Limp Mass membrane material?

Hi all, I'll try to keep it short so you can skip this intro if you want to get to the question. I've always had trouble with my mixes, after putting a 'corrective' eq on the master bus recently I realized it's not my ears or ability. I used some commercial tracks and made them sound 'good' with an eq. Mixed as I usually do (with the eq on) and turned it off at mixdown and it was pretty damn close to what I wanted/expected. I've really tried reading EVEYTHING I can find on acoustics, I do alot of forum surfing and gone thru EWhiner's site. I've done alot of treatment on my room, installed lots of trapping (I physically can't fit anymore in) and I'm still nowhere near. So I'm looking to modify/improve what I already have. My current corner traps are broadband devices, absorbing all highs mids and lows. Further research has led me to think about facing my corner traps with a "limp mass membrane" which will give back some hi's and help with the lows. THIS IS WHERE I'VE HIT A DEAD END, people are very secretive about this 'magic' membrane Now the way I understand it is, the thicker and denser the facing (bonded) material the lower the frequency of the trap. One line of thought has got me thinking I should sparymount some card to the insulation, reflecting highs and letting thru alot of mid and all lows. The other way I'm going is to look for some heavy 1.5 dense rubber (like a doormat) which would make my corner traps low low traps. Any thoughts or comments or advice gratefully recieved Looking forward to your responses S

The most common material is FRK, which is the standard foil/paper facing that comes on some models of Owens Corning rigid fiberglass. You could glue it on with standard spray contact adhesive, on the front end of the trap facing into the room. It will restore some reflectivity at mids and high frequencies, as well as give you a boost in your bass trapping. It looks like your wall/ceiling corners don't have traps in them, it's a good place if you are still having bass issues. Also, any flat panels (ie, not straddling corners) you should space out from the wall a few inches. It will give you better overall absorption, as well as absorb to a lower frequency. This is especially important on the rear wall.

Also, if you can you should re-size your photo according to forum guidelines so it fits into one frame.

Thanks for the good advice jwl. The side panels are 4inches 60kg/m3, open fronted broadband absorbers, hung 4 inches from the wall. Just thought I'd drop in and give you a little update. I did some measurements which confirmed an 8db hole @ 75-115hz, 6db up @ 30-40, and generally wobbly all the way to 300. So I've taken down all treatment off the left hand side (so far). I've taken the front corner trap and spray mounted a very thin sheet of plastic to the face and replaced fabric. I'm also experimenting hanging barrier mat 30mm behind the back of the trap (between the two pieces of rockwool, it can vibrate freely). There was a similar trap running along the floor wall corner, faced that, even though it doesn't really see many reflections being on the floor. Back corner, same as front, no barrier mat. Previously I had 3 big bin(trash) bags full of off cuts stacked in the corners (making the traps stick out a bit), I've now made much smaller bags (200mm x200mmx800mm) and lined them along the floor wall corner (all the way down the left side) This leaves one full upright panel behind each trap. So I've taken stuffed corners and redistributed it along the back wall and long wall, does this (and the other ideas) sound ok?

So I got the mic, got the software, convinced it to work ;) set the mic up, calibrated everything...... and finally hit the test button This is what I got...... SURELY this can't be right? :( (would explain alot though! ;) ) Good news is.... The hole @100hz has gone ;)

well I'm really disappointed in this board. Maybe it was something I said, maybe not. Was hoping to hear from eric D

Well I already answered you elsewhere so I don't feel guilty. :) Here's another tidbit though: If you bought ETF in the past few years I think you can also get the newer R+D for free. One nice feature of R+D is a signal to noise display. This will tell you immediately if your data is valid. If the s/n is down around 1 or 2 dB, it means something is connected wrong. But ETF gladly displays data even when it's meaningless. --Ethan

lol thanks ethan, good to know. Was just trying to get as many different viewpoints as possible, did you see my master plan over@gearslutz? in the monitors lie thread I think (moan zone)

Hey Guys Regarding "Limp Membrane Resonator" or "Limp Mass Resonator" I have been using a new company here in Australia called Thermotec www.Thermotec.com.au They have what is called NuWave Base & NuWave 4 Zero; one is foil backed and you might only want that if using in a corner trap design, the other Nu Wave Base, is a Vinyl Mass loaded mineral material with a Fabric cover on one side and a dark sheeting on the back, about 5 mm thick. It comes in a few variations (Off the top of my head); "Thermotec Nuwave Base" 8-Kg m2 1350 mm x 3000 mm 6-Kg m2 1350 mm x 3000 mm 4-Kg m2 1350 mm x 5000 mm 2-Kg m2 1350 mm x 5000 mm I grabbed some 4-Kg M 2 after feeling the weight of a 1350 mm x 1000 mm piece, they actually come in rolls of 1350 mm x 3000 mm 6Kg- m2/8Kg-m2 and 4Kg-m2 1350 mm x 5000 mm. Also beware; their are many imitations of this stuff either called XYZ Barrier matt or something else and the design is just dreadful alongside being manufactured very poorly, if your getting a 1400 mm plus width it has not been factory cut properly or is an import from China. And no.... it does not look dreadful, it's actually a nice product to work with, hard to cut, though great, unfortunately Thermotec do not sell OEM or their pricing can be wildly differential with Insulation dealers (If they even know whom Thermotec is?) I can also give you a great dealer if you live here in Australia, just PM me or Email....! Cheers ADDAjavascript:emoticon(':D') Jazz