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All About Microphone Pickup Patterns, Cardioid, Omni, Bi-Directional, etc...
Difference between condenser and dynamic microphones

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Photo of a finished SC-1 mic preamp kit!  (Note: XLR jacks and wires shown on picture not included in the kit.)

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 Friday, December 29, 2006
Friday, December 29, 2006 8:39:51 PM (Central Standard Time, UTC-06:00) (  |  )
A mic can have different pickup patterns. What do I mean by that? I mean, a mic does not only pickup the sound that is in the immediate front of it, it may also pick up sounds behind, or to the sides of the microphone.

Here are the different kinds of patterns. Understand them when looking for a mic to buy and your intended application.



Bi-Directional

This is also called figure-8. It picks up sound in front and rear of the diaphragm, but does not pickup sounds from the sides. These types of mics are often used above an instrument or used for "stereo" recording in an M-S matrix technique.

Cardioid

This is the most popular mic pattern. Basically, it looks like a heart.  It picks up sound where the mic is pointed at, but some of the sounds from the rear are also picked up, though not as much. Usually about -10 to -30dB lower.

Just be careful though, because the shape of the cardioid isn't fixed. It varies it's shape depending on the frequency. So it could be sensitive for some frequencies and not for others. This can be used for good use because the mic imparts some "coloration" to the sound.


Sample Cardioid pickup pattern of an MXL 604 mic.

This type of mic is also good for "proximity effect." i.e. the closer you get to the mic, the lower frequencies are hyped up, adding "body" and fullness to the sound. However, sometimes it's too much. So you can do 2 things... one, move the mic farther away, (or you move farther away), or if the mic has a built-in low-pass filter, activate that. (if your preamp has a low-cut filter, you can also activate that).

Omni-Directional


From the word "omni", this mic responds as evenly as possible from all directions.

Stereo Mics

Nowadays, you can buy stereo mics. These microphones have 2 diagphragms in the same body, usually, they're angled toe-in. The capsules are matched for even frequency response for both Left and Right channels. Now... there are 2 kinds of stereo mics.. the cheap ones that are mainly used for videocam cameras (usually, 1/8" jack), and the professional ones complete with XLR jacks.

Rode NT4 Stereo Condenser Microphone

"ALL OF THE ABOVE" Pattern

Due to great advances in technology, there are now mics that are "all of the above" (except stereo). A single mic can be switched to omni, cardioid or bi-directional by the simple flick of a switch. If you're on a budget, these mics are a good buy since it's like buying 3 mics for the price of one.

Rode NT2-A microphone featuring switchable patterns, low cut filter, and pads.

 Wednesday, December 27, 2006
Thursday, December 28, 2006 3:34:10 AM (Central Standard Time, UTC-06:00) (  |  )
There are 2 general types of microphones in the market today. They are 1) Dynamic microphones and 2) Condenser microphones.

There are a few other types like piezo, electret, etc... but we'll discuss those later. For now, let's talk about these two.

How are they different? Which one is better?

First, let's talk about dynamic mics. Dynamic microphones are "mechanical" in nature. No, I don't mean they have gears in them but mechanical movement of the microphone diagphragm causes a small voltage to be induced. Basically, sound waves travelling and causes a moving coil to vibrate in and out of a magnetic field. When this happens, a very small and minute amount of voltage is created. If you amplify this small voltage (using a mic preamp or mixer), you'd hear the original sound.

Does this sound familiar to you? I hope so. Because the same principle works in REVERSE when we're talking about speakers. With speakers, current applied to the coil causes it to vibrate, which produces sound waves which eventually reaches your ear. So think of dynamic mics as very small speakers wired in reverse.

Because of the way they operate, dynamic mics don't need an external source of power like a battery or phantom power supplied by your mixer/preamp.

Also, the voltage generated tend to be on the small side and requires more amplification by your mixer/preamp. Of course, with more amplification and higher gain settings by your mixer or preamp, comes more "noise" because your preamp is going to amplify both the original signal and any noise in the system.

Also, they tend to be less sensitive to sound because it requires a good amount of sound energy to move that diagphragm to cause sufficient vibration to generate an output voltage (or signal).

Some examples of dynamic mics are the Shure SM57, SM58.


