Not a conventional type of loading, but it looks to me like there is bass reflex action going on with a tuning frequency of around 40Hz as indicated by the impedance dip at that frequency.The rear radiation from this woofer exits the cabinet through small openings on each side that feed into narrow slots that vent to the outside at the enclosure's front and rear. TAD calls this bass-loading design bidirectional ADS, for Aero-Dynamic Slot.
It has a gigantic neodymium magnet driving light weight diagram, compare it with Eminence beta8 95db. I have 99db 12" neodymium woofer 4" voice coil with much smaller magnet.That woofer has most likely 85dB sensitivity, which dictates overall efficiency of the speaker. To attenuate mid and tweeter is easy.
98 dB? Where did you pulled this number from?
So you are *assuming* 98dB without any measurement to back that claimIt has a gigantic neodymium magnet driving light weight diagram, compare it with Eminence beta8 95db.
I have 99db 12" neodymium woofer 4" voice coil with much smaller magnet.
I wish I had the specifications of this driver . My purpose is to estimate from different data I dispose. This is P audio SN8mb , it has a tiny neodymium magnet inside the voice coil of 2", with 2mm VC overhangs it has 95db efficiency. To have a 82db efficiency, either the diagram is heavy subwoofer with powerful magnet or light diagram with tiny magnet. The TAD driver with double plied surround, is a high efficiency midrange. I don't have slightest doubt it has a passive equalization that I am trying to find out, to replicate.So you are *assuming* 98dB without any measurement to back that claim
Not the same, and FWIW deduct 3dB from "numbers" published by Eminence.
Their curves are fine, though, and faithfully reflect what I´m saying.
The speaker I am analyzing is CE1 has 82db efficiency 85db sensitivity 4 ohms woofer cut frequency 250hz. , no measurements I could find but that of ME1.I had a look at the Stereophile measurements. They estimate 86.2dB/2.83V/m for the speaker. Looking at the overall FR it is pretty evident that the manufacturer choose an almost full baffle step correction, so the "real" efficiency of the woofer should be around 90dB, maybe 91dB but not more. Your claim of 95dB simply doesn't make sense as no sensible manufacturer would attenuate a woofer.
What the speaker outputs at 34Hz depends heavily on the tuning. If you look at the graphs published, the tuning is at around 40Hz and the FR drops below 50Hz. My estimate is that at around 34Hz the speaker is at around 70dB, down 15dB from reference.