Azden 320ULX UHF Wireless System Microphone Review

Sound Matters

Azden’s latest 320 series discrete dual-channel system is smaller and smarter than all other previous units. We reviewed four components, finding that the UHF dual receiver is powerful and allows selections of up to 240 channels. For the professional videographer, the flaws we uncovered don’t seriously impact the Azden 320 series, when compared to wireless systems that cost much more.

Kit Overview

Inside our Azden 320ULX kit were the 320UPR receiver, a 30XT plug-in transmitter, a 30BT bodypack transmitter and a little workhorse Azden EX-503L omni-directional lapel microphone. For connection between the receiver and the camera, Azden includes a dual-plug XLR-to-stereo mini-plug output, as well as a stereo mini 1/8-inch output connector for smaller cameras. The five-page User’s Guide kit is rudimentary, but an Azden sound technician quickly answered a cold call about a switch that the specs did not define. Lastly, the kit comes equipped with its own carrying case. There’s also a 320ULT kit ($995), which replaces the 30XT with another 30BT bodypack, for those who don’t need the handheld functionality.

Small, Light, Compact

Along with its small size, the 320UPR is lightweight, even with the two AA batteries that run this receiver. That’s a plus for camera-mounted use. UHF systems pull more power, but the DC jack will charge batteries in the camera or from an external source.

It’s easy to read the two digital LCD readouts, with channel selection, battery strength and incoming signal status. This is not a diversity receiver, but the flexible high-gain antennas did the job of bringing in two strong UHF signals on 240 selectable frequencies in our tests. On-off switches and cable lock-down rings do the trick. However, the power switches face the front of the camera, which makes it a hassle if you must mount the receiver before setting up mics and channels.

For those who prefer detachable sound packs, the camera shoe is removable, and Azden provides Velcro to stick the receiver onto a belt pack slung on your tripod or waist. You’re still hooked to the camera, so Azden gives you 36 inches of cord with the supplied 1/8-inch output connector to the camera. For XLR connections, unfortunately, you have only 20 inches of play. Both cords send discrete audio output onto separate channels on your tape.

The 30BT and 30XT transmitters also have LCD displays for channel selection and battery strength, as well as an indicator labeled AF Level. The literature doesn’t explain, but this readout shows mic levels. It doesn’t work very well for fine tuning. Both mics have recessed level gain controls, which you can adjust with a supplied tool stored inside the battery compartment of the 30BT receiver. The 30XT adjustment tool is stored inside the 320UPR receiver, and Azden provides a spare.

The 30XT transmitter runs on a 9-volt battery and has a convenient muting switch, as well as a power switch. It has a recessed phantom-power switch for microphones that require them (that information is not in the manual). The lock-down ring at the cable jack is a nice feature.

The 30BT unit features a belt clip and runs on 2 AA batteries with a simple on-off switch, but it has no muting switch. There are no batteries needed for the EX-503L electric condenser mic, and the frequency response is between 50Hz and 19kHz. We were pleased with the sound.

In the Field

We tested both the 30XT and 30BT transmitters in five physical situations: outdoors with direct line of sight; with and without telephone/power lines; indoors; indoors through one exterior wall (receiver outdoors); and through a second wall. Needless to say, the quality of the signals broke up through the two walls, but it was great through one. Results for the remaining four environments were very good. In all tests, we put from three to 51 yards between ourselves and the transmitters. We found that the signal strength was equal for both systems, with the 30XT having approximately ten yards more range over the 30BT bodypack transmitter when operating in the ideal condition of direct line of sight without power lines between the units.

For the 30XT, the maximum distance for direct line of sight without power lines came in at 51 yards; with power lines, audio broke up at 38 yards. Through a residential building wall, breakup did not occur until 15 yards. The device became unusable after passing behind the second building wall at 16 yards. For the 30BT bodypack unit, we got the same results, except that the test of direct line of sight without power lines was limited to a range of 41 yards.


The system has drawbacks: the inability to monitor signal strength independently from the camera is the worst. On the upside, it offers two independent mic channels in one ultra-small package, and you won’t have a problem finding clean airwaves, even in large cities with big media markets. For professionals who don’t always have the need for a dual receiver, the system can add two mics to provide the assurance of an immediate backup, should one of the microphones go down. At $800 (not including the second microphone), the Azden 320 series is meaty, easy to use and compact, and it delivered two clear transmissions over reasonable distances in our tests.



Frequency Range: UHF 240 selectable frequencies(794-805.950MHz)

Type of Reception: Dual-channel receiver

Oscillator: PLL synthesized

RF Squelch Level: 13dBmV

Frequency Response: 50Hz – 15kHz

Signal/Noise Ratio: >70dB “A” weighted

Audio Out: MIC level – unbalanced – 3.5mm mini-jack

Batteries: 2 “AA” alkaline (2 x 1.5V) 3-4 hours runtime, 2 “AA” rechargeable Ni-MH or Ni-Cd (2 x 1.2V)

External Power: 6VDC @ 0.5A

Dimensions: 2.87″W x 4.45″H x 1.59″D (73 x 113 x 40.5mm)

Weight: Approx. 9.17oz (260g) w/batteries

30BT Bodypack Transmitter

Frequency Range: UHF 240 selectable frequencies (794-805.950MHz)

Oscillator: PLL synthesized

RF Power: 15mW

Frequency Response: 50Hz – 15kHz

Max. Deviation: +/-40kHz @ 1kHz modulation, MIC Input – 11dBm

Batteries; 2 “AA” alkaline (2 x 1.5V) 8-10 hours runtime, 2 “AA” rechargeable Ni-MH or Ni-Cd (2 x 1.2V)

Dimensions: 2.52″W x 3.94″H x 1.06″D (64 x 100 x 28mm)

Weight: Approx. 4.54oz (160g) w/batteries

30XT Plug-in Transmitter

Frequency Range: UHF 240 selectable frequencies (794-805.950MHz)

Antenna: Internal

Max. Input level: -7dBm

RF Power: 15mW

Input Impedance: 6k ohms

Audio Adjust. Range: -63dBm to 18dBm

Battery: 1 9V alkaline – 6-8 hours runtime

Dimensions: 1.57″W x 1.57″H x 3.9″L (40 x 40 x 99mm)

Weight: Approx. 6.4oz (181.4g) w/battery

EX-503L Lavalier Microphone

Polar Pattern: Omnidirectional

Frequency Response: 50Hz – 18kHz

Max Input Sound Level: Approx. 93dB

Power Requirements: None, dynamic microphone element requires no phantom or battery power

Output Impedance: 250 ohms

Output Connectors: 1/8″ (3.5mm) mini-jack connector

Pad: None

Low-Frequency Roll-Off: None


  • Good sound quality
  • Plenty of channels
  • Compact and lightweight
  • Good range


  • No significant weaknesses


The Azden 320 series is a dual channel wireless system that works great in the field and won’t cost you an arm and a leg.

Jeanne Rawlings is an Emmy Award-winning sound recordist and documentary producer. Her former clients include the National Geographic Society, ABC and
Discovery Pictures.

Azden Corp.
147 New Hyde Park Road
Franklin Square, NY 11010


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