Frequency Response

Awesome!  Thanks everyone. Wrik, I haven’t looked into the floor behind the speakers.  Will do!

@MC, thanks dude!  I was thinking theres a mathematical process snd you helped with that, Thanks.  Will research that more for sure.  I never thought about it until right now but yeah, with a wave you’re going to have different response in a rooms height not only width and depth.

I am using room correction software but it doesn’t matter for nulls.  People may think so but it really doesn’t, at least with the software I’m using.  Makes sense though because if its a wave cancelling itself out then turning up the volume does nothing for it,

@Oldhvymch, my response is a bit accentuated in the mids, just like you’d like it!  I prefer for the highs not to be rolled off so I’m enjoying the eq aspect of Somarworks.  I feel like its done pretty well.

Anyhow, Thanks for all the input.  Will def. look into treating the ceiling and with angled panels.  Will also look into that info you suggested MC, thanks!

The flooring between/behind your speakers may not fix your particular issue, but I encourage you to listen to music as you try it. :)

The positive for your situation is that the wavelength of the problem frequency is around 1m and to effectively treat with an absorber the rule of thumb is 1/4 wavelength thickness of material so 25cm or 10" which is pretty do-able. That might sound like a lot but it’s worse when your problem frequency is below 100Hz (>3’). You can also get away with thinner material if there’s an air gap between the absorber and the reflective surface behind it... the important thing is that the surface of the absorber is 1/4 wavelength away from the wall / ceiling.
You really want something dense like rockwool (I think it’s called owens corning in the US) and any covering needs to be porous.
Angling the treatment helps to broaden the bandwidth of frequencies that are treated (lowers the Q of the panel) but to trap 330-400Hz waves the 1/4 wavelength rule still stands (so you’d want the minimum distance from the surface of the absorber to the wall / ceiling to be 10").
Sound on Sound magazine used to run an article called ’Studio SOS’ which you can still find on-line, it’s quite a useful resource for creatively treating the acoustics of small spaces.
One last bit of advice - stop when it sounds right... you’ll never measure a fully flat response in a room with parallel walls, floor and ceiling.