USER MANUAL
Published September 2023
Firmware Version ZMT-4-44
ZMT4-X
Transforming Audio
Device Overview
The Zaxcom ZMT4-X is a wireless audio transmitter. The device features several controls and connectors:
- 1. INC / Record Key: Increases menu item parameters. Initiates recording from the home screen when pressed with the CARD key. Starts playback from the transport control screen. Advances playback in increments. Advances to the next segment when held in the transport control screen. Displays group/unit code and time left on card from the home screen.
- 2. DEC / Stop Key: Decreases menu item parameters. Stops recording from the home screen when pressed with the CARD key. Stops playback from the transport control screen. Jumps back to the previous segment when held in the transport control screen. Accesses sub menus when pressed three times quickly from the home screen.
- 3. Menu / Play Key: Accesses the next menu item. Starts playback of a segment when pressed with the CARD key.
- 4. OLED Display: Shows device status and information.
- 5. Card / Power Key: Powers on the device when pushed and held for 2 seconds. Powers off the device when pushed and held for 3 seconds followed by a quick press of the MENU key. Accesses sub menus when pressed three times quickly. Returns to the home screen when pressed three times quickly.
- 6. Microphone Connector (Microdot x 2): Two Microdot connectors are available for microphone input.
- 7. SSMA Antenna Connector: Connects the external antenna.
Physical Connections
The transmitter has several connection points:
- Micro SD Card Slot: Located on the transmitter. To insert a card, align the contacts facing away from the battery compartment and down towards the slot. Press until it clicks. To remove, press again until it clicks.
- SSMA Antenna Connection: For attaching the antenna.
- Microphone Connector (Microdot x 2): The connector furthest from the antenna connector is for mono microphones, and the one closer is for stereo microphone applications.
- Battery Compartment: The ZMT4-X uses one Motorola BT100 battery. The battery is inserted with contacts facing down. The battery door is secured by magnets. Ensure the battery slides in without resistance to avoid damaging connector pins.
The device includes FCC and IC identification information and is manufactured by ZAXCOM in the USA.
Home Screen
The Home Screen displays essential operational information:
- Frequency: Shows the current transmit frequency. 'NOTX' is displayed if the unit is in RECORD ONLY mode.
- Time Left on Card: Indicates the remaining record time available on the SD card.
- Transport Status: Displays the current recording state: STOP (recording/playback stopped), REC (recording), or PLAY (playback in progress).
- Time Code: Shows the current time code.
- RF Power Level: Indicates the set output power level.
- Modulation: Displays the transmission modulation type.
- Segment Number: Shows the current recorded segment on the micro-SD card (limited to 500 segments).
- Battery: Displays the battery type and approximate remaining power percentage.
- Audio Meter: Visualizes the modulation of the input audio signal.
- Gain: The letter 'G' appears when gain commands are received via ZaxNet.
From the Home Screen:
- Pressing the INC key displays the Group and Unit Code, and ZaxNet IFB status (e.g., GROUP:1 UNIT:1 IFB RX FREQ: 2.404 PKTS:0000 TC:00 REM:00).
- Pressing the DEC key displays Time Code UBITS and Frame Rate, along with the card's remaining time (e.g., TC: 09:18:05:00 23.98 UB: 00:00:00:00 (AUTO) CARD TIME LEFT: 23H).
Main Menu Navigation
Press the MENU key to cycle through the main menu options.
Microphone Gain Set
Adjusts the microphone gain in decibels. A horizontal meter indicates the audio signal level.
UHF Transmit Frequency Set
Sets the UHF transmit frequency. Short presses of the INC or DEC keys change the value by 0.1 MHz, while holding them changes it by 0.5 MHz.
Transmitter Lock Page
Enables a key lock function to prevent accidental parameter changes. A 5-second countdown initiates the lock. Once locked, the display indicates 'LOCKED'. Pressing INC or DEC while locked shows unit code, frequency, serial number, name, battery voltage, or segment number. To unlock, press and hold the MENU key and press the INC keys 5 times (or the number set in Unlock Difficulty) or power cycle the transmitter.
Sub Menus
The ZMT4X has six sub-menu groups:
- Time Code: For setting time code parameters.
- Transmit: For adjusting UHF transmitter settings.
- Record: For managing the on-board recorder.
- ZaxNet: For configuring the ZaxNet transceiver.
- Audio: For adjusting transmitted and recorded audio parameters.
- Setup: For general transmitter operation settings.
