I had a problem not so much with a null, but rather a peak at 40 Hz. Though I had a bit of a null at 80 Hz, the response of the sub in the room was almost +10db higher at 40 Hz. Moving the sub around did help a little, but didn't come close to eliminating it.
After months of heavy lifting the sub to various points in the room and annoying my family and dog to no end with test tones and sweeps, I decided to try and play with the phase of the sub to see if it made any difference. The usual way to set the phase is to adjust it (usually a switch or knob on the sub) so that you get the loudest response at the listening position, which is what I always did. So just for grins, I decided to flip the phase switch on my sub from the 0 degree position to the 180 degree position. I could instantly hear the 40 Hz peak was either gone or significantly reduced. So I re-ran my test tones and calibrated things again with the phase set to 180.
Sure enough, after measuring it with my Radio Shack meter, the 40 Hz peak was reduced to a 1 db peak. No more boom-boom headaches or seemingly one-note bass. Music and HT sound signficantly better.
Not sure if it will work with your null problem but you may want to try it. My system includes Dunlavy Aletha's and a Velodyne FSR-15 sub. Try it and let us know if it works for you.
After months of heavy lifting the sub to various points in the room and annoying my family and dog to no end with test tones and sweeps, I decided to try and play with the phase of the sub to see if it made any difference. The usual way to set the phase is to adjust it (usually a switch or knob on the sub) so that you get the loudest response at the listening position, which is what I always did. So just for grins, I decided to flip the phase switch on my sub from the 0 degree position to the 180 degree position. I could instantly hear the 40 Hz peak was either gone or significantly reduced. So I re-ran my test tones and calibrated things again with the phase set to 180.
Sure enough, after measuring it with my Radio Shack meter, the 40 Hz peak was reduced to a 1 db peak. No more boom-boom headaches or seemingly one-note bass. Music and HT sound signficantly better.
Not sure if it will work with your null problem but you may want to try it. My system includes Dunlavy Aletha's and a Velodyne FSR-15 sub. Try it and let us know if it works for you.