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Software Room Correction For Pro Tools
No matter how much you spend on expensive reference monitors or fancy new mix plug-ins, if you can’t trust your room you can’t trust your mix. In the past, the solution to an uneven room almost always came in the form of cumbersome, and often costly acoustic treatments. Whether it be bass traps, high frequency absorbers, diffusers, or even going as far as re-constructing portions of a space, properly treating a room can be both time consuming and expensive, especially for DAW-users who tend to set up shop wherever they can find free space. While great acoustics don’t come easy (or cheap), IK Multimedia’s simple to use ARC system promises to fix up your room’s trouble spots in a snap, no contractor necessary. I recently had a chance to try out the ARC system in my own space and wanted to share my experience here at the Pro Tools Corner.
What is ARC?
ARC, short for Advanced Room Correction, is the first all-in-one room correction system in a plug-in, designed specifically for DAW-based studios. By measuring the acoustic characteristic of a room using the included calibration microphone, ARC is able to correct distortions caused by room acoustic and monitoring setup that may adversely affect mix decisions. While the idea of using equalization and time alignment to correct monitoring systems is not a new one, ARC is the first plug and play system for DAW-users that is simple to use and actually works fairly well.
Why do you need it?
Many DAW users often find themselves in small spaces, like bedrooms, dens, or home offices. Small spaces tend to be highly susceptible to low end distortion do to room modes or standing waves, making mix decisions almost impossible. Ask yourself this question, how many times have you done a mix only to take it to another playback system and find that the bass is either over exaggerated or non-existent? If you answered yes, then your room is most likely plagued by severe, low frequency standing waves, creating extreme bass build up (or cancelation) at different spots throughout the room.
Just for fun, try the following experiment in Pro Tools:
1. Open up a new session and create a new mono aux track.
2. Insert the plug-in Signal Generator (found under the “other” catagory).
3. Set the frequency to 60hz (or 80hz if you have smaller speakers).
4. Now get up and slowly walk around the room and see if you can notice any bumps/dips in volume as you move around.
5. Now try sitting in your mix position and starting at 40 hz. slowly increase the signal generator’s frequency 1 hz at a time and listen for any “bumps” or “dips” in volume at the mix position.
I bet you noticed more then just a few minor bumps and dips. These “room modes” are facilitated by your room’s dimensions and the way those dimensions cause sound-waves to interact with each other. While I could go on for days about various acoustic phenomena and why they occur, let’s just say that your room most likely has problems, and I am willing to bet these problems are enough to make most DAW-users more then a little insecure come mix down.
How does it work?
The thing I enjoyed most about the ARC system was its simplicity, I was able to get up and running with the software and correct my room in under 20 minutes. The bundle ships in an attractive box including the software installation disc, manual and the calibration microphone (which comes with a nice little hard-shell plastic case), and set-up is broken down into two easy components. After installing the software you are left with two separate ARC components, one being the actual RTAS/VST/AU plug-in, the other being a stand alone calibration utility.
To start, simply launch the calibration utility and let it walk you through the steps. You will need to use the included hard-copy manual to reference the different mic positions to take a multi-point “snap-shot” of your room. This ensures that the software receives an accurate representation of your overall space and allows it to EQ out a sweet spot, rather then basing its decisions on a single measurement point. The manual recommends taking at least 14 readings, I took 16 in my space but you can take up to 25. I found it easiest to use a telescoping boom stand for the calibration mic, leaving the stand fixed at one point on the floor and moving the boom around, which made it easier for me to take readings symmetrically from the mix position.
After taking the measurements ARC automatically calculates the correct EQ curve, monitor trims and delays, and allows you to save these as a preset which you will later recall in the ARC plug-in. Although the manual says that ARC will work with a subwoofer (which I had a bit more difficulty measuring an accurate curve from), you will still need to set the crossovers on your sub/satellites correctly as ARC just EQs out the whole system and does not apply curves to your subwoofer and satellites separately. Also, I found that if you have any sort of room correction features built into your monitoring system, it is best to make sure everything is set to the default position.
Using ARC in Pro Tools
Using the ARC plug-in in Pro Tools is fairly straight forward. Simply create a stereo master fader track and insert the ARC plug-in as the last insert in the chain. Because the plug-in is correcting a specific room’s acoustic problems, make sure to bypass ARC before bouncing a mix. When A/B-ing the mix with and without the ARC plug-in, make sure you make use of its volume trim feature as the corrected output will be a bit softer then the uncorrected output do to the extra headroom required to EQ out problematic room modes. While ARC is an RTAS plug-in (which means it will work in Pro Tools LE/M-Powered/HD), it does not create an enormous amount of latency and since it sits as the last insert in the signal flow chain, I did not have any delay compensation issues with my TDM system.
Is it worth it?
I have to say that I am always a bit skeptical of instant fixes for what are generally serious acoustic problems, but I was pleasantly surprised at how well ARC was able to clean up my space. While I already have a good amount of quality acoustic treatment in my studio, I always felt that “bumps” in the low-mids were seriously coloring my mix decisions and the ARC software did an amazing job at cleaning those problems up instantly. Even listening to my favorite reference mixes, which I thought already sounded quite good on my system, I could instantly hear the difference in clarity and definition, the low-end response of my playback system was significantly improved and the imaging now sounds better then ever. Just to make sure I wasn't crazy, I even took the system over to a few friend’s houses and tried it out in their spaces. ARC was consistently able to improve the overall sound of the room, yielding a tighter, more balanced low-end and improved imaging in every case.
The only down side to the ARC system that comes to mind would be its price (a little out of the range of an entry level DAW-users) and perhaps the fact that it is not ilok authorized. While IK says it is designed for engineers on the go, how am I suppose to take my ARC from studio to studio when I have a limited number of challenge and response authorizations? An ilok authorization would have been much more elegant. All in all, my hat is definitely off to IK for this one. While many acoustic purists would scoff at the idea of using equalization to cure room problems, and it is definitely not a bad idea to invest in traditional acoustic treatments for your space, IK’s ARC is just what the doctor ordered for DAW-users in tight spaces and may be the next best thing to spending $50-100K on rebuilding your studio.
If you have a Pro Tools related question that you would like me to take a shot at answering or have any feedback, please send it to brian@audioMIDI.com. I will do my best to select the questions that seem to stump the most people.
As always, stay tuned to the audioMIDI.com eNews for the latest reviews and new product info.
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