Am running a pair of M1s purchased used two years ago. They are 20 years old but in great shape. Had them shipped to SL to check the panels and upgrade the backplates. The backplates are last generation with midrange control. I tried boosting midrange to see what happened. The sound was terrible in my room with my rig.
Re. the DSP remarks, I’m using it to offload frequencies below 120 Hz to my subwoofer. While my panels will get down below 30 Hz, at regular listening volumes (~85db) the panel membrane will slap the stators at lower frequencies, usually with close-mic’d drums. Not a pleasant sound.
Using Anthem Room Correction installed on my Anthem STR preamp, I’m correcting only to 300Hz. Since the subwoofer integration is in the preamp, it’s well controlled. The other advantage is that a lot of load is transferred off the panels, so they are more efficient. These things need lots of power.
I sent a note to Roger about the stator slap. He confirmed it and basically told me there’s nothing I can do except upgrade to new bass focus panels, which won’t happen.
DSP has worked well for this. I’ve tried extending the top DSP frequency to 5K – sounds terrible. I’m with WillB here. These great speakers don’t need any help with mids and high frequencies. Open. Pure.