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#1
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Are all ribbon mics figure-8 dipoles?
Hello,
A classic ribbon mic has a figure-8 pattern and functions in a dipole kind of way. I was wondering if there are any ribbon mics that *do not* function as a dipole. I know there is a Beyerdynamic ribbon mic (kind of an oxymoron) that is a handheld stage mic. I would imagine that mic has some sort of baffling to attenuate the rear signal. I'm trying to figure out if the figure-8/dipole characteristic is always and necessarily part of a ribbon design, or if there is some way to do something different. Thanks for any insights. |
#2
Posted to rec.audio.pro
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Are all ribbon mics figure-8 dipoles?
On 1/31/2011 9:21 PM, joe h wrote:
I'm trying to figure out if the figure-8/dipole characteristic is always and necessarily part of a ribbon design, or if there is some way to do something different. The directivity pattern can be (and is) changed by the way the sound enters the mic. A classic ribbon mic is open on both sides, and that's what makes it bi-directional. Block one side or create a path so that the sound hits the back side out of phase from the front side and it becomes directional. Block the back side completely and it can become omnidirectional. Ribbon mics are bi-directional because that requires the least amount of acoustic chamber design and makes a useful type of microphone. -- "Today's production equipment is IT based and cannot be operated without a passing knowledge of computing, although it seems that it can be operated without a passing knowledge of audio." - John Watkinson http://mikeriversaudio.wordpress.com - useful and interesting audio stuff |
#3
Posted to rec.audio.pro
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Are all ribbon mics figure-8 dipoles?
joe h wrote:
Hello, A classic ribbon mic has a figure-8 pattern and functions in a dipole kind of way. I was wondering if there are any ribbon mics that *do not* function as a dipole. I know there is a Beyerdynamic ribbon mic (kind of an oxymoron) Not at all. A ribbon mic is a type of dynamic mic. that is a handheld stage mic. I would imagine that mic has some sort of baffling to attenuate the rear signal. Beyer makes or has made several directional ribbon mics - M260, M360, M500, M160, come to mind. I'm trying to figure out if the figure-8/dipole characteristic is always and necessarily part of a ribbon design, or if there is some way to do something different. Thanks for any insights. -- shut up and play your guitar * http://hankalrich.com/ http://armadillomusicproductions.com/who'slistening.html http://www.sonicbids.com/HankandShai...withDougHarman |
#4
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Are all ribbon mics figure-8 dipoles?
A ribbon mic is inherently dipole/figure-8. A conventional dynamic mic /is
not/, because the back of the diaphragm is usually blocked by the structure that supports the diaphragm and magnet. (I think.) Beyer did at one time make a non-dipole ribbon mic. As has been mentioned, the back of the ribbon was blocked, creating an omni pattern (I think). The degree of block can be adjusted to create a cardioid. |
#5
Posted to rec.audio.pro
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Are all ribbon mics figure-8 dipoles?
On Jan 31, 8:21*pm, joe h wrote:
Hello, A classic ribbon mic has a figure-8 pattern and functions in a dipole kind of way. *I was wondering if there are any ribbon mics that *do not* function as a dipole. I know there is a Beyerdynamic ribbon mic (kind of an oxymoron) that is a handheld stage mic. *I would imagine that mic has some sort of baffling to attenuate the rear signal. I'm trying to figure out if the figure-8/dipole characteristic is always and necessarily part of a ribbon design, or if there is some way to do something different. Thanks for any insights. The infamous Shure SM33 "Johnny Carson" ribbon mic was supercardioid, as was the similar model 330. In fact the Shure 333 ribbon was called "ultra-cardioid". rd |
#6
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Are all ribbon mics figure-8 dipoles?
joe h wrote:
Hello, A classic ribbon mic has a figure-8 pattern and functions in a dipole kind of way. I was wondering if there are any ribbon mics that *do not* function as a dipole. I know there is a Beyerdynamic ribbon mic (kind of an oxymoron) that is a handheld stage mic. I would imagine that mic has some sort of baffling to attenuate the rear signal. I'm trying to figure out if the figure-8/dipole characteristic is always and necessarily part of a ribbon design, or if there is some way to do something different. Thanks for any insights. An early RCA design had an acoustic termination chamber covering half of the back of the ribbon. The open half of the ribbon remained bidirectional, the closed half became omnidirectional and the overall result was a cardioid. Reslo produced a close-singing vesion of their standard ribbon mic in the 1950s which had a thick felt pad behind the ribbon. That was sort-of cardioid over a limited range of frequencies. In a converse way, a bipolar ribbon response can be synthesised by placing two cardioid capacitor capsules back-to-back and connecting their outputs in antiphase. The pressure responses cancel and the result is the sum of the velocity responses. -- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk |
#7
Posted to rec.audio.pro
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Are all ribbon mics figure-8 dipoles?
