Horning Eufrodites - help needed with boomy bass

Amuseb

If you listen near any boundary, floor, wall and even the ceiling you will hear more bass travel along those surfaces than travel down the more central areas of the room. The idea I suggest and one I use is to redirect the energy from those flat surfaces and scoop that energy into the central part of he room. Try to eliminate some or all 90 degree angles as mid bass punch and sound stage integration will be enhanced. Elimination of the 90's can look very cool as well.

I have some small portable angled units I put on the floor to reduce standing wave's that also add acoustic air to the performance. These can easily be added or subtracted when the family requests you to do so. Tom

Speaking of grounding speakers- I just wanted to share my personal experience, that doesn't necessarily will apply to any other speaker/system.
I have tried multiple approaches- spikes, cones (Mapleshade, Audiopoints, BDR, etc.), isolation platforms (Mapleshade maple blocks, Sistrum, Symposium, Herbie's), etc., etc.
Now my search is (hopefully) over- the best solution by far is Stillpoints Ultra 5s on Symposium Super Plus platform.
The results are simply amazing- increase in resolution, articulation. Very natural and relaxed at the same time presentaion, without any downside, as I experienced with other support systems.
The whole listening experience is at completely different level- I get involved in every single listening session, regardless of what is playing- something, that rarely happened before. And that's what counts.
Again, your experience might not replicate mine.
Should I mention how much I hated to pay the admission price? Absolutely ridiculous if you ask me! But the funny thing is- it was totally worth it.
YMMV

"I'm also not 100% sure I understand the way the wood boards have to be inserted into the bass port. Can you clarify? Does it matter which wood to use and what the thickness of the board should be?"

Suppose the port is 150 mm tall by 200 mm wide by 300 mm deep. And suppose you have access to 18 mm plywood (the kind of wood really doesn't matter - its main function is to take up space). In this case, I would suggest cutting four or five boards, each about 199 mm wide by 300 mm long, and of course 18 mm thick. See if placing some or all of the boards in the port, thus reducing its cross-sectional area, makes a worthwhile improvement. The theory is, if the box is acting like a vented box down in the bass region, this will lower the tuning frequency and hopefully reduce any upper bass bumpage without detrimental side effects.

"Duke, If one product`s purpose is to "absorb" or hinder vibrantion/resonance(attempting to isolate), this is different than "mechanical grounding"(MG). With MG there`s no attempt to absorb, rather you allow the vibration/resonance a rapid and complete exit channel to "gound" this energy into the floor.One seems opposite from the other.An example of the MG approach is the Star Sound system brass points and stands."

I don't see these two approaches as opposites. Your approach addresses mechanical vibration, and mine addresses airborne vibrations, better known as sound waves. One can have a speaker with a resistive port (such as a Variovent, or a DIY variant like I described above), and that speaker can also be sitting on brass points. The opposite of your approach would be de-coupling the cabinet from the floor, via something like Herbie's Big Dots.

I have not experienced mechanical grounding to make a significant difference in the frequency response of a loudspeaker system. From the description, it sounded to me like a large change in the bass response was called for, and so I suggested a possible acoustic solution. Nothing wrong with trying a mechanical solution as well.

Nothing against bass traps or speaker re-positioning either. The more options Amuseb has available, the greater his chances of success. I'm just trying to add to his options by describing a couple of unorthodox approaches that are inexpensive and easily reversible.

Duke

I think Duke's idea is a very good one and easy to undue if you don't like the results. The following is also easy to try. The replacement or reduction of 90 degree angles that I mentioned earlier there is one major angle you can try replacing. The niche or nook, that angle can be changed in a fairly easy experiment. If you had a solid wood panel like a door or you could take a door off its hinges temporarily you could place that barrier at the niche. The barrier wall of the niche is at a 90 degree and if you experiment by placing that panel at a 35 to 58 degree angle so it intersects the front edge and the side wall I think you will hear a big improvement. You can use this panel to steer the bass and listen for a change in angle and a change in how the room loads the bass. You have to use a solid not a rug or other porous material. If this idea works well you and the family need to decide what looks good and sounds good. I have performed these experiments before and have made permanent changes as a result. Tom

Amuseb, have you had the problem from day one? Lots of interesting suggestions, but maybe this isn't the spkr for your room, period?
I used to run Zu Definitions Mk2s, with xoverless full range drivers and 4 x 10" bass drivers out the rear, so some major similarities with your Hornings. Bass integration was a major issue, and I mostly solved it using the Spatial Computer Black Hole anti-bass wave generator, which sitting behind the listener, uses a mic and dsp to sample the bass from the main spkrs, and pumps bass into the room to eliminate phase issues, standing waves and bass nodes. The problem wasn't totally solved, but improved a good 60-70%.
I've upgraded to the Zu Definitions 4s which dispense with rear firing woofers for a single floor firing one. Bass better than ever, but still helped by the Black Hole.
For $1250, full money back guarantee, it's worth a try.