Hi Paul and thank you for your input , I really appreciate!
Paulus87 wrote:Porous absorbers can have an effect on membranes, so I would treat the ringing according to your measurements rather than your predicted room modes.
I further studied the LMA's and read today what the designer says:
"These traps are intended to tame room modes, so measure your room dimensions and calculate the modes. Measuring with microphones does not necessarily identify problematic modes."
So I think I will go for room's mode.
I have to say though, I am not optimistic about your proposal of creating lots of small traps and only treating a relatively small area on your front wall...
About that he is writing on design notes:
"The box L x W is not critical but should be kept small compared to the wave length of the resonant frequency. The
limp mass bass absorber is not effective beyond 300Hz for this reason. Typical L x W would be 60 x 40 cm for
frequencies below 100Hz, and 40 x 30 cm for frequencies above 100Hz."
I still don't know how many of them will be needed so I will build, measure and keep going according to results.
Mine will be 50x60cm and I 've got space for 12 boxes on front wall.
There is this guy who made just two boxes of 40x60cm, placed on front wall, to tame his first axial mode on 61Hz and had great results regarding decay and frequency.
Check his graphs:
Screen Shot 2014-07-09 at 20.47.06.jpg
t30_empty_room.jpg
t30_tlma_18cm.jpg
spectrogram_empty_room.jpg
spectrogram_tlma_165mm.jpg
I know much of your treatment is already in place now and changing anything will change your measurements again, but I think I would build large traps and cover as much area as possible on the rear wall, behind porous treatment if possible.
Yes the pressure zones for this mode is the front and back wall so both of them will give the best results.
The whole back wall is full of hangers 80-100cm deep already so it already contributes on taming this mode. It was challenging to complete this back wall project so I prefer not to mess with it for now. I will just start with the front which is untreated and see how it goes..
