Unfortunately, there probably isn’t anything you can do that will eliminate the null. A lot of people claim that adding a second subwoofer
could eliminate it. If you can find room for one, that’s an option, but I’m guessing that the WAF won’t allow it. If it helps, an additional sub doesn’t have to be anything as huge as your HSU, since you’re only concerned with the 125 Hz range. However, I’d make sure there’s a generous return policy in case it doesn’t help.
I currently find myself in your situation, in a place with no good corner for a subwoofer, and for the first time ever I have a null – same as you, in the 125 Hz range. The good news is, I found that it’s not that big of a deal.
Here’s the thing: REW graphs only plot low frequency
fundamentals. However, notes from bass instruments are complex signals with harmonics, overtones and undertones. That’s why an “F” note sounds different on an upright bass vs. and electric bass vs. a Sousaphone vs. a piano. So, having a graph will a null doesn’t mean you’re going to suddenly get a “hole” when the bass line hits those notes. There is enough “other” information that you will hear the notes.
In addition, movie bass is all about “boom.” That doesn’t even require as much accuracy as music.
I did find that contrary to conventional wisdom, it made a significant difference setting the L/R speakers to “large.” Strangely, it made no difference with the measurements, but it did give an audible improvement in the mid-to-upper bass – i.e. the range were the 125 Hz null is. So, you might give that a try if you aren’t happy with the way things sound (as opposed to what your graphs look like). That’s my “conservative suggestion.”
Regards,
Wayne A. Pflughaupt
