Studio Recording Techniques – Monitors

Studio monitors are loudspeakers specifically designed for sound production applications such as; recording studios, film-making, television studios and radio studios, generally where accurate audio reproduction is crucial. Whereas reference monitors refer to loudspeakers generally used to gauge what a recording will sound like on consumer-grade speakers.
Among sound engineers, the term monitor usually implies that the speaker is designed to produce relatively flat or linear phase and frequency responses. In other words, it has little emphasis of particular frequencies and the monitor gives an accurate reproduction of the tonal qualities of the source audio giving an “uncoloured” or “transparent” sound, and there will be no relative phase shift of particular frequencies, meaning no distortion in sound stage perspective for stereo recordings. Beyond stereo sound stage requirements, a linear phase response helps impulse response remain true to source without encountering any distortion.

Nearfield

A certain type of monitor is referred to as a near-field Monitor. This is a speaker small enough to sit on a stand or desk in proximity to the listener, so that most of the sound that the listener hears is coming directly from the speaker, rather than reflecting off of walls and ceilings thus picking up colouration and reverberation from the room. Also, studio monitors are made in a more physically robust manner than normal home hi-fi loudspeakers. Normal home hi-fi loudspeakers often only have to reproduce compressed commercial recordings, studio monitors have to cope with the high volumes and sudden sound bursts that may happen in the studio when playing back unmastered mixes.

Many audio engineers use monitor speakers for audio mixing and mastering tasks. This enables the engineer to mix a track that will sound pleasing on the widest range of playback systems, in other words; high end audio, low quality radios in clock radios and “boom boxes”, in club PA systems, in a car stereo or a home stereo.

Accurate sound reproduction will also mean that the engineer is less likely to miss any undesirable tonal qualities of the recording, and so can compensate for them. On the other hand, some engineers prefer to work with monitors that are known to be flawed in ways that are representative of the systems end-users are likely to be listening with. In fact, most professional audio production studios have several sets of monitors spanning the range of playback systems in the market. This may include a sampling of large speakers as may be used in movie theatres, hi-fi style speakers, car speakers, portable music systems, PC speakers and consumer-grade headphones.

Midfield

Midfield monitors are designed to be heard from a reasonable distance from the engineer meaning, mid-way between him and the studio. They are usually passive so can be induced by feedback very easily. As the importance of proper room acoustic trreatment became more evident and available, people started to not only listen to the material coming from the monitors but also how the sounds interacted with the environment. This was the original purpose of mid field monitors. Mid field monitors are normally placed farther from the person mixing the song. Many included larger transducers to reproduce the lower frequencies in the mix as the air needed to be moved farther.

Use of mid field monitors also required proper installation of room acoustic treatment to avoid room acoustics from coloring the sound and biasing the mix. The mix usually sounds very different through near field monitors then mid field monitors. By using near field monitors and switching to mid field monitors, an engineer could hear potential changes to the material as it interacts with the environment.

Active & Passive

Amplification: Studio monitors may be “active”, meaning, they include one or more internal power amplifiers, or passive, this means they require an external power amplifier. Active models are usually bi-amplified, which means that the input sound signal is divided into two parts by an active crossover, used for low and high frequency components, both parts are amplified using separate low- and high-frequency amplifiers, and then the low-frequency part is routed to a “woofer” and the high-frequency part is routed to a “tweeter” or “horn”. Bi-amplification is done so that a cleaner overall sound reproduction can be obtained, since signals are easier to process before power amplification. Consumer loudspeakers may or may not have these various design goals.So monitoring is a vital part of the recording chain.

Two-Way & Three-Way Speakers

To put it simply, if a speaker is referred to as a 2-way loudspeaker it means it has 2 speakers in it. If it is a 3-way loudspeaker it will have 3 speakers in it. Different sound waves are reproduced better by different speaker sizes. High pitched sounds like cymbals require a speaker to move very fast to reproduce the sound, as where low frequency sounds like a bass drum or guitar require a much larger speaker to move a greater volume of air. Although you could have one speaker to do both, a two-way loudspeaker breaks up the task into two speakers, each specializing in producing a specific range of sounds. This means that each speaker will do a better job of reproducing the sounds within its frequency range. Low frequencies usually are those below 150Hz while most speakers can produce sound as high as 20kHzFrequency Range

Frequency Range What type of sounds
Very Low under 30Hz Bottom notes on a pipe organ, rumble of explosion – Subwoofer only
Low 30Hz to 160Hz Bass Tuba, Bass Guitar – Woofer
Mid 160Hz to 3kHz Human voice, Trumpet, Sax – Woofer or Midrange
High 3kHz to 20,kHz Cymbals, Piccolo – Tweeter

Crossovers

To split the sound between 2 or 3 speakers, something called a crossover is used. The crossover takes the signal from the amplifier and splits it into 2 or 3 frequency ranges and sending those signals to the speaker best designed to handle those frequencies. In a 2-way speaker, the sound is split between the tweeter and the woofer. The highs go to the tweeter and the lows to the woofer.

Three way speaker systems include a mid-range driver. This is usually a speaker that is smaller than the woofer in the system, and gets program material in the “middle” of the frequency spectrum. This allows the system to have one speaker that can concentrate on producing things like voices, saxophones and other instruments in this range. 

Although it would seem that splitting the signal into three ranges would increase the accuracy of the music reproduction of a speaker, it depends on how well the crossover is “tuned” and several other items including cabinet design, how well the other speakers are matched to each other, the listening room and what type of sound the engineer is going for.

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