Can You Get Audiophile Two-Channel Sound from Home Theater?

Are you happy with the sound of two-channel music played back in your home theater? It’s not unusual for even a high-quality home theater to deliver less than stellar stereo or 2.1-channel music performance, leading some audio enthusiasts to believe that you have to choose whether you want great stereo playback or a powerful and immersive theater experience. Having both in the same system is a mythical holy grail, always just out of reach. Or is it? Audioholics founder Gene DellaSala recently made an informative video discussing some reasons why your home theater may not be delivering truly satisfying two-channel playback, and some ways to address those issues.

You Can't Get Great 2CH from a Home Theater?  - YouTube Discussion

Let’s dive into a few of the most common problems that Gene has seen during his career in the audio industry.

Bad Speaker Positioning

Speaker positioning can really make or break a two-channel audio experience. In a home theater, you have speakers all around you working together to create an enveloping sound field. And of course, your center-channel speaker ensures a stable and focused center image, no matter where your other speakers are located. When you’re listening only to your front left and right speakers, they are responsible for creating a phantom center channel so that vocalists and other sound sources that are centrally placed in the mix appear to be situated between the speakers with palpable realism. At the same time, your stereo speakers are tasked with recreating a wide and deep soundstage (depending on the recording, of course), so that your music doesn’t feel tied to the speakers themselves, or trapped in a two-dimensional slice of space between them. Proper speaker placement is required to create the illusion that there are musicians in your room, or that you have been transported to a recording studio or performance venue where music is being made.

AH Smarthome Theater Room - Front Stage w 150" Screen Innovations AT Screen

In Gene’s home theater (and in his family-room system as well), he has eschewed on-wall and in-wall speakers for his main left and right speakers, placing only the center-channel speaker behind the acoustically-transparent screen. While it’s certainly possible to achieve great sound using flush-mounted speakers for your whole front stage — particularly if your main focus is movie-watching — it’s extremely difficult to create a deep soundstage when your front speakers are all mounted to the front wall, and therefore all on the same plane. (If you do need in-wall or on-wall speakers that do an unusually good job at this, and you have plenty of cash to spend, check out Steinway Lyngdorf.) Using freestanding speakers allows you to adjust how far the speakers are placed from the walls, how far they are placed from each other, and the angles at which they are toed in. While there’s no way to tell you exactly where to place your speakers for optimum sound in your room, you can start by checking out our articles about room acoustics. Experimenting with speaker placement can be enlightening, and even fun. And if you don’t enjoy the process, you can appreciate that it doesn’t cost you anything but a little time. Even small changes to these parameters can have a significant effect on sound quality.

By bringing the speakers out into the room, you can definitely get an increase in the depth of soundstage that you just can’t get with your speakers behind a screen.

— Gene DellaSala

Excessive Room Treatment

Another likely culprit for compromised two-channel performance in a dedicated home theater is an over-treated room. Specifically, the use of too much absorption can make your two-channel audio sound dry, flat, and dead. When you’re surrounded by speakers, you might be tempted to add more and more absorption in order to reduce reflected sound and allow your speakers, rather than your room, to produce the sonic ambience. To a certain extent this approach makes sense; controlling reflections can improve dialogue intelligibility, and can help a Dolby Atmos system more precisely place objects within the 3D sound-field, for example. But too much absorption can make a room sound unnatural, and this effect is more noticeable when listening to just two speakers.

RBH Sound SVTRS Active Speaker System w Sonitus Room Treatments

Some reflected sound is actually required in order to make stereo work. Don’t believe me? Try setting up a pair of speakers outdoors and see how hard it is to achieve any kind of soundstage. If you’re technically inclined, you can use REW (Room EQ Wizard, a free software for room acoustic measurement) to measure your room’s RT60 (reverberation time) before and after applying treatment. RT60 decay time is a metric that describes the length of time taken for a sound to decay by 60 dB from its original level. Gene recommends shooting for something between 300 and 700 milliseconds. An RT60 decay time in this range should mean that there is enough reverb for two-channel audio but not too much for home theater.

The RT 60 decay measurement below was taken in the AH Smarthome theater room with the front speakers and subs playing at the main listening position. Notice how linear the response is for the entire bandwidth. The acoustical treatments in this room are furnished by Sonitus.

