Ribbon mic是什麼原理和用途?

本文由 BetaTester2002-09-15 發表於 "錄音、音樂製作精華" 討論區

  1. BetaTester

    BetaTester Member

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    我在各位前輩討論mic時去國外網站亂逛,看到一種叫Ribbon mic的,
    Ribbon mic是什麼原理?有沒有什麼長短處和用途?
    為什麼好像不常見,從沒看過也是第一次聽說,請知道的人談談>
    謝謝!
     
  2. realname

    realname New Member

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    Ribbon Mic 和 Dynamic Mic 的原理接近, 但是它用金屬薄膜來感應聲波, Ribbon Mic 最大的好處在於它自然的音色, 非常適合用來收 Acoustic 樂器的聲音. 早期的Ribbon Mic非常脆弱, 那片薄薄的金屬片很容易壞, 但現在的Ribbon Mic就耐用的多, 甚至已有需要Phantom Power的型號(早期的Ribbon Mic一碰到Phantom Power通常那片金屬模就跟著毀了). Royer Lab算是目前知名的Ribbon Mic製造商, 有興趣的話可以到他們網站去逛逛.
     
  3. 掌門人

    掌門人 當代校長張超然

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    Royer Lab 的音色不知道好不好?有一回需新 mic 時差點考慮買它的第一代產品,主要因為怕其輸出太小,又怕用不太慣 figure 8 的 pattern。有人用過嗎?又他們有一新設計,好像還要 phantom power,不知是怎麼回事?我猜是做個 internal preamp 來放大訊號吧!

    還有 Beyer 也有 M500 和 M160 (?) 的產品或 Core(?) 也有,比 Royer Lab 略便宜,不知如何?
     
  4. realname

    realname New Member

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    to 掌門大哥:
    掌門人果然沒猜錯, active的ribbon mic 內建了個含有FET的head preamp. 其實際設計小弟不得而知, 如果有查到定向掌門人稟報.
     
  5. Mr72

    Mr72 Well-Known Member

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    Sequerra audio 最近開始shipping RM-1 ribbon mic,在下剛好有機會試了一下,clarity 相當好,據Mr.Richard Sequerra表示此model除了有higher output level than any previous ribbon mic 之外,,且能承受135 dB source without any clipping!!
    這樣的表現應該很適合classical sessions,and vocal performance....

    對ribbon mics 有興趣的同學可以參考... http://www.sequerra.com/prosound/data/index.html
     
  6. Mr72

    Mr72 Well-Known Member

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    Here is a brief introduce to Mic...

    Microphones are transducers (energy converters) that convert sound energy into electrical energy: i.e. they take sounds and convert them to signals in a wire. Thats all there is to them really. The complexities start when you start having to worry about what type of mic to use in what situation and where to place it to get the best results.

    There are two main types of microphone that are commonly used:

    "Dynamic mics"
    Moving Coil
    Ribbon

    "Condenser/Capacitor mics"


    Dynamic Microphones

    "Moving Coil"
    The moving coil dynamic microphone is probably the most common and robust type of mic generally used, it's only shortcomings being it's limited and slightly uneven frequency response. In construction it can be thought of as functioning exactly like a loudspeaker in reverse.

    It consists of a flexibly mounted diaphragm coupled to a coil that is suspended within the air gap of a magnet. When sound strikes the diaphragm it causes it to vibrate. This vibration is passed on to the coil, and as the coil vibrates in the magnetic field, an alternating current directly proportional to the sound is induced in the coil. It is this current that forms the output of the mic.

    Because dynamic mics are so robust they are particularly suitable for applications such as hand-held vocal use, where they're constantly being manhandled, and mic'ing drum kits where the high SPL (sound pressure level) could damage other mics.

    The frequency response of these type of mics is often limited. This is because the physical mass of the moving coil-diaphragm structure is sufficient to impede the diaphragm's rapid movement at high frequencies, causing a dropoff in response above say 8-10kHz.

    "Ribbon mics"
    Ribbon mics operate using the same principles of magnetic induction as the conventional dynamic mics, the only difference being in the form of the diaphragm used. Instead of having a non-conductive diaphragm attached to a coil, it uses a long very thin strip of conductive metal foil suspended between the poles of a magnet. This ribbon of metal acts as the diaphragm, and as it is excited by sound waves, a current is induced in it exactly as in the coil of the previous type. This current is very small however and requires a step up transformer to be incorporated into the microphone.

    The ribbon mic gives a very smooth frequency response, but is much more fragile than the moving coil type of dynamic mic so is better suited to the micing of acoustic instruments or classical ensembles than a drum kit.

    "Condenser/Capacitor mics"

    The condenser microphone has a completely different method of operating than either the dynamic or ribbon mics in that it doesn't generate a signal using a coil and magnetic field. This is it's great advantage since the diaphragm doesn't need to be

    attached to a coil
    or of a shape and size suitable for positioning in a magnetic field.
    This means that the diaphragm can be made extremely light giving a much improved frequency response.

