ANTHEM STR INTEGRATED AMPLIFIER
ANTHEM AVM SERIES preamplifier/ processors have been part of my home theater toolkit going back as long as I can remember. Though they perform A/V switching, audio processing, and video upscaling as well as anything else on the market, the main feature I’ve come to depend on is the company’s proprietary ARC (Anthem Room Correction), a Windows and ios/android app that lets you measure the effect of your listening environment on your speakers using either a calibrated microphone or the one built into your phone or tablet. The software then creates correction filters that you upload to the processor to eliminate problems caused by standing waves, reflections, and other room-based anomalies. ARC can be configured to cover the full audio band (the default setting is 5,000 Hz, though that can be pushed higher or lower during the measurement and setup process), but its most notable contribution is made at the low frequency range. For systems that include one or more subwoofers, the effects of ARC can be instantly heard and appreciated.
Details of Anthem’s proprietary processing have already been covered in detail in numerous
Sound & Vision reviews. What’s new for ARC is an update to ARC-2 status and its appearance in stereo-only components like the company’s STR preamplifier and STR integrated amplifier. At $4,499, the STR integrated doesn’t come cheap. However, the combination of features it offers—arc, of course, topping that list—makes it a compelling option for serious listeners on the hunt for a new integrated amp.
The STR integrated is by far the biggest integrated amp I’ve encountered—at 17 x 6.75 x 17.5 inches (W x H x D), I could barely fit it on my component rack. The main reason for the Anthem integrated's oversize case is its beefy built-in class-ab amplifier, which is rated to deliver 2 x 200 watts into 8 ohms, 400 watts into 4 ohms, and 550 watts into 2 ohms.
One advantage to size here is that there’s loads of real estate to support a large front-panel display. The black-and-white-and-red TFT-LCD screen shows current volume level at a size that can be easily seen from well across the room, along with source and signal format info and ARC status. It’s also used for speaker setup and input configuration, which can be carried out via remote control or using the machined aluminum control buttons and volume knob on the Anthem’s otherwise sparse front panel. Same as with Anthem’s home theater preamp/processors, volume on the STR integrated can be adjusted in 0.5-db increments.
Anthem’s small but solid remote control is also made from machined aluminum and has a clean, simple layout. Buttons are provided to navigate setup and to call up an onscreen menu that allows for quick bass, treble, balance and subwoofer level adjustments. You also use it to navigate inputs, which are depicted in graphic form on the amp's frontpanel display.
Digital jacks on the STR Integrated’s back panel include a pair each of coaxial and optical, AES/EBU, and an asynchronous USB DAC input that supports stereo PCM up to 32-bit/384 khz and DSD up to 5.6 MHZ. The DAC connection is plugand-play for Macs; Windows users need to first download a USB driver from Anthem’s website. A LAN port is also present, but it’s strictly for ARC configuration and IP control, as opposed to network streaming from Tidal, Spotify, Pandora, etc., or from a DLNA server.
Analog inputs get serious consideration on Anthem’s integrated. There are separate moving magnet and moving coil phono inputs, four stereo RCA inputs, and balanced XLR jacks, all of which can be configured to bypass the internal digital processing. While doing so means you won’t be able to apply bass management or room-correction to those inputs, analog purists may be willing to make that sacrifice. (That said, the STR Integrated’s flexible setup options allow you to have things both ways by configuring the same physical input with and without digital processing for quick comparisons.) Lastly, there’s a pair of subwoofer output jacks labeled
left and right; either one of these can be used for single-sub installations.
SETUP
Once heaved out of the box and onto my rack, I started setup of the STR Integrated by connecting a Pioneer BDP88FD universal disc player, Pro-ject Debut turntable with Aurum Beta/s moving magnet cartridge, and Elac Discovery music server (while there’s nothing wrong with connecting a computer directly to an integrated amp or preamp’s USB input, I’ve become addicted to the convenience of appcontrolled network streaming solutions like Roon). Next came a visit from Anthem’s
John Bagby, who gave me a walkthrough of the latest version of the software and configured a few inputs on the STR Integrated for corrected and non-corrected playback so I could evaluate the effects of ARC processing.
After living with the system for some weeks, I replaced the Totem Acoustic Sky standmount speakers (see review on page 64) and antiquated Mirage subwoofer I was using with Goldenear Technology Triton Five towers and a new Paradigm Defiance V12 subwoofer (review in process). This meant I had to redo the ARC measurements, but that proved easy and quick. Basically, you set the included microphone stand and calibrated mic ear-level at the main listening position, connect the mic and the STR Integrated to your computer’s USB ports (another option is to link the Anthem to your home’s wired network using Cat5 cable, which I did), and then trigger a series of test tones that play through the individual left and right speakers and subwoofer(s). The same step gets repeated at multiple positions orbiting the main seat—you are free to measure up to ten, though Anthem says the required five minimum positions is plenty.
Once that’s done, the
ARC software calculates the correction curves and you then upload them to the STR Integrated. Beforehand, you have the opportunity to make software tweaks to items such as maximum EQ frequency
(the default is 5 khz, though I ended up lowering it to 500
Hz), room gain, crossover point, subwoofer high-pass order, and subwoofer high-pass frequency. (Another example of how the STR Integrated’s flexible setup options come in handy: You can create up to four ARC profiles with separate settings—500 Hz maximum EQ, 5 khz maximum EQ, etc.—and associate them with different unique input configurations to make comparisons.) You can also view onscreen graphs of the before and after frequency curves for the left and right channels and subwoofer, as well as create a PDF version for printing.
