Fig. 1: The ARC plug-in EQ''s your playback system to give it a flat response based on the curve generated by the measurement application and the optional Target Curve.
Wouldn't it be great to trust the acoustics in your studio? To be able to do a mix where you didn't have to take a copy of your song, burn it to a CD, and then listen to it in your car, on your boombox, and even on your living room stereo to see how it translates? The reason why so many personal-studio owners often must do so much referencing during the mix process — even if they have excellent monitors — is that their studios have not been acoustically treated and tuned. As a result, sonic gremlins such as first-order reflections and standing waves wreak havoc with the sound and make it impossible to mix with confidence.
A big impediment to studios' getting treated is an economic one: custom acoustic treatments can be expensive. And many recordists would rather allocate their equipment budget to something sexier, like a new plug-in or microphone. But what if there were a relatively inexpensive way to use computer-based DSP to compensate for those acoustic anomalies? IK Multimedia's ARC System offers just such a solution, using Audyssey's MultEQ technology (see “Tech Page: Got Modes?” in the September issue, available at emusician.com), which was originally invented for the high-end home-audio and home-theater markets. The system is designed to correct both frequency- and time-based (phase) problems.
Can EQ alone cure your acoustic problems? I asked acoustic consultant Bob Hodas about it, and he told me that EQ is typically the icing on the cake of a treated room, used for final finishing-touch tweaks after all the absorbers, diffusers, and bass traps have been installed.
Other products on the market besides ARC use DSP as the primary tool for room tuning, including JBL's LSR-series speakers and KRK's ERGO system. One way in which these three products differ is that they all put their processing in different parts of the signal chain. For the LSR system, it's in the monitor cabinets themselves. For ERGO, it's in a dedicated box that's placed between the audio interface and the monitors. ARC does its processing as a VST, AU, or RTAS plug-in within your DAW (see Fig. 1).
Checking — One, Two
ARC is composed of a standalone measurement application (see Fig. 2), a plug-in for implementing the EQ curves, and a measurement microphone. This omni-pattern condenser (see Fig. 3) is specifically tailored for ARC, and the system won't work correctly if you substitute another measurement mic. The mic comes in a padded black plastic carrying case, and a windscreen and custom clip are included. An IK spokesperson told me that it's of good-enough quality to also use as a recording mic. I tested it out on acoustic guitar, resonator guitar, and shaker, and the results were solid if not inspiring. (To hear it in action as a recording mic, see Web Clip 1.)
After installing the ARC software, the next step is to take measurements in your studio. You start by putting the measurement mic on a stand, pointing it straight up at the ceiling, and placing it at ear height at your listening position, centered between the monitors. You then launch the measurement software, and it prompts you to press the Test button to make sure you're getting enough level through your monitors (it emits a series of test tones). Once your levels are set, you're ready to start measuring.
The software guides you through the testing process and for each measurement emits a series of ten tones each for the left and right speaker. (Currently the ARC System doesn't support surround.) The manual recommends taking at least 13 measurements, preferably 14 to 16 for every set of monitors in your studio. After each measurement, you move the mic to a different spot in and around your listening position. Suggested measurement positions are indicated graphically in the manual. (Kudos to IK for including a printed manual, not just a PDF.) According to IK, the Audyssey MultEQ technology is capable of correcting your room for multiple listening positions (for example, a main position with a client couch behind it).
If you have more than one pair of monitors, you need to take separate measurements for each type. That's because they have different frequency responses and interact differently with the room.
The measurement process goes fairly quickly, and once you've completed it, the software calculates an EQ curve and prompts you to name the preset. It then lets you select a speaker icon to graphically represent your speaker type when you call up a preset. (The graphic reminder is helpful if you have multiple monitors in your studio, because you have to change ARC presets each time you switch speakers.)
Open the DAW
To put your measurements to work, you open the ARC System plug-in within your DAW and insert it either on the master bus or, preferably, on a dedicated monitor bus, assuming you have a multioutput interface and your DAW allows it. I'll explain why in a moment.
The plug-in opens in a large window featuring a level meter, a trim control, a correction on/off switch, and several pull-down menus. The Measurement menu lets you choose the EQ preset that resulted from your measurement process. The Target Curve menu provides several additional presets to further tweak the room response if desired. Besides the default Flat setting, you can choose high-frequency rolloff, midrange compensation, and a curve that offers both.
The plug-in also displays a graph that shows helpful comparative data from the measurements: the original EQ curve of your monitors, the new curve with the ARC processing applied, and the frequency response after the Target Curve is enabled.
