DaveBoswell
Member
Good to hear you are seeing success with multiple subs - it really works if done properly!
Generally if you put two subs only along the front wall, their horizontal separation will help to smooth out the room modes that are transverse in the room (i.e. bouncing between side wall to side wall) but you will not see much of an improvement in the smoothness in the room modes that are longitudinal (i.e. caused by the sounds waves bouncing between the front and rear walls of the room). This is because both subs along the front wall should be time aligned properly with the front LCR speakers, and as such will likely be very closely time aligned to each other and this means that they will both be exciting the same longitudinal modes at the same time, causing greater peaks and troughs. This isn't necessarily the worst thing ever as the peaks can be easily knocked down with the same PEQ in either a DSP or a Receiver, and you gain substantial efficiency of the subs adding their signals together (close to 6dB of output if you get the level and time alignment just right).
That said, most find a better setup when the 2 subs are not at the same depth in the room as you can use a small amount of delay and/or all pass filters to get the subs to add together nicely and be in close to perfect time alignment, but they are not all exciting the same room modes equally which naturally reduces the variability in the Main Listening Position response variation and the seat-to-seat variation - both if which is highly desirable and can sound great. The 2 opposite diagonals works well in many cases, or a corner and along a side or rear wall is good too, or a corner and a near field right beside or behind your seating position can be a lot of fun too.
If you haven't done so already, since you have a MiniDSP, you may want to explore using MSO to really dial in your subs to perfection and get the most of your setup. I've posted a video tutorial for MSO on Youtube - link in my sig below, if you are interested. It's an amazingly powerful and useful tool if you want to get a great understanding of what your bass is doing and how to optimize multiple subs together, though admittedly has a bit of a learning curve.
I would suggest screw the time alignment and let Dirac run on the "nothing aligned"-variant. Can you upload the MDAT again with the correct name for each graph?
