[Trevor]

"~misfit~" wrote in message
...
Somewhere on teh intarwebs DecadentLinuxUserNumeroUno wrote:
On Mon, 22 Jul 2013 00:26:27 +1200, "~misfit~"
wrote:
Alas, on getting them home I discovered that the 'rubber' surrounds
of the 12.5" woofers had gone hard

There is no such animal.

You measure the speaker size by measuring the bolt circle diameter,
not the outside rim of the speaker.

Oh, wait a minute. WTF do you mean by the "bolt circle diameter"? Do you
mean the mounting holes? Because, if you do I've just measured these and
they're *exactly* 12.5" from the centre of one bolt-hole to the centre of
the opposite one. I guess that could be referred to as the "bolt circle
diameter".

(Although *why* anyone would want to use that measurement as a driver size
instead of the cone diameter is beyond me.

It's just historical, and important if you want a drop in replacement, but
your measurement does prove the lie to the claim "There is no such animal",
and why it is difficult to obtain replacement surrounds.


It's asking for manufacturers to 'cheat' by having a really wide flange and
spacing the holes all the way to the edge.)

For comparison and TS measurement purposes active cone area is used instead,
so not a problem.

Trevor.