Triad InWall Bronze/4 SlimSub Review

In-wall subwoofer offers deep frequency response and aesthetic invisibility. 9/20/2013 1:09 PM Eastern


Over the past couple of decades, we’ve witnessed the transition of the full-bandwidth, multi-channel movie theater experience into living rooms all over the world. The standard for even modest home entertainment systems has been 5.1 surround, and now many homes feature sophisticated 7.2 home theater systems presenting even the low frequencies in a stereo image. Family movie night is now an exciting tour-de-force that is rapidly catching up with the movie theater experience. One result of this democratization of experiencing media in a robust, vivid, and exhilarating way is that expectations have begun to rise along with the extended capacity for delivering the thrill of dynamic, high-quality audio. It’s fair for business executives to expect that the audio in their boardrooms will at least be in league with what they experience at home, which they expect, in turn, to be in league with what they experience at the movie theater or amusement park with their families. During the same time that audio performance has increased for the average home (and the average office), visual aesthetics have entered the consciousness of those who will experience the sound. It probably won’t come as a surprise that some of the make-it-invisible solutions will come from the residential custom market.

Indeed, a higher level of success has been reached if the excellent sound appears at our ears magically, with not a visible loudspeaker in sight. Numerous manufacturers work hard to develop in-wall loudspeakers to deliver that very experience. Triad is one such manufacturer, set apart by some uncommon characteristics: nearly all of its models are manufactured in Portland, Ore., and they’re built in batch sizes literally as small as one unit. Triad maintains virtually no inventory—choosing rather to operate lean and mean, building speakers as they’re ordered. In my opinion, this is very positive, since each speaker is being built for a customer with a name and a story—not just to be delivered to a warehouse for purchase by some nameless, faceless buyer. I believe that a little extra TLC goes into construction as a result of this method.

Another positive result of this process is that a speaker’s finish can be customized based on a color sample provided by the client. One fact that truly lifted my eyebrows about Triad’s manufacturing is that it will build speakers in cabinets with dimensions specified by the customer. Considering the quality-oriented mindset of this company, I expected big things, and I was not disappointed.

I spent time with Triad’s latest offering of in-wall subwoofers: the InWall Bronze/4 SlimSub. It’s the slimmed-down version of Triad’s Bronze/6, for installation in buildings constructed with 2x4 and not 2x6 studs. The installation process is much simpler than I had expected. I’m very fond of the mechanism, which essentially clamps the drywall between the speaker’s grillee frame and adjustable retro brackets that extend from the speaker enclosure. Contractors will truly appreciate the simplicity and brevity of the install. The enclosure itself is very sturdy—formed of MDF and heavily braced internally. It’s not light—20lbs., which is not a problem since it’s not going anywhere once installed. Some of the weight is accounted for by the speaker’s magnet, but it’s clear that the construction is substantial, which I strongly prefer. The driver is 10in. in diameter, with a proprietary aluminum cone suspended in a rubber surround. It exhibits a substantial throw and can really move some air.

Any appropriate amplifier looking for 4Ω impedance can be used to power this speaker, but the manufacturer strongly recommends the use of its RackAmp 350 DSP amp, and with good reason. The amp has equalization and limiting tailored specifically for Triad’s InWall Bronze subs. It is impedance-matched (and can drive a pair of optional 8Ω Bronze/4 SlimSubs in parallel for a total impedance of 4Ω), and it also features boundary compensation EQ curves for in-room, mid-wall, and corner orientations, delay and phase angle time-alignment tools, and Linkwitz-Riley crossovers. There are password-protected contractor controls that go beyond the fundamental end-user level controls, as well. A computer with a browser can be used via IP to gain even more advanced control over configuration, including the establishment of a flat response by shooting the room with an RTA and making adjustments to the unit’s six-band parametric EQ, among other things. Two of the amp’s six presets can be set up this way, giving the end-user two more easy-to-recall configurations with distinct EQ and level settings.

