When shopping for a 7-channel amp or AV receiver, one of the key things to look at is the power specs. This long string of numbers, symbols and terms is often difficult to decipher, and even harder to compare between brands. Furthermore, many manufacturers get creative with what they list and how they list it in order to hide the unit’s deficiencies. To avoid these tricks of the trade, watch for these features in the amp power specs list.
The power output will feature a long set of numbers and terminology, but the one spec that you want to check for is whether or not the power rating is continuous. Continuous power refers to the receiver’s ability to consistently push out the amount of power listed all day long without overheating, shutting down or damaging the unit. This may also be called RMS power.
This is in contrast to “Dynamic” power, “peak” power or “IHF” power. These ratings refer to the unit’s ability to output the rated amount of power over a short period of time. This is important information to know, since most soundtracks and music doesn’t need the full rated power all of the time. However, when making the final judgment call, the continuous power is the one you want to pay attention to the most. If it’s not listed, keep shopping.
Speaker impedance (resistance) is measured in ohms and when you’re buying a receiver, you’ll want to see how it performs with your speakers. Some AV receivers aren’t able to power 4 ohm speakers without damaging them, or they receiver may simply not perform particularly well with 4 ohm speakers. If an amp or receiver doesn’t list the power output rating for your speaker type, you may want to try a different model.
Stereo vs. Surround
The amount of speakers being driven by an AV receiver affects the overall power output. For that reason, the power output rating for a stereo system with only 2 speakers will be drastically different than the rating for a surround sound system with 5 speakers. Make sure that the manufacturer lists both, and if they don’t, take the stereo rating with a grain of salt.
Total Harmonic Distortion (THD)
Not all specs list the THD, but this is an important rating. THD refers to how accurately the receiver can amplify sound and music. THD will almost always be below 1%, and the best receivers have THD levels below 0.1%. Without knowing the THD, it can be difficult to compare two models.
To give the most accurate snapshot of how a receiver performs, the rating should be given for a specific frequency range. This is usually expressed in a range of hertz, such as 20 Hz to 20 KHz. The wider the range, the better. If the power output is only rated for a single frequency, it’s impossible to know how it’ll perform with more dynamic soundtracks.
When it comes to buying an AV receiver, the more specs that are listed, the better. If a manufacturer decides to leave off a certain spec or rating, it usually means they are hiding something. Keep this in mind as you shop for the best AV receiver.