[AllanS]

This probably isn’t the right place to ask this question but I didn’t find any better.
I’m at an inflection point in system next steps and want to learn about DSP / options including room correction.
Lately I’ve been burrowing into the analysis hole (REW / MATT), which is leading to additional but targeted room treatments and sub integration.
Before having to explain to my so far tolerant wife why I want to add more of this stuff to the room I’d like to understand how DSP should be considered and in what priority all 3 should be considered (sub, treatments, DSP).
Any thoughts on sources of DSP information and component recommendations?
Thank you.

[HAL]

You are best to start with the room acoustics treaments.  DSP EQ is the final touch,

There are things that DSP cannot correct for like dips in your frequency response that is caused by room mode cancellations.  Best to get rid of the room modes as much as possible before DSP EQ.

DSP correction works on the minimum phase portion of the room problems.  Things like room modes are not minimum phase.

A good place to start is REW is great at finding the low frequency mode problems that are peaks and let you use your parametric EQ available in any DSP processor to do room bass management.

Another good place is MathAudio.com and look at their free plugin for Foobar2000 music player software.  You can use the same mic as you use with REW for measurements.  It also allows the user to create a house response curve if you room is to bright or dark sounding depending on all the surfaces of the room creating high frequency reflections and slap echos.

When it comes to DSP EQ, less is better.  Not saying none is good.

[JohnR]

There are things that DSP cannot correct for like dips in your frequency response that is caused by room mode cancellations.

It can, in a case like multiple subs.

DSP correction works on the minimum phase portion of the room problems.

DSP is not limited to minimum phase.

Things like room modes are not minimum phase.

Actually, they are, which is why your typical sub eq with parametric filters works. You can however get interactions that create non-minimum phase.

[JohnR]

sub integration.

Yep. Do that. That will get you started 

[AllanS]

Thanks for the pointers.  I do have the sense that my next moves are fine tuning speaker and listening position placement, targeted treatments, and subs. 

A problem for me, or maybe just a hang up, is wanting to know what to expect with each change before throwing more money at it.  I’ve already spent too much without a good plan.  I have the least confidence in knowing what to expect of treatments.

As I should have expected, DSP.edu doesn’t start with DSP.  It starts with reasons why we have DSP in the tool box.
Specifically I only got to minimum phase before getting hung up.  Sounds important.

It’ll take more foundational knowledge and more than one read through to digest but REW Help - Minimum Phase discussion https://www.roomeqwizard.com/help/help_en-GB/html/minimumphase.html is a lot of help and as good a place to start as any.

Thanks also for the MATHAUDIO recommendation HAL.  It looks like a promising add on to Foobar which I have already to play with DSD.

[JohnR]

I think treating all these things as tools is a good approach. And that you're on the right track by starting with measurements. What you haven't seemed to do (or just not saying?) is identify what the issues are that you want to address.
Regarding placement, a rethink can sometimes change things dramatically https://www.linkwitzlab.com/rooms.htm#D
Regarding subs have a look at https://www.andyc.diy-audio-engineering.org/mso/html/

[AllanS]

I think treating all these things as tools is a good approach. And that you're on the right track by starting with measurements. What you haven't seemed to do (or just not saying?) is identify what the issues are that you want to address.
Regarding placement, a rethink can sometimes change things dramatically https://www.linkwitzlab.com/rooms.htm#D
Regarding subs have a look at https://www.andyc.diy-audio-engineering.org/mso/html/

I'm really just now learning the tools and figuring out what I'm trying to accomplish.  So that is a helpful question.  Thanks for asking. 
The primary thing I'm trying to fix are easily heard bass resonances, what I suppose are room modes.  The second goal is to smooth the overall frequency response and fill in lower frequency gaps.  Beyond that it's much less clear. 
Generally I want to understand and identify those things I understand to obscure details/skew sound stage and cause fatigue.  Right now that has me struggling a bit with impulse responses and decay and thinking low frequency absorption, a sub or two, and higher frequency diffusion.  The MATT analysis, which makes some sense, came back as overall good but with specific problem areas.  This helps me understand the problem but not well enough to have confidence to know what to expect from each added treatments.  So I'm a bit stuck.
Ultimately I want to get the room as good as I can afford and the spouse will approve of and get gear matched to the room's capability.