Ian,

Better introduce myself - I've been using X-10 stuff since 1997, been installing it for clients since 2000, and been running the UK X-10 training courses for electricians since 2004, so I've come across more X-10 problems than most :-) I also chaired the xAP group for Home Control for a couple of years, so have quite a bit of experience with networking for home entertainment.

On the X-10 problems - if your LV transformer conforms to the latest set of CE specs, then it shouldn't interfere with X-10. The problems tend to come with kit bought before about 2000 (or, to be fair, kit bought on "Chinese Manufacturer CE Self-Certification". We tested one product that put out 230v across the pins for about 15 seconds after unplugged - needless to say, we don't sell that! The FM10U filter is, erm, a plug in device - you plug it into the wall, and the "noisy" appliance into it.

Powerline networks are better, but the kit I've seen isn't great in terms of life expectancy. I had a 12Mb/sec (first gen) powerline network between three zones at home - which ran fine for about 18 months, then died mysteriously.

Turning to the "networked speakers", this is one of the things that more and more of our trade customers are asking for (we don't sell Meridian kit, alas, but sell a lot of the Sonos / RussSound / Opus multi-room audio systems.)

As you say, however, buffering is likely to be the killer for synchronous audio (such as, well, a speaker signal.) Read-ahead buffering works very well for, say, WMA / MP3 audio where the playback device can buffer up a minute's worth of audio, BUT ONLY HAS TO SYNC WITH ITSELF.

In a network where each speaker buffered independantly, it would be a complete 'mare to keep the sync going, without adding an additional load of sync messages.

Personally, my house is flood-wired with CAT5e, and I'd recommend the same for the next few years :-)

Regards,

Mark
Main system: 562v / 518 / 565 / Chord Amps / B&W speakers
Bedroom: 562v / 565 / 555 / Infiniti speakers
Lusting after a 5-series DVD player (or two) :-)