<---cs:What about wireless systems? :cs--->
What about wireless systems?
If you're worried about whipper-snippering the speaker cable, or you are stuck with concrete slabs and nowhere to run cables, you might want to consider wireless instead. Infrared speakers will give you about 10m direct line of sight, which means they aren't always good for locations where trees and other objects (like people) can get in the way. Radio frequency (RF) is a more common technology for outdoor wireless speakers, and these will operate for distances up to 100m, and the signal will pass through walls. The downside to using wireless speakers is that they require power, usually in the form of batteries. You will definitely want to look for a model that automatically switches off after a period of inactivity, or else you will be chewing through batteries like nothing else.
With the added convenience of wireless comes a compromise, however, and that compromise is usually the sound quality. While the speakers may have good specifications, the weakest link is the radio transmission signal. You will get a certain amount of hiss, plus additional interference from other devices like cordless phones, door bells and baby monitors. The exceptions to this rule are speakers that use digital encoding, similar to the way a computer modem works. By isolating the noise during the digital phase of the transmission, the clarity of the original audio signal is preserved. This is a feature that is not clearly described in product specification sheets, so if you want it, be sure to ask for it. At the very least, always try out wireless speakers before buying a pair - the risk of disappointment is just too high.
Outdoor speakers are designed to be able to withstand getting wet, but some are better than others at coping. The problem with waterproofing speakers is that, in order for the sound to be heard clearly, air holes are needed-and where there are air holes, water can get in. To get around this problem, most outdoor speakers have coated drivers. They can get wet, but you should try to minimise their exposure to rain and hose water. Always tilt speakers downwards to maximise the drainage and, if possible, keep them under a cover of some kind.
Water may be the biggest problem with leaving speakers outside, but it's not the only one. Exposure to the Australian sun can dry-out and crack plastic and rubber seals, so a shady spot is always preferable to an exposed one. Some speaker designs are encased in cabinets that look like garden objects such as rocks. While this may seem a little kitsch, the extra enclosure can provide additional protection from both the sun and rain. Alternatively, other garden-friendly designs are shaped like lamps with protective umbrella style roofing. These are not only very durable, but are usually designed to radiate sound over 360 degrees.
Rectangular speaker boxes are best positioned near walls to maximise their bass output. Otherwise, outdoor speakers have a tendency to sound like they have no bottom end because bass frequencies will dissipate quickly when there are no walls to reflect the sound off.
Positioning speakers high off the ground will also maximise their sound projection. If you are using 360 degree speakers, however, place them as centrally as possible. For semi-permanent installations you may need to dig trenches for the cables. Make sure they are at least 20cm down or else there is a risk they will become exposed and/or cut. If you have concerns about council restrictions or potential noise complaints, use directional speakers that are positioned to direct sound from the perimeter of the yard inwards. This way you stand to get the most volume while your neighbours get the least. For specific details of noise restrictions in your area contact your local council.