Digital Room Correction vs Room Treatments

 Not  bad.  I always apply 2) DSP to flatten things out further after 1) room correction. .  Then finally a third layer of DSP 3) to adjust to my personal preferences, and roll off any wasteful low end to help out the amp and steer clear of clipping, if needed. That pretty much covers everything.   Older ears may be well served by ramping up the high end a bit.  A hearing test can help determine. I use Roon for this and may end up with anywhere from 1 or 2 to as many as 7-8 distinct filters per Room, including a single convolution filter for the room correction part.  Works great. Sound is fine tuned in the end exactly to my personal liking which is what it’s all about. 

Always do what you can to set up the room well to start.  Then DSP away towards your own personal sonic bliss.  Make good buying decisions to set up and  integrate everything well up front then anything is possible with DSP from there. 

OP:

If I wanted to take time based plots, is that doable using reasonably priced tools, or is that a pro assessment job?

Room EQ Wizard (REW) has a variety of tools for that, and their forums are very helpful.   Here’s a starter page.

Let me give you a little more background.  For frequency response REW and similar tools (I use OmniMic) gate the signal above the bass.  That is, they stop listening a few milliseconds after the impulse start to arrive.  This deliberately excludes as much of the room as possible to get the response of the speaker.  The sound waves are still busy traveling back and forth around the room for a much longer time period than this.

Our ear/brain mechanism does not hear like a microphone.  We don’t stop listening, but integrate the experience of the direct sound and the reflections over time and this fully integrated perspective is what gives us an impression of the tonal balance.  Often audiophiles only think this is an imaging problem but there is a very significant effect on the perceived tonal balance.

If you ever hear Fritz speakers at a show, he travels with only a few absorber panels.  He knows what he's doing, and that his speakers will sound more full that way.  We should all take a lesson. 

In a very reflective room where the mid/treble bounces around for too long our hearing tends to exaggerate the mid and treble frequencies, so as a result will sound as if the speakers lack bass.   So, a tip I often give which people resist is that adding mid-treble absorbers and diffusors will improve the apparent bass, and none of this is captured by simple frequency response plots. 

The other thing these plots fail to capture is how having multiple direct reflections, and / or the absence of the right diffuse sound field ruins the illusion of an audio image. 

In the bass things are different.  The wavelengths are so long that it’s nearly impossible not to integrate the room, so as a result your frequency measurements are integrated.  Speaker builders always face a challenge with this and use a variety of techniques to try to get the real speaker measurements like putting the mic 1/4" in front of the drivers, measuring outside, etc.

While room correction software may do a lot for the bass and maybe even correct for perceived extra mid/treble they cannot stop reflections.  That’s why in my mind the two approaches are not equivalent but complementary.

OP:

It occurs to me you are using gating and smoothing.  Turn those off and re-examine your measurements.  I think you can re-use what you've already captured. You'll see a much nastier image of your results.

Also, when comparing speakers, it's very much worth measuring off-axis to see how good of a sweet-spot they would provide.  Speakers that measure similarly on-axis may be crap off. 

Guys, really? Sorry to tell you OP that graph posted has a terrible response, about 20dB difference between the major peak and null. The null at about 58Hz is 12dB below the average. That’s a lot of musical information being lost in the most important range. The huge peak at 35Hz taking much longer to decay than the rest is going to make the bass slow and boomy.

I don’t agree with DSP. How can it reduce the long decay times and it can not et rid of that null. No matter how much power you pump into it, it will just cancel with the same power.

You can push the furniture and speakers around all day and you will still have peaks and nulls only at different amounts and frequencies. All rooms. I say again, all rooms will have these issues.

To achieve a smooth response some absorption is needed to avoid long decay and address bass problems with at the very least a pair of subs. They do not need to be the same brand nor size but avoid ported subs and they must, must have variable phase otherwise you’ll be endlessly pushing them around the room. Any ports that resonate at only one chosen frequency complicate matters further. You are adding a frequency invariant bass source with no way of tuning it.

OP I commend you for having the ability to measure as it’s the only way to remove guesswork.

@erik_squires Thanks for spending the time to thoroughly explain those issues.  I can easily turn off smoothing, but at some point, the curves get so crazily jagged (with no smoothing), that I'm not sure what I'm supposed to take from it.

I haven't figured out how to turn off gating yet.  Trying to research that now.

@lemonhaze Thanks for your input.  When you say "some absorption", do you mean bass traps?  If so, are there more economical solutions than the $500/bass trap solutions from GIK?

Yes, with minimal treatment of the room, there's a definite tradeoff between dips at 58Hz and 180Hz.  If I move my LP so the 58Hz dip fills in a lot, it creates a smaller dip at 180Hz.  You can see that 5 posts above in the 60" LP vs 45" LP.  

I do see that 35Hz peak in the many of the plots posted by other people in different rooms, so that one seems common.  The other ones seem more variable and a matter of trade offs.

In a room my size and filled up with record, CD, and gear cabinets as much as it is, I think it's honestly unrealistic to entertain getting two new non-ported subs.  I understand there's a proper way to do things, but I think the question for me is what gets me close enough or good enough to live with while still keeping my room as usable as possible.  

Because if getting things closer to ideal requires my stepping around subs or having to contort to access my media because a sub is blocking clear access to a rack, then it's going to be a daily irritation.  Not sure I mentioned above, but this room is also a TV room with Atmos in-wall/in-ceiling speakers, so I'm admittedly trying to do a lot with the room and one of the consequences of that may be I'm not going to be able to do things as ideally as a pure 2-ch listening room.

I do have a single HT sub (SVS 10" ported sub) and I could dual purpose that if it would help.  It does have a phase dial.  Since I'm using older gear, I'm going to need to sum my stereo signal to mono and then route it to my sub (no speaker level inputs on my sub, just a single RCA).  I could play around with that and if I see the potential, maybe I start to think about how to move some things out of the room and consider a couple of ported subs.

But the room just isn't all that big to begin with unfortunately.

All that being said, I am open to room treatments, preferably beginning with ones that are highest bang-for-buck and seeing how much that improves things before going too far down the rabbit hole and diminishing returns.