I'm considering putting in Power Line Networking adapters to try and solve some network issues that I have in my house.  I'm wondering, though, how putting that signal across my electrical system might affect my audio stuff - mic pres, rack effects, instrument amplifiers, audio interface, etc.  I know this is not really a Sonar question, but I thought someone here might have some experience with it.
 
Any insight is appreciated.
 
Seth

I don't believe you should have any issues. Network frequencies are quite far above audible frequencies. My electronics education was completed in 1980 and I went right into software development, so don't get angry at me if you wire it up and at your next recording session everything sounds like Motown on helium.
 

I connect my studio (built in my garden) to my broadband router in the house using a power line, and have no problems. I even use it to stream my live radio show to the FM transmitter with no trouble. 

I suddenly was no longer able to receive shortwave radio because of electrical interference noise.
I walked with my radio through the entire block of flats. It was everywhere.
I took it out the front door and the interference only started to reduce when I went several houses down the road.
 
About 2 years later, by pure coincidence, I learned someone in our block of flats was operating a powerline network system. I asked him to pull them out just to test and sure enough, I could use my radio again.
 
He even didn't mind if I had them checked out by the authorities. They came and put receiving equipment all over the place (Wow! I really didn't intend to create such a fuss!), and they said yes, they do generate interference but they are within legal limits. Apparently jamming commercial radio frequencies is not a problem. Police and ambulance frequency jamming is illegal.
 
So I gave them back with the info that they were OK. He very kindly offered to stop using them but I said I couldn't expect him to do that. Radio is just a hobby.
 
But wow. Basically, those things were turning our entire block of flats into a jamming station.
And they were not cheap junk. Interesting.

I have two network connections in the house for two TVs, where I watch Netflix. Neither was located in a convenient place to run a cable to, so I had no easy alternative.
 
They'll work fine, at least in a single-family home, with a couple caveats.
 
First, know that the bandwidth may be less than the main service; my bandwidth at the router and all hardwired connections is 30 MB/s but my power-line connected TVs see only about 5 MB/s - still plenty fast enough for Netflix.
 
Second, the transmitter and receiver should ideally be on the same circuit. If they aren't, there is a good chance the connection will be unreliable or not work at all. In my case both TVs and the hub that's feeding them are all on the same circuit, and it's been very reliable.
 
Third, as noted by Mr. Peterson above, they also turn your wiring into a broadcast antenna. However, this has not been a problem for me. I don't pick up any interference on my audio gear, which is physically remote from the house and on a dedicated circuit. I am able to listen to FM radio without interference, and I am able to watch TV on another set that's not networked. But other things might be more prone to picking up the radiated noise, such as police scanners or ham radios or CB radios or AM radios.
 
If you live in an apartment building, condo or duplex there's a chance you could interfere with your neighbors' devices. If that's your situation, you'll just have to try it and see. Buy the gear locally so you can return it easily if it doesn't work out.

I would expect the bandwidth to drop using power lines. The data is riding the 110v line so the signal has to be stripped off the higher voltage AC line and isolated before it can be passed through to the digital world. There must be some losses in the translation.
 
Industry has been doing this for ever. Things like overhead cranes and subway cars can all use the high voltage supply rails for communication and the high voltage gear is heavy duty and unlikely to be effected by most things.

The limitation isn't the voltage difference, but rather reactance - capacitance and inductance. Because house wiring wasn't meant to carry high-frequency signals, there are no standards for conductor/connector spacing like you have with regular network cables. And unless it's run inside conduit, there is no shielding. Conductors usually run parallel to one another so there is no common mode rejection.
 
I assume the network signal is modulated, so the bandwidth is further limited because it's based on the carrier frequency, which would need to be significantly higher than the data bandwidth.
 
And of course, the electrician who installed the wires was not thinking about inductance from tight bends and looping excess wire. He probably wasn't thinking about running conductors near fluorescent lights or electric motors, either. Because house wiring follows none of the guidelines for network cabling, it's always going to have an inherent bandwidth limitation.

I really must look into this type of system and see how the modems work. Sounds like you could build up your own private communication system and run it on the public utility.
 
 

Thanks for the replies! I understand it has some limitations and drawbacks, so it may or may not work for my network needs. As long as it shouldn't pollute my audio chain, though, I'm going to give it a try. Bought some adapters on sale. We'll see.