September 01, 2007

Monitoring Basics

By Emile Menasché

A well-chosen and set up monitoring system is critical in delivering mixes that will sound good outside the friendly confines of your studio.

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Producer and mixer Gustavo Celis (Beyonce, Shakira) sits in the studio


BE REALISTIC ABOUT NEAR-FIELDS
Most home studios use what are called "near field" monitors. These are generally smaller speakers designed to be positioned relatively close to the listenerin the "near field." The theory goes that the monitors' proximity to the listener prevents room acoustics from coloring the sound coming from the speakers, thereby providing a more accurate mix.

That's only partly true, and for several reasons. Let's start with the studio itself: In a room with well-designed acoustics, the audio coming from the speakers will be less colored by reflections, simply because the room will tune so that the reflections don't unbalance the frequency response and ambience of the sound coming through the speakers. That doesn't mean that near-fields aren't the choice for a DIY home studio—they are more effective than consumer stereo speakers that diffuse the sound all over the place—but be aware that you're also hearingsome room coloration.

Another problem: Many of us crank the music up too loud while we're working. Not only is this bad for our ears (and it's really bad—much worse than most of us are willing to accept!); it also affects the speakers' frequency response and lessens the benefits of the speakers' "near field" nature by making reflections off of surfaces like walls and the mixer more pronounced. In essence, loud monitoring makes the room more of a factor in the sound you hear.

Finally, if you're using small speakers, you have to be wary of over-compensating for the speakers' lack of low end by cranking the bass. Adding a subwoofer can help, but subwoofers can rattle a small room. Again, you'll get better results at low to moderate volumes.

The above is not meant to be discouraging. Just be realistic about what you're hearing. Any time you take a mix outside your studio and hear the music in new environments, you're increasing your odds of making sound mixing decisions.

The tools you use to write and record music may have changed, but one central piece of gear remains crucial: The monitors you use to listen as you record and mix. Of course, as with other parts of the creator's toolkit, monitor technology continues to evolve. But unlike, say, the latest recording interface or computer, monitors don't become obsolete overnight. A wise investment in monitors can pay dividends for many years to come.

So: how do you choose monitors for your studio? And is there a correct choice? The answers are, "carefully," and "yes, but it's not the same for everyone." We'll attempt to give you a brief rundown on the options so you can go about picking the right speakersand use them effectively.


The Basics

Studio monitors can be categorized by a number of different critera. The first consideration is the way the speakers project sound over distances. Monitors can be near field, mid field, or far field. Most speakers designed for home and project-recording studios are in the near-field class, which means that they're designed to be heard from a relatively close listening position—three to five feet being optimal. Near-fields are the most popular choice for home use because they tend to be less affected by any acoustical characteristics of the room than the more room interactive midand far field speakers. (See sidebar "Be Realistic about Near-fields").

The next consideration is size, which is generally measured by the diameter of the low-frequency drivers (or woofers). Studio monitors generally range in size from 5" woofers (the Yamaha HS50M) to up to 15" (Tannoy System 15DMT), with 6"-12" being the most popular. It's a common misconception that all small speakers are near-field and all large speakers are far field, but there are plenty of examples of larger speakers that are designed for near-field listening.

Physically, small speakers are appealing for home and project studios for both ergonomic and artistic reasons. Ergonomically, they're easy to position, and can usually be mounted in your work area right next to the monitors. Artistically, they're thought to give an idea of what things will sound like on a boom box or on the kind of computer speakers you'd buy at Staples—the kind of stuff consumers are using to hear music. That's sorta true, but a set to $1600 Genenlecs are not going to sound the same as the set of Logitech speakers that came with your family PC. Nor should they.

All things being equal, a larger woofer means greater low-end frequency response. But the woofer isn't the whole story: Cabinet construction is also a factor. Cabinets have openings called ports that help low frequency sound waves (which are larger) come through. With well-designed ports, a small speaker can get down surprisingly low. Of course, high and midrange frequencies are just as important as their low brethren; tweeter design is critical to a speaker's sound. Most studio speakers are two-way, meaning that they only use separate drivers for low and high frequencies; some models offer a third driver for midrange.

