Raising Subs?

When I had subwoofers in my system the biggest reason for moving them in any direction was to make the response as even as possible in their output band. 

through measuring and listening you find that if they are too close to a wall or other boundary the response might be peaked and have an overly dominant note or frequency.  

moving them away from the bounday is a way to reduce the peak and make the sound more balanced.  

raising the subwoofers off the floor could be a way to make the response more even, especially if your room and furnishings put limits on how much you can move them away from vertical boundaries.  remember, the floor is a bass reinforcement boundary. 

Re "significant improvement"... I really can't say because they generally are working well as is. You know how it is...always looking for something better.

The idea of smoothing  out nodes further is appealing and I may try raising just one to see what happens.

Thanks, everyone,

I tried a half measure by putting a pair of KEF KC62s atop a pair of unused Velodyne HGS-10s. I didn’t care for the effect. Maybe because the KEF app that so carefully integrates the KC62s with the lS50 Wireless IIs has no provision for height.

I have tried this with one and two subs to reduce a vertical room mode. It partially worked, but as usual other frequencies that I worked hard at to get just so were compromised. 

Well something better might just be pair of speakers that make you forget about the bass.