Soundbars are incredibly popular because they adopt a form factor that works perfectly when paired with a screen. Simplified installation and setup as compared to a system based on separate speakers adds to the appeal. However, even high-end soundbar systems are limited in capability. Now consider the Theory Audio Design 5.2 system. Yes, it is obviously a soundbar. But it is a soundbar executed at a physical scale and with sound-making capability that puts it in a category of its own. This is a sound bar that uses carbon fiber cone drivers with compression-driver tweeters, which you’ll see in professional high-performance audio gear, but not in any soundbar you’ll find in a store.

Theory’s is a true active soundbar system where each component is precisely matched and integrates into a whole that exhibits exceptional fidelity. But it’s also a flexible system, with sizes to match 65”, 75” and 85” TVs and a range of multi-use on-wall speakers, standalone subs and in 2021, architectural speakers and subs. Tying it all together is the Theory Amplified Loudspeaker Controller, a 1RU high rack-mountable component that combines deep DSP capabilities with efficient amplification—just add the pre/pro of your choice. Theory Audio Design is CI (custom install) friendly, allowing you to build systems beyond the 5.2 channel configuration featured in this review.

Features and Specifications

This Theory Audio Design system contains four distinct products: the sb85 85” 3-channel soundbar, the sb25 on-wall multi-use loudspeaker (X2), the sub15 15” subwoofer (X2) and the ALC-1809 Amplified Loudspeaker Controller (ALC). Theory systems are configurable for use in a variety of residential and commercial applications including: Dedicated home theater, media rooms, gaming systems, 2-channel Hi-Fi, multi-room distributed audio and even outdoor installations.

Let’s have a look at what each component in this review system is capable of:

Theory sb85 Soundbar

It’s only “passive “in the sense that the amplification is not built in. But when powered by three ALC amplifier channels, it behaves like a finely tuned active system.

This soundbar sports six 5” carbon fiber low frequency drivers and three 1.4” polymer compression driver tweeters. Theory rates the power handling at 200W per channel (AES method), with a 4-ohm impedance. The soundbar’s rated frequency bandwidth is 58 Hz to 23 kHz with a maximum output of 117 dB per channel (over 124 dB all channels driven)—that’s loud enough to provide “reference level” playback, making this system suitable for dedicated home theater applications (at CEDIA I heard this soundbar demoed behind an acoustically transparent screen and you’d never know it was not standalone speakers making the sound).

This rock-solid soundbar weighs in at 72 pounds, so you’ll need a helping hand to hang it. Dimensions are 9.5" H x 75.3" W x 3.8" D.

Theory sb25 On-Wall Multi-Use Loudspeaker

These shallow speakers are ideal for wall-mount applications and share the same form factor as the soundbar but operate as standalone speakers. Like the soundbar, they are designed to be powered by the ALC and behave like an active system would, with a perfect match between amplification and the speaker.

This speaker is akin to a single channel on the soundbar, with identical specs for the drivers and overall performance. Weight is 27 pounds and dimensions are 21.5" H x 9.5" W x 3.8" D.

Theory sub15 In-Room Subwoofer

This is a ported sub with a 15” Theory driver featuring a 3” voice coil. The rated frequency bandwidth is 22 Hz to 125 Hz with 500W (AES) /1000 W (continuous) power handling. This subwoofer requires a dedicated ALC amp channel to drive it, just like the other speakers it acts like an active system when used with the ALC-1809 Amplified Loudspeaker Controller.

This subwoofer is spec’d to offer up to 124 dB of output. The sub weighs 76 pounds and the cabinet measures 21.3” H x 23.5” W x 19.8” D.


ALC-1809 Amplified Loudspeaker Controller

Tremendous power packed into a slim 1RU chassis. Not just amplifier power, although there’s 1800 watts (at 4 ohms) worth in there. Also, DSP power, including all the presets needed for an easy, automated installation, with deep configuration options available through the Configurator software using a laptop and a USB connection. All audio is processed at 24-bit/96kHz resolution.

