yeah, I was in the same boat (still kinda am) with getting more sound in the bow, seen a couple neat options but not sure if I'm gonna follow suite.
I'm actually content now (finally) that I have the M770s up there, but wouldn't mind squeezing in another pair of say M650s in the front, but not sure if its even worth it. So far JL Tech, Odin @ Earmark and my installer in Havasu all said leave it as is and keep those channels open on the 600/6.
I have one idea that I think would create a amazing solution but would take some bold cutting. BUT I think it could be done. I put my hand back there and it felt open, and since its flat you can add a backing ring and some sound deadener to stiffen it up. I think if I use a spacer it would definitely work.
Here's my illustration, but I think it solves all issues in terms of keeping the music in the bow, up high and nearly on plane with the other speaker up there. If it is feasible this is the direction I am going to go since I think it would essentially double the output in the bow with not a lot of fabrication, at least in my mind it would work that way, lol.
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