Recording Monitors

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What are studio monitors?

Studio monitors are essentially speakers designed and built for the specific use of accurately reproducing audio in a recording studio’s control room environment.  They are the “lenses” through which the engineer and the artist perceive their work. It is important to recognize that all recording and mixing decisions are ultimately made based upon the information reproduced by studio monitors. So, you can see why the studio monitoring chain is a critical component for ANY studio, large or small, or whether the studio is for professional use or as a hobby.

The search for a set of studio monitors can sometimes be complex when balancing out factors such as budget, size of woofers, style of tweeter, crossover design, cabinet construction, and amplifier topology, etc.  The question is often asked, “Why are Brand A, Model X monitors $500 a pair and Brand B, Model Y monitors $5000 a pair???”  Ultimately, the balance of the aforementioned factors will determine the quality and overall performance and usefulness of a pair of monitors.

Studio monitors are designed to be accurate and flat, and are not designed to enhance the sound to be more pleasing-sounding, such as what you would find in hi-fi or home theater setups where it is acceptable to have a lifted top, a slightly scooped midrange, and/or a boosted bottom.  In other words, studio monitors are designed to reveal detail that other speakers might hide in order to “enhance” the sound.  Some monitors have frequency curves that lead to mixes that translate good on many other playback systems – the Yamaha NS10M (a very popular passive studio monitor that was discontinued in 2001, but is still prevalent in studios today) worked in this way.

However, despite all this talk about “flat-response” and such, there is no such thing as a perfectly “flat” monitor. Add to that the fact that we all hear and perceive sound differently due to the different genetic physiology of our ears and how we each “decode” audio within the mind, and a fertile ground is before us where personal preferences begin to take over what ultimately is judged to be “the best” studio monitor in the opinion of each engineer. Thankfully, studio monitor designers also hear and perceive sound differently (despite their mathematical minds, they are still human after all!), and therefore we end up with quite a selection of designs and features to choose from. So, in the end there is a set of monitors (or even a few) out there that are perfect for you. To get there, however, we need to understand the different types of monitors and their various, possible features.

What are the different sizes and types of studio monitors?

Studio monitors can be broken down into three main categories.  There are Near-Field Monitors, Mid-Field Monitors, and Far-Field Monitors. Lets take a look at each:

Near-field studio monitors (as their name implies) occupy the close listening range of speakers, and are generally placed just a few feet away from the engineer.  Near-field monitors are often designed as 2-way systems (woofer and tweeter), though there are a few 3-way near-field monitors, such as the Klein + Hummel O 300 that sports a separate mid-range driver.  The frequency band is split at a crossover point, and sound below the cutoff goes to a woofer, while sound above the cutoff goes through a tweeter.  The tweeter and woofer are in the same cabinet.  These monitors can be passive or active designs, and different sizes.  Between 5 and 8 inches is common for woofers, while tweeters are generally around 1”.

Mid-field studio monitors are placed further away than near-fields.  For mid-field monitors, the amount of direct sound from the speakers and reflected sound (off surfaces in the room) that reach the listeners’ ears are about the same.  Mid-field monitors are often designed with dual woofers of the same size in a single cabinet.  This is called a D’Appolito design.  The ADAM S3X-H and ADAM P33A are common mid-field monitors that employ this system.  Mid-field monitors can provide a wider stereo image, and bigger “sweet spot” for listening.

Far-field monitors studio monitors are usually much larger than other studio monitors.  Because they are placed farther away from the listener, the listener hears a lot of room reflections compared to direct sound, so far-fields require more acoustic treatment in the room to get an accurate sound.  For this reason, far-field monitors are mostly found in large professional studios that have been properly acoustically designed.  Far-fields are often mounted in the walls of the studio.  These monitors provide a new dimension of the sound, and can more accurately simulate different sound environments like a club, concert, or theater than near or mid-field studio monitors can.  They can also be better for tracking in this way, since they will sound more live and realistic than smaller, closer speakers will.

What are the components that comprise a studio monitor?

