What is the best way to power my whole-house speakers?
Good- Use a single stereo amplifier in combination with a speaker selector box with impedance protection turned on. A speaker selector box allows a convenient way to connect multiple pairs of speakers to a single stereo amplifier. Most selector boxes include a switch for turning impedance protection "on" or "off". When turned "on", your receiver will never see an unsafe impedance (most selector boxes prevent the impedance from ever dropping below 5 ohms), regardless of how many speakers you connect. The upside to this type of connection is 1) ease of installation, and 2) the ability to turn zones of speakers (HTD offers speaker selectors for 4 and 8 zones) on and off at the selector box itself without having to worry about impedance issues. The downside is that impedance protection has the effect of "choking" your power, meaning you won't be able to get quite the same volume out of your speakers compared to a set-up that employs impedance matching.
Better- Use a single stereo amplifier in combination with impedance matching volume controls. An impedance matching scheme allows you to get the most out of your amplifier. While a speaker selector box is not mandatory, it is still a good idea as it provides a convenient method for connecting your speakers in parallel. In a carefully planned impedance matching scheme, you will turn the protection switch off thereby ensuring you get the most from your amp. The downside is that you must leave all zones turned on at the selector box so you can only turn zones off at the impedance matching stereo volume control.
Best- The best, albeit more expensive, method for powering a whole-house audio system is to use a dedicated multi-zone amplifier, like our DMA-1240. This multi-use/multi-zone amplifier allows you to select between multiple audio sources for each zone and balance the overall volume level going into each zone. 35 discreet watts of power is provided to each of 12 channels (6 stereo zones) which is more than enough for this type of application. And because the amplifiers are discreet, you can connect up to two 8 ohm speakers into each zone without having to worry about impedance issues. And if you need more power in some zones than in others, side-by-side channels can be bridged to create a single 100 watt channel.
For designs that require more than 4 pairs of speakers spread throughout the home, a multi-channel amplifier is really your best bet. And now, the DMA-1240 makes this upscale option affordable to the do-it-yourself enthusiast.
In all of the above cases (good, better, best) you will likely want to position your whole-house amplifier in close proximity to your existing audio sources, e.g. your home theater equipment. You can use a line level auxiliary output (or preamp output) on your home theater receiver to connect to the line level inputs on a stereo amplifier. In this way, the sources you have connected to your receiver (such as a DVD player, satellite receiver, etc.) can also be played throughout your whole-house audio system. If you use a multi-zone amplifier like our DMA-1240 you can also connect each source directly into the multi-zone amp so that you can have multiple sources playing at the same time and you decide which zone hears each source.
If you are in the market for a new home theater receiver and want to power an extra one or two pair of speakers throughout your home, you should consider purchasing a receiver that can handle both. These receivers will have a minimum of 7 channels of power built-in; 5 channels for home theater, and 2 channels for stereo whole-house audio (note: some 6.1 receivers provide the option of using the sixth channel to power a mono whole-house system, but who wants mono instead of stereo?). Such receivers are usually dual source/dual zone, which means you can play two sources at the same time and choose which zone (home theater zone or stereo zone) hears each source. As an example, the home theater zone can be playing a DVD, while the stereo zone listens to a radio or satellite broadcast. The Denon 3803 is an example of this type of receiver.