Installation of the Bronze/4 SlimSub is simple and configuration is also easily accomplished. But how does it sound? I used it in both 2.1 and 5.1 configurations, and listened to a broad range of content, ranging from a multitude of music genres to spoken word, including audio from PowerPoint presentations and training videos. The one word I would use to characterize the output of this subwoofer is “deep.” No funny business with the published frequency response here. Short of actually taking an objective measurement in an anechoic chamber, I’d bet a paycheck that this thing really is delivering perceptible bass down at 20Hz. The response curve is probably tapering off pretty steeply at that point, but as we get up into the domain of 30Hz and above, it’s all there. At higher SPLs, this creates some pretty dramatic fullness, but in my opinion, the real magic is what happens at lower SPLs—a much greater sense of the full spectrum. As Fletcher and Munson showed, we perceive lows and highs as much quieter than mids, so they tend to sort of disappear when we turn down the volume—hence the “loudness” circuits introduced in the hi-fi technology of yesteryear. The extension of the flat part of the Bronze/4 SlimSub’s spectral plot down into the nearly no-longer-sound-but-earthquake domain helps to compensate for this diminished perception, and fills in the bass even when we listen at low volumes—and this is a real treat.

A word of caution—and I discovered this while putting the Bronze/4 SlimSub through its paces—using this subwoofer in a boardroom environment where there are live microphones creates an uncommon possibility that may be new to a lot of AV techs: feedback in the deep bass. Not only does the speaker’s extended and flat response contribute to the issue, but the fact that low end is largely omnidirectional doesn’t help either. We can orient our tweeters and mics in such a way to reduce the acoustic coupling of high frequencies and hence feedback in that range, but omnidirectional boardroom mics and omnidirectional bass complicate the issue a bit. The obvious and simple solution is to apply the HPF that most of our mixers offer to eliminate wind rumble in exterior applications. Triad’s RackAmp offers its own built-in solution, a sub high pass filter with which you can specify low-frequency extension. I recommend to be prepared for this if you install a boardroom sub that extends down deep.

Can the Triad Bronze/4 SlimSub in-wall subwoofer deliver the same thrill we get at the movies or in our decked-out living room home theater? Absolutely it can. It is used in home theater, and delivers the goods there too—rivaling or even surpassing movie theaters. And as to aesthetics, even with the included flush grille, it’s very unobtrusive, particularly if it’s painted to match the wall into which it’s installed. Triad also spells out a means by which the grille frame can be eliminated, and by the use of acoustically transparent grille cloth that can be painted the color of the wall, the install can be rendered virtually invisible. That’s the kind of magic we love—excellent, high-quality audio evidently emanating from thin air. Triad does indeed offer very high-quality products, and they’re not inexpensive, but there will always be clients who are willing to invest substantial money to achieve excellence. I would definitely put the Triad Bronze/4 subwoofer on the very short list for such clients and applications.



Pros: Virtually invisible, high-quality, high-SPL low-frequency reproduction

Cons: Priced above typical industrial in-wall subwoofers

Applications: Boardrooms, offices with extraordinary audio requirements

Price: $1,400 (including RackAmp 350 DSP amp)



Driver: 10in. proprietary aluminum cone woofer

Impedance: 4Ω

2pi Frequency Response: 20Hz – 250Hz (±2dB)

Enclosure Dimensions (WxHxD): 13½’’x19’’x3 15/16’’

Grille: Acoustimesh metal


RackAmp 350 DSP Amplifier:

Output Rating: 350W @ 4Ω

Five User Selectable Preset Modes: Reference, Cinema, Night, THX, Custom1, Custom2

Installer Setup Menu Options: Slope for all filters (6-36 dB/oct); multiple control options: 5V – 20V trigger, IR with discrete controls; auto-sense: adjustable trigger voltage, adjustable off delay; optimize multiple subs: input gain matches levels, delay time aligns subs

Dimensions (WxHxD): 19’’x1 ¾’’x14 ¼’’ (1RU)

Boundary EQ Modes: InRoom, MidWall, Corner

Room EQ: Six-band parametric; 5Hz resolution; Cut/boost -12dB to +3dB; Q 0.3 to 10

Setup Modes: Plug-and-play; front-panel menu setup; advanced setup via IP

DSP on Line Outputs: Delay; Linkwitz-Riley crossover (6-36dB/oct)

Power/Control Options: Auto-sense; Low Voltage Trigger, IR, Manual


John McJunkin is the principal of Avalon Podcasting in Chandler, Ariz., and produces and co-hosts a top-rated morning radio talk show in Phoenix. He has consulted in the development of studios and installations and provides high-quality podcast and voice production services.


Want to read more stories like this?
Get our Free Newsletter Here!
Past Issues
October 2015

September 2015

August 2015

July 2015

June 2015

May 2015

April 2015

March 2015