Re: Speaker Vs. Microphone

[brian whatcott <inet@INTELLISYS.NET>]

At 20:50 8/11/00 -0400, Tom McCarthy wrote:
> Hello all,
>   I have a question concerning the invention of the microphone and, its
> inverse, the speaker.  AG Bell invented the telephone, which I would think
> would make him the inventer of the microphone.  After doing a little
> research, I find that E Berliner and T Edison both invented the microphone
> and that Berliner's version allowed Bell's company get out of a nasty
> dispute with Edison.  If Bell successfully transimitted the human voice,
> wouldn't that classify as the first microphone?
>   Concerning the speaker, the grammophone was invented by Edison using a
> cylindrical disc while Berliner invented the flat, record style grammophone.
> Was the grammophone the first speaker or, was it the ear piece on Bell's
> first telephone, essentially the mouth piece operated in reverse?
>   Thanks, as always for your knowledgeable replies.
> Tom

Voice senders of acceptable quality long predated Bell, Reisz and Gray.
 You are familiar with this prototype - you probably built one.
 It's the string & can type, which has greatly limited range.

 This was the functional principle of Edison's phonograph speaker -
a diaphragm responding to mechanical vibration.

Bell's telephone patent illustration of 1876 shows a moving iron
transmitter and a similar receiver with an electric battery in the
 circuit.(This provides the magnetic field in which the armature
can provide a variable reluctance.)

The memorable "Mr. Watson come here..." was transmitted by a sender of
a later type: (Watson made this sender a month or so after the patent
filing - Bell was manually inept.)
It had an electrode dipping in a liquid to provide variable resistance
when vibrated with sound.  This provided more signal than the feeble
 moving iron type microphone.

The trembling contact type of sender exemplified
by Reis 1861 could transmit tones (and if sound intensity were
carefully controlled *just* send voice badly).

The generalization of the trembling contact with many frictional
contacts in a carbon granule capsule was due to Edison
who was contracted to provide improvements to the microphone.

Very soon, pairs of telephone sets could be rented for points
approaching two miles distant.

brian whatcott <inet@intellisys.net>  Altus OK
                Eureka!