Tata suara

Tata Suara (Sound System)

Tata Suara adalah suatu teknik pengaturan peralatan suara atau bunyi pada suatu acara pertunjukan, pertemuan, rapat dan lain lain. Tata Suara memainkan peranan penting dalam suatu pertunjukan langsung dan menjadi satu bagian tak terpisahkan dari Tata Panggung dan bahkan acara pertunjukan itu sendiri. Tata Suara erat kaitannya dengan pengaturan penguatan suara agar bisa terdengar kencang tanpa mengabaikan kualitas dari suara-suara yang dikuatkan. Pengaturan tersebut meliputi pengaturan mikropon-mikropon,kabel-kabel,prosesor dan efek suara, pengaturan konsul mixer, kabel-kabel, dan juga Audio Power amplifier dan Speaker-speakernya.

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Sebuah contoh system tata suara yang paling sederhana

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Sebuah contoh system tata suara yang paling sederhana

Aspek teknis Peralatan Tata Suara

Secara garis besar suatu tata suara harus paling tidak mempunyai empat elemen penting yaitu: mikropon, Audio Mixer,Power Amplifier dan loudspeaker.

• Mikropon

Sebagai pengubah atau penangkap getaran suara (transducer) kualitas dan karakteristik mikrophon haruslah disesuaikan. Pola pengarahan mikropon adalah penting untuk diperhatikan apakah itu direksional maupun omnidireksional. pemilihan berdasarkan pola pengarahan, sensitifitas mikrophon sangat menentukan kualitas audio yang akan dilalukan kedalam perangkat Audio Mixer.

• Audio Mixer

Sebagai titik kumpul dari semua mic dan juga sumber-sumber audio yang ada, Audio mixer menentukan berapa banyak kanal mikropon yang bisa dilayani dan bagaimana nada yang dihasilkan oleh mikropon dipadukan.

• Audio Power Amplifier

Audio amplifier adalah penguat akhir dari semua sinyal yang telah dipadukan oleh Audio Mixer.Besarnya penguatan diukur dalam hitungan watt (rms).tergantung dari keperluan,besarnya kemampuan amplifier dari ratusan watt untuk pemakaian kecil untuk pesta atau acara-acara pertemuan dan ratusan ribu watt untuk pertunjukan besar seperti acara pertunjukan langsung musik band-band terkenal.

Pengaturan Jalur Sinyal

Sinyal Audio dari mikropon akan memalui input dari atas dan dialirkan ke ujung bawah volume fader

Pengaturan tata suara dimulai dari pengaturan jalur mikropon dan sumber input yang lain ke mixer yang ada. Dari audio mixer itulah nantinya diatur kembali oleh operator ke berbagai keperluan yaitu dikirim ke Audio Power amplifier utama, Booth Monitor, dan juga ke input rekaman jika diperlukan. Peralatan lain seperti audio limiter dan compressor, noise gate, reverb,extra equalizer dapat diatur di konsul mixer tersebut. Letak Konsul mixer sedapat mungkin harus dipilih di depan Panggung jika tata suara itu untuk pertunjukan, dimana diperlukan kabel penghubung terlindung yang menghubungkan panggung dengan konsul mixer. Sedapat mungkin kabel penghubung ini dilalukan pada jalur aman dari injakan kuat yang dapat menganggu.

Bagian-bagian Sistem

Transducer-transducer Input

Banyak jenis trandsducer dapat ditemui dalam sebuah tata suara, Dengan mikropon sebagai jenis trnsducer yang paling banyak dipakai. Mikropon dapat dibagi-bagi menurut cara kerja perpindahan getarannya, dan juga bentuk dari penerapan kegunaannya. Kebanyakan mikropon yang dipakai dalam tata suara adalah dari jenis mikropon dinamik dan mikropon kondenser

Mikropon yang dipakai dapat diletakkan dan dipasang dengan berbagai cara, termasuk pada penyangga dengan dasar pemberat, penyangga podium, jepitan dasi, terpasang di instrument dan terpasang di headset. Mikropon yang dapat dipasang pada jepitan dasi dan headset seringkali digunakan dengan transmisi nirkabel sehingga memudahkan pembicara yang menggunakannya agar bebas bergerak. Ada beberapa jenis transducer lain yang mungkin dipakai sesekali, termasuk didalamnya adalah pickup magnetik yang digunakan pada gitar listrik dan bass listrik. Mikropon hubung yang dipakai pada intrument-instrument berdawai,piano, dan juga katrid pickup phono yang dipakai pada pemutar-pemutar rekaman.

Prosesor-prosesor Sinyal

Pada tata suara profesional prosesor-prosesor sinyal bisa dipakai seperti Audio limiter dan Compressor untuk Mikropon, penambah dinamis nada seperti prosesor reverb dan chorus.

