How to Add Multi-Room Audio For Existing or Older Homes
In order to easily wire and add multi-room audio to existing homes for whole-house speakers there needs to be adequate attic or crawl-space access available in the areas where you want to add sound. For homes with no such easy access another solution is to utilize a wireless kit. Both options will be explored in this section.
For homes with the available access for wiring speakers throughout the house implementation of your project is far simpler than those without. If there is no attic or crawlspace available for routing the necessary wiring you could still add multi-room audio wiring by channeling through wall studs but that method is invasive and would involve a LOT of drywall or plaster repair work and is not recommended unless there is absolutely no other viable option and you should be prepared to spend big bucks to add multi-room audio to your home.
Adding whole-house audio to homes with an attic is preferable to those with a crawl-space as it is much easier to navigate an attic as opposed to a usually dank and nasty crawl-space. Having an attic will enable use of ceiling speakers but with a crawl space you will need to either settle for floor speakers or go through the additional trouble of running wires up inside your walls for ear-level speaker placement.
If you do indeed have the required access to areas where you would like to add multi-room audio the process is fairly simple. Select where you will locate the hub or distribution device and then pull your wiring from that location to areas above or below the rooms where you want to add sound. In an attic, find a "landmark" such as ventilation vents or existing cable drops to locate the wall header which will be a 2x4 laid on its side. Wall studs will be indicated by nails driven into the stud. Use a powerful drill equipped with a 1 1/2" paddle bit to penetrate the header and allow dropping the wire down the wall to the distribution hub.
To locate the speakers -- find the ceiling joists with a stud finder, drill a small hole (slightly larger than the speaker wire diameter) and place a two foot length of stiff wire up (or down if in a crawl-space) in place as a placeholder to run the wires to. When you get the wiring to the length of stiff wire simply push the speaker wire through that hole. If you are adding flush-mount ceiling speakers - cut the speaker mounting hole, mount the speaker, connect the wire to the terminals and you're done on that end. You may also want to refer to speaker installation tips for more wiring info.
Wireless Multi-Room Audio Solutions
If you don't have access for running wires you can still add multi-room audio by using a wireless speaker system. It is actually the simplest solution to implement but is not the most ideal due to limitations in speaker placement and available audio quality. You simply connect the extra-zone or "B" side output of your A/V receiver to the input of the wireless transmitter and then place the wireless receiver(s) in your room(s). Depending on which of the below solutions you go with - you then either connect the receiver to speakers in the room or in the case of the Audio Unlimited system merely turn on the supplied receiver/speaker. Here are the two best options I've found for wireless speaker distribution --
1 - Audio Unlimited Wireless Speakers with Remote
This system is pretty slick. Each speaker is a self contained unit that includes a receiver and can either be powered by 6 C batteries or an external AC adapter. It also comes with a remote to control the volume level of the speakers which is a nice touch. The main disadvantage of this system is that the speakers are mono but an advantage of that drawback is that you only need to place one speaker per room. Additional single speakers are also available for just over $40 so you don't need to buy in multiples of two if you have an odd number of rooms to fill. The basic kit is under $99.99 with free shipping here at Amazon.com.
2 - Wireless 5.8GHz Digital Audio Link
This device from Shoptronics is a transmitter and receiver with an internal 25w/channel amplifier with a volume control knob on the receiver. Speaker placement with this unit would be somewhat limited as the receiver needs to be wired to your speakers and its AC adapter must be plugged into a power outlet. An upside is that allows use of high quality speakers and a major advantage is that when you add multi-room audio with this system it will be stereo. Check out Shoptronics' system for $149.99 at Amazon.com.