I am currently running a Hsu vtf2.3 in my dedicated theater room about 2700' ^3 used 100% for movies. I like this sub a lot. The more I am reading here has made me thinking about making it even better. Should I get a vtf2.4 and run it with the older version vtf2.3 i have in a dual subs configuration (any problem mismatch two different versions of the same sub here?)? Or should I just get the vtf15 and use it singlely without my vtf2.3? Or should I add the vtf15 to my vtf2.3 for dual subs (again any mismatch problem here?)? I am using the Denon 3312 as receiver. All sub will be placed in front of the room between the front L/R speakers. What would you do? Thanks.
Based on what I've read from others and some light research, there really is nothing inherently wrong with what you're considering so long as you level match the two subs. Personally, and just recently, I upgraded from a VTF3 MK3 to the VTF-15H. I also have a Velodyne Impact-12 sitting around unused. Weekend project, I'm thinking of integrating both the VTF3 and the Impact in the rear with FMOD 50Hz High-Pass filters to give the room a bit more power in the mid-bass.
I don't know for sure that it'll work, but it seems like a fun weekend project. I'll first try opposing corners in the rear and possibly even stack them to see which one will give a better response and more SPLs.
If you did try to blend a VTF2 with a VTF15h, the one thing you wouldn't want to do is level match them. The VTF15h is much more powerful, the VTF2 would not be able to keep up with it. The only way I would try to make that setup work is if you used the VTF2 in near-field, and at a lower level then the VTF15h, where it won't have to try so hard to keep up. I would go for the VTF15h, and see if the VTF2 can contribute in a significant way. If it can't, sell it or use it in another system.
Without taking away too much from OP's initial question, I was thinking 50Hz test tones while adjusting volume at the amp with SPL meter. You don't think this would work to even out the response across the entire room?