Kenjit is correct.....almost all commercial speakers can benefit from felting, removing the xover from the box....changing all wire, caps, coils and resistors to better parts, hardwiring it all, etc. etc.. Clarity cap MRs bypassed by copper foils are way, way better than CSA caps....there is no end to tweaking.
You can use just cheap thin wool felt. You really want to cover the entire baffle around the tweeter and also the midrange...right up to the edge of the speaker....the only thing not covered is the actual driver.....right to its surround...covering any frame. major improvement.
I have been building my own speakers or modding the ones I bought for over 40 years......never used a stock speaker for more than an hour (except in the mid 70s). I have modded Quad Electrostats, Acoustats, Gallo, VMPS and Sanders sound Electrostats.
Back in the mid 70s I had a three way speaker I made using the Altec 500 cycle horn and driver and an Electrovoice horn tweet.....also 15 inch Trusonic driver in box.....Speakerlab xover. It was horny sounding as hell. Burned my ears off. So, I thought all horn speakers were horny and bright. I found this store in Berkeley (first high end store I was ever in) run by a very tweaky guy. He had Klipsch corner horns and also Quad electrostats in the same room. His corner horns were unfinished and he had taken the Electrovoice horn tweeter out of the front of the speaker and mounted it right on top of the midrange driver against the corner of the room....essentially time aligning the drivers. I asked him if we could A/B the Quad and the K-horn.....to my amazement....they sounded very, very close.....blew my mind! Roger, the store owner, told me that if he moved the tweeter back to its stock position I would go running out of the store. I am sure he is right. Why would you want the tweeter sound to hit your ear a year before the midrange does? The K-horns midrange horn was a straight shot jobbie and smaller (giving less resonance and distortion) whereas my Altec horn was weird inside and made from tons of ringing aluminum.....we did not know notin back then. Klipsch to this day does not time align his bigger speakers.....some learn, some never learn. Also, I cannot quickly find a pic of the xover on the latest K-horns but I bet it uses ordinary parts.....the binding posts are cheap looking.
There are incredible speakers today.....Spatial, GR Research, Tekton Moab, Lii full range super inexpensive drivers.....lots and lots of cools stuff. However, a lot of the stuff out there needs some serious work to make them sound the best they can. Even the stock Spatials, GR Research, Tektons and Liis sound great. But, of course, you can tweak them more......it never ends for the perfectionist.
