Digital Room Correction vs Room Treatments

You got a few issues going on. Think you have a couple nulls going on.

The bass energy spike 30-40 is huge, then that massive hole at 50-80. Some peaks in the middle, with treble dropping off.

This tells me you have a boomy setup, with bright mids, and low highs. DSP will not fix this, just adjust. Don't think you can room treatment out of this.

Your speakers are in the wrong spot, or your listening spot is totally off. Think you should move the speakers around. It looks like the walls are enhancing the low bass, nulling out the mid-bass, the room appears to "dark" already with the highs. Maybe remove a couple of panels, or move them around the room. 

Do you have any tones controls active? Turn them all off, if you are taking readings, then adjust them after the readings.

The 35Hz spike is there regardless of speaker placement and LP - varies a tiny bit in magnitude, but not much.  Room is 11.5’ wide by 15.5’ long and 8’ high.  Probably a characteristic of the room.

The 60Hz dip can be filled in at the expense of creating a more shallow one around 180Hz.

The speakers are places 1/5 of the room length from the front wall and 1/5 of room width from the side walls.  It was recommended to place the LP about 1/3 room length from back wall (60”), but I found I preferred my LP 54” from the back wall.

No tone controls active.  I’m using Pure Direct mode on my AVR to bypass the Audessey room correction.  I’m only using the AVR for the sweeps because it can accept the HDMI from my MacBook.  Normally, I use a McIntosh C35 preamp that has a 5-band EQ, but I normally listen flat.  Sometimes with a small bit of loudness contour, but mostly flat.

OP, let me apologise for assuming your SVS sub could do what I mentioned. Looks like you’ve got one of those  early models. I’m using an SVS SB 1000 PRO which sells for about $600 and has a very useful feature. Download the App and you can adjust all the parameters I mentioned from your phone but forgot there is also a few bands of PEQ. Check out their site. This is the sort of sub you need. There are other good subs available but the SVS is great value and I prefer it to my REL which has 0 or 180 degree choice so means I have to keep trying different places to get it dialed in.

I am using OmniMic to measure and I am not familiar with REW which  essentially does the same thing. I play a CD with sweep tones and have the mic. at my listening position sampling the combined sound of the speakers and sub/subs and while changing settings on your phone you can watch the frequency response change. The second sub will smooth the response even more. REW will also display  RT60 as a waterfall plot (CSD), the time it takes for the sound to decay by 60dB. The average room will be about 300ms.

I have 2 large floor to ceiling bass traps, broad-band absorbers, extra heavy curtains plus 2 subs and the bass is dynamic, very detailed, informative, clean and powerful.

Sorry for contributing only infrequently.

A point that I may not have properly addressed earlier is that the benefit of a sub in a situation like this is not it’s bass output but the ability to move it to an ideal location.  However if you are severely space constrained, then a sub is almost useless. 

TO place the sub you’d put the sub in your listening location, then move the mic around potential locations until you find the best measuring place.  That’s where you put your sub.

My earlier advice to clip the peaks and lift up the entire bass region still stands.

If you can’t do this and your sub is generally where your main speakers are there’s no point.

I’ve posted pics of my room in other threads w.r.t. other questions/topics, but it might be helpful to show what I’m dealing with here.

Front of room:

Right side of room with entry door in middle of wall:

Back of room:

Left side of room:

I can remove things like the single speaker in the back, the beverage fridge, as well as the “side table” to the left of the chair.  But all the record racks and wall cabinets for CDs are my media storage and have to remain in the room.  The front cabinets both hold gear (active and spare) and I really prefer not to replace them.

So it’s a crowded room filled with “stuff”.  The sub is currently within 6” of the back wall firing toward the left wall is the room with records in rack about 42” away.  The speaker front baffles are about 3ft from the front wall and near the cabinets, which prevents the inside doors from swinging open without moving the speakers.  Which is fine, I can deal with that.

But my options for placing a sub are limited to the remaining periphery of the room, which means to the right of the record rack on the left wall near the window, anywhere on the back wall, or I could use it as a side table in place of the 1x2 cubby I’m currently using as a side table.  I suppose also on the front of the room between the main speakers as well.

I’m already somewhat having to step around things in certain places to access the records.  I’d prefer not to place the sub somewhere in the middle of the room and have something else to step around.

So this is what I’m working with. No complaints as I’m trying to do a lot with this room and the agreement with my wife was to store all my media and audio gear in my room to avoid clutter in the rest of the house.

But there are somewhat limited options left for placing the existing sub or adding a second one.