You will find the paper has disintegrated. I replaced them (there are two in each headrest) with 2 x 4" speakers and had to carve a bit of the foam out to get them a tight fit. The seat cover keeps them snugly in place but I added some hot glue gun to them as well.
When you have finished, Hiding a key is sensible. I have, in the past, on a couple of my first cars (Austin 1300 and Type 2 VW), screwed a key to the plastic liner under the wheel arch and then covered it with a quick spray of black paint.
Whilst working on the new headrest speakers, I thought that the speaker compartment would be a great place to put a cut into the foam and wedge a key inside. It would not be visible if someone unzipped the headrests (why would a thief do that anyway?). It is relatively easy to unlock the doors in any case as you can ( sensor rest of sentence ) - this would be a convenient emergency solution if you have lost or locked your keys in the boot (it happens!).
Anyway, back on topic
These are the new speakers that were bought from eBay - under £35 for four speakers (you will need two each headrest).
Speakers - 2 pairs required
This shows how the speakers will fit on the “lid” inside the headrest. As you can see, there is just enough room for the two 4" speakers to fit side-by-side. I did not want to have anything sharp in the headrest, so did not use screws or bolts or anything that could impact with my skull in an accident - out came the new glue gun - it takes 2 and a half glue sticks for the job, by the way.
Speakers positioned on the lid.
The connectors on the original wiring were identical to the tags on the speaker, one small and one large female spade connectors, so no rewiring required.
For reference, taking the photos, uploading them, resizing and writing this post took almost more time than the job itself.
A very easy job, no electrical knowledge required and a 1000 percent improvement to the ICE.
Jeff