Thank you for the reply Wayne. As you can tell I am a bit of a noob when it comes to this stuff. I will admit that it doesnt make any sense to me to not take measurements with both speakers on because ultimately that is what I will me hearing. How can I be sure that the filters I apply to each individual channel actually produces the response I want?
Your question is valid. Conventional wisdom is to apply the same filters to the L and R through the range where the ears can detect phase differences (roughly 100 Hz to 3 kHz), assuming
- the speakers match well
- speaker positioning and room and treatment are symmetrical
The ears can detect phase differences in the soundstage & imaging (SS&I) through that range. Below 80 Hz, multiple subwoofers should also be EQed together as one.
Bottom line, best approach to set up and treat with maximum symmetry
- so L & R FR measurements match well
- so SS&I sounds as sharp and clear and specific as possible - listen closely - the measurements can look pretty good (until you dig deep) and still give lousy SS&I
then EQ them the same to keep them matching.
Fixing differences in phase & frequency response can SOMETIMES be done (an advanced topic). Better to not mess them up in the first place.
As a related point of discussion, it seems there is no way to verify that the EQ filter actually gives the response predicted by REW? For this to happen, there will need to be a way to do a measurement with the filters applied. Am I right to assume that REW cannot do this?
Correct, REW omly calculates the values and shows what FR should look like with those filters applied. But REW will not not actually apply the filtering.