Where did intermodulation distortion go?

Discussion in 'AV Receivers' started by Stephen Weller, Jan 15, 2004.

  1. Stephen Weller

    Stephen Weller Stunt Coordinator

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    This question is probably aimed at the older crowd. No offense intended, but the "kids" at BB and CC hadn't even *heard* of IM.

    While shopping for a budget receiver, I noticed the conspicuous absence of the IM distortion rating. One highly rated receiver had a THD of 10% [​IMG] at rated power, but without knowing the IMD, I wouldn't touch it.

    Have audio engineers found a magic way of eliminating it?

    For the younger crowd: The "old" school taught me that IMD was important because it's distortion you "feel." Over the course of a feature film, it can cause you to feel fatigued and can literally wear you out. THD, on the other hand, is distortion you hear.
     
  2. David Judah

    David Judah Screenwriter

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    10% THD in a solid state receiver? I didn't know that happened these days, even in the cheap stuff, especially with designer's willingness to artificially bring it down with negative feedback.

    Anyways, it's so easy to fudge the numbers that the figure would probably be next to useless(with THD also), so critical evaluation would still be the best measure.

    DJ
     
  3. Stephen Weller

    Stephen Weller Stunt Coordinator

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    Pioneer VSX-D412S. Hey! I *said* I was looking for a "budget" receiver. [​IMG]

    Anyway, once upon a time, the FTC regulated THD (and I *thought* IMD) specs. Did something change? Does anyone remember? *AM* I as senile as my Mrs. tells me I am? [​IMG]
     
  4. Tim Streagle

    Tim Streagle Stunt Coordinator

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    I remember IMD spec's. These days, we're lucky to get full-bandwidth power ratings... with all channels operating. This is more common:

    100 watt total music power at 1000Hz, low distortion, going downhill with the wind behind thee.
     
  5. Jerry Parker

    Jerry Parker Stunt Coordinator

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    IM distortion is much more of a problem in speakers these days than the amplifiers....
     

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