The heart of your system, your Audio/Video Receiver filters the input signals from your computer, phone or TV and forwards the enhanced audio signals out to all of your speakers along with a healthy dose of power from the built in amplifier. When picking out a receiver you want to be wary of a number of things.

How Many Speakers Will You Have?

First and foremost, how many speakers do you need to hook up to it? If you’re only try to listen to music through a stereo system (two speakers) then a cheaper stereo receiver may be all you need. The most common A/V receivers are 5.1 channel (two front speakers, center speaker, two surround speakers and a subwoofer), though a full surround setup with two side and two rear surround speakers requires a 7.1 capable receiver. The 5 and 7 are the number of speakers in your setup, while the 1 after the decimal point describes the number of subwoofer connections. A 2.1 system will have two front speakers and a subwoofer and is the optimal setup for listening to music in the vast majority of cases.

A 5.1 receiver is recommended for home theater setups unless you have a dedicated theater room which could house a 7.1 system (four surround speakers). If you plan to watch movies with full surround sound and a complete set of Atmos height speakers then you’re going to need a much higher end and more expensive 11.2 receiver. One final caveat is that if your speakers are bi-amp capable (generally only on higher-end equipment) and you plan to take advantage of that then your front speakers will eat up two channels each, meaning you need a bi-amp capable 7.1 receiver for a bi-amped 5.1 setup.

Impedance

The next thing to think about is speaker impedance. Most modern speakers are 8 ohm impedance, but there are still those that run as low as 4 ohm, especially if you’re using grandad’s speakers from before the war. A 4 ohm speaker will draw a significantly higher current, burning out your receiver if it isn’t designed for the occasion. Most budget oriented receivers only support 6-8 ohm speakers, so make sure to check the impedance of any speakers you plan to use before making your final purchase, and read the manual to ensure you set up the receiver and speakers correctly for the impedance.

HDCP 2.2 for 4k Video

If you’re buying a receiver to watch 4k content on your TV you need to make sure the HDMI ports are HDCP 2.2 compliant, a standard to which all new 4k content is encoded. Otherwise you’ll end up making another receiver purchase in the near future when you can’t watch any of your favorite new movies. Be careful for older receivers on the cheap that are marketed as 4k capable but which aren’t HDCP 2.2 compliant, you don’t want these if you plan on watching anything through them. Many receivers have a few compliant ports mixed in with the others, so make sure you have enough HDCP 2.2 ports to run all your 4k devices.

Wattage – Less Important Than You Think

Wattage is another consideration. Having a larger amplifier is great for some reasons, but in general it isn’t as important as many people seem to think. Contrary to popular belief, a high wattage amplifier is actually less likely to blow your speakers out, and that’s where the main advantage lies.

If you actually have your music turned loud enough to overload your receiver’s capabilities (you won’t, you’ll likely go deaf first) then chances are it will start clipping signals. Normal audio signals are sinusoidal, like a gentle wave. When clipping occurs, the signals can be corrupted and square-off, causing your speaker drivers to undergo harsh periods of acceleration. This is when they ‘blow-out’ (a catch-all term for ‘ya dun goofed and it’s broke’).

If you really insist on shopping your receiver for the highest power output, make sure you’re comparing power at the same impedance, over the same frequency range, with the same number of channels driven. It’s very easy to produce high power numbers when running a single 4 ohm speaker (higher current from lower resistance means higher power draw) at 1kHz as compared to a pair of 8 ohm speakers over the whole 20Hz-20kHz range. Look for specs with two-channels driven at 8 ohms from 20Hz-20kHz, and make sure the THD (Total Harmonic Distortion) spec is as low as possible (under 0.1%).

Sound Qualities

Finally, different brands of receivers have different Digital Signal Processing and room correction software, with the higher end models having significantly more sophisticated control and accuracy. Beyond the software’s limitations, different processing boils down to different sound qualities being enhanced.

One receiver might be described as eliciting a ‘bright’ sound as opposed to, say, a ‘warm’ sound. This topic is much more subjective than just looking at specs, so you really can’t do much besides read other people’s reviews of the product you’re looking at or test it out yourself.

In reality any receiver is going to be fine, but if you become a true audiophile down the road the model of your receiver really can make a difference in the sound. There are also options within most receivers to try and change the qualities that are emphasized. Ideally your receiver’s qualities will work well with your speaker’s to create a pleasant sound that isn’t tiring to listen to and is pleasing to the ears.

Which Receivers Should I look At?

In terms of what to buy, Denon is a receiver brand that is highly recommended by many individuals raving all over the internet, with the X1400 and X3400 being a common starting point, while I personally have owned two Yamaha receivers (RX-V483: 5.1 and RX-V683: 7.1) and enjoyed both of them. The online retailer Accessories4less often has incredibly low prices on manufacturer refurbished receivers, so check them out if you have the chance.

One final note, the volume on your receiver will likely be displayed in negative decibels. This is the relative volume level compared to the reference level. In order to know the true sound level in your room you need a sound meter to read the dbA level. Prolonged periods of 80+ dbA listening are ill advised as they can cause hearing loss over time. Take a look: Dangerous Noise Levels