[Boatanchors] Do Headphones Age-Away?

[Brian Clarke]

Just consider the magnet strength. I reckon it would be impossible for any electrical signal to the coils to move the diaphragm to convex. The induced magnetic force would have to exceed that of the permanent magnet.
73 de Brian, VK2GCE

-----Original Message-----
From: boatanchors-bounces at mailman.qth.net [mailto:boatanchors-bounces at mailman.qth.net] On Behalf Of hwhall at compuserve.com
Sent: Sunday, 14 August 2022 12:15 PM
To: boatanchors at mailman.qth.net
Subject: Re: [Boatanchors] Do Headphones Age-Away?

It is my understanding from reading old documents that its not correct that the permanent magnet is there to "hold the diaphragm in place" - or at least not the way that reads to me.  It puts a mechanical bias on the diaphragm, making it concave (pulled toward the magnet) so that the induced motions of creating sound never take the diaphragm through flat to convex.  The transition between concave to convex was said to induce buzzing.
Wayne
WB4OGM

-----Original Message-----
From: Brian Clarke <brianclarke01 at optusnet.com.au>
To: 'Al Klase' <ark at ar88.net>; boatanchors at mailman.qth.net
Sent: Sat, Aug 13, 2022 8:05 pm
Subject: Re: [Boatanchors] Do Headphones Age-Away?

I think you'll find that the permanent magnet is there only to hold the diaphragm in place. I cannot see how increasing the magnet strength would increase the audio loudness. The amount of variation in magnetic force to move the diaphragm is probably a thousandth of the permanent magnet's strength.
73 de Brian, VK2GCE.

-----Original Message-----
From: boatanchors-bounces at mailman.qth.net [mailto:boatanchors-bounces at mailman.qth.net] On Behalf Of Al Klase
Sent: Sunday, 14 August 2022 2:02 AM
To: boatanchors at mailman.qth.net
Subject: Re: [Boatanchors] Do Headphones Age-Away?

Jeo Conner said:  Sometimes, it's simply the "aging" of our ears. LOL.

That's not a joke.  I tested some headsets back in 1997.
http://www.skywaves.ar88.net/xtalset102/headsets.htm

I repeated the tests with some of the same 'phones last year.  I'm about 
10 dB down.

That said, it may be possible to spiff up the classic metal diaphragm 
'phones by stroking the pole pieces with a strong (Chinese) rare-earth 
magnet.

Al

ARK Sig Block Al Klase - N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net/ 

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