XPost: alt.audio.pro.live-sound, rec.audio.pro   
   From: lcargill99@comcast.com   
      
   Phil Allison wrote:   
   > "Peter Larsen"   
   >>   
   >> A sane way to design the 4 Ohm box would btw. be to stick with the same   
   >> midrange and top components as in the 8 Ohm box.   
   >   
   > ** Long as similar woofers and compression drivers are available in 4 and 8   
   > ohms, that is the easiest way to do it.   
   >   
   >    ( Note that the 8 ohm version uses a 16 ohm compression driver. )   
   >   
   >   
   >> But there sees to be no valid technical reason to make a 4 Ohm box for   
   >> those that can't afford large amplifiers if it ends up in toy class   
   >> efficiency so that they get more sound from the same amp by getting the 8   
   >> Ohm version.   
   >   
   > ** Obviously true.   
   >   
   > Another way to convert any box from 8 to 4 ohms is to simply install a   
   > matching transformer at the input,  ie an auto-transformer that gives a 41%   
   > step up in voltage.   
   >   
   > A toroidal cored type would make it quite small and inexpensive too.   
   >   
      
   That seems like a free lunch. It isn't, but it seems like one :)   
   1.41 is dangerously close to sqrt(2).   
      
      
   > BTW   
   >   
   > The size of the magnet does not change with rated impedance -  4, 8 and 16   
   > ohms versions have identical magnet structures.   
   >   
      
   I think that's probably true, based on what I've seen.   
      
   > Speakers have been made with impedances from 0.5 ohms ( eg Bose) up to   
   > hundreds of ohms and the only thing that changes in the gauge of the wire   
   > wound on the voice coil.   
   >   
      
   FWIW, I have found trolling through the Eminence online catalog to be   
   a source of a great deal of data on loudspeakers.   
      
   >   
   > ....  Phil   
   >   
   >   
   >   
   >   
   >   
      
   --   
   Les Cargill   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)