Subwoofer. Great one song. Not so great the next song.

I should say the problems the OP listed can be dealt with crudely but effectively.

On Android, get a calibrated mic:


https://amzn.to/3eYDGBa


 and AudioTools. Play the crappy songs. You’ll see the frequencies that are bad. Add a PEQ to kill them. Done.

N80 wrote: " On some songs the combo with the sub just sounds stellar. On others it sounds boomy and thumpy. My audiophile hang up is taught, clear, concise bass. I do not like boomy and thumpy at all. I can get up and turn the output on the sub down a little and it sounds okay again. "

It is not unusual for there to be changes in bass balance from one recording to the next, but I don’t think that’s the whole story.

My guess is that some songs have strong bass energy where you have in-room peaks, and some do not. In-room peaks and dips in the bass region are virtually inevitable. You can re-arrange them by moving the sub and/or moving your listening position. You can reduce their magnitude by a small amount with bass traps. You can significantly improve the in-room smoothness at one location within the room via EQ, with the strong possibility of making the response worse elsewhere in the room.

" The system was meant for casual listening throughout the whole room, not just me alone in one place. That alone is a challenge."

Bass trapping will be beneficial throughout the room, but neither repositioning the sub nor using EQ are especially promising if the goal is significant improvement throughout the room. If you have a problem at a specific frequency throughout the room then of course EQ can be beneficial in addressing that issue. A distributed multisub system is specifically intended to offer significant improvement throughout the room.

I see that you read the article Erik wrote and posted on his website. In it he devotes a fair amount of virtual ink to discrediting the distributed multi-sub concept by labelling its advocates "cultish". If you are open to hearing an opposing viewpoint on the merits of a distributed multisub system, let me know.

"This set up is not my primary system and it is in a formal living room. Just the presence of 4’ tall speakers was quite a concession by my wife."

In that case a distributed multi-sub system is probably impractical, though small subs can sometimes be hidden in unorthodox locations like atop bookshelves.

So assuming that you’ll be plowing with the horses you’ve got for the foreseeable future, here are some setup suggestions:

First, set the level control on your subwoofer amp. This is the control which makes the most subjective difference.

Next, set the lowpass filter frequency control on your subwoofer amp.

Finally, set the phase control on your amp.

Then cycle back through several times to fine-tune.

Sometimes it makes sense to have the sub’s frequency response overlap the bottom end of the mains somewhat, and then put the sub largely if not completely out-of-phase as needed to smooth the transition in that region.

It can take a long time to dial in the level control because the ear is especially sensitive to small changes in SPL at low frequencies. A 3 dB change at 40 Hz is subjectively comparable to a 6 dB change at 1 kHz. This is counter-intuitive but is revealed by the way equal-loudness curves bunch up south of 100 Hz. On the other hand, this implies that small improvements in the in-room frequency response pay disproportionately large perceptual dividends.

If you can try a second (small) sub, positioned far away from and asymmetrically with respect to the first, you may find that it makes a worthwhile improvement in the in-room bass smoothness over a large listening area. And "smooth" bass = "fast" bass, so arguably that would be a step in the right direction, IF you can get away with it.

Duke
subwoofer manufacturer

I have a similar setup.
You have to get the sub blended properly with the mains and all those adjustments are your tools. First level but then also rolloff frequency and then phase.
The trick with one sub is get that all right at your listening position because bass levels will vary within the room no matter how you adjust a single sub.
Try getting it right at the sub location first where you can make fine adjustments fast and easy as needed and get familiar with how the controls affect the sound.
Then take what you’ve learned and listen from you main listening position and make the adjustments for that until right.
Leaving ports open will extend the low frequencies of the mains and allow the sub to come in at a somewhat lower frequency that is less directional and less likely to call attention to a single subs location in the room.
Also helps to know at what frequencies your mains and sub roll off to help determine the rolloff frequency range to shoot for when adjusting that on the sub.
In general, the larger and more extended the mains, the larger and more extended the sub will need to be to fill in the low end missing otherwise rather than just boosting existing bass levels which is generally not what you want.

Also remember that bass levels and sound will vary largely from recording to recording.   Use a good quality track or two or three with lots of good extended bass as your reference tracks and adjust for those so that bass is good but not overwhelming.   Then see how that works but do not expect great bass from all or even most recordings else you will be tuning forever. 

I see that you read the article Erik wrote and posted on his website. In it he devotes a fair amount of virtual ink to discrediting the distributed multi-sub concept by labelling its advocates "cultish". If you are open to hearing an opposing viewpoint on the merits of a distributed multisub system, let me know.

The only negative thing I have to say about the concept and technology is the added complexity of the idea. Hawk it all you want to, I won’t interject.  It is the behavior I have been subjected to.  Be nice and I'll be nice.  Simple enough concept for most.

Leaving ports open will extend the low frequencies of the mains and allow the sub to come in at a somewhat lower frequency that is less directional and less likely to call attention to a single subs location in the room.

True but if your mains are 2-way, they will have more IM distortion in the midrange, and will have much more excursion below resonance, leading to limited dynamic range. Well integrated, an 80 Hz cut off is just fine. Maybe even 100 Hz.


Honestly though, in my mind integration is such a difficult task for most that whichever way you find easiest to integrate well s probably the right one and then leave it alone. :)

Best,

E