Once you've found the best setting for your room, the idea is to do your mixing while monitoring through the ARC plug-in with the correction on. When you're ready to bounce your mix down, you turn the correction off (assuming you have the ARC plug-in on the master bus; if you have it on a monitor bus, you can leave it on because it won't affect your mix).
Although turning off ARC before bouncing seems counterintuitive, it actually makes sense. By mixing while listening through ARC's processing, you're setting levels, EQ'ing, and adding effects with the corrected acoustics as your guide. You're making mixing decisions with ARC's processing compensating for the acoustic inaccuracies of your space. In a sense, ARC's EQ curves are fooling you into mixing as if you were in a “flat” room. That's why, if you're using ARC on your master bus, you must remember to bypass the plug-in before bouncing. Otherwise, you'd be redundantly adding the ARC processing, and you'd totally skew your mix.
One problem I ran into is that it's easy to forget to turn the ARC processing off when it's time to bounce. That's because it's basically a set-and-forget system. You don't need to interact with it except at the beginning of a session when you're opening the plug-in and getting levels set, unless you're switching between monitor pairs. When I first began mixing with ARC, I found that I often left it on by mistake and had to rerun my mix. My life was made easier after I inserted the ARC plug-in on an aux bus that fed a separate output pair — other than the main L and R — for monitoring.
Another awkward aspect of the ARC System's architecture — specifically the fact that it does its processing from within your DAW — is that once you've bounced your mix and you want to listen back to it in your studio, you need to import your mixed track back into your DAW (or into a 2-track editor that lets you monitor through plug-ins) with the ARC plug-in turned on. This is necessary in order to hear the music as you mixed it; that is, with ARC compensating for your room's acoustics. (According to IK, a solution to this problem is in development.)
Into the ARC
Those issues aside, the most important question about the ARC System is: how well does it work at flattening the response of your studio? To help answer this, I tested the system both in my studio, which has acoustic treatment (both absorber panels and bass traps), and in another room in my house that's completely untreated.
Not surprisingly, the differences in my treated studio were mostly subtle ones. There was a little less tubbiness in the monitors, and slightly more present highs when listening with the ARC processing on. The stereo image seemed to shrink a tiny bit when the processing was engaged.
In the untreated room, the sonic differences were much more dramatic. That room is of medium size and has a rectangular shape, and the speaker system in it is an inexpensive consumer 2.1 setup.
In that room, the comparative graph in the ARC plug-in showed that the room had a significant bump in the low end and lower midrange. With the ARC processing switched on, that bump went away. To compare the difference, I listened to mixes of songs that I was very familiar with. Sure enough, with it on, everything sounded clearer, less muddy, and more open. According to IK, one of ARC's strong points is its ability to make a bad-sounding room usable, and this was born out in my testing.
Mix and Match
I did quite a bit of mixing through the ARC System in both the treated and untreated rooms, and I was a little surprised to find that I didn't hear a major change in how those mixes translated to other speaker systems. Oddly, in my treated space, ARC's reduction of bass, which aimed to flatten the response, actually helped cause me to put too much bass into several mixes. Even in the untreated room, the differences between mixes done with and without ARC were less dramatic than I had expected.
FEATURES 1 2 3 4 5 EASE OF USE 1 2 3 4 5 AUDIO QUALITY 1 2 3 4 5 VALUE 1 2 3 4 5
Although I was surprised that ARC wasn't immediately improving my mixes, my contact at IK wasn't. He said that my ears were accustomed to my room's normal acoustics, and that it would take a while for me to get used to ARC's corrected sound.
Overall, my opinion of the ARC System is mixed. I was impressed with its ability to apparently clean up the sound in a room, but I was disappointed when that didn't translate into substantial mix improvement. To be fair, there are other factors that affect how a mix turns out (mixing skill, ear fatigue, lack of objectivity, and so on), which certainly could have come into play. Still, I mixed close to ten full-length songs with ARC, over a number of weeks, and never saw significant changes in how my mixes translated.
A key question you have to ask yourself is: would you rather put the money you'd spend on the ARC System toward traditional acoustic treatment? If you're on a relatively tight budget and have a really bad-sounding room, ARC might be a cost-effective way to quickly improve the sound in your studio. But if you can afford physical acoustic treatment, I still think that's the best way to go.
Mike Levine is EM's executive editor and senior media producer and the host of the twice-monthly Podcast “EM Cast” (emusician.com/podcasts).
room correction system
PROS: Can substantially improve playback in an untreated room. Good documentation. Target Curves allow further sound tailoring. Measurement process easy to complete. Allows for wide sweet spot.
CONS: Must turn off ARC processing before bouncing on some systems. Playing back bounced mix through ARC processing requires extra steps. Must switch EQ curves when switching monitors.