[CW] Resonant speaker

[W5JMW]

Remember back in the 70's a cylinder with a speaker and a movable cone.I 
think it was branded "skytec".But you moved the cone for resonance..it 
worked well..john
----- Original Message ----- 
From: "Henry Meils" <meils at get2net.dk>
To: <ken.d.brown at hawaiiantel.net>; "CW Reflector" <cw at mailman.qth.net>
Sent: Monday, August 31, 2009 12:57 PM
Subject: Re: [CW] Resonant speaker


> True there are modern super-effective electronic selectivity methods but
> there's fun in experimenting with different approaches and I found it
> amusing to be resonatng audio wavelenghts rather than radio wavelengths --
> makes you speculate about the analgous behaviour of Maxwellian described
> waves (electromagnetism) and Newtonian-mechanics defined waves 
> (aucustics)--
> in fact I also built an LC circuit resonant at audio freqs., tuned with a
> ganged bc-band  variable air capacitor - just for the fun of it - this was
> based on a CQ article using a tuned AF amplifier. I also found it amusing 
> to
> tune a LC circuit to peak AF response.
>
> Henry, OZ1UF, Copen.
>
> ----- Original Message ----- 
> From: "Ken Brown" <ken.d.brown at hawaiiantel.net>
> To: "CW Reflector" <cw at mailman.qth.net>
> Sent: Monday, August 31, 2009 9:03 AM
> Subject: Re: [CW] Resonant speaker
>
>
>>
>>> I understand that at one point, the Germans produced headphones where
>>> the diaphragm spacing/tension could be adjusted to peak at a
>>> particular frequency.
>>>
>>>
>> Some older communications headphones have very non-flat frequency
>> response. I can understand how it could be helpful with an old receiver
>> that does not have sharp IF filters and very little in the way of audio
>> filtering. What I do not understand is how it can be much help with a
>> modern receiver with really good narrow IF filtering and low pass audio
>> filtering. The resonance in a speaker or headset would seem redundant.
>>
>> Ken N6KB
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