Window Treatment?

[SAPHANA]

In my listening room, the wall behind me has four 35”x70” windows. There are no other windows in the room, and I don't care if I have to cover them all. BTW, I don't like drapes.



I am debating the following options:

OP1 - cover the whole wall with Ikea Kallax shelves (I already had the two side walls completely covered with Kallax, and I still need more shelves);

OP2 - cover the 4 windows with GIK acoustic panels, custom sizes;

OP3 - wood shutters;

OP4 - leave the current plastic blinds there, no change.



The first 3 options cost almost the same: ~$1K.



How do you deal with your windows? Any suggestions?