Can’t help with a high ceiling as I have never had to deal with it. The kicker is it is a fixed distance. Hopefully you don’t have cubed dimensions.
To get a little more scientific. you can look at 1/4 wave lengths. 1/4 length cancel because by the time it bounces off the walls and comes back it is a 1/2 length out of phase with the driver.
The tricky part is the front wall, back wall, side wall and ceiling all count. So it is best to have different distances between all of these so the cancellations blend together to fill the holes. Worst case it have the side wall and back wall be the same distance as in both 4’. Get ready for a giant hole in the sound of this is the case.
The short version is all walls between between 3’ and 6’.6” should be avoided for bass. Closer than 3’ is actually better than between 3’ and 6.6”’. After 6.6 the bass lumps tend to go away and the speaker soundstage opens up. But closer than 3’ and your mids get muddy.
If you can’t get your mains 7’ off the walls one of the best solutions is to use subs so you can cross them over and tuck them less than 3’ off the walls and pull your mains out 4-5’. This will fix a null issue as you can place different frequency drivers in different places.
Chart so you can calculate it for yourself. http://www.soundoctor.com/freq.htm
Video for the reading impaired myself included lol. https://youtu.be/T10_MLGOBfc
To get a little more scientific. you can look at 1/4 wave lengths. 1/4 length cancel because by the time it bounces off the walls and comes back it is a 1/2 length out of phase with the driver.
The tricky part is the front wall, back wall, side wall and ceiling all count. So it is best to have different distances between all of these so the cancellations blend together to fill the holes. Worst case it have the side wall and back wall be the same distance as in both 4’. Get ready for a giant hole in the sound of this is the case.
The short version is all walls between between 3’ and 6’.6” should be avoided for bass. Closer than 3’ is actually better than between 3’ and 6.6”’. After 6.6 the bass lumps tend to go away and the speaker soundstage opens up. But closer than 3’ and your mids get muddy.
If you can’t get your mains 7’ off the walls one of the best solutions is to use subs so you can cross them over and tuck them less than 3’ off the walls and pull your mains out 4-5’. This will fix a null issue as you can place different frequency drivers in different places.
Chart so you can calculate it for yourself. http://www.soundoctor.com/freq.htm
Video for the reading impaired myself included lol. https://youtu.be/T10_MLGOBfc