XPost: alt.audio.pro.live-sound, rec.audio.pro   
   From: digilyd@hotmail.com   
      
   Peter Larsen wrote:   
      
   > Phil Allison wrote:   
      
   >> ** From your graphs, the woofers seem close in level but there is   
   >> something fishy going on with the other two drivers.   
      
   > DHL found and delivered the other PL315/4 today. Like the 8 Ohm box   
   > it has a bit too much bass, midrange and treble but a nice open   
   > sound, so this does appear to be about a somehow broken box,   
   > measuring comes later, 4now I just wanted to verify that it arrived   
   > OK.   
      
   A bit of initial data: bass resistance some 2.5 Ohm, mid some 7 Ohm and   
   piezo some 3.3 Ohm. Bulb resistance around 1 Ohm. After opening and   
   assembling the deviant one its mid and treble went totally silent. Opened   
   rear panel for bulb access. The main cause of problems was the bulb fixture.   
      
   The bulb has small bullet on end that should match a contact surface that is   
   loaded by spring. That surface was not perpendicular to the bulb axis and   
   consequently the bulb had gone from lacking to no contact.   
      
   Finagling with the contact surface and repeatedly rotating the bulb removed   
   the majority of the difference between the two 4 Ohm boxes. Sound - nor   
   curves - are not totally identical, but making physically identical   
   measuring setups so exactly as required by an off-axis tweeter is   
   non-simple. It probably will require soldering a bypass of the   
   bulb-protection device to eliminate it as a cause of difference, at least   
   during measurement and it is a long long way from being roadworthy in my   
   understanding of that word.   
      
   Consequently - and with the total cost of them, shipping cost included, in   
   mind - I have informed the seller that I have accepted them as OK within   
   what they are.   
      
   The boxes are totally clean inside, conformant with the sellers description   
   of them as having been used for ballroom dancing and being stored inbetween.   
   I wonder whether they have led too silent a life ...   
      
   Opinions on replacing the piezo with a Beyma CP16, impedance curve looks   
   benign and there may be enough front panel real estate for it?   
      
   >  Peter Larsen   
      
     Kind regards   
      
     Peter Larsen   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)