Airport express for airplay only, not extending network

Question

I have just bought an airport extreme and airport express.
The extreme is plugged into modem, and the express is in my living room, plugged into some older speakers.  The point of the express is to airplay-enable these speakers, not to extend the network.
I've got both set up and they're working, except that the audio drops out of the airplay every so often, in light of which a couple of questions:
1.  Even though I the point of the express is not to extend my network coverage, I guess it is doing that by default anyway?
2.  Isn't a downside of that that accessing the network via the express will be slower than accessing it via the extreme directly?
3.  Also, might the reason the express drops the audio be that other devices are using it to access the network?  If so, and this is the BIG QUESTION:  is there a way of continuing to use the express to airplay-enable my speakers, but not allow devices to use it for anything other than airplay?
thanks lots
d

Answer 1

is your point that devices near the Express but far from the Extreme will tend to receive a weaker signal since they're not permitted to use the Express (which in Join mode is restricted to communicating with the device that's streaming music to it) hence must communicate with the Extreme, which is some distance away?
Yes
had thought that communicating with the Extreme rather than the Express might be faster (provided the Extreme is close enough for an adequate signal) since the Extreme is simply a faster bit of kit, but you've already said that might not be right -- I'll do a speed test.
You can make the argument either way that you want, but you won't know what the actual results will be in any given situation until you try things out in your own particular installation. In other words, there is no one "right" way to do things that will be correct in every situation.
I get five bars indicating good wifi signal strength but sometimes (as now) very very sluggish internet connection.  I thought the Extreme/Express combo might solve that but not really.
There are so many things that can affect wireless performance at any given time, that it is almost impossible to list them all. And, things are changing all the time.....cordless phones, other wireless networks, radio and TV broadcasts, wireless security systems.
As far as the AirPort Express is concerned, remember that it can only "extend" the quality of signal that it receives from the AirPort Extreme.  In other words, if you have an AirPort Extreme at one end of the house and an AirPort Express at the other end, the Express will receive a poor signal to extend.
In this example, the correct location of the Express would be a point that is about half way between the AirPort Extreme and the other end of the house.
The way to solve the wireless strength issue with an AirPort Extreme and AirPort Express.......is connect both devices together using a wired Ethernet cable connection. Then, you can locate the Express exactly where it is needed, since there is no signal loss in a wire......and a lot of signal loss whenever a wireless signal must pass through a wall or other obstruction.