A crossover splits the audio signal and determines how low and high frequencies are fed to the woofer and tweeter, respectively. Most speakers in home studios have built-in crossovers that can't be adjusted, but we mention the feature here because subwoofers also use crossovers, and may be adjustable. We'll talk about sub woofers in a moment, but first, let's discuss power-which plays a huge role in the performance of monitors.



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Side and rear views of the Genelec [MODEL] powered monitor. Note the variety of connections and controls, as well as the bass port at the top.

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The Mackie Big Knob lets DAW users control volume to powered monitors and switch among several sets, ideal for A/Bing mixes.

Power up

Back in the day, all speakers were what we now call passive: they needed a separate power amplifier to work. In pro studios, you'd typically find very high powered amps, each driving its own set of passive monitors, and in some cases, separate amps feeding the speakers' low and high drivers, a setup known as bi-amping. In home studios, you might find one power amp of moderate power, with perhaps a switch letting it connect to different speakers. Either way, the match between the speakers and the amps was critical to achieving the best performance.

Today, however, we have the option of active speakers, in which the power amplification is built into the speakers. Many of these models are bi-amped, meaning that they have separate internal power amps feeding the woofer and the tweeter of each unit.

So: Which is best? Active monitors are very popular, and for good reason: Aside from the convenience of not having to buy and install an additional piece of gear (the power amp), active monitors have the inherent advantage of having the power section specifically designed to match the drivers, thereby insuring optimal performance. The built-in amp makes it easier to set up a surround monitoring (you don't need six channels of amplification) and to take the speakers with you (if your studio consists of a laptop). Active monitors connect directly to a mixer or audio interface, and many models are designed to hook up to both pro gear (XLR balanced connections) and semi-pro gear (with RCA or 1/4" connections). Some even have digital inputs.

The passive option does have some advantages, however, especially if you already have the amp(s). Passive speakers are less expensive than their active counterparts, and if the power amp breaks, you can repair or replace it without losing the use of the speaker itself. But if you go the passive route, get a good amp and make sure it's got enough power to drive the speakers; if you use the stereo receiver that's been sitting in your garage since your roommate left it in college, you're not going to get great performance from your speakers. (A PA amp might work, but be aware that these usually have loud cooling fans, which can be a problem in the studio. If that's the case, put the amp in another room, running longer cables between it and your system. Do not stick the amp in a cabinet with no ventilation: It'll fry.)



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Powered subwoofers like the JBL MODEL add bottom end.


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IK Multimedia's ARC software


Subwoofers

A subwoofer is a dedicated speaker designed to deliver bass frequencies. They're popular companions to small bookshelf monitors because they help compensate for the low end "missing" from these compact speakers. Since low frequencies are not "directional" you only need one subwoofer in a system; it will delivers the lows for both speakers in a stereo setup. Active subwoofers, like active monitors, have built-in power amplification.

Sub woofers are available as standalone devices, but many models are designed to work with specific near-field monitors and can be bought as part of a three piece system (the two near-fields and the sub). That's an attractive option because it's more likely that the sub will match well with the speakers. On many active systems, you can connect both channels to the subwoofer, then run an output from the subwoofer to the smaller speakers. Your mixer sees the sub and the monitors as one system.

But here's tricky part; even small speakers have some low midrange and low frequency response; and most subs reach into the lower midrange. If there's too much overlap between the two, you're not going to get an accurate read on your mix.

Fortunately, the better subwoofers—and the better near-fields—can be adjusted so that they work together well. Remember the crossover we discussed above? Look for a subwoofer that lets you decide what frequencies will pass through its outputs to the monitors, and look for monitors that let you adjust how low their internal woofers will go. By adjusting these two parameters correctly, both the monitor and the sub will work most efficiently.


AVOID RECORDING AND MIXING ON THE SAME SPEAKERS

This is a common problem in small studios. You have one set of speakers; you've obviously used them throughout the creation of your song. Now you go to mix and you have zero perspective on what you're hearing. That bass sound you loved when you were tracking is now dominating the track. What can you do?

