I've had an idea for a video short. Basically, I want to have a camera focused on someone talking on a cell phone. The audio heard would be what she is saying into the cell phone, while the person on the other end is heard through a regular studio microphone. The idea is kind of a disconnect between who is seen/not seen and how they are heard.
To record this properly, I thought of cell phone headsets. As far as I can tell, they are little more than a signal going to the earpiece and a signal coming from the mouthpiece, in and out of the 2.5mm jack on the phone. My recording device is the FR2-LE. So here is the signal path I envision:
1) 2.5mm (out of cell phone) > FR2-LE XLR input (left channel) > WAV
2) microphone [ > SD MixPre] > FR2-LE XLR input (right channel) > WAV > RCA monitor out (right jack) > 2.5mm (in to cell phone)
So I'm basically recreating the experience of the headset, albeit with better equipment and a somewhat more convoluted path. The first step captures what the person on the other end of the phone is saying with that oh-so-familiar tinny phone quality we all know and love. The second step records someone talking into a microphone before pumping it back into the cell phone. The additional preamp step is put in there so I wouldn't have to enable phantom power on the FR2-LE. I think the effect, when synced up with video, could be interesting.
My problem is in designing the cabling to get this done. I'd need some sort of split cable. Coming out of the cell phone, it would be "2.5mm jack > XLR" (it could be a 1/4" TS phono plug, but I don't really want to deal with attenuation). Going back into the phone would be "RCA > 2.5mm jack". It's an odd looking cable setup, to be sure.
So I have a few questions. Can this (or a similar) setup work? I'm not knowledgeable about how cell phone technology works, so there very well may be parts in a headset that I couldn't recreate in this setup. If this can work, splendid. How hard would it be to put this together? I've had some experience with soldering and splicing, but not a whole lot. And short of buying a headset and cannibalizing it for parts, I'm not sure where I would get all the parts to put this thing together. Should I try having one of the cablers around here to put together this custom cable? And if so, just who has the parts to put together such a monstrosity?
I await your replies.