Monitors are also designed with different materials which ultimately make up the quality of the speaker.  Woofers are comprised of different materials, typically including: Paper, Polypropylene and Kevlar.  Tweeters are comprised of different materials, typically including: Silk Dome, Metal Dome and Ribbon.  These different materials provide different sound, and have certain advantages or disadvantages. Ultimately, you will have to listen and make your own decisions based upon your initial impressions of what you like.

Studio Monitor Woofers

Paper Cone - The most basic and most common material for woofer construction is also considered by many to be the best sounding. Many manufacturers use paper as it is the traditional material used. They are arguably the most natural sounding and are the easiest to create a crossover network for.

Polypropylene - Polypropylene woofers are what you might call “plastic cone” woofers though they may be a paper cone only coated with Polypropylene.  This “smooth” woofer approach is not without it’s potential pitfalls. The reflectivity of the surface and the relative un-natural sound of this material necessitates the use of more complex crossover and/or filter networks (corrective equalization via circuitry or digital signal processing) in order to create a more natural sounding result. Some purists will argue that no amount of corrective measures will make a polypropylene woofer sound as natural as a properly designed paper cone woofer.

Kevlar - Kevlar woofers are very strong and help the woofer maintain it’s shape at excursion. Kevlar woofers visually recognizable for a look that appears much like perfect canvas weave (it is in the Nylon family of polymers and has a higher weight to strength ratio than steel!) which also helps to reproduce a strong yet relatively uncolored midrange. It is a perfect material for the control of standing waves due to it’s high internal damping. However, it is a relatively difficult and expensive material to work with. Therefore, it will usually only be found among the more expensive monitoring solutions.

Studio Monitor Tweeters

Silk Dome - Though paper was used early on in tweeter design, the Silk Dome tweeter is durable and lightweight when coated with a polymer. Silk dome tweeters’ light weight allows the diaphragm to respond very quickly to high frequency signal. Like paper cone woofers, silk is the most common and arguably the most natural sounding material for tweeter design. Characteristically, these tweeters feature a smooth response that is not considered harsh and is preferred by many audiophiles.

Metal Dome Tweeters - Some people prefer the “clarity” that they experience when listening to titanium tweeters. However, the risk is run of this brighter sound being more fatiguing on the ear; meaning, you might not be able to listen or work as long. In recent years, the presence of Beryllium tweeters has become a very popular selling point for many high-end monitors.  The idea here is that if light-weight is crucial to fast response, then the ideal would be to find a metal that will be extremely light. When comparing elements’ atomic weight on the periodic chart, Beryllium clocks in as the 4th lightest element (Aluminum is 13th).  The trouble with Beryllium is that it is incredibly brittle and must be combined with other metals in order to keep from breaking. It is also toxic – which yields no danger to the user, only the person building the tweeters and working directly with the Beryllium itself.

Ribbon Tweeters - The ribbon tweeter is by far the most radical departure of all the tweeter designs listed here. For those already familiar with ribbon microphones, the ribbon tweeter relates to the ribbon microphone element much like how a regular silk or metal dome tweeter relates to the dynamic moving coil microphone element. Ribbon tweeters are characterized by an extremely smooth sound that is accurate and is much less fatiguing to the ear when listening back. Ribbon monitors are also noted for superb stereo imaging. ADAM Audio monitors are excellent and very popular examples of this style of monitor.

Passive vs. Active Monitors

Monitors require an amplifier in order to amplify the audio being provided from your mixer, DAW, or tape machine and drive the woofers and tweeters.

Active Monitors - Active studio monitors have either a built-in amplifier or even a set of amplifiers for each component (An active monitor with a separate amplifier for the woofer and another amp for the tweeter is called a Bi-Amped monitor), while passive monitors require an external power amplifier which must be matched to the monitors for best performance. This matching process ultimately comes down to listener preference and can take a lot of effort arranging demonstrations of various amplifiers and monitors to determine the best combination for each person’s particular application.  For this reason, active monitors are generally a simple solution for most studios and are what you will find in many control rooms.  An active studio monitor’s amplifier section is designed to properly and optimally work with the speaker(s). You only need feed them a line level signal (+4dBu Balanced [1/4 Inch TRS or XLR-male] or -10 dBv Unbalanced [1/4 TS]), and with some basic placement and level adjustment, they are ready to use.

