Why don't they invent a mic like this?

[ironpony]

There are different types of mics you need depending on the situation, which all have their own trade offs. However you can get a camera that can shoot in multiple situations. Unlike mics, you don't need a different camera for indoors and outdoors, and you can adjust accordingly for the environment.

But with mics, you cannot adjust the pick up pattern. Why don't they invent a mic where you can adjust the pick up pattern, all the way from a polar pattern, to an omni pattern?

 

[Noiz2]

But with mics, you cannot adjust the pick up pattern. Why don't they invent a mic where you can adjust the pick up pattern, all the way from a polar pattern, to an omni pattern?

First off it's an apple and oranges comparison. A better one would be with lenses. The camera is a recorder the lens is what determines what the camera "sees". Likewise a mic determines what the recorder "hears". It's not an exact analogy but close.

Then your question is why don't they make a "zoom" mic like a zoom lens.

And actually they do sort of. There are mics with variable pickup patterns. BTW "polar pattern" is the mic's pick up pattern not a specific pattern. Shotgun and omni are both polar patterns.

Anyway most mic's that use an M/S arrangement that comes out as L/R have a variable pattern, and there is a very pricey super directional mic that can be adjusted to all kinds of patterns. Many studio cardioids are multi pattern and many small condensers have interchangeable capsules.

There are two big issues. First a lens concentrates light, a mic rejects what you don't want. So while a zoom lens can effectively amplify what you want a mic can't.(*)

second, light moves faster and farther than sound. Sound actually has to push molecules around to exist, so it drops off fast. Technically I believe they both drop by the square of the distance but practically sound gets useless faster because other things get in the way more. There isn't as much light "noise" as there is sound noise. Plus the need for sound to actually physically move something to get recorded means it's junk at a much higher level than light is.

(*) There are parabolic reflectors that you can attach to a mic and amplify the sound from a direction but they don't sound "natural".

And that brings up another point. You can have people all kinds of colors and folks will accept it but you better have your people sound like people or your in trouble. It's a little like CG motion. WE are very trained to pick up on the nuance of sound where visuals are more about the raw information. So you can get buy in visual quality in ways you just cant in sound. If your image is noisy as hell you can make it black and white and it becomes very "real", but noisy junky sound is always noisy and junky.

 

[Alex H.]

But within the camera/lens analogy, there are mic systems with interchangeable capsules so that, like swapping lenses, you can change from omni to cardioid to super/hyper cardioid to figure-8. And many have shotgun capsules as well.

 

[Noiz2]

Thanks for reenforcing that. I kind of slipped it in. I actually have a set that has omni, cardioid, hyper, and shotgun capsules.

 

[Greg Smith]

Large diaphragm studio microphones like the Neumann U87 (or the much cheaper Shure KSM44's I own) often have two separate microphone capsules with different directional patterns (typically one omnidirectional and one figure-8 pattern). By turning them on and off or mixing them together in different phase arrangements, you can switch the mic to omni, cardioid or figure-8 modes, sometimes with a "wide cardioid" or more directional hypercardioid setting as well.

These mics typically are of very high quality, but there are three downsides to the arrangement:

1) Having two capsules and all the internal baffles and such to make them mix together properly without phase cancellations makes the microphone large and heavy;
2) With two sets of capsules and electronics mixed together, you are effectively getting the electronic noise of two microphones;
3) There's twice as much stuff inside to fail.

These are not big considerations in the studio or controlled indoor location environments where these microphones are designed to be used, and expensive components and design can mitigate the second and third problems to a large degree. But they make such mics less suitable for life on a video set. And none of these are as directional as a shotgun, which needs an interference tube to cancel sound incident from the sides.

- Greg

 

[bruceallen]

Um, you can have a mic like this - and select pattern in post

You just have to build it out of several recording channels, fed from different capsules:

For example, with a Sennheiser MKH800Twin
http://www.radio.uqam.ca/ambisonic/dsp800.html

Or record double MS schoeps.
http://www.schoeps.de/en/products/dms_plugin

Bruce Allen
www.boacinema.com

 

[ullanta]

But with mics, you cannot adjust the pick up pattern. Why don't they invent a mic where you can adjust the pick up pattern, all the way from a polar pattern, to an omni pattern?

Yes, mics with switchable patterns are pretty common in the studio, and available at all price levels; mics with switchable capsules are available and more common for production (due to their size).

 

[Petrus]

It can not be invented because light and sound do not behave identically (sound curves around objects), and a lens and a microphone can not be compared just like that to each other.

Interference tube shotgun is the only practical way of making a (relatively) narrow pattern mic. Trying to make a multipattern microphone which has an interference tube would be quite pointless.

