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Microphones: Understanding The Different Types

rocksure

rocksure

I see plenty of questions on this forum about microphones written by people that know more about cameras and picture than they do about sound. A basic understanding of microphones is something that everyone who plans on using one should have. So I decided to write a tutorial on the basics of microphones. It covers quite a bit on the different categories, what they are and what they are generally used for. There is also a section on polarity patterns, powering options such as phantom and T-Power. Hopefully it can help some people that may have questions regarding mics, their uses and what type to choose for any given application. It doesn't cover individual makes and models, but gives some basic info on the configurations, and includes a "not too technical desription" of what condensor, dynamic, ribbon, electret, lavalier, shotgun, PZM microphones etc are all about. I thought perhaps this may be of interest to some of you on this forum, and I believe it may answer some of your questions, so I will post a link to the tutorial here:

Microphones: Basic Understanding Of The Different Types
 
^
I love that site. A true audiophile hangout.
 
Lot's of top-notch audio post folks contribute there. Geo's Corner and the Standard Mixing Levels stickies are invaluable resources.
 
Under "Special Purpose Microphones" --- There is no such thing as a boom mic. Almost any mic can be put on the end of a boom-pole, not just shotgun mics.

Under "Polar Patterns" you left out the cardioids - standard cardioid, supercardioid, and hypercardioid. Most shotguns are a hypercardioid polar pattern with an interference tube to narrow the pick-up pattern (lobar). Most production sound mics used on a boom-pole are either hypercardioid or lobar (shotgun) pick-up pattern, while most lavalieres used for production sound are either omni or cardioid. SInce these are what will be primarily encountered on shooting sets they deserve some more detailed attention.
 
Alcove Audio said:
Under "Special Purpose Microphones" --- There is no such thing as a boom mic. Almost any mic can be put on the end of a boom-pole, not just shotgun mics.

Under "Polar Patterns" you left out the cardioids - standard cardioid, supercardioid, and hypercardioid. Most shotguns are a hypercardioid polar pattern with an interference tube to narrow the pick-up pattern (lobar). Most production sound mics used on a boom-pole are either hypercardioid or lobar (shotgun) pick-up pattern, while most lavalieres used for production sound are either omni or cardioid. SInce these are what will be primarily encountered on shooting sets they deserve some more detailed attention.
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I guess you missed it because I didn't put them in bold or separately, , but the cariod patterns are there in the section on polar patterns as follows:

Unidirectional microphones come in several polar patterns, the most common of which is the cardioid microphone. The sensitivity pattern of a cardiod mic is heart-shaped. Hyper-cardioid microphones are similar but have a tighter area of sensitivity towards the front, and the lobe towards the rear has less sensitivity. A super-cardioid microphone is similar to a hyper-cardioid one, but has more frontal pickup and less rear pickup.
Because unidirectional microphones are relatively efficient at rejecting sounds form directions other than straight in front of them, they are often used for recording vocals and speech.

Technically you are correct that there is no such thing as a boom mic, but I wrote it this way thinking that some people who are inexperienced may search for the term boom mic. To quote:

"The Shotgun microphone is a highly directional one. Often also known as boom mics on account of the fact that they are generally suspended by a boom"
 
indietalk said:
^
I love that site. A true audiophile hangout.
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Yeah I agree..me too. I am a fulltime audio engineer and musician and I do tend to hang out and post on Gearslutz quite a bit. It's a great site, though there is a lot of mis-information on there, as well as some great stuff.
 
Hmm.

Cardioid lav? Good luck if one of those slips around and gets pointed away from the guy's mouth.

I always try to use Omni lavs anywhere.

A boomed wider cardioid pencil condenser will sound good indoors.

One thing I try to teach the production sound mixers on set is:

It's a movie that runs linearly. This scene you're shooting on the beach will cut into this scene where they are in a living room. The guys have to sound similar and have similar timbre recordings or it will be very hard to mix.

If you use a cardioid lav on someone indoors, chances are the proximity effect will make the person sound more "chesty" or boomy. The omni won't cut well in contrast with the cardioid when the actor is outdoors because it will be more natural and have less of a proximity warmth.

I try to stick with the same mic if possible throughout - but sometimes that's impossible.
 
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Alcove Audio said:
Unidirectional and cardioid are two different polar patterns.
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I have to disagree. You are usually correct in things you post on this forum, but rather than take my word for it, I decided to do a search roun dthe net and came up with these references to back up my assertion. Here are:

from wikipedia:-
Cardioid
The most common unidirectional microphone is a cardioid microphone, so named because the sensitivity pattern is heart-shaped

From:- unidirectionalmicrophone.org/

. There are various types of unidirectional microphones employed for capturing different sounds. These are:

1.Cardioid Microphones – This unidirectional microphone is extremely sensitive to sound from front of the microphone. It completely avoids sound that comes from its back.


from:
http://www.audio-technica.com/cms/site/62073812c42084c8/index.html


In a place of worship, however, most applications are better served by unidirectional types of microphones described as "cardioid" (Fig. 3). These microphones pick up sound best within a 120° conical area at their front called the "acceptance angle." Outside the acceptance angle, microphone sensitivity is reduced.
 
