Absorber placement for behind speaker

[tjcinnamon]

I have towers that are 4' tall. I had some leftover fabric and built four 2'x2'x4" absorbers which I plan to put on the front wall behind the speaker. My question is how high/low do I put them? I was thinking about having one extend 15" above the speaker then 9" below and then I'm wondering do I put the other one above or below the speaker?

Based on pictures online what I've seen is people put them well below the speaker

 

[Eetu]

I would place them centered behind the drivers. That's where the SBIR effect is the strongest and also where the front wall first reflection is height-wise.

Also hang them with an air gap (between the wall and the panel) if you want max bass absorption. 4" if possible.