The home-theater marketplace—what’s left of it these days—is awash with slim A/V receivers that prioritize room-friendly aesthetics and/or outright unobtrusiveness over performance-oriented specs and features. And I don’t mean that in terms of amplified output, since the 50Wpc you get from most slim receivers is probably more than enough for most mixed-use spaces. It’s rare, though, to find a compact AVR that delivers the goods in terms of room correction. The most popular models, such as the Marantz Cinema 70s ($1200, all prices USD), rely on bog-standard Audyssey MultEQ—which in my opinion is worse than no room correction at all—instead of the more advanced and better-sounding alternatives like MultEQ XT or XT32. And that’s just one of the many things that sets Anthem’s new MRX SLM ($1299.99) apart from most of its svelte competition.
The MRX SLM relies on the same Anthem Room Correction system—aka ARC Genesis—employed in the company’s $7500 flagship AVM 90 8K preamp/processor, and it benefits from all of the installation flexibility of the rest of the MRX and AVM lineups. True, it doesn’t boast a ton of inputs and outputs, but what’s here is highly configurable. What’s more, the form factor of the MRX SLM means you can easily install it behind a wall-mounted TV, or even stack a few of them in the same rack space that would normally be reserved for one AVR.
When I say the MRX SLM isn’t overly burdened by an excess of I/O, by the way, I’m not kidding. At a time when most AVRs pack at least six HDMI ports, Anthem’s itty-bitty offering has just one HDMI 2.0b input and one HDMI eARC in/out for connection to your display. It won’t handle HDR10+, but the other main high-dynamic-range video formats are supported. It also, needless to say, doesn’t support HDMI 2.1 or 2.1a features such as VRR or ALLM, but it is HDCP 2.3-compliant and can pass through 4K video up to 60Hz.
All told, in addition to the one HDMI input and the HDMI eARC port referenced above, the MRX SLM features a single 3.5mm stereo analog audio input, an optical digital input, a Euroblock/Phoenix speaker connector with five amplified channels of output (50Wpc into 8 ohms, two channels driven, or 92Wpc into 4 ohms, two channels driven, with THD+N of <0.005%), a subwoofer out, an ethernet port, two wireless antennas for Wi-Fi and Bluetooth, and an IR extender input (3.5mm). The receiver supports AirPlay 2 and Google Cast, as well as Spotify Connect. That’s all in a chassis measuring just 11″W × 1.5″H × 11″D.
What that laundry list of physical and wireless connections—short though it may be—doesn’t accurately reflect, though, is the MRX SLM’s support for up to 30 virtual inputs, a feature for which Anthem is known, but is still a pleasant surprise at this price and in this form factor. We’ll dig into that more in the next section.
Setting up and dialing in the MRX SLM
Before we get to the concept of virtual inputs, though, we need to talk about the physical setup of the MRX SLM, because there are a few considerations worth detailing. Firstly, the receiver comes with a bracket for vertical wall-mounting (likely behind a display); a rack-mount kit is available as an option. I did not use the wall-mount kit, but its inclusion is a nice touch. After years of experience in the custom-integration industry, I expect such hardware to be optional and sold separately.
Physical installation did require a bit of finagling on my part, since my speakers—in this room an RSL CG3 5.2 system, although I could only use one of the subs with the MRX SLM—are all terminated with banana plugs, so I had to snip those off and run bare Monoprice Choice Series 12AWG wire into the Phoenix connectors. The screws to clamp down on the wire are on the opposite side of the plug from the labels, which made for slightly slow going, but I was happy to discover that the block took such thick cable without issue.
The problem I ran into was stripping the jackets to allow for precisely the right length of bare wire. Too long and there’s a real chance of shorting out some wire. Too short and . . . well, you run into the most frustrating problem I ran into during setup.
After getting my speakers connected and then configuring the receiver with the web setup utility—on Windows 10, that’s as simple as navigating to the Network section in File Explorer and double-clicking on the MRX SLM—I launched the ARC Genesis app on my laptop, connected the included calibrated microphone via USB, and attempted to run room correction. And I simply couldn’t get it to run. I remember having an issue with some previous Anthem MRX receivers whereby if the HDMI input was selected and a signal was played, that could interfere with ARC Genesis setup, so I switched to the analog input, played some sounds via my phone, and ran into the same issue.
Long story short, going back into the web configurator again and sending test tones to the speaker revealed that no sound was coming from the front left speaker—the speaker that delivers the first ARC Genesis test tone. Hence the low-signal/high-noise error I kept getting.
Turns out, all I needed to do was re-strip the jacket to give me an extra few millimeters of bare wire, and that did the trick. ARC Genesis thereafter ran without problem. So, lesson learned—run test tones through all speakers in a setup before you start trying to run ARC.
