unknown speaker.

hello everyone.
can you tell me what it is exactly? I understood that it is a field coil but I don't know anything else.
I was told that it is most likely a speaker used in movie theaters in the thirties.
were they powered by high voltage?
do you think it is possible to detach the speaker body from the lower part and use it in a container, a home speaker?
 

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Do you have the speaker or are you just trying to figure out the details from the 3 images?

Is that a tube socket on the left-hand side (when looking from the front)? Could be a wall voltage powered transformer/tube rectifier circuit supplying the field coil DC.

My guess is the second transformer is for the audio signal, stepping it down from tube to voice coil voltage. Voice coil impedance could be anything if that's the case. It's hard to make out the wiring though, so I could wrong about that. I'm no expert on this kind of speaker.

Here are a couple similar items, but you'd need to know the exact model to be sure about the details of the one in question.

This e-bay seller has several similar speakers listed, so maybe they could tell you what it is if no one else can give you a definitive answer.
https://www.ebay.com/itm/254385158253

https://www.worthpoint.com/worthopedia/italian-jensen-12-inch-field-coil-49516459
 
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You could use the speaker with about 250 to 275 volts on the field coil. You want fairly well filtered DC. Some get more special and need super regulated field coil supplies because the speaker is special. The voice coil is likely closer to 16 ohms impedance going by 10 ohms DC resistance.
You would need an open back enclosure instead of sealed or ported. The field coil supply would produce just enough of a problem inside a sealed box.
Also I suspect the cone is not original going by appearance.
Maybe the field coil transformer could be used if it is still good.