The golden section tells me I need to make one of my walls absorbant and also a foot of the surrounding walls.
What in the world is the "golden section", and how does it predict absorption needs( ie RT-60/room modes).
Now the point is, that particular wall, is almost entirely glass. It has 'lamellen' (don't know the english word) and curtains in front of it.
Describe lamelllen. Is it like a sheer fabric "light diffuser" curtain?
Does it need more absorbing stuff?
Well, that would depend on what your "golden section" predicts as absorption requirements in Sabines, vs the absorption coefficients of the materials used in your absorber panels. Also the room dimensions. It would also depend on whether this is a studio, control room or both. Its kind of like telling us your hungry, and a book tells you to eat watermellon, and you ask how much is enough
As to the glass wall, glass is highly reflective, although HEAVY curtains will absorb high frequency to an extent, depending on the weight, and how far from the glass it hangs, and how much area. There are other factors to consider too. In relationship to your monitors, is this a rear, side, or front wall?
Generally speaking, if this is a very small room, and you record in this room, you need all the absorption you can get, especially in corners. And since this will deaden the room acoustics, you will have to add ambience(reverb) in the mix. If this is only a control room, then treatment should be focused on the mixing environment, which translates into a symetrical monitoring position in relationship to the speakers, sidewalls, early reflections, and rear wall distance, just to name a few.
Of course, this is only my .02
fitZ