I managed to extract the filters from the old center speaker, as well as the “ludd” that dampen the air in the enclosure.
I cracked the glue joint with a chisel and a lot of persuation. I dreaded that the three filters would be tangled together as one and I would have had to understand it.
Luckily for me there were three separate filters. One highpass for the tweeter and two bandpass (if I remember correctly) where the one for the outer speakers cut of a bit lower than the front ones. I traced the wires from the speakers and found (and remembered) that when first built the phase was wrong on the tweeter and we had to switch phase a few times until we found out that it was the tweeter that was out of phase. The wires had been swapped on the filter and when connected according to the markings it became inverted. The filters were glued to the lower box which had a aluminium sheet at the bottom for some unknown reason (can’t fathom what difference it would make as it isn’t magnetic). Strong freaking construction adhesive. But with some careful chiseling I pryed them free.
I hade to rearrange a few components on the filters to make them fit into the small space behind and between the speakers. This is the way they must be positioned.