Beyond ARC, the Anthem’s setup menu offers a wide range of customization options. You can create various speaker profiles (e.g., Stereo Plus Subwoofer, Stereo No Subwoofer, Mono). Inputs can be renamed and linked to a specific speaker profile, ARC status, and playback mode.
The options get even more interesting for phono inputs. Along with all the other settings, vinylphiles get the choice to turn analog conversion on or off (when on, incoming signals are sampled at 32-bit/192khz resolution), set phono EQ to various options other than the standard RIAA curve (Capitol, Columbia, or London LP, for example), and set the rumble filter frequency in 1-Hz steps. All of these options make the STR Integrated especially appealing for someone who routinely taps vinyl as a playback source.
PERFORMANCE
I’m a big believer in the benefits of room correction. That’s mostly because I’m lazy about tweaking— I want to place speakers in a room and have them automatically sound good. While ARC has been a mainstay in my home theater, the only serious room correction tech I’ve explored on my stereo rig is Trinnov’s Optimizer, which is the primary feature of that company’s $10,000 Amethyst preamplifier.
There are key differences between the Optimizer and ARC. For one, while ARC processing is based upon a “lab standard” target curve, the Optimizer provides a range of preset curves, and it also has editing mode where you can define your own curves based on subjective listening preferences. That said, I’ve mostly employed ARC to correct for room anomalies in the sub-500 Hz range where the processing has the most obvious audible benefits.
What are those benefits? When I switched between Pioneer disc player inputs with ARC on and off, for example, the standup bass on “Blues Dream” from Jazz guitarist Bill Frisell’s
album With Dave Holland and Elvin Jones tightened up considerably with ARC while still retaining impressive low-end extension. There was also a dramatic increase in definition and body, with Holland’s instrument now sitting palpably in space.
Cleaning and tightening up bass might be ARC’S most obvious contribution, but lower midrange and midrange clarity were affected in my setup as well. Listening to Mazzy Star’s “California” from the Seasons Of Your Day CD, David Roback’s strummed acoustic guitar had a full, fleshed-out quality, and Hope Sandoval’s voice came through with all its cool, breathy detail intact. When an electric bass guitar joined in near the song’s extended outro, the low notes sounded powerful and clean, and were perfectly integrated with the other elements in the mix.
Along with the improvements in bass clarity and midrange detail brought by ARC, Anthem’s integrated offered up morethan-ample power reserves. When I streamed a jazz track, “Good on the Ground” by the Vijay Iyer sextet (from Tidal via the Elac Discovery server), I heard a crisp rendering of the dynamic track’s somewhat chaotic instrumentation.
Iyer’s piano tone sounded full and natural, and the blaring horns had an airy, effortless quality. What really grabbed me when listening to this song was the drums. A slamming solo around four minutes in had a dynamic, lifelike quality, and I could push the volume to near-uncomfortable levels without hearing strain. Checking another drum-driven track, “Sentient Oona,” by California Psych-rockers The Oh Sees, I experienced the same sense of clean, unimpeded power, with the double-drummer onslaught sounding like it was in the room and wrapping around my head.
As I stated earlier, the Anthem’s range of phono input set-up options make it a great choice for vinyl. Listening to a Kraftwerk cut, “The Telephone Call” from Electric Cafe, with the STR Integrated’s analogto-digital conversion, bass management, and ARC all enabled, the electronic kick drum had a tight envelope, and the explosive bass notes that punctuate the track displayed impressive power and extension. When I turned off digital processing and bass management for comparison, the sound was less dynamic, and definitely less appealing.
Better bass, yes, but analog absolutists may be wondering if the Anthem’s digital-to-analog conversion was transparent. Listening to a more strippeddown track on LP, Ray Lamontagne’s “Barfly,” I heard no real difference in the song’s cleanly recorded vocals and acoustic guitar when comparing the analog bypass and digital conversion input modes. The transparency of the conversion was good enough for my ears, and I expect most other listeners will feel the same way.
CONCLUSION
Anthem’s STR Integrated amplifier brings the benefits of the company’s excellent ARC room correction processing to a stereo-only component. And not just any stereo-only component, but a powerful, feature-packed unit with a 200 watts-per-channel amp, a DSDcompatible DAC, and separate moving magnet and moving coil phono inputs. The only other features I could ask for would be network streaming capability and Roon Readiness, but those omissions are ones that a $35 Google Chromecast add-on device can fix.
Is the STR Integrated a good fit for everyone? At $4,499, the cost isn’t entry-level, and the extensive setup and room correction features it provides make it best suited for tweaky types who enjoy digging in and making adjustments to tune their system's performance.
That said, all of those features are optional—if you simply want to connect speakers and sources and play music, the STR Integrated is as easy to use as any competing product, and its sound quality is fantastic. ARC in a stereo component was a long time coming. I’m glad Anthem got around to making it happen.
The Verdict
ARC room correction on Anthem’s STR integrated amp makes it a must-audition option for anyone putting together a high-performance stereo system.