wiring help

[Kwacker]

Hi All,

I am trying to tidy up a bit of a bodge in a car I have just bought.

It has screens in the headrests and headphones that are wireless.

However the person that installed it decided to use an inverter to plug in the transmitter for the headphones. The inverter has a fan I assume to keep it cool, but the fan is very noisy, and I don't like the idea of something that might get hot tucked away in the recess of the car.

They have wired the inverter straight off the cars wiring. And the transmiter uses a small plug in transformer to power it.

What I want to know is can I just wire the transmitter to the cars wiring?
I know that I will need to do some adjustment as the cars supply is 12v and the transmitter needs 8v 200mA.
What sort of electronicry do I need inbetween?
Is there something I can make? (i'm not afraid of buying components and soldering them together)

And I know there is probably a general solution I can buy but I want it to be a bit more specific.

Thanks in advance and waiting with ears open to suggestions.

Kwacker