From: dpierce@cartchunk.org   
      
   geoff wrote:   
   > David Nebenzahl wrote:   
   >   
   >   
   >>Meaning the right *resistance* value. Not necessarily the same   
   >>*wattage*. Since it's been pretty well established that this is NOT a   
   >>fusible resistor that can "protect" the drivers, there's no harm in   
   >>using a higher-power resistor.   
   >   
   > Naa, Dick suggests indirectly that  (say) a cap +10% and/or  a resistor -10%   
   > won't compromise any paramter of a crossover design.  But he'll say he never   
   > suggested any such thing.   
      
   Probably because, in fact, he didn't say any such thing.   
      
   What he DID say is that in particular circumstances, a   
   wide tolerance in value will have negligable effects on   
   actual performance, even to the point of being unmeasurable.   
      
   If one actually takes the time to actually look for and   
   READ what he said:   
      
       "If, for exanmple, such a resistor is used as a tuning   
       element in a parallel conjugate compensator, it can be   
       shown that a +-20% variation in its value might lead   
       to a +-0.05 dB or less variation in the electrical feed   
       to the driver OUTSIDE of its passband. 0.05dB corresponds   
       to a 0.5% variation in signal voltage, well beyond the   
       means to reliably measure under other than absolutely ideal   
       conditions.   
      
       "For example, say a 5.2 ohm resistance is needed for a series   
       element in such a conjugate network. Well, 5.2 ohm 7.5 watt   
       resistors are exceedingly hard to find, so a designer uses   
       two common values, a 4.7 in series with a 0.47, the resulting   
       5.17 Ohms being within 1% of the desired 5.2 (which itself   
       is a compromise, because it depends not only on the DC   
       resistance of the voice coil, but the TEMPERATURE of the   
       voice coil, among other things).   
      
       Now, say we  are stuck with +-10% variations in the 0.47   
       ohm resistor. The result is effectively a +-1% variation   
       in the combination. The difference in the passband response   
       resulting is well within 0.02 dB, and within 0.05 dB to   
       below the -40dB level. A difference in voice coil temperature   
       of 30C is going to cause more variations.   
      
   Now, what's interesting, if you read what he said, NOWHERE   
   did he say anything even remotely like what you claim:   
      
       "won't compromise any paramter of a crossover design"   
      
   It seems that YOU made this rather absurd claim up and attributed   
   it to him.   
      
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