DIY mobile traps

Hi, I would like to track some vocals/acc.guitar on location. Some customers perform their best at their own livingroom, so want to try to capture that. I saw the micro/mini traps at realtraps.com and would like to build some (4 or more) my own, to mount it on stands (make mobile) The reason to build my own is because here in the netherland these things are hard to get and to fly them over is to expensive... I can get my hands on some rigid fibre here. This is the stuf: http://rti.inforce.dk/graphics/RTI-NL/product_information/NL/industrial_slab_203_213_223_233.PDF Is this ok? Should i go for the 223? I want to place the panels arround the vocal/guitar player to capture more of the source instead of the room. Is this going to work? The right material or should i go for more fluffy fibre? Is thin/open cotton good cloth to place around it? Thanks for al the help! Jeroen StudioWolff

Can please somebody give me any help / tips? Thanks, Jeroen

Jeroen, If you want something light and moveable, and isn't to sensitive to damage, in this case you could go for flat foam. Search the yellow pages or the net for Merford (Netherlands company). They also have a shop for this kind of smaller customers. But only go for the flat thick foam. They can inform you about this stuff (in base that's a huge industrial acoustic company with high knowledge, but having made something to make stuff also accessible for smaller not industrial customers) It's one of the only companies I know that publically states that if linear or good absorption is a priority you should go for flat foam, and if eastetics or high frequencies are defining you should go for sculpted foam. You can go for the boards you referred as well and cover them with whatever breathable cloth. The choise between these series I should let it define by stability and weight of the board (not the lightest type). They all suit your purpose. The 223 should be a good choise (others too). You'll notice the higher the number the more expensive (increasing density). And if you want nicer tiles, I don't know where you can find them in small quantities, but there's Rockfon and Ecophon. If you call them maybe they can point you to distributors able to deliver small quantities. Possible Merford has even left-overs from own projects.

Thinking about it, also Illbruck has flat foam in relative thick versions directly covered by nice textiles. These things are sold as wall panels (glued) for office use. I assume they must be usable as well.

Eric_Desart wrote:

Jeroen, Search the yellow pages or the net for Merford (Netherlands company). They also have a shop for this kind of smaller customers.

That's http://www.akoestiekwinkel.nl/ ? And this is the stuff that's useable for my purpose? http://www.akoestiekwinkel.nl/akotherm.html Thanks !

studiowolff wrote:

Eric_Desart wrote:

Jeroen, Search the yellow pages or the net for Merford (Netherlands company). They also have a shop for this kind of smaller customers.

1) That's http://www.akoestiekwinkel.nl/ ? 2) And this is the stuff that's useable for my purpose? http://www.akoestiekwinkel.nl/akotherm.html Thanks !

1) Yes 2) It looks like it's OK but I should ask for absorption curves to make sure. Eric

Heavy price for a wool alternative material.... Like Eric, I'd like to see some specs (haven't really searched on the site tho... lazy)

This is the link to the info http://www.akoestiekwinkel.nl/uploadedf ... otherm.pdf it's in dutch....:) but you can read the graph... Thanks for all the help!!!

Jeroen, An important note for people not able to read Dutch and/or not familiar with the name "Kundt" and that Standard number underneath that Graph in that text. And also for you: This are impedance tube measurements. Hence the y-axis is really absorption in % or real energetic absorption coefficient unlike Sabine absorption coefficient values. Also this is measured exclusively at straight incidence unlike the normal Sabine method in reverberation rooms where random incidence is measured. Hence this graph can not directly be compared with the graphs most people are used to see. Normally these numbers should become better when measured in a reverberation room resulting in the traditional Sabine absorption coefficient numbers. There is no simple formula to calculate from one to the other, but in the low frequencies differences are possible upto 40% (as per some authors). This Kundt name: Kundt is the inventor of this tube.

Eric, Thanks for your explanation. The vendor also stated that this was not a measurement in a reverberation room. There is data of such a measurement, but he hadn't it available yet. Hopefully he can give it soon. But is this the right material for the purpose? A mobile trap which can isolate more of the sound source to the mic when i place it around a mic? Jeroen

Jeroen, The material itself looks OK to me. And it seems very suitable, stable and lightweight to make whatever mobile screen from it. But since you are asking about the use in recording techniques and how this best should be designed I rather like others to drop in here with related experience. I'm no sound/recording engineer, and know this stuff more from watching from the sideline. Others will certainly help you further. You don't need to wait for Sabine reverb values. They will be just a better version compared to these graph values.

Eric, Thanks!