There is one recent approach which uses a Soundfield ambisonics microphone and manipulates the spatial signals digitally. With this system you can point the microphone and adjust the angle after the shoot. http://soundfield.co.uk/products/products.php and http://harpex.net/

Another modern approach is an array of dozens if not hundreds of omni microphones arranged on a plane, and the directionality can be precisely steered with a complicated delay system. As it is up to several hundred square meters in size this makes it a bit unpractical and expensive for every day video use.

 

[John Willett]

There are different types of mics you need depending on the situation, which all have their own trade offs. However you can get a camera that can shoot in multiple situations. Unlike mics, you don't need a different camera for indoors and outdoors, and you can adjust accordingly for the environment.

But with mics, you cannot adjust the pick up pattern. Why don't they invent a mic where you can adjust the pick up pattern, all the way from a polar pattern, to an omni pattern?

There are hundreds of mics. where you can adjust the polar-pattern from omni to fig.8 - there are even some (like the Sennheiser MKH 800 TWIN and Gefell UM 930 twin) that you can continuously adjust from omni to fig.8 without switching - these you can even adjust the polar-pattern in post production.

Switchable pattern microphones have been around for decades - where have you been? rogar-Happy(DBG):

 

[John Willett]

Large diaphragm studio microphones like the Neumann U87 (or the much cheaper Shure KSM44's I own) often have two separate microphone capsules with different directional patterns (typically one omnidirectional and one figure-8 pattern). By turning them on and off or mixing them together in different phase arrangements, you can switch the mic to omni, cardioid or figure-8 modes, sometimes with a "wide cardioid" or more directional hypercardioid setting as well.

Sorry Greg - this is very wrong and not at all how these microphones work.

Switchable-pattern microphones have two cardioid capsules back-to-back.

If you activate only the front capsule you have a cardioid response.
If you activate both front and back capsules you have an omni response
If you reverse the voltage on the rear capsule and activate both, you will have a fig.8 response
If you activate both front and back capsules, but with half voltage on the rear, you have a wide-cardioid response
If you reverse the voltage on the rear capsule, halve the rear voltage and activate both, you will have a super-cardioid response

Simples rogar-Happy(DBG):

 

[Doc Bernard]

Sorry Greg - this is very wrong and not at all how these microphones work.

Switchable-pattern microphones have two cardioid capsules back-to-back.

If you activate only the front capsule you have a cardioid response.
If you activate both front and back capsules you have an omni response
If you reverse the voltage on the rear capsule and activate both, you will have a fig.8 response
If you activate both front and back capsules, but with half voltage on the rear, you have a wide-cardioid response
If you reverse the voltage on the rear capsule, halve the rear voltage and activate both, you will have a super-cardioid response

Simples rogar-Happy(DBG):

Yep. On an LDC multipattern, you only have 3 leads going to the capsule. If it were two separate capsules there would be 4 leads. Cardioid only mics only have 2 leads to the capsule.

 

[ben_r_]

The way I see it, my SD 702 and Canon 5D2 are my bodies, mic bodies are like my camera lenses, and capsules for my mic bodies are like filters for my camera lenses. Tripods are like boom poles and shock mounts are like tripod heads. Windshields are like stacking filters. Not one of them can do the job of all, so there must be many. And higher quality costs more money. Same game, different players.

 

[Noiz2]

Interference tube shotgun is the only practical way of making a (relatively) narrow pattern mic. Trying to make a multipattern microphone which has an interference tube would be quite pointless.

There actually is a mic that uses a small, five I think, capsules and some digital manipulation to adjust the pattern. It's not very large but very $$$. They use it in sports mostly (at least that is what it was pushed for) in place of a parabolic mic because it can be very directional.

But we are all basically saying the same thing.

Not going to happen because they are apples and oranges.

 

[Noiz2]

Switchable-pattern microphones have two cardioid capsules back-to-back.

If you activate only the front capsule you have a cardioid response.
If you activate both front and back capsules you have an omni response
If you reverse the voltage on the rear capsule and activate both, you will have a fig.8 response
If you activate both front and back capsules, but with half voltage on the rear, you have a wide-cardioid response
If you reverse the voltage on the rear capsule, halve the rear voltage and activate both, you will have a super-cardioid response
Simples rogar-Happy(DBG):

Thanks I never really though about how they worked ,I just knew there was more than one capsule.

 

[j1clark@ucsd.edu]

It can not be invented because light and sound do not behave identically (sound curves around objects), and a lens and a microphone can not be compared just like that to each other.

Interference tube shotgun is the only practical way of making a (relatively) narrow pattern mic. Trying to make a multipattern microphone which has an interference tube would be quite pointless.

There is one recent approach which uses a Soundfield ambisonics microphone and manipulates the spatial signals digitally. With this system you can point the microphone and adjust the angle after the shoot. http://soundfield.co.uk/products/products.php and http://harpex.net/

Another modern approach is an array of dozens if not hundreds of omni microphones arranged on a plane, and the directionality can be precisely steered with a complicated delay system. As it is up to several hundred square meters in size this makes it a bit unpractical and expensive for every day video use.

