A
amdx
- Jan 1, 1970
- 0
Hi guys,
I ran across this electromechanicoustic device (speaker) called a Gallows
headphone.
This is used as the speaker for a crystal radio.
It is pictured about 2/3 of the way down the page.
You will understand it's operation by its picture.
http://www.hpfriedrichs.com/
I have cross posted looking at this as having three disciplines, acoustics,
electronics
and magnetics.
I would like to see ideas to design one with these objectives in mind.
Objectives:
Maximum audio from minimal (crystal radio) signal (high sensitivity)
High impedance, if we can get enough wire on the electromagnet, the matching
transformer could be eliminated. (100k to 1 meg ohms, tapped) That's a wish
Questions;
What should the diaphragm look like? low mass? with ridges? needs to be
magnetic at
some point.
Can we put an electromagnet on both sides in push pull? Can needs to be
sealed.
Earphone is connected with hollow tubing, what type of tube would be low
loss?
does length matter? I'm thinking stethoscope earphones till something better
is found.
Do we want the center of the diaphragm to move or the whole circumference to
breath?
How do we focus the magnetic field, if we do.
Thanks for your input, MikeK
I ran across this electromechanicoustic device (speaker) called a Gallows
headphone.
This is used as the speaker for a crystal radio.
It is pictured about 2/3 of the way down the page.
You will understand it's operation by its picture.
http://www.hpfriedrichs.com/
I have cross posted looking at this as having three disciplines, acoustics,
electronics
and magnetics.
I would like to see ideas to design one with these objectives in mind.
Objectives:
Maximum audio from minimal (crystal radio) signal (high sensitivity)
High impedance, if we can get enough wire on the electromagnet, the matching
transformer could be eliminated. (100k to 1 meg ohms, tapped) That's a wish
Questions;
What should the diaphragm look like? low mass? with ridges? needs to be
magnetic at
some point.
Can we put an electromagnet on both sides in push pull? Can needs to be
sealed.
Earphone is connected with hollow tubing, what type of tube would be low
loss?
does length matter? I'm thinking stethoscope earphones till something better
is found.
Do we want the center of the diaphragm to move or the whole circumference to
breath?
How do we focus the magnetic field, if we do.
Thanks for your input, MikeK