[CW] Headphones or Loudspeaker?

[sbjohnston at aol.com]

You can build an audio filter to provide a peak at that frequency using an op-amp.  Such circuits are described here:


http://www.ti.com/lit/an/slyt134/slyt134.pdf


Or an inexpensive audio equalizer could be put in the line to the headphones and you can then add gain or attenuation at any frequency.


Here's an example:


http://www.fullcompass.com/prod/080968-Behringer-MINIFBQ-FBQ800


 

Steve WD8DAS

sbjohnston at aol.com
http://www.wd8das.net/
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-----Original Message-----
From: John Westerlage <JOHN at N5DWI.COM>
To: CW Reflector <cw at mailman.qth.net>
Sent: Fri, Jun 15, 2018 10:20 am
Subject: Re: [CW] Headphones or Loudspeaker?



I would like to use headphones to keep from bothering the rest of the household.


BUT - the frequency one prefers seems to have something to do with the ear's
physical structure as well as other factors.  


For me, a tone of around 432 c.p.s seems to be MUCH louder than any other freq
either higher or lower.


So, I have built speakers tuned to that frequency, but I cannot find any headphones
that do the same thing.  I suppose some sort of R/C network as pre-filter in the  
earphone line could do the job, but I haven't been able to come up with the right 
combination.


Any suggestions on how I could do this ?
vy 73, John, N5DWI
"If it's not at least an hour, it's not a contact !!"
Houston, Harris County, Texas EL29ht
Sent from my 1910 Spark Gap Transmitter.   
Morse FOREVER !!!
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