The 5.1-channel output supported by the receiver doesn’t necessarily have to be run as 5.1, by the way. You can also just as easily do a 3.1.2 object-based system with fronts and two heights, since the MRX SLM decodes Dolby Atmos and DTS:X.
You can also use the aforementioned virtual inputs to create several use-case scenarios based on activities instead of source devices, meaning that if you have a universal disc player, for example, connected to the HDMI input, you could have one virtual input named “Movies” that features a 5.1-channel configuration with ARC room correction and another named “Music” that defaults to stereo with no room correction. And yet another on the same HDMI input named “Surround Music” that adds some matrix decoding to the mix.
You won’t have access to those virtual inputs via the included remote control, mind you, but the Anthem Remote app available for iOS and Android will let you both set up and recall them, as will the IP drivers for Control4, Crestron, RTI, Elan, Savant, and URC smart-home systems.
I added the receiver to my Control4 system via the SDDP IP driver, and found the virtual inputs just as easy to configure there. So no matter how you control the system, you have pretty easy access to its more advanced features. That said, the only physical source device I used during the course of this review was my Roku Ultra. Otherwise, most of what I listened to was via my iPhone 12 Pro Max, in the final days of its life, connected through AirPlay 2.
It was really edifying to dip back into ARC Genesis after a long time away from it. I haven’t reviewed any Anthem gear since joining the SoundStage! family, but ARC was the system that originally convinced me of the validity of room correction to begin with, at a time when I was highly skeptical, many moons past.
On paper, ARC Genesis isn’t as advanced as something like Dirac Live, especially when you consider features like Dirac Live Bass Control. Anthem’s solution operates entirely in the frequency domain, and is largely focused on addressing the problems that DSP addresses best—namely, problems below the Schroeder frequency of the room. It also factors things like boundary gain into the equation and performs bass management as a function of room correction, but not in the same way Dirac Live Bass Control does.
The long and short of it is, I had the Anthem MRX SLM up and running in my system within an hour of uninstalling the Onkyo TX-RZ30 I recently reviewed, which means that, although I couldn’t do direct A/B testing, this was an opportunity to compare the results of Dirac Live and ARC Genesis in much more rapid succession than had ever been possible for me. And most of the observations in the performance section below flow from those comparisons.
How does the MRX SLM sound?
So how did ARC Genesis stack up against full-fledged Dirac Live with Bass Control? In large part, extremely well. Better than I expected, in fact. Let’s start our listening with one scenario in which Dirac Live Bass Control took a slight lead, though, just to get it out of the way.
In my review of the Onkyo RZ30, I spent a lot of time talking about the scene early in Star Wars: Episode II – Attack of the Clones in which Jedi Masters Yoda, Mace Windu, et al, sit across the desk in a tense meeting with Chancellor Palpatine. As a refresher, this is typically a tough scene to render convincingly via my RSL CG3 system—in fact, it’s the scene that best illustrates a few of that system’s imperfections, because the dialog of all the characters is mixed pretty dry into the center channel, and the reverberation of their voices gets mixed into the front left and front right. So if your satellites and sub don’t sum well, you get this sort of hollow quality to the dialog, and there’s a mismatch between the direct and ambient sound that registers subconsciously even if you’re not quite sure why.
The MRX SLM didn’t jackhammer my RSL CG3s into performing perfectly with this scene, but it came as close as I’ve heard, aside from Dirac Live Bass Control. So close, in fact, that I’m not sure I would have heard any issues had I not been listening for them with hypervigilance. What’s interesting is that ARC Genesis set quite different crossover points than did Dirac Live Bass Control, settling on a 160Hz crossover point for the front left and right speaker, and what I would consider to be a relatively high crossover frequency of 130Hz for the center speaker.
And yet, it worked.
Here’s the thing, though: skip back a chapter (well, since I was streaming from Disney+ on the Anthem, it would be more accurate to say “skip back to the beginning of the film”), and the MRX SLM handled the punishing bass of the opening sequence—the flyover and subsequent explosion of Senator Amidala’s ship—brilliantly. And keep in mind, we’re talking about a system with one sub versus two, a point we’ll return to in a minute.
The bass wasn’t quite as chest-slamming via the MRX SLM as with the RZ30, but it was, on the other hand, even better controlled. I go back to my distraction model of hi-fi here: If I were simply sitting down to enjoy the film with the Anthem slim receiver in my system, would I be distracted? Like, even a little bit? I wouldn’t.
Now, getting to an evaluation of the hardware itself, as opposed to a treatise on its room-correction capabilities, I did find that I was pushing the amps to their limits with this scene. In fact, I had to roll the volume down to -4dB to avoid some clipping in the surround channels. But still, it was easy enough to dial into the web interface for the MRX SLM and set the max volume to -4dB, which still left me with a listening level that was more than satisfying in my 12′ × 15′ listening space, averaging in the low 80s dBC and maxing out around 91dB peak. Which says to me that if you like your movies loud, the SLM might leave you wanting a little more output in rooms measuring any larger than mine.
