Are all ribbon mics figure-8 dipoles?

[joe h]

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.

[Mike Rivers]

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

[hank alrich]

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/HankandShaidriAlrichwithDougHarman

[William Sommerwerck]

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.

[RD Jones]

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

[Adrian Tuddenham[_2_]]

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

[Scott Dorsey]

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."

[Adrian Tuddenham[_2_]]

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

[Scott Dorsey]

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."

[Roy W. Rising[_2_]]

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!"

[Ty Ford]

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

[geoff]

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