The Amplifier Power Ratings Game Page 3
What to Look For: The Bad As I said earlier, the grayest area by far when it comes to power ratings is that found in HTiB systems. A lump specification such as 200 watts total power (in some cases, you'll be lucky to dig up that much data on the product) doesn't begin to tell you what the system is capable of, or if it will even the exceed the output of your TV's own built-in speakers significantly. Even some of the more expensive all-in-one systems reveal certain eyebrow-raising elements stashed among their specifications. One popular system, for example, boasts of in excess of 1,200 watts total power. But after reading between the lines, it turns out that per-channel measurements are limited to a 1-kHz tone as opposed to the entire audio bandwidth, and with a sizeable 10% THD. Not exactly Hendrix territory, but lots of distortion nonetheless!
Even some well-known makers of mid-priced receivers are known to play the numbers game. One current seven-channel model, for example, has its power spec'd at 150 watts per channel - a sizable amount, given the product's reasonable price. But a second glance at its data sheet reveals the power rating to be for a 6-ohm load, rather than the standard 8-ohm specification. Not surprisingly, its test-bench performance puts it on a more even playing field with its similar-price competition, most of which is spec'd for around 100 watts per channel or less into 8 ohms.
A Better Future? Will the consumer-electronics industry get its act together and decide on a consistent method of measuring, rating, and specifying power for audio components? In the absence of strictly enforced government regulations, the answer is probably no. Despite this, the Consumer Electronics Association's Audio Systems Committee is currently drafting a new standard for rating home theater receivers and amplifiers. Details on the progress of those discussions - and on the players involved - aren't yet available, but the new standard's intended scope is to tighten and expand recommended measurement procedures in the existing one. Most interesting of all, the new standard will reportedly cover the exploding HTiB category. That might possibly be good news for the average consumer, who would presumably be given a better shot at having a satisfying audio experience when he carts home an all-in-one system to go with his 50-inch flat-panel TV.
Sussing out what's behind the numbers in receiver ratings and specs can be difficult. In most cases, you have to take the manufacturer at his word - although it's always a good idea to check the detailed test-bench results in reviews such as those found here at soundandvisionmag.com for confirmation. Just remember: As with any purchase, proper research can give you a more solid footing as you prepare to make your launch into higher-quality audio. Here's to finding truth in numbers!
For more, read our In-Depth Guide to Power Specifications.
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