Panel absorbers

Hello, I want to make a basstrap, because I can hear a very heavy bass in the rear of my mixing room, and I can actually can hear it trough my whole house. After using a testtone from this page http://www.nt-instruments.com/flash_vie ... PageId=465 I have noticed that 40 Hz is causing the heavy bass. So is it wise to, as written on the SAE site (http://www.saecollege.de/reference_material/index.html), to build a few panel absorbers that have the size 1 meter x 1 meter (3'x 3') and have different depths? or Is it possible to make one panel absorber, that absorbs the 40 Hz frequence? I can imagine the last option would be usable, but isn't it better to absorb more then just that frequence? Can you give me the sizes also of the panel absorber(s) I need to know? If it's needed my room's sizes are: Lenth 4 meter and 45 cm, hight 2 meter and 63 cm and 3 meter and 3 cm broad. (2,54 cm = 1') Thank you! Ben

Ben - what treatment do you have in your room currently?? cheers john

Hello John, I have two panels in my room with the sizes 103 cm x 120 cm and a depth of 12 cm each. They are both filled with 4 plates of rockwool. I case it's usefull, here is a illustration of my room: ----- The windows are on this side > | |_ |____| < Here's the door ^ This is the rear of the room As you can see, there is a gap in the room that leads to the door. I hope this makes it clear. Thanks

Mate you need more than Two panels in your room. Have you checked out what others have in their rooms at http://johnlsayers.com/Studio/index.htm ?? cheers john

I like to work to those kind of solutions, but is it possible to get rid of that heavy bass with a relatively simple solution? Like building a basstrap or something?

the bass wouldn't be your only problem - in fact it's probably the least of your problems. Youmust bring the reverb time of your whole room down from where it is - panels of rockwool/insulation will do this but you will need a lot more than you currently have. Once done then you are in a position to see how much bass trapping you will need. cheers john

Just a small comment. Concentrating on the fact that you hear it in the whole house: If this is typical 40 Hz there are a few options. Is there a weak point as door, window? Your lowest axial room mode at x-axis is 38.6 Hz. How are the walls made? Drywall? How? This can be a mass-spring resonance making the wall a filter at 40 Hz. Can be a combination of the above. Absorption with wool will only help (in function of insulation) for a few dBs. This does not mean that you probably must upgrade your room as John said. Creating a panel trap at 40 Hz will worsen the problem. A panel trap is a mass-spring system absorbing at that frequency in the room but simultaniously creates a weak spot in the insulation at the very same frequency. This insulation leakage is much more significant than the absorption. What seldom is told: A panel trap can be a good and space saving low frequent absorber, but simultaniouly this absorption is at the expense of the insulation of the wall on which it is mounted (mass-spring), and on a drywall it will shift in frequency (depends on mass ratios) and creates a triple leaf system. Conclusion: A panel trap tuned to a specific frequency in order to increase insulation is counter productive and has the REVERSE effect as intended. Eric

Welcome Back Eric, where yah been?? Bryan Giles

Thank you for your help. I am going to focus me on the reverb time of my room.