.YOUR ROOM YOUR MONITORS


Very few recording studios are suitable for mastering. For optimal mastering, use a different room than your recording studio or room. The typical recording control room has noisy fans, a large console and acoustic obstacles that interfere with evaluation of sound. With few exceptions, you won't find near-field monitors in a professional mastering room. No little speakers, cheap speakers, alternative monitors. Instead, there's a single set of high quality
loudspeakers. The loudspeaker-room interface in a mastering room is highly refined, and the mastering engineer tuned into their sound, so that he/she knows how the sound will translate over a wide variety of systems.


What's wrong with near-field monitors?

Near-field monitoring was devised to overcome the interference of poor control-room acoustics, but it's far from perfect. In many control rooms, with large consoles and rack gear, the sound from the "ideal" big speakers bounces from these surfaces, producing inferior quality. Reflections from the back of the console are often neglected. Even with absorptive treatment, you can't defeat the laws of physics; some wavelengths are going to reflect. But near-field monitors mounted on console meter bridges are not necissarily cures. Nearby surfaces, especially the console itself, cause comb filtering, peaks and dips in frequency response. The mix engineer may try to compensate for problems which are really caused by monitoring acoustics; resulting in recordings with boomy or weak bass, peaks or dips (suckouts) in the midrange, thumpy bass drums, and so on. Sound travels over more than one path from the loudspeaker to your ears - the direct path, and one or more reflected paths, especially the bounce off the console. That reflected path is so
problematic that it's almost impossible to locate nearfield monitors without breaking a fundamental acoustic rule: The length of the reflected signal path to the ears should be at least 2 to 3 times the direct signal path. Very few near-field monitors pass the "bandwidth and compression test". Almost none have sufficient low frequency response to judge bass and subsonic problems, and very few can tolerate the instantaneous transients and power levels of music without monitor compression. If your monitors are already compressing, how can you judge your own use of compression?
Near-field monitoring also exaggerates the amount of reverberation and left-right separation in a recording. Clients are often surprised to learn their singer has far less reverb than they had thought, and the sound less stereophonic when they hear the recording played with more-normal monitoring. Yes, the best mix engineers have learned how to work with near-field monitors and mentally compensate for their weaknesses, but these same mix engineers know better than to master in that environment. There's no excuse for monitor weakness in a mastering room.


Subwoofers

Subwoofers, or prime loudspeakers with infrasonic response, are essential for a good mastering studio. Vocal P pops, subway rumble, microphone vibrations, and other distortions will be missed without subwoofers, not just the lowest notes of the bass. Proper subwoofer setup requires knowledge and specialized equipment. I've been in too many studios where the subs are inaccurately adjusted, usually "too hot", in a vain attempt to impress the client. But the results won't translate when the subs are incorrectly adjusted.


Room Acoustics

Whether your loudspeakers are mounted in soffits, or in "free space", a properly designed room must have no interfering surfaces between the loudspeakers and your ears. Secondary reflections will be carefully controlled, and the dimensions of the room and solidity of the walls defined. A good mastering room should be at least 20 feet long, preferably 30 feet, and the monitors, if not in soffits, anchored to the floor, and placed several feet from walls and corners. There's obviously a lot more to this part of the story, but the bottom line is to get an acoustic consultant unless you really know what you're doing.


Monitor Translation

Mastering engineers have long ago learned that the widest-range, most accurate loudspeakers translate to the widest variety of alternate playback systems. If you follow all of the above in your mastering room, your masters will translate to the majority of systems out there. Good mastering engineers hit the mark the first time, better than 7 times out of 10.


Monitoring Levels and Fletcher-Munson

There is a scientific reason for not monitoring too loudly. The Fletcher-Munson equal loudness contours reveal that the human ear does not have a linear response to bass energy. The louder you monitor, you can be fooled into thinking a program has more bass energy. Thus it is extremely important to monitor at approximately the same level as the ultimate listener to your recording. No matter how good your monitors, if you turn them up too far, then you will put too little bass into the program, and vice versa.


When you go to a concert, do you identify an 80 Hz resonance under the third balcony?



Quelle: Bob Katz