DanDan wrote:What are the boundaries made of..... Concrete.... wood... plasterboard? A light structure will not have strong reflections at LF, which would be great.
Can you post the REW file so we can look at Waterfalls and Topt with our own choice of scales and filters?
I would broadly concur with Glenn but some slight divergence....
I would focus treatment on the Back wall. In many cases it proves best to not treat the Front Wall at all.
A little bit of a tangent, but still somewhat related.
I also understood that lightweight structures do not have strong LF reflections, however, I've recently been reading everything I can on anechoic chamber wedges. In all of the papers I have read (some very detailed with complex maths completely over my head) they state, in my own words, that the porous wedges absorb highs and mids, and LF waves are reflected between the wedges, ricocheting back and fourth until the energy is dissipated into nothingness. Of course, it depends on the wavelengths involved and the usual gradual transformation between rays and waves as you go from high to low frequency. The wedges need to be long/deep enough in order to have an effect on the desired LF.
But it is a mechanism of reflection which obliterates the LF energy, not the absorbent properties of the porous fibre. My point is: you can't get much lighter in weight than fibreglass or similar and yet LF energy is reflected off of it according to these papers. The wedge shapes provide a gradual impedance increase which sucks in the ping ponging waves, more and more energy is lost with each bounce. I was surprised to read this, since what does it mean for flat panels and deep whole wall trapping?
From personal experience: My control room in it's current state of progress is simple a timber frame with 1 single layer of 18mm OSB, yet it is clear from the measurements that strong LF reflections exist, the walls are not lossy enough that no strong LF reflections exist.
Therefore, invisible alpha, membranes, lightweight structures and porous absorbent can all be reflective or absorbent in one way or another.
of the room. 3 on front wall and 3 on back wall, 3 spaced across ceiling. plus 1 on stand for in-room damping.