Apologies if this is asked and answered but it's a complex issue and searching this forum (and others) has not yielded any meaningful results.
I have a client with a fancy Bose wireless hi-fi speaker system -- sounds like treacle but that's not my problem..... It transmits on the 2.4 GHz frequency, along with just about every other wireless device on the planet. They have a wireless 2.4 GHz ADSL modem/router and an old (54g) Airport Express hooked up to the Bose system. The wireless speaker signal to the kitchen messes this up beautifully, as you might expect. Airtunes will play for a couple of minutes, and then continually drop out -- very unsatisfactory. As soon as they turn off the wireless speakers in the kitchen, all is dandy.
My solution to this was to create a pure 5GHz network on an Airport Extreme, running a second 5 Ghz only network and picking up its internet access by hardwiring it into the first (2.4 GHz) modem/router. This worked perfectly, and their 2 laptops (MacBook Air and 10-month old MacBook) could connect to it and surf the internet via the new 5 Ghz network. So, far so good...
So I then put in a new Airport Express (802.11 n) but that was where my cunning plan fell flat on its face. Nowhere in the settings could I "force" the Airport Express to operate on the 5 GHz frequency while it was a client of the Airport Extreme 5 Ghz network, meaning that the signal to the Aiport Express and Airtunes still caused conflict with those wretched wireless speakers in the kitchen.
So, quick switch to Plan B: I created a new, completely separate network for the Airport Express, set it to broadcast on the 5 Ghz spectrum, and Airtunes worked PERFECTLY. No dropouts, not interference, just a nice steady stream. Only problem then is that the laptop cannot connect to the internet, as the Airport Express has formed its own little breakaway group from the main network and is operating entirely independently of either the modem/router or the Airport Extreme.
SO, here's my question: Have I missed something simple or is there really no way to get the Airport Express to become a client of the Airport Extreme and for it to broadcast only on the 5 Ghz spectrum. My logic was that if the Airport Extreme was in 5 Ghz only mode, then the Express would automatically be the same. It does broadcast on the same 5 Ghz channel as the Extreme but the streaming drop out/failure issues remain, and I can't begin to guess why that would be so.
If anyone has any thoughts or knows of a solution to this, I would be incredibly grateful. As would my client -- although it won't fix the overall muddy and rubbish sound he gets from his hi-fi of course....!