ML Aerius/room tweak

I use the Aerius in a rather large room (30x20x13). The room interaction was producing a +6 to 8 dB peak between 4K and 8Khz. Most of the room acoustic tweaks I'd read about were for the lower end of the spectrum. Recently, I bought some acoustic foam to see if it would help. Until I figure out where to place it, I thought i'd just lean it against the back of the speaker (behind the electrostat). I noticed a change in the sound and measured that the peak was no longer there. Has anyone else tried this?

I'm now debating whether I should just cut the 2'x3' foam to the same width as the ML and just leave it leaning against the back of the speaker (vs. mounting on stand/wall). Any thoughts? What else do I need to consider? I am a newby at this and would welcome any help.

I also removed the woofers on the ML and replaced them after adding speaker putty for improved sealing. This seems to have improved the bass (I have not measured yet) -- or it may just be the case of "experimenter's expectancy"

Are there any other common tweaks for the Aerius? I have the speaker cookbook on order. I am thinking of altering the stuffing to see how that changes the performance of the speaker in the environment that it is now.

Thanks in advance.

A cheap tweek to improve the overall clarity: remove spikes and slip four #3 Vibrapods under each speaker. Worked for me.

Let's start from the beginning. These speakers love well designed tube gear and if they sound a bit bright and out of control, it may well NOT be the room, but rather the equipment. I've run these before and they display none of what you mention when given proper source, amplification and cabling. It's all a ballet.

The perceived improved bass may be simply better cabinet dampening from the 'silly putty'. Do NOT lean things against the back of a dipole electrostatic. Purchase some SONEX or RPG and do it right placing directly behind and/or to the sides on the walls.

Forget Vibrapods. They work for electronics. Spike these babies with German solid body brass cones and place those silly plastic furniture carpet protectors under them as the cones will not penetrate the carpet to subflooring.

Good luck Mr. Phelps.

Have you tried the acoustic foam at the first reflection point on the side wall? That will likely give you a near flat response and won't destroy the reflected waves from the rear of the speaker. In order to create the electrostatic magic, you really need those rear reflected waves (but not the side reflected waves). Ceiling reflections can also be an issue, but work on the side reflections first.
Those speakers are to small for that large of a room. The aerius was designed for people who live in a very small aprtment and want the logan sound. If your trying all those tweaks then you are not truly happy with the speakers performance to begin with.You need at the least a martin logan ascent or a request. And if you call martin logan they will tell you the same thing. I ahd the aerius the bass is awful and the sound is thin.(sorry) I sold them and bought the sl3s which had a larger presentation and better bass but the bass didnt intergrate well with the panel. The sound was more natural. Then I sold the sl3s and bought the Martin Logan Ascents and all is well the bass is great and the intergration is the best I have yet to hear from a Logan. So with that in mind the best advice is call martin logan and then sell your speakers and get a bigger panel to fill that large space. (side wall reflections should be adressed first) Here is how sit in your listening seat have someone run a mirror down the right wall and when you can see the center of the panel that is where the sound treatment belongs. And repeat that again for the left side. The panels should be two to three feet wide and five to six feet long.and in a room like that two will not cut it. Good Luck
Though the room is large, it is divided into three sections by a low wall and the kitchen counter. My listening position is restricted to ~ 9.5' from the speakers. The speakers being about 28" from back wall (to panel)

I really like the sound to the Aerius in my room (perhaps because I've not heard better). My tweaking urge stems from the desire to see if incremental improvement is available (as opposed to being unhappy with what i have now).

I will try the suggestion of placing the foam at reflection points instead.