Reviews of Attainable Hi-Fi & Home-Theater Equipment

Reviews of Attainable Hi-Fi & Home-Theater Equipment

Elac IW-S10EQ measurements can be found by clicking this link.

It’s almost impossible to get smooth, natural bass reproduction without a subwoofer -- and this principle is easy to prove, despite the dominance of 2.0-channel systems in high-end audio. But a subwoofer is also the most troublesome component in audio: the most prone to distortion, the most difficult to place and adjust, and the most obtrusive. With its IW-S10EQ in-wall subwoofer, Elac aims to solve the latter two problems.


The IW-S10EQ combines an in-wall subwoofer with 10” cone and a separate, 400W RMS BASH amplifier; amp and sub together are priced at $1299.98 USD. In-wall subwoofers appeal to some because they take up no floor space -- all you see is a grille, usually painted to match the wall. But they have two downsides. First, installing them requires cutting holes in a wall and fishing wires through walls and floor or ceiling back to the equipment rack. Second, their performance is typically compromised because they’re mounted in a drywall enclosure of unknown volume, which makes it difficult to equalize them for optimal performance. (Some in-wall subs have an integral back box, which helps.)

Elac’s solution is Cabinet Volume Correction, probably the most sophisticated auto-equalization system ever created for an in-wall sub. The IW-S10EQ’s amp is controlled through a smartphone app similar to the one accompanying the Elac Adante SUB3070 standalone subwoofer, which I reviewed in June 2018. The app and amp address the problem of the sub’s designer’s not knowing the volume of the enclosure the woofer is mounted in, and thus being unable to optimize the sub for that enclosure.


As with the Adante SUB3070, the listener places the smartphone near the sub, then activates an automatic test sequence. To this procedure the IW-S10EQ adds two more automatic sweeps. The first measures the frequency response of the installed sub. The second sweep measures the response again, but with a resistor switched into the amp’s output. By processing the data from these measurements, and from the factory-supplied measurements of the sub outside its enclosure, the app can calculate the impedance of the driver in the enclosure, and thus the volume of the enclosure -- and the optimal correction curve for the amp to use.


The app then automatically runs a third sweep to find the sub’s response with the correction curve added, and to compensate for any inaccuracies in the smartphone’s internal microphone. Then, while sitting in the primary listening chair, the listener activates one final sweep so that the amp can calculate a correction curve that takes into account the acoustics of the room. The process may sound complicated, but it requires only two pushes of a button on the phone’s screen.

The IW-S10EQ app also provides the same eight-band parametric EQ found in the SUB3070’s app, with center frequency, bandwidth, and gain controls for each of the eight bands. Four EQ modes (Normal, Cinema, Music, Night) are available through the app, which also controls such minor functions as auto on/off, and the low-pass filter frequency for the built-in subwoofer crossover.

Elac app

The amp normally connects to a smartphone using Bluetooth. Or, if the amp is kept in an equipment closet, which would likely block the Bluetooth signal, it can be controlled via Wi-Fi from the phone to the router, and then an Ethernet cable from router to amp.


I installed the flush-mount IW-S10EQ subwoofer in two different fake walls that I use to test in-wall speakers. Each wall is 48” high and is built with studs spaced 16” on-center (or 14.5” apart) -- the standard for residential wall construction in the US. One fake wall is made with 6” studs, the other with 4” studs. Standard walls use 4” studs (aka 2x4s), but in custom home theaters, 6” studs are sometimes used in the front wall to accommodate larger speakers. My fake walls simulate the acoustic environment of actual walls, almost all of which have a stud going across about midway between floor and ceiling to act as a firebreak. I’ve stuffed them with denim insulation, as any diligent installer should; this absorbs much of the speaker’s backwave, so it won’t come back out through the driver cone. Like most in-wall speakers, the IW-S10EQ has dogleg mounts that flip into place and clamp the speaker to the wall when the mounting screws are tightened.Elac

