Have to fall back on some interpretation and common sense when
it comes to the grill cloth. The cut-away in the FAM illustration
shows the cross hairs in the weave of what I would 'interpret'
as cloth. Having worked with a few radios over the years I've
seen a lot of speakers that were hidden and or protected by a
plain Jane black cloth behind a variety of grills, very common
in table radios and car radios. If you think a speaker can
project properly thru a sheet of thin cardboard, try placing a
sheet over a loudspeaker and observe the results.
The installation sheet packaged with the 986771 radios does
state that you should: "(f) Remove the radio grill screen from
the rear side of the radio grill." and in the Note: REMOVE AND
DISCARD RADIO GRILL SCREEN. However, as mentioned earlier, the
FAM clearly shows a screen of sorts with the radio installed in
their illustration. My guess is that there was a screen cloth
held against the back of the grill with a sheet of cardboard.
After removing the cardboard the rubber gasket would hold the
screen, which would still be located in place by the tabs.
Can't document any of that, just my guess as to how they were
originally installed.
The cloth that I've seen between many speakers and grill bars,
has been an inexpensive course open weave that appears to have
been starched or lacquered to give it some stiffness.
Something along the lines of the first few samples here:
http://acoustonespeakercloth.com/ACOU_AMP_CLOTH.asp But once again, with it hidden behind the dash, anyone can do
it any way they wish and no one will know the difference.
Denny Graham
Sandwich, IL