september.org> ccffb784   
   From: shaun.at.pukekohe@gmail.com   
      
   Somewhere on teh intarwebs gregz wrote:   
   > "~misfit~"  wrote:   
   >> 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.   
   >>   
   >> I called them 12.5" drivers as that's what Wharfedale call them (as   
   >> well as contemporary reviews of the speakers). Also they need about   
   >> 1/2" bigger holes to mount them than three (so-called) 12" drivers I   
   >> have here.   
   >>   
   >> However I agree - and get very annoyed at the way drivers are   
   >> 'sized' by hole-to-hole - or chassis size. IMHO a cone-type speakers   
   >> quoted size should be the diameter of the cone - the same way a   
   >> tweeter is sized by the diameter of the diaphragm. Either that or   
   >> the size of the hole required to mount them.   
   >>   
   >> So, just for you, they're 25cm drivers. That's the outside diameter   
   >> of the cones. Now, can you help me with sourcing (or making)   
   >> surrounds for them?   
   >>   
   >> 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 asking   
   >> for manufacturers to 'cheat' by having a really wide flange and   
   >> spacing the holes all the way to the edge.)   
   >   
   > Because that is the size you want to bolt into existing holes. That's   
   > the way I have always gone by.   
      
   I understand why they're measured that way for system builders but by far   
   the majority of speaker-owning and buying people never unbolt a woofer in   
   their lives. It irks me when a "10" woofer" can have a cone that is smaller   
   than 7" in diameter.    
   --   
   /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.]   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)