The IW-S10EQ amp has stereo speaker-level and line-level inputs, so it can work in stereo and surround-sound systems. It also has jacks for RS-232 control and 12V triggers, so it can interface with a home automation system. I used the left-channel line input, fed from the subwoofer output of my Sony STR-ZA5000ES A/V receiver or Parasound Halo P 5 stereo preamp. I used the IW-S10EQ in a 2.1-channel system with the Halo P 5, two Outlaw M2200 monoblock power amps, and a pair of Revel Performa3 F206 speakers; and in a 5.1.2-channel system with the Sony STR-ZA5000ES, Sunfire CRM-2 and CRM-BIP speakers, and Focal 300 ICW in-ceiling height speakers. With the 2.1 system I used an 80Hz crossover frequency; with the 5.1 system I selected 110Hz, to better suit the Sunfire speakers’ small woofers.


For all of my testing, I placed the fake wall holding the sub in the front left corner of my room. This position reinforced the output from the 10” cone, and also presented a tougher challenge for the auto EQ -- corner mounting usually makes subs sound boomy. It also reflected real-world installations of in-wall subs, which I’ve often seen mounted in or near corners, where their grilles are less noticeable. For most of my testing, I used the fake wall made with 6” studs. I did try using the wall made with 4” studs, but the difference in sound between the two was pretty subtle: just a bit less deep-bass power with the 4” studs.


I find that the benefits of subwoofer auto EQ systems are most audible in music, which usually has bass notes at many different pitches. This makes it easier to hear when a certain notes are boosted or attenuated. I began with the title track of jazz bassist Sam Jones’s Something in Common, a medium-tempo swing tune (256kbps MP3, Muse). When I used the app to switch the IW-S10EQ’s auto EQ on and off, the benefits of auto EQ were easy to hear. Without auto EQ, Jones’s double bass boomed, bloated, and blurred; it was hard to distinguish individual notes, much less appreciate the harmonic construction of his walking bass line. This is what I usually hear when I put a sub in the corner without any EQ to tune it. With auto EQ on, the “growl” of Jones’s bass was readily apparent, and the notes became easy to pick out. Suddenly, this corner-mounted in-wall sub came fairly close to the performance of a good freestanding sub placed in an acoustically optimal position.


A very different kind of jazz bass can be heard from a different Jones on Miles Davis’s Decoy (320kbps Ogg Vorbis, Columbia/Spotify), which features electric bassist Darryl Jones (now best known as the Rolling Stones’ bassist). In “That’s Right,” a slow, bluesy tune that showcases the subtler side of Miles’s mid-1980s band, Darryl Jones’s bass guitar without auto EQ sounded much like Sam Jones’s double bass had in “Something in Common”: boomy and indistinct, his fingers producing thuds rather than notes. Of course, I wasn’t present at either recording session, so I don’t know what their basses are supposed to sound like, but I think I’m pretty safe in saying that Darryl isn’t supposed to sound like Sam. When I switched on the IW-S10EQ’s auto EQ, the intricacies of Darryl’s fingerpicking became evident, and it was easy to hear him moving from behind to ahead of the beat and back, as the groove demanded.

As the IW-S10EQ has only a 10” cone, with a driver that’s not as beefy as many I’ve seen, and it was mounted in drywall, I wanted to find its choke point. I put on “Love Lockdown,” from Kanye West’s 808s and Heartbreak (320kbps Ogg Vorbis, Roc-a-Fella/Spotify), which begins with a few very deep, loud bass notes. To my surprise, the IW-S10EQ reproduced these tones cleanly and loudly -- I could easily distinguish their pitches. Even with the system cranked pretty loud -- an average of about 92dB at my listening chair -- I heard no distortion in the bass.


