Microphone Frequently Asked Questions

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What are the differences between the wired and wireless versions of Crown head- worn mics? The wired versions are the CM-311A and CM-312A. The wireless versions are the CM-311AE and CM-312AE. 
The headband and mic elements are the same on the wired or wireless versions. The wired versions can be used with phantom power or powered by an internal 9V battery. If you want to use your mic "wireless" sometimes, and "wired" other times, that is best achieved with the CM-311A or CM-312A models. The important thing to consider is that you will be wearing the mic electronics AdaptaPack AND your transmitter, and using batteries in both, but this setup will give you added flexibility.

The wireless head-worn versions (CM-311AE and CM-312AE) can ONLY be used with a compatible "three-wire" wireless transmitter of your choice (see the FAQ concerning wireless systems above). Adding an XLR connector to those models and plugging them into your sound system directly will result in damage to the microphones.

What wireless systems are compatible with Crown head-worn mics? Crown CM-311AE and CM-312AE mics will work with most wireless transmitters that have a three-wire configuration (separate ground, audio and bias pins) and have from 3V to 9V bias available. These mics will NOT work on transmitters that combine the audio and bias together (two-wire configuration).


Crown offers versions of the CM-311A and CM-312A mics that come pre-wired for AKG (systems using TA3F connectors), Audio-Technica (systems using Hirose HR10 connectors) and Shure (systems using TA4F connectors). The mics will not work with a system having a 1/4" input on the transmitter.  


What is phantom power? Phantom power is 12 to 48 volts DC (typically 48V) applied to pins 2 and 3 of a condenser microphone's XLR connector to power the microphone's electronics.  Pin 1 (shield) is the ground for the phantom voltage.

All condenser microphones require power to operate. In professional microphones, this power is supplied through the microphone cable via phantom powering. Phantom power is supplied either by 

  • a standalone phantom power supply (such as the Crown PH-1A)

  • or by
  • a mixer that has phantom power built in.

The microphone receives power from, and sends audio to, the mixer through the same cable conductors.

Let's explain this another way. In a balanced microphone cable are two wires (conductors) surrounded by a shield. A DC voltage is applied to those two wires on pins 2 and 3 of the mic's XLR connector. The audio signal uses the same cable conductors that phantom power uses. The audio signal is not affected by the phantom DC voltage since the signal is AC.

Dynamic or ribbon microphones connected to a phantom-power input are protected from damage, theoretically, since the system results in a net zero DC potential across the coil or ribbon. However, if the dynamic or ribbon microphone is unbalanced internally (one side of the coil or ribbon accidentally tied to ground), damage is sure to occur.

What type of power do the various Crown mic models require?

All Crown microphones are condenser types which require power to operate. Most work on standard 12- to 48-volt phantom power only, with the following exceptions:

  • The Sound Grabber II only works with the internal AAA-type battery. Be sure it is new, otherwise the mic level might be low.
  • The PZM-185 works with the internal AAA-type battery or external phantom power.
  • The head-worn CM-311A and CM-312A mics will work with the internal 9V battery or phantom power.
  • The PZM-10LL is powered by 12 to 24 VDC.
  • The PZM-11LL and PZM-11LLWR are powered by 12 to 24 VDC or phantom power.
  • Crown mics designed for wireless transmitter use only (CM-311AE, CM-312AE and GLM-100E) use the bias voltage supplied by the transmitter.  

What is the difference between dynamic and condenser microphones?  The terms dynamic and condenser refer to the two most common forms of professional microphones. They refer to the method in which the microphone generates an electrical signal.


The dynamic (moving-coil)microphone operates by electromagnetic induction to generate an output signal voltage. It is like a miniature loudspeaker working in reverse. The diaphragm is attached to a coil of fine wire. The coil is mounted in the air gap of the magnet such that it is free to move back and forth within the gap. When the sound wave strikes the diaphragm, the diaphragm vibrates in response. The coil attached to the diaphragm moves back and forth in the field of the magnet. As the coil moves through the lines of magnetic force in the gap, a small electrical current is induced in the wire. The magnitude and direction of that current is directly related to the motion of the coil, and the current then is an electrical representation of the sound wave.


One of the major drawbacks of the dynamic microphone relates to the mass of its moving coil. Due to this mass, the dynamic mic has a relatively poor transient response, and is less sensitive on the average than the condenser mic.


The other major microphone type is the condenser. The diaphragm of a condenser microphone is a very thin plastic film, coated on one side with gold or nickel, and mounted very close to a conductive stationary back plate. A polarizing voltage is applied to the diaphragm by an external power supply (battery or phantom power) or by the charge on an electret material in the diaphragm or on the backplate charging it with a fixed static voltage. All Crown mics are the electret condenser type.

