I pick up a pair of these while looking for a larger omni-directional speaker. They were cheap and sounded very nice with a sub crossed at 60 hz. Tried reading up on them, saw the adding poly fill to the bottoms and did that a couple months ago.
Read about the Skiing Ninja crossovers and discussed with Danny about upgrading to this. The cost was more than I paid for the speakers with shipping. I asked for advice and got a concensus that changing the caps in the stock crossover to Sonic Caps is the biggest bang and most worthwhile upgrade to the AV123 crossovers.
The stock caps did not look bad, and are bypassed with Sonic Cap Gen 2 caps. I asked Danny about chokes and purchased the correct values from him to upgrade to the Alpha Core copper foil inductors. My LCR meter is not super accurate are measuring sub ohm resistors but it repeatedly indicated the DCR is slightly less for the foil chokes compared to the stock air core wire. I needed something to solder the foil leads to anyway, used some 0.005 ohm Dale LVR-5 resistors. The 0.01 added DCR may not make any difference. These are non-inductive and non-magnetic current sense resistors with very low tempco.
I saw some hillbilly wax coated chokes here, so coated the chokes with beeswax. May not be audible, but has to add a little mechanical dampening.
Looked over the stock binding posts, wanted to put Speakons on, decided to just replace the stock with my old standby EF Johnson 5 ways. These are NOS lab grade. The stock posts are non-magnetic, the nuts and washers are steel. The EJ Johnson are all brass.
Was ready to bolt up and swung a magnet over the stock resistors. Steel leads and end caps were indicated. Went hunting at ACE Eelectronics for 10 watt 5,6, and 15 ohm non-magnetic resistors. All I could find were Ohmite thick film types. Never used them in a speaker crossover but have worked great in higher values as dampers across chokes in amplifiers. Microphonics was a concern for these ceramic chips in a loudspeaker so more of the beeswax was slopped to the bottom to attach them to the circuit board.
Quit taking pictures after the first crossover. The thick film resistors and binding post are not much to look at. Neither is sloppy applied beeswax.
Results, even better sonics. The bass is much punchier. Sound is smoother and yet more detail. Cannot tell if it is the foil chokes, beeswax dampening, binding posts, or the non-magnetic and non-inductive resistors that made this improvement. Suspect it all four in the order listed.
Would like to get a pair of the Skiing Ninja crossovers to compare sometime.