RT 60 Decay Time AH Smarthome Theater Room (approx 360 msec)

Every room has a specific balance of direct to reflected sound that will make the room feel natural to listeners. You need some absorption, yes, but also some reflections. Typically, you should only cover about 25% of wall surfaces with absorption. Exceed that amount and the room will start to sound too dead. 25% absorption means that 75% of the wall surfaces will still be hard, leading to reflections that could cause errors in sound clarity. You can simply break up these reflections with diffusers. They generate uncorrelated and random acoustic energy that sounds more like the pleasant reverberation of a concert hall and less like the annoying hard reflections you often hear in small rooms. The right balance of absorption, reflection, and diffusion results in a more pleasing sound field, with better envelopment, better imaging, and a wider sweet spot.

— Anthony Grimani, expert in home theater acoustics and design

Bad Subwoofer Integration

One common mistake that Gene sees when providing home theater consultations is that people concentrate so much on achieving flat bass response below 80 Hz that they forget to examine the combined response of the main left and right speakers with the subwoofer(s) when they’re playing at the same time. Users sometimes have delay times set incorrectly in their AV receiver or processor, or they have poor subwoofer positioning, or incorrect phase or volume settings on their subs. Any number of factors can contribute to flawed subwoofer integration. The result is often a deficit of sound in the crossover region between the speakers and the subs, yielding a noticeable disconnect between them. If you’ve ever heard a cheap home-theater-in-a-box satellite/sub system, you know how ineffective the combination can be without a smooth transition and seamless blend between speakers and subwoofers. Many frustrated users will simply turn off their subs and run their speakers full-range when listening to two-channel music (I always did this with my first subwoofer, a $200 Sony that I bought when I was in high school in the 90s). But a properly integrated sub will only enhance your two-channel audio experience, completely disappearing into the sound of your main speakers. The use of multiple subs can also smooth out the bass response within your room, allowing for a wider sweet spot and satisfying low-end in more than one seat. If you’re having trouble achieving the results you’re after, it may be worth consulting a pro like Gene (or a specialty AV dealer/installer like Audio Advice) to help you out.

AH Smarthome Theater Room w Tuscany Valencia Seating

Bad Seating Positioning

Unless you’re lucky enough to have a dedicated listening room, you may not have complete control over where to place your speakers and your furniture. That said, the location of your listening seat in relation to your speakers — and in relation to the walls — can have an enormous effect on sound quality. For example, it’s best not to have your seating off to one side, or pushed up against the back wall. Start by forming an equilateral triangle using your speakers as two points and your main listening position as the third. For example, if your speakers are 10 feet apart, your seat would be 10 feet from each speaker. If you find that the center image isn’t as rock-solid as you’d like, try moving your speakers a little closer together — maybe 8 feet apart instead of 10. Just make sure that your seat remains equidistant from the two speakers. Ideally, your seats should be located away from the back wall — ideally about 1/4 of the length of the room (ie. 6ft from the back wall in a 25ft long room). If you’re too close to the back wall, you’ll likely experience very uneven bass because of the standing waves that tend to form in that part of a room. These are just guidelines, of course. You will have to do some experimentation to find what works best within the limitations of your space.

Acoustically-Transparent Screen Tip

AH Smarthome Theater Room 150" AT Screen Framed out with Acoustic Treatments  and Center Channel

Gene also has a great tip for anyone wanting to maximize two-channel performance in a room with a large acoustically-transparent projection screen on the front wall. First, he suggests framing the screen and installing it off the wall by at least four inches, with the ideal distance being 8 to 10 inches for the best acoustic performance. Then, fill the space behind the screen (with appropriate cutouts for any speakers) with a dense foam, such as the memory foam commonly used in mattresses. This will provide effective absorption of reflections off the front wall and prevent the tympanic membrane effect of a vibrating screen. In Gene’s home theater, this relatively affordable memory foam installation worked better than the foam products commonly sold for absorption, resulting in more focused imaging when listening to two-channel audio.

Building a Home Theater Around an Existing Stereo

So far, we have been looking at reasons why you might not be getting great two-channel performance from your existing home theater setup, even if you have great home theater gear. But let’s flip the scenario for a moment. What if you already have a high-end two-channel system, and you want to find a way to build a home theater around it without sacrificing the two-channel performance that you already enjoy? Can a home theater and a two-channel system coexist in the same room? That’s precisely the question I received from Sharad, an audiophile who lived in my apartment building when I was in college. These days he is married, with two kids, and his family just moved into a new house. In his old place, he was lucky enough to have a dedicated listening space for his fairly traditional 2-channel rig in a spare bedroom. In the family room, he had a big TV and a soundbar. In the new house, the two kids are no longer sharing a bedroom. Instead, the TV and the stereo have to share space in the family room. This new family room was pre-wired for 4 in-ceiling speakers, plus two surround speakers in the back of the room. It is also located on the opposite side of the house from the kids’ bedrooms, making it ideal for late-night listening sessions after the kids go to sleep. It was not Sharad, but his wife, who suggested ditching the soundbar in favor of a “real” home theater built around the existing stereo system. Sharad agreed, on one condition: it must not compromise the sound of his beloved two-channel setup. He asked for my advice, and it turned out to be a pretty straight-forward job.