    The condenser mic works on the principle that if one plate of a capacitor is allowed to move in relation to the other, then the capacitance will vary, so allowing the generation of a signal proportional to the sound as in the dynamic mic.

    However, the major difference between dyanamic and capacitor mics is that for capacitor mics to operate they require an external power supply to charge up the capacitor. This external power supply is called phantom power. Phantom power is a supply of +48V(nowaday it is not has to fixed on 48 Volts only,,) that is supplied to the mic via the mic cable. This voltage is supplied by the console, and without it the condenser mic just won't operate.

    The much improved frequency response and general higher quality of capacitor mics has lead to them being the standard mic used in all applications where sound quality is paramount.
     
  7. GTR1954

    GTR1954 New Member

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    請問一下 Mr.72
    那支要phantom power的 ribbon mic號稱比一般的多15dB,
    這是用internal的preamp去boost,可是ribbon mic本來訊號很小,
    相對之下雜訊就多,那internal preamp boosts上去不就也讓雜音比例一樣或更多?
    分兩階段boost真的有比較好嗎?有的preamp也有做到能boost 72dB的.....
    如果ribbon mic做到訊號可以很大高頻又好,那用condenser不就好了?
    為什麼要用 ribbon mic?
     
  8. Mr72

    Mr72 Well-Known Member

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    To GTR1954

    你指的雜訊應是hardware noise,,這類問題在組裝原件提升後會有十足的改善,,,in this case,hardware noise floor 通常不一定隨著 internal boosting 而提升......而internal preamp 的問題若影響ribbon mic,當然condenser mic 也逃不掉....我想這是造價和品質的問題,未必代表Mics 製作理論的高低.....

    Ribbon mics 對頻率的反應較smooth,,特別是一些 HF percussive attacks,ribbon could round it over in a typical way...這類選擇,不如把他想成不同的GT pick-ups,,,喜歡最重要,倒不必從原理上去分優劣,,.........as matter of fact, internal preamps & mic pres work in a quite different way to affect sound results,,.. don't get confused,....just like GT pick-up and GT pre amp don't work as the same function in Gt playing !!,,,,
     
  9. GTR1954

    GTR1954 New Member

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    to Mr72
    Royer Lab做的ribbon用phantom的和原來的那支設計都幾乎一樣,
    只是多了internal preamp,小弟不懂的是這樣雖多15dB,
    用外部的preamp多給15dB不就一樣,反而還少掉多一些元件的雜音,
    像有的preamp不是也可以做到72db,比很多牌子的60dB還多。 <BLOCKQUOTE>quote:</font><HR> Ribbon mics 對頻率的反應較smooth <HR></BLOCKQUOTE>
    這也是很多人強調的,但是我看很多condenser的圖表顯示也很smooth,
    那這倒底是怎麼回事?
     
  10. Mr72

    Mr72 Well-Known Member

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    To GTR 1954

    <BLOCKQUOTE>quote:</font><HR>Royer Lab做的ribbon用phantom的和原來的那支設計都幾乎一樣,
    只是多了internal preamp,小弟不懂的是這樣雖多15dB, <HR></BLOCKQUOTE>

    我想你可以上Royal Lab 的網站,,再查查看數據...
    Royal Lab claims that :
    Conventional ribbon microphones are, on average, 15 to 20 dB less "sensitive" than condenser mics,...... necessitating the use of high-quality, high-gain microphone preamplifiers for recording softer sound sources like acoustic instruments, vocals and room ambience.

    this claim also address that you might need a decent mic gain while using a "conventional ribbon microphones"............

    The Active Series ribbon mics,R-122, contain fully balanced, discrete head amplifier systems utilizing ultra-low noise FET’s. ......,(designed by David Royer and Rick Perrotta)...., is extremely quiet, can handle "135 dB SPL" and allows our Active Series ribbons to deliver a" sensitivity of –38 dB!"

    this claim also address that you might not need a decent mic gain while using a " active R-122"............

    Sensitivity dB value is not the same as SPL dB,,....當然這些數據也不一定保證任何事....用過才算數,,,,

    <BLOCKQUOTE>quote:</font><HR> 這也是很多人強調的,但是我看很多condenser的圖表顯示也很smooth,
    那這倒底是怎麼回事? <HR></BLOCKQUOTE>

    這樣說吧!!一樣250 匹馬力的兩部車,,,,一部後驅,一部四驅......有人愛甩尾,選後驅,,,有人愛轉彎平順...選四驅.....

    你說哪部好呢???............我都O.K.啦!!,,對我來說250的馬力 才是重點!!...馬力不夠,開也開不快,,,,談驅動模式,,or 駕駛技術,,,都有點沒必要!..........hope this would give you some imagination,,,,,
     

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