be needed
Don’t buy “acoustic” foam, it’s utterly useless for absorbing energy and are a complete scam.
You’d do better with buying a couch or a bed and placing it in the room instead, curtains work if you just want to eliminate higher frequencies.
So you’re placing the rockwool/membrane panels near the floor , the ceiling, or at speaker height?
Ideal would be from floor to ceiling but if you want to save some money then you are right,
speaker height/ear height is the perfect placement.
So I have a subwoofer on the floor… should I place a couple of the panels at floor level at the nearest corner of the room ? and then some more without the membrane ( for the mids and highs) at the height of my monitors ? (the monitors have a 5inch woofer and the sub’s crossover is set to 55Hz)
The membrane traps are kept in corners where the bass accumulates the most.
You want the bass traps all to be at speaker level if you’re not doing floor to ceiling treatment.
You’re trying to create a reflection free zone where you are sitting in front of you’re monitors.
So if you only have a few membrane traps it’s best to place them in the corners of the room, you can put traps where the floor meets the wall and ceiling meets the wall but it’s less important to treat those spots.
cool, thanks! Can you link to the article where that diagram came from?
Is it necessary to close the back of the panel with wood?
Returning to the acoustic treatment project! Moved to a new house with a separate studio room.
This time going the slightly more scientific route. Borrowed a cheap Behringer ECM8000 measuring mic from a colleague and using REW software.
Getting the wisdom from these resources:
All “treatment” I have done so far was done by ear: set monitor and listening position, and dumped the 2 packs of rockwool sono that I had from my old house in the boomiest corner. It s a small, non-symmetrical attic room and I expect trouble dealing with that later on. It s easy to tell low frequency response has heavy peaks and throughs that I couldn’t solve with positioning. Mids and highs sound pretty balanced already.
I spent some time learning about how to use and interpret REW. Then ran some measurements and did first, easy adjustments on my Genelec 8040B’s : +2dB treble, -2db bass tilt.
Measurements now show this:
1/3 octave filtered: (useful for mid/high frequencies, not precise in low freqs)
no filtering: (useful in low freqs)
This shows what I was hearing already: mids and highs not too bad but big problems in the low. Next chapter will be trying to improve that low end.
Been working on getting the low end more balanced, without adding materials yet. Spent a lot of time moving the monitors around. Then moved the 2 rockwool packs to the corners behind the monitors instead of against the back wall. That already sorts quite a bit. (black: before, brown: after)
Next: get 2 extra rockwool sono packs to fill the back corner again. They were doing beneficial things there, preventing that 40hz dip for example. And then get or make reflection absorption panels for the walls, to improve the combs in the mids and highs. I think a rug on the floor would be quite helpful too.
Also. To the ones who previously said that dumping packs of rockwool (in their plastic wrapping) in corners would be pointless as bass traps: you are wrong
If you need any help building panels for your wall, let me know. I’ve built them with instructions from the web. Really easy to build.
What guide did you follow to build m?
Ha! Always good and important to experiment.
The studio control room I built, but no longer use, has a rear wall that has about 1,000 lbs of rockwool in it. Due to its geometry and build design (consulted with JohnL. Sayers), the rear wall was left with a large cavity and I had already bought so much rock wool for the inner and outer walls of the other rooms, plus the floor, that I figured why not just fill it?
The rear corners are open/exposed, no drywall, with fabric in place for extra absorption.
What always amazed me was how good that room sounded after just adding a little bit of diffusion added. No right angles in the place helped immensely.
All the brown area was total fill:
But these days I’m in a rectangular box in the house. One of my recent Covid projects was buying (not building, have done it before and prefer to pay someone else) and mounting some new bass traps from atsacoustics.
All 4 ft tall, I got a corner trap for a corner near a window, since i like that it can stand free, also a 4" thick low bandwidth panel mounted and spaced off the door next to it,
and a 4" thick low bandwidth panel for the other corner next to it, which rests on two doors, and is movable.
These tightened up the room so much. Mixing on my Genelecs was relatively effortless before, but now it’s downright immediate.
Like you are finding, rear traps do wonders for the 35-40hz range in my room as well.
I’ll probably get some 2’x3’ 4" bass traps for the front corners eventually. And since there is a basement underneath, i want to put the last large bag of rock wool i have from the old project left in storage in under the floor some day.
Don’t know the exact guide. But along the lines of this.
I constructed them a bit simpler. I left the wood on the back away and didnt put wedges in the corner. Between the rockwool and the fabric I put a layer of painter fleece.
What people say is to build them as thick as possible. As I recall this is more true for corners as the bass builds more there. I’m building side and ceiling panels soon that will be thinner as the ones I already built.
I have professionally built panels here too and don’t notice any difference. They do look a bit nicer, but that’s up to your skill.
I think it’s really easy diy stuff.