Shure SM57 Cardioid Dynamic Microphone Shure SM57 Cardioid Dynamic Microphone
View more products from Shure

The SM57 is a cardiod (unidirectional) dynamic microphone with a contoured frequency response of 40 to 15,000 Hz, perfect for clean reproduction of vocals and instruments. Read Reviews...

List Price: $146
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Shure SM58 Dynamic Handheld Microphone Shure SM58 Dynamic Handheld Microphone
View more products from Shure

Consistently the first choice of performers around the globe, the SM58 vocal microphone is a genuine world standard and a true audio legend. The Shure SM58 is a unidirectional (cardioid) dynamic vocal microphone designed for professional vocal use in sound reinforcement and studio recording. Read Reviews...

List Price: $188
Click for Sale price   FREE SHIPPING!




Condenser microphones on the other hand work on the principle of capacitance. "Condenser" is another word for capacitors back in the olden days of vacuum tubes. So anyway, a capacitor has 2 plates and it's capacitance is dependent on several factors like area of plates, distance between plates, and dielectric used. Anyways, for this discussion, one of the plate is made to vibrate by sound waves. This effectively varies the capacitance of the condenser diagphragm.

This varying capacitance is proportional to the displacement of the plate, which is proportional to the strength of the sound waves. Current flows through the wire when the distance between the plates change (caused by the sound vibrations). This is a very small current that must be amplified before it even goes to your mixer/preamp. So yes, condenser microphones have little preamplifiers inside them.

Also, unlike dynamic microphones... condenser mics require power to operate. This may come in the form of a battery housed inside the mic unit, or via the microphone cables through the XLR jack, supplied by the mixer/preamp. This is called phantom power. Basically it's 48Volts supplied by the preamp to the mic.

Condenser microphones are very, very sensitive. It can pick up the sound of your breathing easily, or air coming out of an A/C duct, or the fan noise in your computer. So if your bedroom (ahem, recording studio) is very noisy... using a condenser microphone may leave you feeling frustrated as every sound will be captured by it.... even sounds/noise you don't like.

Here are some examples of condenser-type microphones.

Neumann TLM49 Cardioid Condenser Microphone Neumann TLM49 Cardioid Condenser Microphone
View more products from Neumann

The TLM 49 is a large-diaphragm studio microphone with a cardioid directional characteristic and a warm sound which is especially optimized for vocal performance. It is supplied as a set, with an elastic suspension. Read Reviews...

List Price: $1699
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Rode NT1000 Studio Condenser Microphone Rode NT1000 Studio Condenser Microphone
View more products from RODE

With its ultra low-noise transformer-less circuitry the Rode NT1000 brings new standards to the recording industry. Read Reviews...

List Price: $599
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Rode NT1A Studio Condenser Microphone Rode NT1A Studio Condenser Microphone
View more products from RODE

The Anniversary Model NT1-A is a complete redesign of the now legendary NT1 classic studio microphone. From the new nickel-plated body to the state-of-the-art surface mount electronic circuitry, the NT1-A will leave you asking "how can RODE offer a microphone that sounds this good, for so little money?" It takes advantage of the huge RODE investment in advanced large scale manufacturing allowing premium performance, durability, consistency, and construction at a price that anyone can afford. Read Reviews...

List Price: $349
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So which type of mic is better? Condenser or Dynamic?

The answer is.... NEITHER.

There is no clear winner with regards to which mic is better performing. There are crappy dynamic mics that will get beaten by condenser mics and there are condenser mics that will get beaten by dynamic mics.

We talked above how condenser mics require power to operate in the form of a battery or phantom power. This requires that the mixer/preamp you picked/used can supply phantom power. Otherwise, your condenser mics will be useless. In this case, if you have a non-phantom power capable mixer/preamp, you're better off with a dynamic microphone.

But dynamic microphones can be heavy since it requires better shielding. (Remember, inside the mic are coils and magnets that generate electricity.) Dynamic mics are susceptible to stray magnetic fields which will cause noise to be generated in the mic. What do I mean by stray magnetic field? hmmm... like motors, ballast in flourescent lights, high-tension power lines, and things like that.

The thing is, there are excellent dynamic mics and there are excellent condenser mics. One should look at the bigger picture, and the required application when choosing a mic. You can't make a generalized statement that X is better than Y.