Phased array microphone projects have been studied at MIT for years... some with more practical applications for ordinary people, some with applications for sonar... or similar.

The problem, similar to using the parabolic reflector, which works well... is that the resulting sound has little or no low frequency content... the phased array if it were 'big enough' could avoid this sort of problem while still having the beam forming capabilities that would allow for post production 'moving of the virtual mic' from one actor to the other, and 'filtering/suppressing' sound from other areas...

 

[dre83]

With one camera (fix lens) you can change: whitebalance = putting a blimp or not on the mic (windjammer)
But you can not "pull off" the lens = same mic all time

You can zoom...Well in sound that would be "level up" (with background noise going up also). And still there's a big difference between
"zoom", and "going closer"....

So "changing mic" would be as "changing lenses". And adjustments would be like windjammer, Lowcut, gain....all with the same mixer/recorder..

And I know this answer has been given but I wanted to type something as I was here

 

[j1clark@ucsd.edu]

With one camera (fix lens) you can change: whitebalance = putting a blimp or not on the mic (windjammer)
But you can not "pull off" the lens = same mic all time

You can zoom...Well in sound that would be "level up" (with background noise going up also). And still there's a big difference between
"zoom", and "going closer"....

So "changing mic" would be as "changing lenses". And adjustments would be like windjammer, Lowcut, gain....all with the same mixer/recorder..

And I know this answer has been given but I wanted to type something as I was here

I think the OP was thinking in terms of focus, and changing 'field of view' that camera lenses are capable of.

In the case of the parabola, the audio energy 'reflected from the dish, say 1 meter in area' is focused to the 2 cm area transducer. There is a 'multiplicative'
effect here. The mic by it's self, is only capturing that 2cm area... a significant lowering of the energy...

But depending on the placement of the mic relative to the reflector, and the curvature of the reflector, one could change the 'angle of view' of the
microphone.

 

[ullanta]

Argggh! Too many metaphors! But, for example, the Sennheiser K6 has available capsules for everything from omni to shotgun; I'm sure others do, too. Certainly, whatever metaphor, there are mics that can be adapted to different situations, whether internally switchable, through changing capsules, through different acoustic attachments (like many DPAs), through MS or other types of matrixing, etc. Mics adaptable to different situations were around long before video cameras adaptable to different situations... long before video cameras, and I'm pretty sure before video.

 

[henryqiu]

However you can get a camera that can shoot in multiple situations. Unlike mics, you don't need a different camera for indoors and outdoors, and you can adjust accordingly for the environment.

First, if you are referring to a P&S camera or whatever camera with a lens that cannot be swapped out, it's typically a camera for non-professionals. For non-professional purposes, the mic on your cell phone, consumer camcorder, voice recorder, and so on, is more or less a mic that you can use just about everywhere, indoors or outdoors. You won't get (or can hardly get) professional results, of course.

Second, if you are talking about a professional camera, you know it has to have a lens before you can use it to take pictures. Most professionals use multiple camera-lens combos for different situations - just like they do multiple mics. It's unusual to use a single lens with a single camera everywhere, unless ultra mobility and/or flexibility and/or lightweight is their top priority at the cost of image quality and creativity. It's not unusual that professionals do need different camera-lens systems when moving between indoors and outdoors.

Third, for photography, the difference between indoors and outdoors is merely the quantity and quality of light. Just remove the roof, and everything indoors becomes outdoors. If you add a roof, everything outdoors becomes indoors. This is why you don't need to swap camera bodies (tools to capture light) when you move between indoors and outdoors. However, many professionals do change lenses when shooting different subjects and/or shoot for different purposes, just as others do with their mics.

Why don't they invent a mic where you can adjust the pick up pattern, all the way from a polar pattern, to an omni pattern?

Such mics, as already mentioned, have been there for long. I own a mic with variable pickup patterns, which allows you to get numerous possible patterns between omni and typical polar patterns. It's one of the mics that you assumed had not been invented yet. It's somewhat like a zoom lens. You can use this single mic virtually everywhere, and don't have to swap it, as long as its physical size, weight, design are acceptable.



Overall, I think if you do want to compare between mics and cameras, you will eventually run into the same or similar usage pattens. For professionals, it's almost always the case of different tools (be it mics, camera bodies, or lenses) being used for different situations and/or for different purposes. And for non-professionals, you can always find a "universal" camera or mic that you want to use everywhere all the time.

 

[John Willett]

Yep. On an LDC multipattern, you only have 3 leads going to the capsule. If it were two separate capsules there would be 4 leads. Cardioid only mics only have 2 leads to the capsule.

3 leads because the two cardioid back-to-back capsules share the same backplate.