Quote:
Originally Posted by
knightonabicycle
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diffusion couch problem
-maybe i make something like a variable part in the QRD where you can replace this part with a broadband absorber. or are there other ideas to solve this?
Evaluate the need to actually have a diffusor that size there.
Since you're DIY , first fix the LF properly then make sure that by adding the large diffusor you're not going to mess up the LF by reflecting energy again before it hits the bass trap.
Quote:
Originally Posted by
knightonabicycle
➡️
speaker wall construction
-is there something i should change or do you think that I (my friends) can start building up the brick wall in the meantime?
Thank you very much

You need to revise your front wall geometry (ratio between side walls and center area). As such, you're going to have issues.
Avoid the forward pitch too if possible.
Incorporate speaker decoupling in the front wall design from the get go and not as an after thought - otherwise you should expect issues and to have a real hard time getting it 'right'. Build around the decoupling system, not the opposite.