Power Ratings
When you are looking at receivers, you’ll see power ratings for how much power the receiver can provide. Way back in the 1970s, when there was a “power war” going on among brands, you would see all kinds of crazy power ratings as there was no standard. People in the business from back then fondly remember the term 1000 watts ISBL. This jokingly meant 1000 watts, If Struck By Lightning! The FCC soon jumped in and made brands standardize on a power rating and it was easier to compare models. The FCC made the brands say the wattage rating was with all channels driven, and at what frequency range, and at what distortion level. A typical rating might have been 100 watts per channel, with both channels driven from 20hz to 20Khz at .01% distortion. Most brands rated their power within this specification criteria to make it easier for consumers to compare.
We are seeing the wild west appear again in power ratings. You really have to read the fine print to determine if the stated power is real or not. The brands are still doing what the FCC requires, but printing ratings do not apply to real life. One of the easiest frequency ranges to push with an amplifier is 1000hz. We see some brands rating their power at 1000 Hz instead of the entire audio range of 20hz to 20,000 Hz. We also find power rated at only one channel driven, instead of all 5, 7, or 11 and we see very high distortion numbers on the spec. What may read like a 100 watt per channel receiver may actually be only a 30 watt per channel unit if you measure it with all channels driven, across the whole frequency range, and at a normal distortion level.
Why is this important? Movie soundtracks can be extremely dynamic. This means they could jump from a whisper to a loud crash in a split second. To deliver those great dynamics, your power source (receiver typically) needs to be able to handle those transient power demands. Being able to do 100 watts at 1000 Hz does you no good when you want to capture the sound of an explosion, you need the full frequency range. It's even more important now with Dolby Atmos. In the past, the power needs of the surround speakers were somewhat minimal, but with Dolby Atmos, those surround speakers now get big, full-range sound, and at the same time as all of your other speakers.
You want to get a receiver that has a big power supply. This is the part that provides power to all of the components inside the receiver. The bigger the power supply, the better the receiver will handle the dynamics of a movie.
Audio Advice Tip: If you don’t want to try and dissect all the power ratings, just look up the total weight of the receiver. If it's heavier than 20 pounds, it probably has a decent power supply and a pretty good amplifier section. Just be very leery of components quoting a lot of power (over 100 watts) that are lightweight because they will likely not sound very good. There may be some instances where the receiver has a very good Class D amplifier section, which could weigh less, but it's hard to tell good from bad. The even better solution is to call or chat with our experts at AudioAdvice.com. As you might imagine, since we live and breathe audio and home theaters, we already know which products have inflated specifications and which actually conservatively rate them. So our experts can make sure your receiver has the necessary power for your particular home theater.