Passive Monitors - Passive monitors are usually less expensive than active monitors. However, power amplifiers will add to the cost of a passive system, depending on which route you decide to go. Contrary to popular thought, the amplifier you use should be able to handle more wattage than the speaker requires.  A good rule of thumb is to use double the wattage for the power amp than what the speaker manufacturer says the monitor needs.  This results in providing you with headroom, so you can avoid clipping within the amp, which causes lots of high-frequency harmonics that can result in a tweeter burning out. You want the amplifier to work well within it’s operational range and never having to work at its maximum limits.  While your wattage will differ by the 2:1 ration we just discussed, you will want to take care to ensure that your wattage calculations are based on the impedance (measured in ohms) between your power amp and your monitors. For example, if your speakers RMS (commonly referred to as it’s “average”) rating is 200 watts at 8 Ohms, then your amplifier should be able to provide 400 watts at 8 Ohms. Check the manufacturer’s manuals for details.  Because passive studio monitors require a separate power amp, choosing passives can be a good way to get more control over the sound, since you have more variables to work with (speakers and amp).  Don’t forget you will need speaker cables to hook the power amp up to the monitors.

How to choose your studio monitors

The first thing you should do if you are thinking about buying a set of monitors is to consider your needs and intended application.  Are you recording scores for films that will be played in theaters and need far-fields, or are you a home studio guy mixing in an untreated room?  If your room is not acoustically ideal, you should definitely consider near-field monitors and room treatment (acoustic treatment will solve tons of issues that even the best of monitors cannot solve on their own).  Of the three types of monitors, near-fields are the least affected by the room.  Because near-fields sit so close to the listener, the ratio of direct sound to reflected/indirect sound is much larger than for mid-fields or far-fields.  So, indirect room sound is somewhat attenuated compared to the direct sound.  However, the room sound is still there and will definitely still have an effect, especially depending on the height and angle of your ceiling, ceiling and wall material, and general speaker placement in relation to the walls.  Remember, room treatment options are available, as well as room-correction systems like KRK ERGO and IK Multimedia’s ARC.  Also, consider that some monitors have room controls to cut out problematic low frequencies if you are forced into a corner, or have a small room

Do you need the extended bass of an 8” woofer or sub-woofer over a 5” cone?  Bigger woofers can push more air, and thus have more bass.  Extended bass frequencies might be bad for small or untreated rooms, especially if you have to place your speakers against the wall or in corners, which cause bass build-up.  Monitoring with a sub in conjunction with your monitors is good for spot-checking the balance of your mix.  However, sub-woofers should probably not be left on for the whole mixing session.  Foot-switches for subs are available and provide an easy way to turn your sub on an off.

If you have more than one set of monitors, you may consider an A/B monitoring setup.  This would allow you to listen to your mixes on each speaker set at the touch of a button.  This way you can easily reference the sound on different speakers to get a new perspective on your mix.  Some monitors like the Avant Electronics MixCubes are designed to sound more like consumer-grade speakers, which may help you cut down on the need to take your mixes to other systems to check the sound.  There are many options available in terms of monitor controllers that allow A/B monitoring.

The best thing you can do when choosing monitors is to go out and listen to the ones you are considering.  Different monitors work for different people.  It is a preference thing.  One person’s “transparent and detailed” is another person’s “overly-bright and harsh.”  Make sure the monitors sound clear and detailed, rather than muddy or cloudy.  They should sound open, rather than boxy.  Bring listening material you are familiar with if you can when you go to demo the gear, as this will help you judge the monitor’s character.  Also, keep in mind you may be using your monitors for hours at a time.  Make sure they don’t sound overly fatiguing to your ears.

