Recording - December 2012 - 46

Last month we concluded our three-part look at signal flow with a discussion of personal monitor mixes for performers in the tracking room and the vagaries of latency in performers’ headphones. Now we turn our attention to monitoring in the control room.

Features An obvious difference between studio monitors and consumer stereo speakers is the presence of professional connectors. Home audio equipment typically connects on either unbalanced low-level (–10 dBV) RCA plugs or speaker-level bare wire or banana-plug connectors. Professional monitors, however, typically offer a higher level (+4 dBu) balanced input on TRS or XLR connectors, or a speaker-level input on banana or Neutrik speakON jacks. While discussing the subtleties of these interfaces is outside the scope of this article, professional connections are usually both more reliable and better at rejecting pesky noise gremlins such as hum and buzz. Pro studio monitors typically differ in physical construction as well. Many are constructed heavier than consumer speakers to avoid lowfrequency resonances that can cloud up bass reproduction. Other studio-focused features can be present too, such as LEDs that indicate power status and activation of built-in protection limiters, bass roll switches to minimize boundary effects, and even digital signal processing that can attempt to compensate for acoustic issues in the room. I will discuss some of these fancier accoutrements in a later issue when investigating monitor placement. By Eric Ferguson

Chapter 12: Monitors Part 1
What is the most important piece of gear in your studio? A fancy tube mic? An expensive Class A preamp? A DAW, fully loaded with ungodly amounts of processing power? While these and other shiny objects typically get the lion’s share of gear worship, studio monitors, often overlooked due to their pedestrian purpose, are perhaps the most important items in day-to-day recording and mixing. Monitors dictate our very perception of sound. Practically every decision, opinion, and debate originates from listening through our studio loudspeakers. With so much at stake, it is essential that we understand the strengths and weaknesses of our monitors. The distinction—flat is good So what makes a speaker a monitor? Can any garden-variety loudspeaker be used for the critical listening so central to music production? Sure! Records have been made with all sorts of speakers, so don’t be discouraged if you have not yet invested in a professional set of monitors. This said, there are some real differences between the typical hi-fi boxes available at your neighborhood electronics store and the monitors for sale at your favorite pro audio retailer. The most important distinction between reference monitors and the rest of the loudspeaker world is the monitors’ stated goal to be flat. By flat we understand the frequency response of the speaker to be such that no portion of the spectrum is emphasized— a graph of the response should be essentially flat. When recording and mixing, it is critical that the monitors you employ color the sound as little as possible, to let you hear exactly what you are working on without changing source frequency response. Consumer loudspeakers, on the other hand, typically hype tonality, with treble and bass boosts commonplace. While the exaggerated response of consumer speakers can make music reproduction exciting, it can also give engineers a false sense of balance. By contrast, studio monitors aim to be as honest as possible, improving the chances that your mixes will sound similar on as many playback systems as possible. Of course, it must be said that no monitor is truly flat in frequency response. In actuality, absolute flatness is marketing hyperbole, as no speaker can ever be perfect. This caveat aside, professional studio monitors, particularly the better ones, will typically get closer to flat than the average home stereo speaker box.
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RECORDING December 2012

Multi-Way While some small studio monitors use only one driver, most are two-way. This means that two separate drivers transduce electrical energy into acoustic energy. The woofer handles the lows and the tweeter delivers the highs. Multiway loudspeakers are essential because no one size of driver adequately reproduces all frequencies, especially at higher sound pressure levels (SPLs). Larger monitoring systems, more suitable for bigger rooms and greater loudness, are sometimes three-way, with the lows, mids, and highs sent to three different drivers. Still larger systems are four-way, often with a separate subwoofer handling the lowest of lows. While three and four-way loudspeakers may be more appropriate for larger spaces and higher SPLs, the size and electrical complexity of these boxes can make use as reference monitors difficult. The physical spacing of the separate drivers is one issue, as a listener hears each driver with a slight difference in arrival time. This creates comb filtering (phase interaction) in the crossover zone, messing with frequency response. What’s the crossover zone? All multi-way loudspeakers require some type of frequencydividing network to split frequencies into ranges appropriate for each driver. The filters in dividing networks are typically gentle in slope and neighboring drivers overlap in coverage of some inbetween frequencies. In this zone of overlap,

Recording - December 2012

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