How to Use an AV Receiver to Add Surround to a 2-Channel Setup

There’s a surprisingly wide range of preferences among audio-video fans. I’ll categorize them here into two broad groups: classic 2-channel audiophiles and home theater fans. Not that these groups don’t overlap. They often do. But there are listeners in each group who don’t intersect with the other. That’s mostly true of 2-channel fans, who often dismiss anything involving video or surround sound. There are certainly surround-for-music enthusiasts, but they’re a minority. Attend any hi-fi show and you’ll rarely experience music in surround. And while more surround music sources exist than you might imagine, it’s swamped by the tsunami of 2-channel-only recordings.

The 2-channel audiophile (again, with exceptions) isn’t typically a film fan, or at least is likely to satisfy what interest he or she has in movies either in a theater or on a 2-channel TV setup at home. In many cases the latter involves hearing the film over the TV’s internal audio. Yes, you can route film sound from your TV to your main 2-channel speakers, but that might not always be easy to do. And there’s often no convenient way to do it and also add a center speaker, surrounds, and a subwoofer or two for surround on films.

Yes, you can replace your existing electronics, or at least a 2-channel preamp, with a surround sound A/V receiver or pre-pro and a multichannel amp. But that’s likely to not only be pricey but also risk audio withdrawal and/or exile from your 2-channel social media group. A less drastic solution involves adding an affordable A/V receiver (new or used, as long as it offers preamp outputs for the left and right front channels), plus possibly a modest Blu-ray player, a pair of surround speakers, and the now or later option of a center channel speaker and one or two subwoofers.

I’ll limit the discussion here largely to the addition of the AVR and a pair of surrounds. The latter can be modest and don’t have to precisely match the timbre of the fronts. The A/V receiver should offer the number of on-board amps you anticipate either now or later for the added channels beyond your 2-channel setup; I’d recommend three as a minimum (two surrounds and a center, even if the latter isn’t added immediately). The power rating for the receiver amps’ output matters little if you never plan on adding a center, but I’d recommend at least 100 watts per channel for an average-sized room if a center is in your present or future plans (the center speaker, as it’s commonly mischaracterized, is not just for dialogue).

In this arrangement the 2-channels of audio amplification currently serving the main 2-channel speaker setup are unchanged for 2-channel listening. (The connections for its current sources remain plugged into the main channel’s preamp/amp or integrated amp). When listening to a 2-channel source, the receiver and extra speakers can be powered off.

The left and right analog preamp outputs of the receiver should be connected to an unused set of L/R inputs on the 2-channel preamp or integrated amp that drives the existing L/R, 2-channel speakers. The new, added speakers (surrounds plus possibly a center channel and/or subs) should be connected to the similarly designated amp outputs on the A/V receiver.

New surround sources should all be connected to appropriate inputs on the A/V receiver. The latter should be set up using the level matching settings found in all AVRs. Set the preamp/amp driving the main L/R speakers to the input connected to the AVR so that the main L/R levels are included in this level calibration process. When listening to 2-channel music without surround you can reset the main preamp/amp level control to whatever volume level is needed, but always return it to the setting used in the level calibration process when the AVR is engaged for surround sound. In surround use the overall level will be set at the AVR.

Also set the configuration controls on the AVR to appropriate settings. When using a center and surrounds, if you set the left and right channels on the AVR to full range and the center and surrounds to 80Hz (or the bass rolloff frequency of your choice), all of the bass below 80Hz will be directed to the presumably more bass-capable left and right front 2-channel amp and speakers. If you’re also using a subwoofer connected to the AVR, set the subwoofer output to on and all of the other speakers settings to 80Hz, or whatever crossover frequency you select. This will send all of the bass to the subwoofer, even the bass that would otherwise go to the left and right main front speakers if no subwoofer were involved. I don’t recommend setting the left and right speakers to full range when a subwoofer is also engaged; this won’t harm anything but it will mess up the bass room modes and likely produce inferior results. Note that when you turn off the AVR in this setup and use only the main L/R speakers and their resident amps for 2-channel playback, the left and right speakers will handle the bass and the subwoofer will be silent. Some 2-channel audiophiles might prefer this for 2-channel music listening, particularly if the subwoofer isn’t overly accomplished.

(The setup described here can instead be configured to engage the subwoofer at all times, with and without the AVR in the chain. But this can be complicated to do properly as most 2-channel preamps or integrated amps don’t offer subwoofer outputs, and if they do they can’t always filter the audio going to the main speakers so that only the subwoofer handles the bass.)

The sources available for surround sound using this setup will include either a disc player (preferably Blu-ray) and/or streaming. Since most video streaming devices are either enclosed within the TV or designed to be connected directly to a TV’s HDMI input, sending the audio from there to the AVR will require that both the TV and the AVR offer ARC (audio return channel) or better yet, eARC. The latter offers superior (lossless) audio. Most new AVRs offer ARC or eARC, but many older ones do not. Ditto older TVs.

If you can’t use streaming, a relatively basic Blu-ray player is a viable alternative if films will be your primary surround source. Don’t have a large collection of video discs, or don’t want to buy them? Check your local library. Mine, in a town of under 15,000, offers hundreds of movies on disc for free checkout.

One other downside here is that if your add-on AVR offers room correction, that can only be employed with the AVR engaged and on AVR-connected sources. Only the rarest of 2-channel amps and preamps offer any type of room correction, since most 2-channel enthusiasts avoid complex audio processing.

Sound & Vision

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