The impressive power output capabilities are spread between nine total channels. Three subwoofer channels are able to output 300 W each. The speaker amps are 100 W each and bridgeable to 300 W (for use with speakers, not additional subs). Amplifier frequency response is 20Hz-20kHz, +/-0.2dB. Signal-to-Noise Ratio for channels 0-2 (subwoofer channels) is 108dB and 105 dB for the speaker channels.

Not only is the Theory ALC-1809 remarkably compact and powerful, it is also lightweight at 13 pounds.

ALC-1809 DSP functions:

Automatic Configuration of Surround System Settings
Loudspeaker Processing For All Theory and PRO Models
Input Trim
Signal Routing
Delay (up to 75msec per channel)
160 Parametric EQ Filters (20 per channel)
Automatic Audio Ducking for Audio Zone Paging
8 x 8 Parametric Bass Management (Bass Steering)
8 x 8 Matrix Mixer
Mono Summing: 8 Stereo + 4 mono Signals
Bass and Treble Controls
Master Volume
Clip Limiter
Internal Sine and Pink Noise Sources


This Theory Audio Design system is the first I have reviewed that eschews room correction based on measurements and instead calculates the appropriate system response based on speaker distances. The method is simplicity itself using measurements that you enter the Music and Surround Automator configuration software. All you need are the distances from each speaker to the listener and from each speaker to the wall and to the nearest corner.

For placement, the sb85 soundbar sat on an IKEA credenza, perfectly centered underneath my 110” projection screen. I’d guess most owners would opt for mounting the soundbar on the wall, but Theory will have an accessory if you use it freestanding. Since I rent and am only borrowing the unit, I took the freestanding route.

The two 15” Theory sub15 passive subs flanked the credenza and integrated perfectly. The resulting response, at least in my “typical”-size living room, is spot-on accurate versus the result I’d expect when manually tuning the system using measurements (either automated via Dirac/Audyssey, or manually with REW and parametric EQ). I’d consider this result miraculous, except that at the end of the day sound is physics, which means you can calculate and predict a system’s response, as long as you know enough about the speaker and the room.

The sb25 speakers flanked my sofa, acting as standalone surrounds. The Music and Surround Automator allows you to account for this during setup, the result is as promised and tuned to the space.

Once the system parameters were applied, I did something heretical… I ran Audyssey room correction on the AVR-X8500H. The theory being that if the Theory system setup worked, Audyssey would have little or nothing to correct. This turned out to be the case, for levels and distances and EQ. So, I turned Audyssey off and let my AVR act purely as a “transparent” pre/pro.

A key thing to remember is that you can build out a much more extensive surround system using multiple ALC-1809s and subs and speakers. 5.2 sounds amazing, but you could easily scale up to accommodate the latest pre/pros that offer 16-channel processing or more.

Hands-on Listening

I have little patience for mediocre performing systems. So, I restrict reviews to gear I have auditioned and am confident will provide the requisite fidelity to make the evaluation process exciting. With Theory Audio Design, I already knew what the system can achieve thanks to CEDIA demos. But, it’s only when I have a system in my home and set up where I’d normally have my system that I can subjectively gauge how well it performs, and gauge how it measures versus a speaker system set up using Audyssey room correction on the Denon AVR-X8500h AVR.

What I found is the Theory system’s in-room response is so close to what advanced room correction strives for (Dirac Live, for example) that there’s practically no difference in the resulting room response curves of the two approaches, as measured at the main listening position. I discussed this result with Paul, and he noted that since it is physics, the math should all work out so long as the room itself is not unusually large or small. I can verify this to be the case since the only adjustment I made to the software’s default settings was to increase the subwoofer level by 1 dB, thus tweaking it “to taste.”

What I found is that the Theory Audio Design 5.2 system can replicate the entire listening experience of my full-sized speaker system, after it’s been meticulously set up and calibrated. Whatever listening parameter you wish to discuss—be it soundstage and imaging (width and depth), clarity and lack of listener fatigue, surround envelopment, tight bass that exhibits different “textures”, treble that reveals layer upon layer, or an overall balance that’s a “textbook” house curve—this system brings fidelity that’s above and beyond what you’d get out of premium standalone speakers from popular brands (like Klipsch, Paradigm, Definitive Technology, etc.).

