6243645f   
   From: mynamespacedbydots@xs4all.nl   
      
   "Patrick Turner"  wrote in message   
   news:11ff8b3a-229f-4637-814a-8fabf89adf93@r16g2000prh.googlegroups.com...   
   On Dec 16, 7:33 pm, "GRe"  wrote:   
   >> "Patrick Turner"  wrote in message   
   >>   
   >> news:3c55a994-c0a8-4691-803b-d3192958bef8@o23g2000prh.googlegroups.com...   
   >>   
   >> [...]   
   >>   
   >>> Many modern speakers are rated for 88dB/W/M, or for 2.83V input.   
   >>> This can be misleading if the speaker has Z of 4 ohms for a   
   >>> substantial part of its F range.   
   >>   
   >> I have seen SPL specs like that before, and, as above, without   
   >> the 2.83V part being referenced to a particular impedance.   
   >>   
   >> If f.e. a speaker is spec'd 88db/W/M, fine.   
   >> Or 88dB/M at 2.83V into 8ohm, fine.   
   >> Or 88dB/M at 2.00V in 4ohm, fine too.   
   >>   
   >> Is it a simple omission stating volts without Z?   
   >> Or am I missing something?   
   >>   
   >> Rgds,   
   >> Gio   
   >   
   > 2V for 4ohms is 1 watt, and OK if a maker says that. But some don't.   
   >   
   > They just say 2.83V gives 88dB, and ppl assume its for 8 ohms and 1M.   
   > But if the Z = 4 ohms then the sensitivity is 88dB for 2W, which means   
   > you need twice the amp power because the real sensitivity for ONE WATT   
   > is 85dB/W/M   
   >   
   > There are plenty of makers who are a little bit dishonest in order to   
   > boost sales, and they don't care about accurate specifiations. De jus'   
   > want de money.   
      
   So, grin, SCI(*) in a mathematical context (sort of):   
      
   SCI < 1 for 88dB/M @ 2,83V if one finds Z to be 4ohm.   
   SCI = 1 for 88dB/M @ 2,83V if one finds Z to be 8ohm.   
      
   * Seller Credibility Index, a number between 1 and 0.   
      
   :-),   
   Gio   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)