first post, have what i believe is a null and looking for help

[lazyjss]

pair of 6.5 bookshelf speakers, a matching center channel and a single sub centered on front wall of listening area, two feet from side walls and a little over a foot from wall behind the speakers.
room has 8 foot ceilings and is apprx. 22feet long and 15 feet wide.

while either running a rew sweep or producing a sine wave in the 115hz region i have a dip in spl output, when i move the mic and or using my ears i can find an increase in spl elsewhere in the room.
i have tried toeing speakers in and out, the sub, center and front mains all produce this dip in the 115hz region.

i am looking for a way to mitigate this problem and have been researching acoustic treatments.
i am new here so any wisdom is appreciated.

thank you

 

[JStewart]

i am looking for a way to mitigate this problem and have been researching acoustic treatments.

It wasn't mentioned if this happens with each speaker separately or if you are measuring L+Sub, C+Sub and R+Sub.

I'd suggest measuring each speaker separately and with a Timing Reference.

Posting your REW .mdat file can be helpful, too.

 

[skid00]

You can either move the speakers, move your listening position, or get subs.