The diaphragm and back plate, separated by a small volume of air, form an electrical component called a capacitor (or condenser). The capacitance between these two plates varies as the freely suspended diaphragm is displaced by the sound wave. When the diaphragm vibrates in response to a sound, it moves closer to and farther away from the back plate. As it does so, the electrical charge that it induces in the back plate changes proportionally. The fluctuating voltage on the back plate is therefore an electrical representation of the diaphragm motion.

Because the diaphragm of the condenser is not loaded down with the mass of a coil, it can respond very quickly to transients. Also, the condenser capsule can be made very small. Condensers generally have excellent sonic characteristics, and are widely used in high-quality professional  microphones in sound reinforcement, measurement and recording.

What is the difference between a PZM microphone and a PCC microphone?  While both microphones are considered boundary or surface-mounted microphones, they are quite different in application and use. The Pressure Zone Microphone (PZM) has an omnidirectional capsule that "looks down" at the boundary, while the Phase Coherent Cardioid (PCC) microphone has a supercardioid capsule that "looks across" the boundary.

The PZM has a hemispherical pickup pattern when used on a boundary like a floor, wall, ceiling or tabletop. Another way to look at that is to say that it is omnidirectional above the boundary plane. This makes sense when you consider that it generally can't pick up sound from behind the boundary. The PCC microphone is a directional (half-supercardioid) boundary microphone that rejects sound from the side and rear. This directional pattern adds gain-before-feedback.

Why have different PZM microphone models?  Crown makes different PZM models for different or specialized applications.


The PZM-30D and PZM-6D are identical in response and share the same capsule and circuit design, and require phantom power. However they have different chassis designs and features.
The PZM-30D is larger, with the XLR connector built into the plate. It accepts a detachable mic cable. Use it when you need extra ruggedness, either in the studio or on the road.
The PZM-6D is smaller and lighter, with a permanently attached thin cable and XLR connector at the end. Use it when you need a light, inconspicuous microphone. For example, tape it to the underside of a raised piano lid, or tape it to a clear plexiglass panel.


The PZM-10/10LL and PZM-11/11LL/11WR are  designed for security, surveillance, and observation room applications. They can be mounted on the ceiling or wall other locations where they won't be easily noticed. The PZM-11LLWR has the added ability to be mounted outside in the elements due to its weather-resistant housing.


The Sound Grabber II is a low-cost, high impedance, unbalanced microphone designed for general-purpose consumer use such as office meetings, group discussions, interviews, home video productions, and music recordings. An internal 1.5V AAA battery powers it. The PZM-185, while sharing the same appearance as the Sound Grabber II, is designed as a balanced, low impedance device. It is powered by an internal AAA battery or phantom power.

What is the difference between a CM-30 and a CM-31 microphone?  The only difference between the two models is in the housing of the electronics module. The CM-30 electronics interface module installs in a standard single-gang electrical box. The CM-31 has a cylindrical (tube) electronics interface module.

The CM-30 would be a better choice for a permanent install that will not be moved (example: most house of worship choir areas). The CM-31 would be a good choice for applications that need to flexible in location (example: theater stages, temporary sound systems). In both choices, the microphone remains a professional-quality, supercardioid condenser designed for inconspicuous miking.

What is the difference between the LM-201 and the LM-300A series microphones?  The LM-201 and the LM-300A lectern mics both are professional quality electret-condenser mics. They have a supercardioid polar pattern which helps reject background noise and room reverberation, and also improves gain-before-feedback, compared to a mic with a cardioid pattern. They are meant for use on lecterns and pulpits, and in teleconferencing applications.

The LM-201 has a rigid boom arm mounted in a heavy-duty ball-and-socket swivel mount. It is extremely rugged and ready to withstand daily use. The mic capsule is shock mounted to reduce handling noise and lectern thumps.

The LM-300A is a dual-gooseneck mic with a slender, low-profile design a perfect choice where appearance is more important than ruggedness or shock mounting. It plugs into an XLR-type female panel or cable connector.

The LM-300AL is the same as the LM-300A but with a longer gooseneck.

The LM-SM is a shock mount for the LM-300A and LM-300AL.

Where can I find retail prices for Crown products?  Go here for retail prices for Crown products.

My Sound Grabber is louder with the supplied battery than with a different battery. Why? The Sound Grabber should sound the same with any fresh AAA battery. Make sure your battery is new and is putting out 1.5 volts. Packaged batteries can be low voltage or dead if they have exceeded their shelf life.

How do I purchase Crown Products? Crown products are sold through dealers and mail-order catalogs rather than directly from Crown. If you are in North America, click here to see a list of Crown sales agents who can help you find a local dealer. If you are not in North America, click here to see a list of international distributors.