joe h wrote:
A classic ribbon mic has a figure-8 pattern and functions in a dipole kind of way. I was wondering if there are any ribbon mics that *do not* function as a dipole. Sure. They are ribbons that have something behind them in order to block free motion of air. I know there is a Beyerdynamic ribbon mic (kind of an oxymoron) that is a handheld stage mic. I would imagine that mic has some sort of baffling to attenuate the rear signal. That would be the M-500. The M-160 and M-260 also both have arrangements behind the ribbon to make them hypercardioid. I'm trying to figure out if the figure-8/dipole characteristic is always and necessarily part of a ribbon design, or if there is some way to do something different. It is harder to do something different, but possible. The classic RCA 77DX has a labyrinth behind the ribbon and a knob that you turn to go from figure-8 through hypercardioid and cardioid to omni pattern by increasingly blocking the rear vents. Problem is, the tonality changes as you adjust it. And the RCA BK-5 is another classic example, although has a fixed labyrinth arrangement. Thanks for any insights. Get Acoustical Engineering by Harry F. Olson. It explains how all this stuff works. There is also some description in Music, Physics, and Engineering. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#8
Posted to rec.audio.pro
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Are all ribbon mics figure-8 dipoles?
Scott Dorsey wrote:
joe h wrote: A classic ribbon mic has a figure-8 pattern and functions in a dipole kind of way. I was wondering if there are any ribbon mics that *do not* function as a dipole. Sure. They are ribbons that have something behind them in order to block free motion of air. I know there is a Beyerdynamic ribbon mic (kind of an oxymoron) that is a handheld stage mic. I would imagine that mic has some sort of baffling to attenuate the rear signal. That would be the M-500. The M-160 and M-260 also both have arrangements behind the ribbon to make them hypercardioid. I'm trying to figure out if the figure-8/dipole characteristic is always and necessarily part of a ribbon design, or if there is some way to do something different. It is harder to do something different, but possible. The classic RCA 77DX has a labyrinth behind the ribbon and a knob that you turn to go from figure-8 through hypercardioid and cardioid to omni pattern by increasingly blocking the rear vents. Problem is, the tonality changes as you adjust it. And the RCA BK-5 is another classic example, although has a fixed labyrinth arrangement. Thanks for any insights. Get Acoustical Engineering by Harry F. Olson. It explains how all this stuff works. There is also some description in Music, Physics, and Engineering. Also "Microphones" by A.E.Robertson (BBC training manual) -- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk |
#9
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Are all ribbon mics figure-8 dipoles?
Adrian Tuddenham wrote:
Scott Dorsey wrote: Get Acoustical Engineering by Harry F. Olson. It explains how all this stuff works. There is also some description in Music, Physics, and Engineering. Also "Microphones" by A.E.Robertson (BBC training manual) That IS a great book, but someone has borrowed my copy and never could find a replacement. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#10
Posted to rec.audio.pro
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Are all ribbon mics figure-8 dipoles?
joe h wrote:
[snip] I know there is a Beyerdynamic ribbon mic (kind of an oxymoron)... . [snip] Not oxymoronic at all. A ribbon mic is a type of dynamic mic. I view it as a half-turn "winding" suspended in a magnetic field. That Beyerdynamic makes condenser mics might seem strange until one considers the other meanings of "dynamic", such as "energetic" and "forceful". -- ~ Roy "If you notice the sound, it's wrong!" |
#11
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Are all ribbon mics figure-8 dipoles?
On Mon, 31 Jan 2011 21:21:14 -0500, joe h wrote
(in article ): Hello, A classic ribbon mic has a figure-8 pattern and functions in a dipole kind of way. I was wondering if there are any ribbon mics that *do not* function as a dipole. I know there is a Beyerdynamic ribbon mic (kind of an oxymoron) that is a handheld stage mic. I would imagine that mic has some sort of baffling to attenuate the rear signal. I'm trying to figure out if the figure-8/dipole characteristic is always and necessarily part of a ribbon design, or if there is some way to do something different. Thanks for any insights. Not all are figure of eight. Regards, Ty Ford --Audio Equipment Reviews Audio Production Services Acting and Voiceover Demos http://www.tyford.com Guitar player?:http://www.youtube.com/watch?v=yWaPRHMGhGA |
#12
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Are all ribbon mics figure-8 dipoles?
joe h wrote:
Hello, A classic ribbon mic has a figure-8 pattern and functions in a dipole kind of way. I was wondering if there are any ribbon mics that *do not* function as a dipole. Some of the new ones with offset ribbon are not 'true' dipoles, because the characteristics are different on each side (which must limit their usefulness to a degree in some modes of operation). But I guess that's not what you meant ! geoff |
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