[Elecraft] Noise-cancelling headphones mystery

[CUTTER DAVID]

Noise cancelling that I've come across is limited to low/medium frequencies.  If your hearing takes you higher, the noise-cancelling has finished by then.  This is probably not the ability of the sensing mic but the circuitry and/or room acoustics, echo, etc.  I'm a little out of date on the subject but that's probably the essence of it.
David G3UNA

> On 09 December 2018 at 15:26 "Dave Cole (NK7Z)" <dave at nk7z.net> wrote:
> 
> 
> As a guess, I would say the response of the mic used to derive the phase 
> canceling audio does not adequately cover the audio noise spectrum of 
> the 1500 puts out...  Thus it can't phase cancel very well...
> 
> That or your 1500 is filled with bad magic because it is supposed to be 
> my KPA-1500 and it is mad at you.
> 
> 73s and thanks,
> Dave (NK7Z/NNR0DC)
> https://www.nk7z.net
> ARRL Technical Specialist
> ARRL Volunteer Examiner
> ARRL OOC for Oregon
> 
> On 12/9/18 5:16 AM, eric norris via Elecraft wrote:
> > I have owned a pair of Heil noise-cancelling headphones for many years.  They worked very well to reduce the noise of my old AL-1200 amplifier, and the 5 fans on my cantankerous man-killer Henry 2002A EME amplifier.  However, they are completely ineffective against the KPA1500.  I bought a pair of Bose noise-cancelling headphones recently, and they work much better but are a bit tinny and eat batteries.
> > My question for the audio experts on this list is why don't the Heils work with the KPA1500?  Does anyone have a recommendation for a pair of really good noise-cancelling headphones with a more flat response?
> > 73 Eric WD6DBM
> > 
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