Accessing Menu Groups: From the home screen, press the CARD key three times or hold the MENU key during boot-up. Use the REC or STOP keys to cycle between menu items.
Entering and Exiting Sub Menus: Press the MENU key to enter a selected menu group. To return to the top of the menu, cycle through menu items or hold the MENU key for 1.5 seconds. To exit the extended menu, press the CARD key 3 times or cycle through sub-menu items until HOME MENU is displayed, then press the MENU key.
TIME CODE MENU
Time Code Frame Rate Set
Sets the time code frame rate. The ZMT4-X supports standard rates including 23.98, 24, 25, 29.97DF, 29.97DF, 30 DF, and 30 NDF.
Time Code Source Select
Selects the time code source. Options include ZAXNET (RF) or AUDIO INPUT. For AUDIO INPUT, the signal level should be between -30 and -10 dBFS on the unit's meter to ensure proper reading.
TC Jam Mode Select
Controls recording behavior based on time code reception. Options are AUTO-JAM NORMAL (records on ZaxNet command or manual trigger) and AUTO-LOAD REC RUN (records when time code is rolling and stops when it stops). If time code is lost, the unit continues its current state.
Mute Time Code Transmission Until Jammed
When set to ON, the ZaxNet transmitter will not broadcast time code until its internal time code generator is jammed, preventing the transmission of incorrect time code to other devices.
Auto Frame Rate Enable
When enabled (ON), the ZMT4-X automatically sets its frame rate to match the ZaxNet transmitter's frame rate. This feature requires time code to be received via ZaxNet and does not function with time code from Audio Input.
TRANSMIT MENU
UHF Transmitter Power Level Set
Sets the UHF transmit power to 10mW or 50mW. Higher power settings consume more battery power.
UHF Transmit Modulation Set
Determines how the ZMT4-X sends audio to the receiver. The modulation format must match the receiver's setting. A reboot is required after changing the format.
| MONO | STEREO | XR | ZHD 96 | |
| Modulation Bandwidth | 200 kHz | 196 kHz | 200 kHz | 96 kHz |
| Minimum Channel to Channel Spacing | 400 kHz | 200 kHz | 400 kHz | 300 kHz |
| 6 MHz TV Channel Capacity | 15 | 30 | 15 | 30 |
| Latency | 3.5ms | 6ms | 6ms | 6ms |
Transmitter Disable - Record Only Mode
Allows selection between two modes:
- Record Only Mode: The ZMT4-X functions solely as a recorder, conserving battery by disabling transmission.
- Normal TX Mode: The ZMT4-X transmits audio and records on its internal micro-SD card.
RECORD MENU
SD Card Format
Formats the Micro SD card, which is necessary before recording. Cards must be formatted in a Series 4 transmitter for proper operation. The transmitter can be optionally renamed (see Setup Menu) to include the name in recorded file names for easier identification.
Partial Format
If the card's FAT32 file structure becomes corrupt, a partial format can be performed by pressing the STOP key 9 times. This rewrites the file structure without affecting recorded audio.
Playback Control
Allows playback of recorded files. The display shows the current mode (REC, PLAY, STOP), time code, segment number, and audio level. Controls include playing, stopping, jumping back/forward by segment, and advancing playback in increments.
Time Left on Card
Displays the remaining record time and time already used on the SD card.
Automatic Record after Boot Up
Configures the recorder to start automatically upon boot-up (ON) or wait for a ZaxNet command or manual trigger (OFF).
Low Battery Stop Set
Sets the behavior when a low battery warning occurs. The recorder can either NEVER STOP (requiring manual or ZaxNet stop) or stop after a set interval (1-99 minutes) to prevent file corruption.
ZAXNET MENU
ZaxNet Mode
Sets the ZaxNet transceiver mode:
- OFF: ZaxNet is disabled.
- RX: Receives ZaxNet commands and time code, displaying received data.
- TX: Sends ZaxNet confidence audio and time code.
ZaxNet Receive Frequency Set
Sets the frequency for receiving ZaxNet commands and time code. This frequency must match the ZaxNet transmitter. Signal strength is displayed.
ZaxNet Transmit Frequency Set
Sets the frequency for transmitting ZaxNet confidence audio and time code. The expected range is less than 20 feet.
Group Code Set
Assigns the transmitter to a group (1-99) for controlled grouping via ZaxNet.
Unit Code Set
Assigns a unique unit code (1-200) to identify each transmitter within a group for independent control.