• Invest in a second set of speakers and a switcher that lets you go back and forth between the sets. You don't have to spend a ton of money: Home speakers, computer speakers, cheaper powered speakers can all work fine when you're tracking.

• If you can't add another set of speakers to your rig, try to create a "buffer" between your tracking listening and your mixing listening. Step out of the studio and listen to the music in the car or on your iPod. Reset your mixer so that you're starting fresh at mix time. Listen to other music on your system before you start mixing the song.

What about Headphones?
Thanks to the iPod, it seems headphones have become the main way people listen to music these days. Should you monitor with them? Most pros would say no: Prolonged headphone use can damage your ears, even if they're not up all that loud. They also color the sound to various degrees. That said, many of us rely on headphones, especially when tracking. If you do use headphones, invest a good outside the ear model like the AKG K 141, Sony MDR-7506, and Sennheiser HD280s. Avoid using iPod ear buds for extended periods— though they can be useful for cross checking mixes.

Additional Features

On top of the basic qualities we've discussed above, other features to consider include:

Port position: Speakers have ports that allow low frequencies to disperse. The position of the port may be important depending on where you're planning to place the speakers. Rear-ported monitors, for example, may not be ideal if you're putting the speakers on a wall shelf because the port is going to send sound to the wall. In that case, look for front-ported speakers.

Adjustments: We've mentioned how some speakers let you adjust their frequency response for use with subwoofers. You may also find adjustments for treble response, damping, and, with active speakers, overall volume. These are conveniences, but are not all necessary: There are some great speakers with few, if any, onboard controls.

Ins and outs: While an increasing number of good speakers have connections suited to home studios, you'll still find active models that have balanced XLR inputs only. It's no big deal to make (or buy) cables that convert the XLR to the connectors used by your mixer. Some models, such as the 5" active Roland DS-30A, have built-in digital inputs, letting you connect a digital mixer or audio interface directly.

Shielding: Because so many of us make music with computers (and work on music for video) it's common to find speakers shielded against RF interference. It's a useful feature.

Convenience: This probably should not make or break a purchase, but it is nice when active speakers have front-panel on/off switches, multiple input connectors, input meters, and other little details that make life easier.



Accessories

Good monitors are a serious investment in and of themselves, but a good monitoring system is more than the speakers and the amp.

Cabling: use the best you can afford. If there's one cable run that's critical in your studio, it's this. Junky cables will color the sound, sometimes enough that regular people can hear the difference. Use good cable, good connectors, and keep the cable lengths as short as possible.

Speaker stands and isolators are also worth considering, especially if you're putting the speakers on a shelf on your desk. These decouple the speaker from the desk (which reduces the desk's influence on the sound). How well this works is an open question. If your room has other acoustical problems, decoupling the speakers can't hurt, but it's unlikely to help that much, either.

Switchers: My pet peeve about small mixers and audio interfaces is their lack of built-in switches to A/B between different sets of monitors. Fortunately third party switchers like the Mackie Big Knob and PreSonus Control Station allow you to connect multiple monitors and switch among them. If you can afford the extra monitors and the switcher, this is highly recommended because it lets you ear-check your mix as you go.



Setting Up

When listening on near-field monitors, positioning is critical. You've probably heard engineers refer to the "sweet spot"-the position behind the board that gives the most accurate picture while you're working. All "room" factors being equal, the sweet spot on most near-fields is determined by an equilateral triangle, with you on one apex, and the monitors on the other two. For example, if the speakers are four feet apart from one another, you should be sitting in the middle, four feet away from each speaker.

The speakers should be set up so that the tweeters are at you ear height or thereabouts, and they should point straight at you, not up or down at an angle. Laying speakers on their sides used to be popular, but not all speakers work well this way. Consult the manual for the manufacturers recommendations.

Make sure nothing is blocking sound from the speakers. A computer monitor, for example, can be a barrier, as can other assorted stuff you stick on your shelf. Keep the area around the speakers clear at all times.