Konsul Mixing

Konsul mixing (Audio Mixer) adalah pusat dari sistem tata suara dimana operator dapat menyampur, menyamakan dan menambah efek-efek pada sumber-sumber suara. Berbagai konsul mixer dapat dipakai untuk berbagai keperluan dalam satu sistem tata suara tunggal. Dalam tata suara, konsul mixer utama (FOH, Front of House) harus berada dimana operator dapat melihat dan mendengar aksi di panggung. Mixing dengan booth monitor terdekat akan mencegah operator dari pendengaran yang campur aduk antara suara artis, umpan balik Loudspeaker utama, gaduh penonton dan juga efek akustik ruangan. Pada pertunjukan skala besar, sering kali menggunakan konsul mixing untuk monitor panggung secara terpisah, dimana diperuntukkan untuk menciptakan monitor hasil mix bagi monitor-monitor diatas panggung. Konsul-konsul ini sering kali terletak di samping panggung sehingga operator dapat berkomunikasi dengan yang sedang tampil diatas panggung.

Equalizers

Equalizer ada dalam sistem tata suara dalam dua bentuk : Equalizer grafik dan Equalizer parametrik. Keduanya dipakai dengan filter-filter End-cut.qualizer parametrik mempunyai pemutar paling tidak tiga parameter yakni : frekuensi, Perbesar-potong (boost/cut) dan Q(lebar jalur). Equalizer tersebut lumrah ditemukan berada dalam setiap kanal dalam konsul mixing, namun ada juga yang dibuat terpisah. Equalizer grafik mempunyai penggeser-penggeser yang mengacu pada sebuah kurva dari response terplot pada sebuah grafik. Pada sistem tata suara biasanya didesain pada tengah-tengah 1/3 oktaf. Filter-filter suara End-cut akan membatasi lebar jalur melewati batasnya, dimana akan mencegah gangguan-gangguan subsonik dan pengaruh RF atau ganggunag-gangguan dari pengatur lampu yang dapat mengganggu sistem suara. Bagian-bagian dari filter-filter End-cut seringkali termasuk dengan equalizer grafik untuk memberikan pengaturan penuh. Sebuah penekan umpan balik (Feedback suppresor) adalah jenis filter yang akan secara otomatis mendeteksi dan menekan umpan balik suara dengan memotong frekunsi suara mana yang menyebabkannya.

Compressors and limiters

Compressors and limiters are used to maintain an average signal level by automatically reducing the level of louder sound. Signal compression is necessary because the dynamic range of equipment may be smaller than that of the signal and cause distortion, or clipping. When the signal is compressed, there is a smaller difference between the volume of the loudest and quietest sounds. The output level of a compressor can then be turned up to optimize the efficient use of a systems dynamic range.

Compressors also have attack and release settings, which determine how long the compressor will wait before turning down the volume on a loud sound, and how long to wait before turning the volume up again. Attack time is usually within the range of microseconds, while release time is in the range of seconds. There is also a threshold setting which determines at what minimum sound pressure level the compressor should start compressing. Compressors are useful for restricting the volume of vocalists with a large dynamic range. Vocalists using microphones need to learn how to distance their mouth from the microphone when singing especially loud notes, such as high notes. Compressors provide for safer signal handing by avoiding distorting and clipping.

A limiter is essentially a compressor with the most extreme setting in effect, and sets a sound level ceiling on a signal instead of a slow curve. Limiters suppress very loud pops (such as when unplugging a guitar or dropping a microphone) which could damage the audio system.

Noise gate

A noise gate sets a threshold where if it is any quieter it will not let the signal pass and if it is louder it "opens the gate." Thus the noise gate's functions are very much opposite to those of a compressor. There are also attack and release settings, which work in the same way as a compressor. Noise gates are useful for microphones which will pick up noise which is not relevant to the program, such as the hum of a miked electric guitar amplifier or the rustling of papers on a Minister's podium.

Noise gates are also used with the microphones placed near the different drums and cymbals in the drum kits in many hard rock and metal bands. Without a noise gate, the microphone for a specific instrument, such as the floor tom, will also pick up sounds from nearby drums or cymbals, which bleed into its microphone. With a noise gate, the threshold of sensitivity for each microphone for each instrument from the drum kit can be set so that only the direct striking of the instrument will be picked up by the microphone, and not the nearby sounds.

Other effects and accessories

Reverberation and Delay (audio effect) effects are widely used in sound reinforcement systems to give the effect of natural reverb. Less commonly, modulation effects such as Flanging and Phaser (effect)s are applied to some instruments for an unusual sound effect. The Exciter (effect) "livens up" the sound of audio signals by applying dynamic equalization, phase manipulation and harmonic synthesis of (usually) high frequency signals.

A wide range of accessories are used in sound reinforcement systems. High-end audio cables are shielded to prevent hum and interference. Rack-mount cases, such as the industry standard 19-inch racks are used to store and transport effects units and amplifiers. Some racks have cushioned shock-mounting to protect equipment from impacts.

Power Amplifiers

Power Amplifiers increase the signal level, and provide current to drive the loudspeaker. All output transducers require amplification of the signal by amplifiers, including loudspeakers, monitor speakers, and even headphones. Most professional amplifiers provide protection from overdriven ("clipped") signals, short circuits across the output, or thermal overload. Compression and limiting features are often used to protect loudspeakers and amplifiers from signal overload.