I also spent some time casually watching TV and movies with the IW-S10EQ in my system, most notably for a viewing of Avengers: Infinity War (HD stream, Sony/Amazon Video). While a single in-wall subwoofer with a 10” cone isn’t my first choice for watching a slam-bang action blockbuster, I found the IW-S10EQ did a decent job of keeping the sound full and conveying some of the impact of this movie’s explosions and body punches. Using the Cinema EQ mode added a bit of oomph to these effects, but to get the big, full sound I wanted I had to turn the sub’s level up 6dB. Fortunately, the app made this much easier than it would have been to raise the level through the Sony receiver’s menu.

Still, the deep bass was a bit boomy, probably because of the drywall vibrating along with the sub. Putting a hand on the drywall during the final battle of Infinity War confirmed this -- touching it felt like laying my hand on the side of a car as the driver revved the engine.

The limits of the Elac’s power became more apparent when I loaded up my favorite test movies, such as U-571 (BD, Universal). The IW-S10EQ didn’t have the deep-bass power necessary to reproduce the boom in the “Face to Face” chapter, in which the submarine fires its deck cannon at a destroyer -- it sounded more like someone whacking a big metal trash can. It did better in the scene that comes a minute later, in which the submarine dives under the destroyer -- it didn’t shake my chair as a bigger subwoofer would have, but I did get a nice sense of the rumble of the sub’s and destroyer’s engines. But I also heard the drywall vibrating again.


If I bought an IW-S10EQ -- or any other in-wall sub that doesn’t include a back box -- I’d replace the drywall panel I mounted it in with a half-inch panel of MDF spanning the two studs, caulk around the edge of the panel, then skim-coat the MDF panel with drywall joint compound to make it match the wall. This would cost very little, but would minimize extraneous vibrations and get better sound from the sub.


To my knowledge, I’m one of only two people who’s reviewed more than one or two in-wall subwoofers. Even so, I can remember reviewing only five others in the last 20 years -- and only one since the CEA-2010 measurement protocol for subwoofer output was standardized. And that sub, the OEM Systems ICBM, isn’t really comparable to the IW-S10EQ because it uses a single amp powering multiple subwoofers, each with a single 8” cone. For what it’s worth, the ICBM amp with two 8” subs, each in its own back box -- a package costing $1600 -- delivered 4.2dB more average output than the IW-S10EQ between 40 and 63Hz, but 5.3dB less output than the Elac between 20 and 31.5Hz.

An obvious competitor to the Elac IW-S10EQ would be the Klipsch RW-5802 II plus RSA-500 amp ($1399.98), which employs a single in-wall sub with dual 8” drivers. There are also Polk’s CSW155 ($1299.98), an in-wall sub with 10” driver, plus amp and back box; and Definitive Technology’s IWSub 10/10 ($1648), an in-wall sub with a 10” driver and 10” passive radiator in an integral back box, plus amp. None of these competitors has a room-EQ system built into its amp. A back box like the ones included with the Polk and Definitive would significantly improve the Elac’s sound quality -- but anyone with enough skill to install an in-wall sub could probably also build themselves a back box for the IW-S10EQ.


The Elac IW-S10EQ is a very well thought-out and reasonably priced solution for those who want deep bass but lack the space for a subwoofer -- or who don’t want to listen to complaints about their sub taking up too much space. I think one IW-S10EQ will work fine for most music-only systems. A single IW-S10EQ will probably also work pretty well for small home-theater and media-room systems -- unless you’re an action-movie fan, in which case I recommend getting two.

. . . Brent Butterworth 

Associated Equipment

  • Speakers -- Focal 300 ICW, Revel Performa3 F206, Sunfire CRM-2 and CRM-BIP
  • Preamplifier -- Parasound Halo P 5
  • Amplifiers -- Outlaw Audio M2200 monoblocks
  • A/V receiver -- Sony STR-ZA5000ES

Elac IW-S10EQ In-Wall Subwoofer
Price: $1299.98 USD
Warranty, repair or replacement: Three years, driver; one year, amplifier.

Elac Americas, Inc.
11145 Knott Avenue, Suites E & F
Cypress, CA 90630
Phone: (714) 252-8843