Introducing the Zaxcom ZMT4 Transceiver

Zaxcom has a way of introducing new products during incredible times. The new ZMT4 is no different. It is arguably one of the best Digital Wireless Transmitters on the market today. With its 30% better power consumption, NeverClip™ in all modes, and power for all microphones ranging from a 5V lavalier to a 48V phantom powered mic, the ZMT4 will feel right at home in your Zaxcom arsenal. But why is this such an incredible advancement that seems to be overlooked by most? In this blog post, we are going to really dive into what this thing does and how it can make your life in the field much easier with a much smaller footprint.


Let’s start by taking a look at the build quality of the ZMT4. It is an incredibly small and lightweight transmitter that can easily be hidden anywhere. It weighs next to nothing (only 2.2oz). The ZMT4  has an impact-resistant nylon polymer casing with rounded edges and machined metal that’s cool to the touch. It does not feel like a toy. Besides the button overlay, there is a Microphone Input (3pin Micro Lemo) and an SMA Port for a replaceable antenna to be mounted. On the back, is a hinged door that opens to allow for the NP-50 style batteries.

It’s All About the Input

Most people would say, “this looks just like the ZMT Phantom Units that have come out in the past. The ZMT4 replaces those units because of its expansive connection capabilities. Simply put, the ZMT4 can supply a wide range of power to cover nearly any professional analog microphone. This means you can operate the transmitter at a variety of voltages. For sound mixers, it means that you can use 3.3V – 5V lavalier mics. That’s right, there is no limitations on the lavaliers you use.

In the past, all Zaxcom transmitters were at 3.3V, which allows for use with DPA 4063 lavaliers (which can function on a lower voltage). Now, the ZMT4 will supply 12, 24, 36, or 48V. This means any lavalier as well as any shotgun microphone. Now, users that have 5V lavaliers that didn’t want to switch over to a new system because of the additional charge (think about it – if you have 10 lavaliers, that is easily an extra $3000-5000 purchase for lower voltage lavaliers. With the ZMT4, you no longer have to worry about this. Keep your lavaliers from different systems!

The ZMT4 also features an all-new preamp design. This new design allows for the implementation of NeverClip, which works by utilizing two A-D converters to extend the dynamic range of the transmitter. The design allows for up to 136 dB, which eliminates limiter distortion. This Neverclip capability is available for both lav and balanced boom mics, making the environment and self-noise of the microphone the dominant noise components.

Adaptive Antenna Optimization

One of the newest features of the ZMT4 is that it improves radiation of the bodypack’s antenna when it’s placed in contact or near the human body. Have you ever placed a transmitter on a woman’s thigh, only to have the signal drop out almost completely? It can be stressful and obtrusive to continually figure out a way to not have the skin of the talent absorb the RF. With adaptive antenna optimization, the external antenna is actively matched to its condition to optimize radiation and minimize distortion, keeping the signal at its best. Long story short, it displaces where the RF is radiating out because it will sense the antenna’s output being absorbed.

Internal Recording

Zaxcom is the goat when it comes to internal recording in transmitters. They were the ones that thought about it a long time ago when RF was plentiful and not really an issue. Now that things are getting difficult in the RF Spectrum due to the FCC selling off our space, the Zaxcom Ecosystem of Recording Transmitters is definitely a great choice to use. Audio is simultaneously transmitted and recorded to a removable microSD card using the highly reliable MARF (Mobile Audio Recording Format) which eliminates file corruption common to recordings due to a dead battery or early card removal. To learn more about MARF, click here.


Zaxnet is probably the most coveted feature of wireless transmitters in the field today. Simply put, it is seamless control of your transmitters. Zaxnet allows the user to change the frequency, pre-amp gain, sleep mode, and more in your transmitter – all without ever needing to disturb talent. You can even place the internal recorder in multiple transport modes.

Every transmitter in the current lineup of transmitters are equipped with ZaxNet™, and the ZMT4 is no exception. It is the longest-range remote-control system out there (however, it does not seem that could be the case for long with companies like Shure hot on their heels with the Shure Axient Wireless system.



Even knowing the ZMT4 has many features that weren’t available in previous models, this transceiver utilizes to 30% better battery life than its predecessor. A single NP-50 battery can provide up to 6 hours of runtime with a lavalier running at 5v and up to 4.5 hours of runtime while using a 12-48v boom microphone. These are current estimated runtimes from Zaxcom, and will be updated as real-time tests roll out.

One of the best ways that Zaxcom can extend its battery life so easily is with its PowerRoll™ feature. This capability adjusts the ZMT4’s power level during different stages of production. For example, when in-between takes, the ZMT4 can easily decrease its broadcasting power from 50mW to 10mW (which drastically lowers the battery draining in the transmitter). Once you hit record on the Zaxcom Nova or Deva 24, the transmitter will receiver a “wakeup call” from the Zaxnet Transmitter in your recorder to boost the power back up to 50mW. This allows the transmitter to run cooler (even knowing they don’t run that hot anyways) and use less battery life while not essentially needed.