But assuming your space isn’t too cavernous, I think you’ll find that the MRX SLM delivers a gorgeous sense of natural space from well-mixed films and TV shows. The aforementioned ship flyover from Episode II, once I had a max volume set to safer levels, was delightfully seamless in its transition from rear to front of room.
Since I was only running a 5.1 setup, I decided to throw one of the only Atmos mixes from recent years that I actually enjoy—Guillermo del Toro’s Nightmare Alley—at the receiver via Vudu just to see how well it held up. After a few scenes, I realized I’d fallen into that oldest of audio-reviewer clichés, in that I’d forgotten to scrutinize the sound and was simply engrossed in the film.
The sonic landscape of Nightmare Alley is truly impressive, from the scenes in the first act, in which a brewing storm grumbles away on the horizon nearly constantly, through to interiors later in the story, where overhead mercury-vapor lamps create this sort of ominous aural texture that sets an undeniably unsettling mood, and the MRX SLM delivered them all beautifully, creating a genuine sense of space that ranged from miles-wide and open to cramped and confined, even despite the lack of overhead speakers.
Here again, my only grumble was that a single subwoofer resulted in more seat-to-seat inconsistencies with the lowest frequencies, so if the MRX SLM were mine, I’d put a y-splitter on the LFE output and run two subs.
With music, the receiver performed every bit as admirably. Listening to “The Wind” from Cat Stevens’s Teaser and the Firecat (16-bit/44.1kHz ALAC, UMC / Apple Music), I found the receiver’s delivery of the tones and textures of the vocals truly delightful. I also rediscovered my love for AnthemLogic-Music, the company’s own proprietary stereo-to-surround decoder, which enhances the spaciousness of the mix without getting heavy-handed or, as was the case with “The Wind,” without even really registering as surround sound, but rather deeper, wider, richer stereo.
What other AVRs might you consider in this price range?
If you’re looking for a solid 5.1-channel AVR with good room correction in this price range, you’re not going to find one this slim. If you’re looking for a slimline AVR in this price range, it’s not going to have room correction this good. If you’re looking for a slim AVR with room correction this good, I don’t even know what to recommend, but I can’t imagine it’s going to be anywhere near this price.
Anthem is in a weird position here of having created a product without anything I’d recognize as meaningful competition.
TL;DR: Is the Anthem MRX SLM worth the money?
As I was wrapping up my evaluation of the Anthem MRX SLM, I was chatting with SoundStage! founder Doug Schneider about the review, and he asked me a point-blank question: “I’ve never really listened to these slim receivers. Are they any good?”
My reply was something along the lines of, “Most of the slim AVRs I’ve auditioned kinda suck from a performance standpoint. This one doesn’t.”
“There’s your conclusion,” he said. But I’d argue there’s more to say in wrapping this one up. The MRX SLM isn’t merely a good receiver in a seemingly impossibly slim package; it also changed the way I think of how an AVR can and should be used. My wife and I are in the final stages of completely de-Amazoning our lives, which means turning off the Echo Studio speakers in the bedroom, which we’ve long used to listen to thunderstorm sounds as we sleep. (I’m a pluviophile, and she’s prone to tinnitus-related insomnia, so the thunderstorm recordings are psychotherapy for me and white noise for her.)
I’ve never really considered the AVRs installed in that room as a viable source for our thunderstorm sounds, because that just strikes me as wasteful overkill. But the MRX SLM sips such an insubstantial amount of power from the wall that I honestly don’t think running it in surround sound at reasonable volumes eats much more energy than a pair of Echo Studios.
After the first night of this new arrangement, I ran my hand across the top of the MRX SLM, expecting it to be a little toasty, only to find that it was just sort of pleasantly warm, like a cat napping in a pool of afternoon sunlight on a comfy rug. That alone makes me more frustrated than ever that most AVR manufacturers refuse to embrace class-D amplification. And, oddly enough, it’s probably going to be the thing I miss most about the MRX SLM.
. . . Dennis Burger
dennisb@soundstagenetwork.com
Associated Equipment
- Speakers: RSL CG3 and CG23
- Subwoofer: RSL Speedwoofer 10S
- Sources: Roku Ultra; iPhone 12 Pro Max
- Speaker cables: Monoprice Choice Series 12AWG
- Power conditioner: SurgeX SX-AX15E
Anthem MRX SLM A/V receiver
Price: $1299.99
Warranty: Three years, parts and labor
Anthem
205 Annagem Boulevard
Mississauga, ON L5T 2V1
Canada
Phone: (905) 564-1994
Website: www.anthemav.com