I’m thrilled to report that this system will render a soundfield that perceptually extend well beyond the bounds of the room. If it’s in the mix, it comes through—including a sense of depth to the front soundstage. And there was zero apparent cabinet coloration, no grain, no sibilance, no dynamic compression, nothing to spoil the illusion of a cohesive audio illusion, whether its music or movies or TV shows or games serving as the source.

Crucially, this system coalesces into a cohesive whole in the way you’d expect from an active system that’s been fine-tuned for optimal performance. You are never listening to the soundbar, or to the subs, or to the surrounds. You are hearing sound, coming from wherever it is placed in the mix. The panning and tracking is smooth and accurate, sounds don’t get “stuck” at a speaker because the speakers themselves are acoustically invisible, as you expect from high-end stereos, but here this effect is achieved in surround-sound.

One of my favorite movies is Star Trek: Into Darkness. It has a Dolby Atmos mix that is backward-compatible with 5.1 and I must confess, the amount of immersion I experienced with the Theory Audio Design system exceeded my expectations. Sure, it lacked the height effects of Atmos, but that could easily be added. The 5.1 experience was holographic in nature, the bridge sounds of the Enterprise existing in a psychoacoustic space that mimicked what you believe to be on screen. As with any good simulation, suspension of disbelief is achieved through fidelity.

Explosions test the ability of a home theater system to achieve reference output levels. And I can report that this system’s subs are hyper-detailed, delivering extremely nuanced texture. I could feel all the visceral sound effects found in movies, for example the intense battle scenes in The Outpost. Speaking purely from subjective opinion, I “felt” the sound from movies with greater nuance than other subs—some would call this effect “fast” but it’s better described as “accurate and free of distortion” Anyhow, it did not take huge blasts to get sound effects you can feel from this rig, the crunch of gravel in Mad Max: Fury Road’s opening was also visceral.

I can’t say I much missed Atmos with this system, there’s so much to enjoy about how good it sounds.

When I booted up Grand Theft Auto Online, the sound of the game world had the expansive ambience of a city, with a real sense of distance and direction to all the effects. It’s very helpful in gaming if the direction of sound effects is crystal clear, like with this Theory system.

For music, you can opt to run the system in stereo (2.1) and listen to the left and right channels of the sb85 soundbar with the subs handling bass. This works well, but since it’s a soundbar the channels are likely a little closer to each other than standalone speakers would be. However, if (like me) you use the Dolby Surround (or similar) upmixer, the entire system comes into play and does a remarkable job of widening and deepening the soundfield. This is achieved without compromising the integrity of the front soundstage, so I left it on for most listening.

The same combination of detail, depth and power that came across with movies and games is present when listening to 5.1-upmixed music on this 5.2 system. Put on live jazz and you’ll feel as well as hear the instruments. Grab some good electronic music like Liquid Stranger or The Orb and get lost in floating soundscapes plus subterranean soul-shaking bass drops. All delivered with a notable force and energy that you associate with live performances in spaces with good acoustics. The Tron Legacy “Disc Wars” playback test proved the point, the Theory Audio Design 5.2 system did not diminish it in any way, it delivered the full force of the London Symphony Orchestra and the subwoofer-crushing barrage of electronic bass from Daft Punk that a lot of systems choke on. It’s nothing short of a miracle how much power the ALC-1809 puts out, and yet the sound is clean, transparent, free of coloration or grain or distortion.


“Theory Audio Design has built the world’s finest soundbar system” is the only reasonable conclusion I could arrive at after a thorough audition. From build quality to sheer audio output capability, you won’t find another soundbar system that delivers reference-level output with the fidelity of a high-end speaker system.

The form factor chosen by Theory Audio Design makes it possible to have a reference-capable surround-sound system that takes up minimal space and is easy to configure for optimal performance. The system is just a part of a line of products that is expanding and is usable for many residential and commercial applications. This is a simple system, just two speakers, a soundbar, a couple subs and the remarkable ALC-1809 Amplified Loudspeaker Controller. And yet it is one of the finest sounding systems I’ve reviewed, regardless of channel count. It’s a Top Choice for anyone seeking the ultimate soundbar system, or who is interested in the fresh approach to getting great sound taken by Theory Audio Design and Paul Hales.