Help with Subwoofer Phase (Dual REL subs)

[andrew1]

Hello, REW amateur here but reading and learning as I go along. Was hoping to get some help to take a look at these two sweeps, labels on the left hand side. Using an UMIk1 mic.

One was done with both REL subs switched to Phase 0 (solid orange line) on the subs, the other with 180 phase (solid green line) on the subs. For those with experience, which one looks correct?

I've added another image with both overlayed solid orange at 0 phase, 180 phase in green.

Any advice is very much appreciated, thank you!

 

[John Mulcahy]

180 is right for that setup, preventing the huge dip around 50 Hz.

 

[andrew1]

180 is right for that setup, preventing the huge dip around 50 Hz.

Hi John, thanks very much for your reply. I believe I made an error and one sub was flipped to 180 while the other 0 (apologies) would that contribute to that dip? I've run sweeps again (attached) and both phase at 0 and phase at 180 look a lot more similar now without that dip at 50 Hz, does this make more sense? Apologies for the error. Really appreciate the help. Thank you

 

[John Mulcahy]

Dips in the response like that are usually caused by combining sounds with are out of phase with each other. Interpreting the result depends on what was playing when you made the measurements. If you were playing both subs and one main speaker you could test all 4 combinations of the phase setting for the two subs to see what looks best. If your room is symmetric and the subs are placed symmetrically across the width they are likely to work best when they both have the same phase setting, which setting that is will depend on how the output of the main speaker compares to the output of the subs through the crossover region.