Learning Your New Monitors

When you get new monitors, you need to get accustomed to their sound.  One way to do this is to listen to music you are very familiar with through the monitors.  Listening to and learning your monitors will help you to use your monitors to get your mixes how you want them to sound.  This is debatably more important than the flatness of the frequency curve of the monitors.  The more you use your monitors, the more comfortable you get with them and the better you will become at making judgments on the sound.  If you can, listen to your everyday music on your monitors.  This will help you get accustomed to their sound and allow you to reference your mixes to the professional mixes of your favorite artists.  If you know how music is “supposed” to sound on your monitors, you will be that much closer to getting the perfect mixes on your new speakers.

Monitor throughout the volume spectrum.  Make sure your mixes sound good both at quiet volumes, average loudness, and loud levels.  Remember, your music will be played at vastly different volumes by people who hear it, and you want the music to sound good not just anywhere it’s played, but at any volume as well.

Take your monitor mixes to other listening sources.  This can be your home stereo, your car, other studios, etc.  See how it sounds.  Again, this will help you learn your new monitors by seeing how their sound translates to other playback systems.  Plus, your mixes are likely to be heard on cheap speakers, or in the car, rather than on professional studio monitors, so referencing on these systems will give you a new, but common-consumer perspective and reference-point.

How to connect your monitors

Interfacing your new monitors with your other gear depends entirely on your setup.  If you are using a mixer, you will need to connect the monitors (or power amp if you are using passives) to your mixer’s line output jacks.  These are probably balanced ¼” or XLR plugs, but look on the back of your mixer or check the manual.  If you are using a DAW to record, you probably have an audio interface or even a separate D/A converter.  Connect your power amp or active monitors to the line outs or monitor outputs on these devices.  They may be XLR connectors or balanced ¼” jacks.  You can use regular instrument wire for these connections.  If you are using passive monitors, you will need speaker cables to connect them to the power amp.  You don’t need speaker cables if you are using active monitors.

Where and how to place your monitors

The placement of your monitors is very important.  Near-field monitors should be placed about two to five feet from your listening position.  You should avoid placing your monitors near walls or in corners of the room as this causes a bass build-up and unwanted resonance. This disruption of the frequency balance will creates general boost of low frequencies which will, in turn, cause you to cut more low frequencies from your mixes.  Consider using products such as Primacoustic’s Recoil Stabilizers or Auralex’s MoPADs to put under the monitors.  These help to de-couple the monitor from your desk.  If you don’t use isolation pads, your monitors can cause your desk to resonate, again causing increased bass.  You can also consider monitor stands in conjunction with isolation pads.  This clears space on your desk, can facilitate monitor placement, and eliminates monitor-desk coupling.

Your monitors should be placed in such a way that their location creates an equilateral triangle with your listening position.  In other words, if your speakers are four feet apart from each other, your speakers should each be four feet away from your ears in listening position.  This is the sweet spot of the stereo image, where you hear the stereo field properly.

The tweeters of the monitors should be aimed in line with your ears.  Since you have formed an equilateral triangle with the monitors, they should be pointed to form a 60 degree angle with an imaginary line connecting to two monitors.  High frequencies are more directional than lower frequencies, so it’s more important to have the tweeters (rather than the woofers) pointed at your ears. For proper monitoring, create a direct path for the sound to travel, taking care to ensure that no objects are between the monitors and you that could block the sound.  So, computer screens should be placed either directly between monitors, or situated on a lower plane than that of the monitors path of sound emanation towards your ears.  Though we can’t always get around the need for specific functional placement of these items, mixers, desks, control surfaces, etc. will cause reflections depending upon placement that can color the sound you are hearing.  Ultimately, you are after the loudest direct to indirect sound ratio you can get.

Closing Thoughts

Now that the various types of monitors have been identified, as well as some of the potential pitfalls that can be encountered in the mixing environment, you should have a good idea of the direction you should be heading in regards to solving your monitoring situation. And, if you have any lingering questions at all, the staff at Front End Audio is extremely knowledgeable, with years of professional and project studio experience that, combined, identify with the challenges you face and provide the tools needed to help solve the technical end of your quest for great mixes.