Like most sound reinforcement equipment, professional amplifiers are designed to be mounted on 19-inch racks. Many power amplifiers have internal fans to draw air across the heat sinks. Heat dissipation is an important factor for operators to consider when mounting amplifiers onto equipment racks, since they can generate a significant amount of heat

Since transistor power amplifiers used for large venues need to produce a high output, this usually means that most powerful amplifiers are very heavy. Most powerful amplifiers are Class AB amplifiers, which need bulky transformers made of copper wiring and large metal heat sinks for cooling. However, Class D amplifiers, which are much more efficient, weigh much less than Class-AB amplifiers producing an equivalent power output.

Digital loudspeaker system controllers (DLSC), also known as digital crossover networks, are most commonly used to process the final mix being sent from the mixing console to the amplifiers, and in turn to the loudspeakers. Multiple loudspeakers with a more narrow-band response, tailored to specific frequency bands, can be used together (i.e. lows, mids and highs) to obtain a more accurate reproduction of the input signal. This also makes more efficient use of amplifier power by sending each amplifier only the frequency band that its respective loudspeaker can reproduce. The crossover function of a DLSC does this splitting of the input signal into separate outputs for each speaker. Most DLSCs have calibration and testing functions, such as a tone generator, a pink noise generator coupled with a real-time analyzer and automated room optimization.

Output transducers

Loudspeakers

Loudspeakers (also known as drivers) are the main speakers which project the sound to the audience. A basic, inexpensive PA speaker may only have a single full-range loudspeaker system. Professional PA speakers usually have different drivers that provide the low-, middle-, and high frequency sounds. In the 1960s, most PA speakers were "columns" with several speakers mounted in a tall cabinet, which evolved into cube-shaped speakers mounted on stands by the end of the decade. In the 1970s, PA speakers developed into stacks of "bass bin"s and high-range horns. By the 1980s, PA speakers became easier to use and set up, because they increasingly contained a range of different drivers (woofer and horn) with built-in crossovers.

In the 1990s and 2000s, professional PA speakers were often "actively controlled" with electronic processors that automatically adjust crossover and equalization settings and protect the speakers. In the 2000s, PA speaker cabinets were increasingly built with protection circuitry that protects high and mid frequency drivers from accidental exposure to low frequency sound material. Some PA speakers also protect the high frequency drivers with "current-to-light" conversion circuitry, which takes excess current which would otherwise damage a horn, and uses it to light a small light bulb. Another circuit protection technique used to protect horns is current sensing / self-resetting breakers, which protects the horn in cases of high-volume feedback (e.g., a microphone being accidentally dropped into a monitor).

As well, many PA speaker companies have begun providing Neutrik Speakon multi-pin connectors, instead of the decades-old 1/4" jacks. The Speakon connectors provide a much larger metal contact area for high current PA applications.

The four different types of transducers (woofers, compression drivers, and tweeters) all use the same components: a voicecoil, magnet, cone or diaphragm, and a frame or structure. PA speakers have a power rating (in watts) which indicates their maximum power capacity, to help users avoid overloading them with excessively powerful amplifiers. However, even an amplifier with less power output than a speaker's power rating can destroy the speakers if the amplifier signal becomes heavily distorted, especially if the distortion is from low-range sounds. The power rating of speakers is expressed either as RMS (Root Mean Square) or PGM (Program). The PGM rating became more widely used in the 2000s; it means "do not use more than the indicated power with this speaker." Trapezoidal or "wedge-shaped" speakers have a shape which allows the speakers to be grouped into arrays so that they can be mounted on rigging.

Professional PA speakers are usually designed with internal brace "flying" hardware (e.g., steel eyebolts) for safe suspension of speakers from rigging or ceilings. Many speakers are designed with interlocking corners so that they can be vertically or horizontally stacked for large concerts. Large, heavy PA speakers are often equipped with wheeled dollys, to facilitate on-stage placement.

Monitors

Speakers

Monitor speakers are usually full-range speakers which are directed towards an individual performer, a sound operator or entire sections of a stage. Most monitor speaker cabinets have a wedge shape, so that they will point up towards the performer when they are placed on their sides on the stage. Monitor speaker cabinets usually contain a speaker (driver) for low- and mid-frequency sounds and a horn for high-frequency sounds. Some monitor speakers include an L-pad for controlling the volume of the horn. In the 2000s, PA speaker companies began offering a range of powered monitor speakers, which contain a power amplifier. Another trend of the 2000s was the blurring of the lines between monitor speaker cabinets and regular speaker cabinets; many companies began selling wedge-shaped full-range speakers which they state can be used for monitors or regular Front of House purposes.

Headphones

Headphones are typically used by the sound board operator to monitor specific channels or to listen to the entire mix. Some performers may use headphones as monitors as well, such as drummers in pop music bands. In the 2000s, some bands and singers have begun using small "in ear"-style headphone monitors. In-ear monitors allow musicians to hear their voice and the other instruments with a clearer, more intelligible sound, because the molded in-ear headphone design blocks out on-stage noise. While some in-ear monitors are "universal fit" designs, some companies also sell custom-made in-ear monitors, which require a fitting by an audiologist. Custom-made in-ear monitors provide an exact fit for a performer's ear.