Modulation Choices for your Environment

The next amazing thing about Zaxcom is its range. Depending on the modulation mode (there are many), you will be able to not only increase the range of your system, but also the number of channels you can fit into your spectrum space. The range will always vary depending on your environment, but you’ve got choices to optimize transmission for peak performance. Don’t let this confuse you too much. There are two main modes: XR and ZHD (Zaxcom High-Density). XR is the normally recommended modulation with the least amount of latency (around 3ms), while ZHD is used when you need more range and more channels in a densely populated space.

ZHD increases the number of available channels from 4 to 9 for every 1 MHz of spectrum space, perfect for reflective environments like busy city streets. XR gives you the maximum distance in less dense / more controlled spaces. The great thing? You can easily pop into different modes depending on your location if you need to try something different. Usually, if XR isn’t working, ZHD will. There will be a slight bit more delay (less than 9ms), but it is definitely a godsend when everything else isn’t working. We will be going over modulation modes more later in future blogs and courses.

The “Perfect Setup”

You will have a lot of sound mixers that call this the “end-all-be-all” transmitter. Simply put, it does everything. You have a transmitter that is extremely small. It uses rechargeable batteries which are good for the environment. It can use any voltage lavalier. It can be used as a wireless boom setup with a shotgun microphone. It has Neverclip, which means it essentially cannot distort unless if you distort the capsule on the microphone. It can be remotely controlled with a variety of devices…

With a list of options this long, it makes building a Zaxcom Nova with 8 ZMT4 transmitters a very big possibility. Check out this list below:

(1) Zaxcom Nova

(2) MRX414 Receivers

(8) ZMT4 Transmitters

Pair this with an Orca OR-30 or the new K-Tek Stingray Jet-X Bag for one of the most expansive ENG Mixing Setups in 2021 and beyond. It allows for any number of wireless booms, up to 8 talent being wired with any voltage of lavaliers, or even plant microphones. Your productions will go faster and smoother with less gear that takes up less space overall. Zaxcom users are definitely rejoicing at this magical setup. This setup paired with our Recording Better Interview Audio Course will get you up and running in no time.

What are your thoughts on the ZMT4 Transmitter? Leave them in the comments below the specs!


ZMT4 is available in the following frequency bands:

ZMT4.5 (512-608 MHz)

ZMT4.6 (578-698 MHz) (Not Available in the U.S.)


RF Modulation: Proprietary Digital Method
ZMT4.5 RF Frequency Range: 512 – 608 MHz
ZMT4.6 RF Frequency Range: 578 – 698 MHz
RF Frequency Step: 100 KHz
RF Bandwidth in ZHD96 Mode: 100 KHz
RF Bandwidth in XR Mode: 200 KHz
Channel Separation in ZHD96 Mode: as close as 200 KHz
Channel Separation in XR Mode: 400 KHz
Antenna Connector: 50 Ω SSMA Female
Emission Designator: 180 KV2E, 100 KV2E
FCC Part: 74.861

Transmitter Audio

Dynamic Range: 136 dB
Distortion: 0.01%
Frequency Response: Mode 0: 20 Hz to 16 kHz / T & M Mode 0.2 Hz to 16 kHz
High Pass Filter: Off or 70 to 220 Hz, Steps: 10 (6dB Per Octave)
Unbalanced Lavaliere Mic Power: 5.0v @ 10mA max
Balanced Mic Power: 12v @ 25mA max
Balanced Mic Power: 24v @ 10mA max
Balanced Mic Power: 36v @ 10mA max
Balanced Mic Power: 45v @ 10mA max
Mic Connector: 3-Pin Micro LEMO
Mic Configuration: Balanced (3-wire) / Unbalanced (2-wire)
Input Range: -60 to -30 dBu
Mic Impedance: 3.4 k Ω (680 Ω with 12v power mode)
ADC Bit-Depth: 32 Bits
ADC Sampling-Rate: 32 kHz

Timecode Reader / Generator

Clock Accuracy: 1.54 PPM (1 Frame in 6 Hours)
Timecode Type: SMPTE
Timecode Frame-Rates: 23.98, 24, 25, 29.97NDF, 29.97DF, 30NDF, 30DF

Internal Recording

Media: MicroSD Card (Flash Memory)
File Format: .ZAX / Converts to BWAV or MP3

2.4 GHz ZaxNet Receiver

RF Frequency Range: 2.403 to 2.475 GHz
RF Modulation: Digital Spread Spectrum
RF Frequency Step: 0.001 GHz (1 MHz)
RF Bandwidth: 1 MHz
Channel Separation: 2 MHz
Sensitivity: -96 dBm


Weight: 2.2 oz / 62 grams with Battery
Dimensions (H x W x D): 2.2″ x 1.6″ x .55″ / 55.8mm x 40.6mm x 14mm
Display: Graphic OLED


Power Output: 10 / 50 mW – Software Selectable
Power Consumption: 125 mA @ 4.2v with 50mW TX (no ZaxNet or Phantom power)
Battery Type: NP-50
Lavalier Battery Life: Up to 6 hours
Phantom Power Battery Life: Up to 4.5 hours

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