How to Choose an AV Receiver

The AV receiver is the switchboard of a home theater: every source plugs into it, it decodes the audio, drives the speakers, and passes video to the display. It is also the component with the most confusing spec sheet, where a "150 watt" receiver can deliver 50 watts and an "11.2 channel" unit can power only nine speakers. This guide explains what the numbers mean so you can match a receiver to your room, your speakers, and your plans for both.

Channels: processing versus amplification

A receiver's channel count is written as three numbers, for example 7.2.4:

• The first number is the count of ear-level speakers (front left, center, front right, surrounds, rear surrounds, and wides).
• The second is the count of subwoofer outputs. Two outputs are common; on most receivers they carry the same signal, though some higher-end units process them independently.
• The third is the count of height or overhead speakers for Dolby Atmos and DTS:X.

Common configurations:

The catch is that the channel count in the marketing name is the number of channels the receiver can process, not always the number it can amplify. A receiver sold as an "11.2 channel" unit frequently has nine amplifiers. To run all 11 speakers, you connect an external two-channel amp to the receiver's pre-outs for the remaining pair. Read the spec sheet for "amplified channels" or "power amp channels" separately from "processing channels."

Power ratings, read honestly

Watts are the most abused number on a receiver box. Here is what a legitimate power rating looks like and what each part means:

"100 watts per channel, 8 ohms, 20 Hz to 20 kHz, 0.08% THD, two channels driven"

• 8 ohms is the load. Ratings at 6 ohms will look higher; ratings at 4 ohms higher still, but only if the amp can actually sustain it.
• 20 Hz to 20 kHz means the rating holds across the full audible band. A rating at "1 kHz" only tells you about a single test tone and inflates the number.
• THD (total harmonic distortion) is the distortion at the rated power. Anything under 0.1% is fine. A rating at 10% THD, which appears on some spec sheets, is clipping and meaningless.
• Two channels driven is the standard test condition and the important caveat. With all channels driven at once, the shared power supply sags. A receiver rated 100 watts with two channels driven may deliver 55 to 70 watts with five channels driven and 40 to 55 with seven. Independent bench tests publish "all channels driven" numbers; manufacturers rarely do.

The good news is that you need less power than the spec-sheet race implies. Doubling amplifier power gains only 3 dB of output. Going from 50 to 100 watts is a modest, audible-but-not-dramatic difference. What matters more is the combination of amplifier power, speaker sensitivity, and listening distance.

Impedance and sensitivity

Two speaker specs determine how hard the receiver has to work.

Sensitivity is how loud a speaker plays with 1 watt of input, measured at 1 meter. Typical home speakers range from 84 dB to 92 dB. Every 3 dB of sensitivity is equivalent to doubling the amplifier power. A 90 dB speaker on a 50 watt receiver plays as loud as an 87 dB speaker on 100 watts.

A quick worked example for a THX reference level of 105 dB peaks at the seat:

• A speaker at 88 dB sensitivity, 3.5 meters (about 11.5 feet) from the seat, loses roughly 11 dB to distance in a typical room.
• To hit 105 dB peaks, it needs 105 minus 88 plus 11, which is 28 dB above 1 watt, or about 630 watts.
• That is unrealistic from any receiver, and it is why almost no home system actually reaches THX reference peaks at every speaker. A 95 dB target, which is still loud, needs 95 minus 88 plus 11, which is 18 dB above 1 watt, or about 63 watts. Most systems live in this range.

Impedance is the electrical load the speaker presents. Most home speakers are nominally 8 or 6 ohms. Some, especially larger towers, are nominally 4 ohms and dip lower at certain frequencies. A 4 ohm load draws twice the current of an 8 ohm load at the same voltage, and many receivers cannot supply it without overheating or going into protection. Check that the receiver's rated impedance range covers your speakers. If your speakers are 4 ohms, look for a receiver that is rated for it, or plan on an external amp for the front three.

HDMI 2.1 features

Video capability matters as much as audio because the receiver sits in the signal path. The HDMI Forum's 2.1 specification brought several features that a home theater receiver should support on at least some of its inputs:

• 4K at 120 Hz for gaming consoles and PC gaming. Needs 40 Gbps of bandwidth for 4K120 with 10-bit HDR and full 4:4:4 chroma, or 48 Gbps at 12-bit.
• 8K at 60 Hz, mostly future-proofing, since 8K sources are rare.
• eARC (Enhanced Audio Return Channel), which carries full-bandwidth audio, including lossless Dolby TrueHD and DTS-HD Master Audio with Atmos and DTS:X, from the TV back to the receiver. Original ARC was limited to compressed 5.1. If you use the TV's built-in apps, eARC is what lets the receiver decode their audio properly.
• VRR (Variable Refresh Rate), which lets the display match the game's frame rate to eliminate tearing.
• ALLM (Auto Low Latency Mode), which switches the display into game mode automatically.

