[~misfit~[_3_]]

Somewhere on teh intarwebs Trevor wrote:
"~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.

Indeed.

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.

Yep, I've made a few boxes (and have the software to prove it - these days)
so know all about TS params. However, as I alluded to in my other post -
I've seen "10 inch" drivers (for instance) with cones that vary by around
two inches in diameter. As most speaker-buyers will never need to know what
size a replacement driver will need to be it could potentially be very
misleading.

I mean, if your average punter is looking to buy speakers and it's a toss-up
between two different brands, both 3-way with a "10 inch" woofer (which vary
by the afore-mentioned 2" or thereabouts) said punter might not know that in
fact one woofer has 30% more cone area than the other. After all they're
both 10" right?

Cheers,
--
/Shaun.

"Humans will have advanced a long, long, way when religious belief has a
cozy little classification in the DSM."
David Melville (in r.a.s.f1)
[Sent from my OrbitalT ocular implant interface.]