I have a 15x23 room would either of these make good surrounds? Or would they be overkill and I should get something smaller? I see the HT-8s are 7.25" deep and the HT-10s are 8.75" deep. I would like to put these in columns. If this works, I might cut into the wall so the enclosure sits in the wall some, and the rest sits in the column. Or could I use these as a Infinite Baffle in the columns? Or do they need enclosures? If they need enclosures, can the boxes be made shallower and sound ok? Thanks in advance, i'm sure i'll have more questions.
Without changing the crossover the cabinet has to have the same porting and cubic volume as the standard design, but if you want to build a differently shaped cabinet then that's up to you. Making the boxes taller and shallower is fine. Making the front baffle flush with the wall like an IB or in-wall will change the response.
I wouldn't see the need to go larger then the HT-8's for surrounds in that size room. Both do require use of an enclosure unless you are fine with crossing these over to your subs at 120-150hz which is roughly where the bass response will be when used sealed/IB. The cabinet could be made taller/shallower but the depth of the waveguide does limit how shallow you can make the cabinet (~6.25" - 6.5") depending on 1/2 or 3/4" material.
