issues with (uncommon?) precision devices pd.806

Hello!
not new to the forum but it is (weirdly enough) my first post here.
Ive been interested in horns and horn design for a long time now and ive been making progress on my hornresp skills.
The other day I picked up 4 pd.806 drivers (6,5") and i want to design a mid horn section for it for a 3way horn loaded top speaker (12" 6,5" 1") 
Quite hard to find anything about them, the are for sure not on the official website..

Im running into some issues with the parameters though..
the driver is supposed to have a fairly flat (around 90dB/1w@1m) response from 150Hz to 5kHz
But im not seeing those frequencies at all when calculating designs and i suspect the driver parameters that are the problem.

on the datasheet it specifies MLSSA paramaters. and im having a hard time figuring out what to do with: L1, L2, R2, RMSE-load, RMSE-free
and therefore I doubt the current values I'm using for Le and Rms are the correct ones
I also added a screenshot of the driver parameters.

Perhaps they wont even be suitable for horn loading but I cant get it to simulate anything even close to the HF range..

anybody have any ideas about the deisgn for these drivers?
I'm thinking to put them in pairs loaded with a relatively short horn and possibly some kind of horizontal phase plug..

Again.. I have been reading and trying to design for years but never really got in touch with the community to solve my problems.. or confirm my methods for that matter
A lot can definitely be found but sometimes a (more specific to my issue) answer feels like the only solution

Looking forward to recieve some response and finally interacting with the community..

regards,

You can also easily measure the Thiele-Small parameters yourself, with any audio interface that has a line output and line input, a 1K resistor, and some crocodile clips.

There's a full guide with a diagram of how to hook it all up in the included help file for the free software Room EQ Wizard (REW).

You'll get the most accurate results if you hang the driver up in the middle of the room, or clamp it to something by the magnet away from as many boundaries as possible. Also, having a small magnet of known weight, or something else that you can tape to the dust cap will let you determine the mass parameters.

Considering that even pro drivers have acceptable manufacturing tolerances of 10-20 %, it's good practice to measure the drivers you have and to find the average values for a design anyway.

I'd also recommend reading through a copy of the famous Leach paper regarding the specification of horn parameters based on drivers, or vice versa. It's part of the AES library, but some scoundrel has helpfully uploaded it here:
https://www.scribd.com/document/241200350/On-the-Specification-of-Moving-Coil-Drivers-for-Low-Frequency-Horn-Loaded-Loudspeakers-W-Marshall-Leach-Jr

Edited by toastyghost - 16 December 2021 at 1:26am