I was a bit curious about the different cones, maybe one could reuse the E/K110 cones in a 2121H build, just replacing the surround and the dustcap? So I had a look into the Thiele-Small parameters.
Flux is about the same for all drivers. Since the alnico magnets probably are weaker, the gap is probably a bit narrower.Code:MODEL FS QTS QMS QES VAS EFF PE XMAX RE LE SD BI MMS FLUX
2121 35 0.19 5.5 0.2 110.4 2.7 75 1.52 6.8 0.9 0.032 12.7 25 1
2121H 35 0.16 5.5 0.17 110.4 2.7 75 1.52 6 0.8 0.032 13.7 26 1.02
2122H 40 0.23 1.9 0.26 65.1 2.4 100 3.05 5.8 0.6 0.032 13.2 28 1.02
2123H 85 0.32 2.5 0.37 19.8 3.5 250 2.54 4.2 0.4 0.032 13 25 1.07
E110 65 0.36 4 0.4 45.3 3 75 2.54 6 0.4 0.032 12.1 21 1.03
K110 65 0.36 4 0.4 45.3 3 75 1.52 6 0.4 0.032 10.3 17 1.02
MMS is about the same, could the cone itself be the same for all drivers?
Bl is about the same. They all have about equal number of coil turns in the gap.
Xmax differs a lot. Different voice coils in different drivers. K110 is close to 2121(H). Is E110 correct?
Pe and Eff is close between 2121 and K110.
Vas differs a lot. Must be the surround. 2121 has soft surround. E/K110 has cloth surround. Spiders?
Qes differs too much. I don't believe Qes can be changed by replacing the surround. Or maybe the spec sheet is wrong? It has happened before :-)
Qms is pretty close. Softer surround should get higher Qms, right?
Fs differs a lot. Softer surround should give lower fs.
Model differs a lot. Can be fixed with foilcal :-)
I will try to convert a pair of E110, replacing the surround and the dust cap.
Mårten
