Closet behind studio monitors

I have a basement studio that I use for electronic music production and mixing (and some live DJ mix recording). Outer Construction: It is/was a center bedroom with other rooms on the outside of 3 walls and a cement retaining wall behind the short wall that I am facing. There is normal (non-acoustic) insulation on the outside of all surrounding walls, as it is a finished room. Problem: I am trying to figure out the best way to deal with the 2 foot deep closets behind my studio monitors. (see picture) I will be adding foam wedge bass traps in the room corners, but this is just outside of the closets. The edge of the closet door openings are 11" from walls (just enough for foam wedges) to cover the room corners, but with the closets, this isn't the only room "corner". [please ignore the PA speakers, they are temporary for my DJ mixing purposes] The issue is, what to do with the closets behind the monitors. I thought of just covering the folding doors with 2-3" foam for high-mid frequencies, but I worry about the closets just becoming a big bass bin since the doors will vibrate. I don't want to get rid of the closets, just in case this becomes a bed room again. I could remove the doors, but then I've extended the space behind my monitors AND have two more corners to deal with. Questions: Any suggestions of how to deal with these closets? Which corners are the "true" corners - outside the closets or the ones inside? Without the 2 foot deep closets, here are the room dimensions: Room: Basement Studio, length 16.67 x width 11.17 x height 7.17 feet Acoustical Purpose: Pop/Dance music Recording and Mixing Studio with some Voice Over within the room.

Hi there " judgemental", and Welcome! :)

Any suggestions of how to deal with these closets?

Assuming this is going to be a control room, I'd say your best bet is to take off the closet doors and fill the closets entirely with suitable insulation: They'll make pretty good bass traps.

Which corners are the "true" corners - outside the closets or the ones inside?

For calculating modal response, the true acoustic boundaries of the room are the hard, solid, rigid surfaces of the walls, not the closets. So the "real corners" are the ones inside the closets, where the actual walls meet. The closets are too small to even be "seen" by the waves taht cause modal issues. For the purposes of acoustic treatment, it is the surface of the treatment that is counted. - Stuart -