Seeking help with a low end null

[RoadRecording]

Hi all, I sure could use some help. I think I'm sitting in a pretty big null in the low end, and it's driving me crazy. I had hired an acoustician (Jeff Hedback) to help, and we improved it some, but in the end, there is still a giant crater. But first, the details. I read through the forum rules, and I hope I got all the information included in my post.

Room Dimensions

My room is in the basement of my home. I have attached the layout and dimensions. Note the closet spaces and location of sump pump. Concrete basement walls run front and right side. The ceiling is a drop-ceiling with standard drop-ceiling tiles. Floor to drop ceiling is 86”, drop ceiling to joist is 4.5”, and depth of joist is 9”. The joist cavities are filled with R-19 where there is no duct work.

Room Dimensions.JPG

I have an abundance of acoustic treatment:

6 x DIY Broadband 703 panels (24x48x3.5)
12 x DIY Bass Traps 705 panels (24x48x5.5)
1 x GIK Monster Bass Trap (48x24x7.31) - Black, Full Range
1 x GIK Monster Bass Trap (48.25x20x7.31) - Black, Full Range
4 x GIK 244 Bass Trap (40x12x5.25) - Black w/ Range Limiting Membrane
4 x GIK Monster Bass Trap (48.25x12x7.31) - Off-white w/ Range Limiting Membrane
1 x GIK Monster Bass Trap (48.25x24x7.31) - Black, Full Range w/ Diffusion (Scatter Plate)
2 x GIK Corner Bass Tri-Trap (47x16.5x16.5x23.5) - Black (Scatter Plate, Full Range)
4 x GIK 244 Bass Traps (48.25x12x5.25) - Off-white (Full Range)
9 x Sustain Lens Panels (23.5x23.5x3) - natural bamboo
6 x Sustain Prism Panels (23.5x23.5x3) - natural bamboo
2 x Real Traps RFZ panels (42x32x2) - off-white
2 x GIK Acoustics Q7d Diffusors (46x19x6) - brown
4 x GIK Tri-Trap (47x16.5x16.5x23.5) - off-white, full range
2 x GIK Tri-Trap (40x16.5x16.5x23.5) - black, full range
4 x GIK 242 Acoustic Panels (48x12x3.6) - off-white

Here is the design that Jeff Hedback gave for installing the acoustic treatment:

AcousticsDesign.JPG

And here is a short video of what my room looks like now, with the acoustics installed:
https://youtu.be/0v5q7-Blv4g

My monitors are a pair of Atomic SixTens (w/ rear firing subs) and a pair of Amphion One15's. I also use Dirac Live for room correction. I prefer it correcting from about 200 down on the Atomics and around 1K down on the Amphions. I've used the trick for monitor placement that involves sweeping the area with a measurement mic (while playing pink periodic) in REW, in both listening position and speaker position. Honestly, there wasn't much of a change. There is no spot that makes it better. Only different.

Here is my REW data as of today. It includes data for both sets of monitors, and measurements with Dirac correction applied. You can see the giant null from about 60-150hz or so.
(note: the REW file exceeded the max allowed, so I hosted on my Google Drive), https://bit.ly/REWdata

I think that's all the information that I have, and that is requested that I supply. Please let me know if I've missed anything.

One thing to note, I had originally approached Jeff with the idea of renovating this space and doing a purpose build, but surprisingly he said it wouldn't be doable. So I kept the room as-is and applied acoustic treatments in hopes to even out the frequency response to track and mix. I would LOVE a purpose built space, and I may approach that in a new thread on the Studio Design and Construction subforum. But for this thread, I am seeking help in getting a more even FR in the low end.

[DanDan]

Nice looking workroom, but it's fun to work there. Looks like your speakers are quite far from any solid boundary. I don't know the Atomics but have seen other Amphion rigs lacking LF. I believe that room acoustics, including virtually anechoic, utterly dominate what we hear. So I see no point to secondary reference speakers. Unless they are in another room.
Dirac, two sets of speakers at unlikely locations...... Simplify I reckon. Speaker and corresponding Listener location are the most powerful treatment.

[RoadRecording]

Nice looking workroom, but it's fun to work there. Looks like your speakers are quite far from any solid boundary. I don't know the Atomics but have seen other Amphion rigs lacking LF. I believe that room acoustics, including virtually anechoic, utterly dominate what we hear. So I see no point to secondary reference speakers. Unless they are in another room.
Dirac, two sets of speakers at unlikely locations...... Simplify I reckon. Speaker and corresponding Listener location are the most powerful treatment.

The Atomics are voiced completely different than the Amphions. The Atomics have rear firing subs, and a more extended top end. By contrast, the Amphions provide more detail and midrange. But I get what you are saying. I don't think my room is big enough for two sets of monitors. But the issue is, even for a single pair, the position is making little difference. I've tried it all. It's the same null, just slightly different no matter the monitor position.

I have been considering downsizing and getting a different style of desk. Something more traditional, like an Output desk. That would let me sit closer to the monitors and maybe give me more/different positioning options.

What do you think?