Sharad’s system included some high-quality electronics from Parasound. The preamp was the Parasound Halo JC 2 BP ($4,000). He had recently upgraded from an old Parasound A 21 power amplifier to the newer JC 5 ($6,500). He still had the A 21 sitting in a closet. His sources included a turntable with outboard phono preamp, an SACD player, and a streamer. For speakers, he had a pair of impressive floorstanders from Bowers & Wilkins (I think they were the 803 D3, but don’t quote me on that). He didn’t use a sub. Because his preamp included a feature called home theater bypass, building a home theater around this system was not only possible — it was fairly easy. Home theater bypass is fairly common on high-end integrated amplifiers, and it’s not unusual to see on preamps either. Basically, it is an input (RCA or XLR) to which you connect the front left and right preamp outputs from your AV receiver or processor. (This works with any AV processor, and any AV receiver that has preamp outputs.) When you select the home theater bypass input on your integrated amp or stereo preamp, the incoming signal from the AVR bypasses everything — the volume control, tone controls, etc. — and is sent straight out to the power amp. It allows the stereo gear to operate as normal, without any of the home theater equipment in the signal path, yet it also allows the AVR to control the main speakers’ volume (along with the rest of the theater system) when watching movies. So, everything in Sharad’s existing system remained the same — all of his interconnects and speaker cables remained untouched. He did have some gear to buy, including a 9-channel AV receiver with preamp outputs, four in-ceiling and two in-wall speakers from one of B&W’s more affordable custom-installation lines, and a pair of powered subwoofers from REL’s home theater line. His one big-ticket purchase was a center-channel speaker from B&W’s flagship 800 Series to match the towers serving up the front left and right channels.

Here’s how it all came together. The only source for the home theater is an AppleTV 4K, connected to the receiver via HDMI. A second HDMI cable connects the receiver to the TV. The receiver’s internal amplification is used to power the two surround channels and the four overhead channels for Dolby Atmos. The REL subs are connected to the receiver’s subwoofer outputs. The receiver’s center channel preamp output goes into the left channel of the old A 21 power amp, which now powers the new B&W 800 Series center speaker. (The A 21’s right channel is unused.) The preamp outputs for the AV receiver’s main left and right channels are connected to the home theater bypass input on the Parasound JC 2 BP preamp, which is of course connected to the JC 5 power amp. Sharad used the AV receiver’s auto-calibration system to set the necessary levels, distances, and crossovers. Now when Sharad wants to enjoy two-channel audio, he throws a heavy blanket over the TV to provide a little high-frequency absorption, and uses his stereo as he always has. He is happy to say that the presence of the AVR and its associated gear has absolutely zero negative effects on the sound of his stereo system. When it’s time to watch a movie or TV show, Sharad and his wife simply select the home theater bypass input on the stereo preamp, turn on the AV receiver, and enjoy sound quality that makes their old soundbar seem like a distant memory. The front left and right channels are routed through the preamp directly to the JC 5 power amp, allowing those B&W towers to shine in both systems. And because he repurposed his old Parasound A 21 amplifier to power the center-channel speaker, the whole front stage has plenty of power and a unified sound.

How to Change Audiophile's Mind Against 2CH Upmixing Music  - YouTube Discussion

Many old-school two-channel audiophiles believe that home theater gear and stereo systems can’t be enjoyed in the same room without compromising the performance of one or the other, but that’s simply not true. And some hardcore home theater folks might think that their surround systems can’t deliver compelling two-channel performance, but it doesn’t have to be that way! While there’s nothing wrong with up-mixing your two-channel content into more immersive formats if that’s how you want to enjoy it, doing so should be something you choose because you like it, not something you do because stereo music sounds bad in your home theater. So, are you happy with the two-channel audio experience in your home theater? Do you have separate systems in separate rooms, or have you found a way for two-channel audio and home theater to coexist? Share your thoughts in the related forum thread below.