Crown CM-311A Differoid® Head-Worn Condenser Microphone

Review by Stacy Zemon

Used by world-renowned artists such as Garth Brooks, Britney Spears and Janet Jackson, the Crown CM-311A Differoid microphone is the headworn microphone of choice for the live-performance industry.

Featuring clear, crisp vocal performance in a lightweight package, this microphone signifies the quality and performance value of the Crown CM Series of microphones.

One of the benefits of this headset design is it allows DJs to get on the dance floor and interact with the crowd.

The Crown CM-311A is a cardioid pattern which uses Crown’s Differoid® technology to reject sounds from the rear of the microphone. This innovation allows crowd noise to be rejected for a high gain before feedback.


With a headset weight of only 2.1 oz, one can barley notice it is being worn. The headset is hard wired into a belt pack to prevent a mic jack from popping loose or connection related problems The belt pack with battery installed has a insignificant weight of only 6.1 oz.

Belt Pack

Accessible on the top of the belt pack is a programmable mic on/off switch. This switch can be set up to work in three different ways, push on or push off, momentary on, or as it is supplied from Crown, momentary off. Removing three screws to the belt pack case allows access to a miniature switch to change the switch settings.

The flexibility of these switches would allow an MC to turn the mic off completely or just press and hold the button in the instance of coughing or clearing ones throat.

Next to the switch is a small red LED, which lights after the unit power switch has been turned on. A large metal belt-clip is permanently attached to the belt pack for hands free use. For ease of hook up, a male XLR connector is recessed within the bottom of the high-impact plastic belt pack.


The headset headband is made of bendable steel wire. The mic boom is constructed from durable non-flexible brass tubing. The 2-conductor shielded cable is 42 inches in length from headset to belt pack. A small clip is fastened to the cable for attaching to one’s clothing.


The microphone element is housed within a small rounded silver grill, which is attached to the fully adjustable brass mic boom. A large user friendly knob or thumbscrew allows for complete adjustment of the boom, in or out and down or up. Attached to the underside of this knob is a large padded foam block. This block sits just below the right ear and becomes the stabilizer for the mic boom and element.

Mic Boom

To prevent the mic boom from bouncing, Crown suggests bending the headband wire, both side ear pieces and the wire assembly which holds the padded block for the best fit possible. Included with the mic is a foam pop filter which snaps down over the metal windscreen. The transducer on the head set is called an electret condenser.

The element reproduces frequencies from 50 Hz to 17 kHz and has a cardioid pattern. This element can take up to a maximum SPL of 148 dB with only 3% THD according to Crown’s manual. The manual also states, up to 110 hours of battery usage can be achieved.

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Street Price: About $250

Stacy Zemon – Publisher and Chief Scribe

Stacy Zemon is internationally considered a leading authority and leader in the DJ industry. She has reached an audience of millions as a Radio, Club, Karaoke and Mobile Disc Jockey.

What’s more, Stacy’s efforts as a Writer, Author and Publisher have enabled her to spawn the largest number of DJ business owners in the world!

She is author of the world’s best-selling DJ books: The Mobile DJ Handbook, The DJ Sales & Marketing Handbook and The Mobile DJ MBA, and was a longtime writer for DJ Times magazine.

Stacy is also the Founder & President of DJ Video Network – Internet TV for DJs, by DJs.

Her mission is to provide educational resources for DJs that support their professional growth and financial prosperity.

Write to her c/o or call 877-442-7170.

For the longer version of Stacy’s story, click here. To learn about the business services she provides for other DJs, click here.


  • Stacy Zemon is the Founder, Former Publisher and Former Chief Scribe of She is a veteran DJ Entertainer who is widely considered an authority on the DJ business, and has become a distinguished industry leader over the course of her illustrious 30+ year career. Stacy’s mission is to provide educational resources for DJs that support their professional growth and financial prosperity. She is a longtime writer for DJ Times magazine, and author of the world’s best-selling DJ books: The Mobile DJ Handbook, The DJ Sales & Marketing Handbook and The Mobile DJ MBA. Stacy is a self-described serial entrepreneur (Equal parts creativity and business). From her efforts, she has spawned more professional disc jockey business owners than any other person in the mobile DJ industry!

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