Count how many HDMI 2.1 inputs the receiver has, not just whether it has "HDMI 2.1." Some units put full 48 Gbps bandwidth on only one or two inputs and 18 Gbps on the rest. The HDMI cables guide covers what bandwidth each format needs and which cables carry it.

Room correction

Every mid-range and higher receiver includes a room correction system. You plug in the supplied microphone, place it at several seat positions, and the receiver plays test tones and measures the response. From that it computes:

• Speaker distances and delays, so sound from every speaker arrives at the seat at the same time.
• Channel levels, so each speaker plays at the same volume.
• Crossover points, deciding which frequencies go to the sub versus the speakers.
• Equalization, a set of filters that flatten peaks and dips in the measured response.

What it fixes well: distance, level, and the broad tonal balance of each speaker, plus the biggest bass peaks caused by the room. A properly run correction pass is the largest single improvement most systems can get for zero additional cost.

What it does not fix: deep nulls caused by cancellation (you cannot EQ a null, adding power just adds power that cancels), poor speaker placement, reflections and reverberation, and the fundamental character of a bad room. Room correction is the last step, applied after speaker placement and treatment are right. See acoustic treatment basics and check your room's problem frequencies in the room modes calculator before relying on EQ.

Pre-outs

Pre-outs are line-level outputs, one per channel, that carry the processed signal to an external power amplifier instead of the receiver's own amps. They are the most important upgrade path feature on a receiver, for three reasons:

1. Adding channels. The "11.2 channel, 9 amplified" receiver described earlier needs pre-outs to power the last two speakers.
2. More power for the fronts. The center channel and front left/right do most of the work. Running those three on a dedicated 150 to 200 watt amp, and leaving the receiver to drive the surrounds and heights, relieves the receiver's power supply and improves dynamics across the board.
3. Future separates. A receiver with a full set of pre-outs can eventually become just a processor, with all amplification external, without being replaced.

Entry-level receivers usually have only subwoofer pre-outs. Mid-range units add front left/right, or the full set of 7 to 11. Look for the full set if you intend to grow the system.

Atmos, DTS:X, and formats

Any current receiver with height channels decodes both Dolby Atmos and DTS:X, along with their lossless carriers (Dolby TrueHD and DTS-HD Master Audio) and the lossy versions used by streaming (Dolby Digital Plus with Atmos). Also check for:

• Upmixers (Dolby Surround, DTS Neural:X) that send stereo and 5.1 content to height speakers. These are used far more often than native Atmos content.

For placing height speakers and choosing between in-ceiling and up-firing modules, see the Dolby Atmos setup guide.

Streaming and multi-room

Almost every receiver includes built-in streaming (an integrated music service platform, the major wireless casting protocols plus Bluetooth) and a network connection. The differences are in multi-room: a Zone 2 output lets the receiver send a second source to a second room, either as line-level pre-outs (needs an amp in that room) or by reassigning two of the receiver's own amplified channels. If you reassign channels, they are taken from your main system, so a 7.1 receiver with Zone 2 active becomes a 5.1 receiver.

Recommendations by room and system

These tiers are about matching capability to need, not spending the most possible.

Small room, 5.1 or 5.1.2, seat within 9 feet

A 7 channel receiver with 70 to 90 watts per channel (two channels driven, 8 ohms, full bandwidth) is plenty. Look for eARC, at least one 4K120 input if you game, and a basic room correction system. Full pre-outs are nice but not essential. Pair it with 86 to 90 dB sensitivity speakers of 6 to 8 ohms.

Medium room, 5.1.2 to 7.1.4, seat 9 to 12 feet

A 9 or 11 channel receiver with 90 to 120 watts per channel and a full set of pre-outs. At this distance and speaker count, the shared power supply matters, so favor a heavier unit with a larger transformer over a lighter one with a higher printed wattage. Room correction with multi-subwoofer support and a desktop editing app pays off here. Two or more 4K120 inputs.

Large room, 7.1.4 or beyond, seat over 12 feet, or 4 ohm speakers

An 11 or 13 channel processing receiver with full pre-outs, plus a 3 or 5 channel external amplifier for the front stage. Or skip the receiver and go to a dedicated processor plus amplifiers. At this scale the receiver's amplifiers become the bottleneck, and the pre-out architecture is what lets you fix it. Independent multi-sub bass management, 12-bit 48 Gbps on every input, and 4 ohm stability are the boxes to check.

Once you have narrowed down the receiver, the home theater budget guide shows how it fits with the rest of the system, and the speaker wire gauge calculator covers the cable runs to each speaker.