ROC said:
Hmm.

Cardioid lav? Good luck if one of those slips around and gets pointed away from the guy's mouth.

I always try to use Omni lavs anywhere.

A boomed wider cardioid pencil condenser will sound good indoors.

One thing I try to teach the production sound mixers on set is:

It's a movie that runs linearly. This scene you're shooting on the beach will cut into this scene where they are in a living room. The guys have to sound similar and have similar timbre recordings or it will be very hard to mix.

If you use a cardioid lav on someone indoors, chances are the proximity effect will make the person sound more "chesty" or boomy. The omni won't cut well in contrast with the cardioid when the actor is outdoors because it will be more natural and have less of a proximity warmth.

I try to stick with the same mic if possible throughout - but sometimes that's impossible.
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At no point did I recommend using a cardiod lavalier mic over other microphones. I simply stated that such microphones exist. A cardiod lav is likely to exhibit a variable proximity effect that according to the way they move their head. If one is placed on the chest area and they look down it will likely sound more bassy than if they look up for example. if they tend to move round then the sound will change with movement and that is not usually desirable.
 
ROC said:
A boomed wider cardioid pencil condenser will sound good indoors.
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Thanxx for the input on Lavs...Im still quite the hack...I just ordered a set of Behringer C2 to play with for indoor recording, might work, might be a total waste of $. But $64 for a pair ?

These guys got decent reviews so Im waiting for delivery of my new toy.

C2_P0263_Reflective_web.png
 
Well,

I like to think that I could get a better product with those Behringers than a fool who doesn't know what he's doing with a 2,000 Schoeps CMIT5U shotgun mic. I think it's safe to say that 80% of the sound quality (maybe even more) comes from where you place the mic - 20% from the make of the mic. When you've mastered the placement, then it's time to start upgrading and making things sound better and better - but those C-2s 8 inches away from the actor pointed on axis will sound way better than a fancy shotgun from 6 feet away.

I was just in an ADR spotting session the other day and the sound super says "God I love _____ (name of the boom op - one of the best in the world). You see that mic drop into frame? God I love him!" - referring to the fact that he didn't care how close he was or how much he got shouted at by the DP - he was getting his product.

If you know how a mic works and where to place it, you'll get a pretty good product with those mics. I haven't personally heard them, but I use a $150 AKG dynamic mic instead of a $3,000 vintage legend sometimes because it just sounds better on that particular voice - it's the end product that is important. Not the price of gear you use.

Granted, I'd choose the $2,000 mic over those POS Behringer's any day, but if that's all I had to work with, then so be it.

Those C-2s will most likely sound wonderful indoors - just make sure you don't try to mic anyone in a glass box or bathroom or whatever. Keep the rooms baffled as much as possible, and get the mic within 12 inches to the guy's mouth and I think you'll sound pretty good.

If you don't mind - can you place a youtube video up testing the mics? These might be perfect as stunt dummy mics for a recording session I'm about to go do with a pyrotechnic expert in a few weeks.

You never know about Behringer. They have a reputation of being crap equipment, but one of their outboard expanders works so well at removing ambient noise that I've seen them used right alongside the top of the line CEDAR systems on dub stages. True fact.
 
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ROC ... :yes:sure thing when I get them, I'll do a vid for ya...Im hoping to get them in soon. I ordered them off Amazon last Sunday and the seller has yet to ship the. The folks at Gearslutz seem to like the C2's ( for overhead micing on drums ) some say they are cheap wonder mics. Soo I shall give them a try for dialog,
 
IndieBudget said:
ROC was replying in regard to my question of Omni Lav Outdoors / Cardioid Lav Indoors ??





AND would a Cardioid Lav be best hidden in a plant or ??
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I don't know that I would want to use a cardioid Lav too much in making afilm. Especially not if people are moving. For TV shows they can be handy at times. About 7-8 years ago I worked on a weekly lifestyle TV show where for much of it a presenter sat in a chair and interviewed one or two guests seated on a couch. We had cardioiod Lav's on each of the people. Before recording each segment of the show, someone would help the guest's put on their wireless mic, and the presenter ( a very pretty blonde) got good at positioning her own own one. The show was prerocorded rather than aired live. The idea of the cardioid mics was that we recorded each person to a separate track, and since the were fairly close together, it lessened the spill between mics because they were more directional.
In practice when the mics were positioned right it worked well. But there were times when the mic would shift position if the people moved and if the mics weren't securely positioned, instead of them pointing at the mouth ( like they should) they might slip and face out in a different direction and the sound of the voice would change, even becoming hollow if too far off postion. There were times when sound checking before recording when I would have to tell the presenter in her earpiece to reposition her mic because I wasn't getting the best sound to tape, or send someone onto the set to adjust the guests Lavs.
It wasn't a problem most of the time, but if we hd been live to air and a mic slipped it would have changed the sound a bit ( to the detriment).
 
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