Hi all...been reading & researching for a year & a half now, and just recently finished the basement so I've started calibrating my subs...i'm in the process of trying to identify my room modes so that I can place the subwoofers in best locations for minimal eq necessary with the BFD and to eliminate nulls at the seating positions...
this is my room layout (home theater/media room in lower left, or south west corner):
basement layout.gif
The media room is closed off from the rest of the basement, with framed drywall walls all around. the south and west walls have concrete block behind the framed walls, the walls are all filled with insulation. concrete floor with carpet.
I've run the spreadsheets to identify what room modes I theoretically should encounter, and had some ideas to combat those modes with 2 svs 25-31 pci's...but what I'm finding is that some modes are showing up, and some aren't, and some are coming out of nowhere...
These are the predicted room axial modes:
room modes predicted.gif
And this is the process I've followed so far, please correct me if I'm misunderstanding something...
1. Put 1 subwoofer in southeast corner, put spl meter close to floor in north east corner (near 2 closed doors)
2. Ran 15-200 hz sweep with REW
I see easily recognizable 19, 38, 57, and 77 hz modes/peaks for sure…but the puzzling thing is that there’s a 31-32 hz NULL in the corner…and it seems to remain in other measurements also when I move the mike out to seating positions too…
I will try to post REW graphs soon, but for now wanted to see if I’m doing something wrong, or if I’m misguided…how can you get a null in a corner? That’s my main question right now…