ZaxNet Voting Enable
Allows the ZaxNet receiver to select the strongest signal from multiple ZaxNet transmitters. The second transmitter's frequency must be 2MHz higher.
Record Beep Set
When ON, an audible beep is sent to the ERX via ZaxNet during recording. The beep is not recorded or sent to the UHF receiver. Intervals can be set from 2 to 18 seconds.
AUDIO MENU
High Pass Filter
Filters out low frequencies from 40Hz to 220Hz in 10Hz increments. An example setting is 90Hz.
2K Notch Filter
Helps remove digital RF interference from microphones. Can be turned ON or OFF.
ADC Impedance
Adjusts microphone impedance to potentially lower the noise floor. The default setting is 10K.
Up-Key Function
Assigns functions to the INC key in the Home Screen:
- PUSH TO TALK: Audio is muted until the INC key is pressed and held.
- PUSH TO MUTE: Mutes the transmitter when the INC key is pushed and held.
- TAP TO TOGGLE: Toggles mute on and off with a tap of the INC key. 'Mute' is displayed when active.
Dynamics
Includes a soft knee compressor and expander to limit dynamic range and prevent clipping. Parameters include:
- Link L-R: Links left/right signals for stereo operation.
- SPEED (Decay Speed): Controls how gradually gain decreases after threshold. Options range from SLOWEST to FASTEST.
- ATTACK (Attack Speed): Controls how quickly gain is reduced after exceeding threshold. Options range from SLOWEST to FASTEST.
- CMP RATIO (Compressor Ratio): Sets the compressor's gain reduction ratio, from 1.0:1 to 5.0:1 in 0.1 steps.
- CMP THRESH (Compressor Threshold): Sets the level at which gain reduction occurs, from 0 to -96dB in 1dB steps.
- CMP KNEE (Compressor Soft Knee): Adjusts the soft knee characteristic, from 0 to 20dB in 1dB steps, for smoother transitions.
- EXP RATIO (Expansion Ratio): Sets the expansion ratio, from 1:1.00 to 1:4.00 in 0.01 steps.
- EXP THRESH (Expansion Threshold): Sets the threshold for expansion, from 0 to -96dB in 1dB steps.
- REDUCE (Expander Gain Reduction): Limits the amount of gain reduction from the expander, from 0 to -36dB in 1dB steps.
- GAIN (Make-up Gain): Adds gain to compensate for compressor-induced level reduction, from 0 to 30dB in 1dB steps.
SETUP MENU
Test Tone
Provides an internal tone generator for gain staging. Options include 500Hz at -20dB, 1000Hz at -20dB, or 500Hz at full scale.
Standby Mode After Boot Up
Sets the transmitter's boot mode: NORMAL MODE (standard boot) or REMOTE STANDBY (low power mode, awaiting ZaxNet 'WAKE' command).
Key Lock On Boot Up
Determines key lock behavior after boot: LOCKED (keys automatically lock) or UNLOCKED (keys remain unlocked).
QRX / ERX Firmware Update
Facilitates firmware updates for QRX or ERX receivers. The ZaxNet mode (OFF/RX or TX) dictates which receiver type can be updated. Refer to the FIRMWARE section for detailed instructions.
OLED Brightness Adjust
Adjusts the OLED display brightness from 0 to 3.
OLED Display Dim
Sets the time (1-60 seconds) after which the display dims following the last key press.
Unlock Difficulty
Configures the number of INC key presses required to unlock the transmitter after it has been locked, ranging from 5 to 45 presses (default is 5).
Information Page
Displays current firmware version, serial number, DSP version, and option code.
Hide Encryption Menu
Allows hiding or displaying the encryption menu for streamlined navigation.
Encryption Code Set
Sets a 6-digit encryption code for audio transmission. For un-encrypted operation, set both codes to 000.
Hide Transmitter Name Menu
Allows hiding or displaying the transmitter name menu.
Transmitter Name Set
Enables naming the transmitter (up to 8 characters). This name is incorporated into recorded audio file names and BWF metadata.
FIRMWARE
Firmware updates are available from the Zaxcom website. It is recommended to back up the 'SNXXXX.ME' file for each transmitter, which contains setup parameters.
Updating the ZMT4-X Firmware
Steps involve formatting an SD card, downloading the firmware file, copying it to the card, and powering up the transmitter with specific keys held down. A warning advises ensuring a fresh battery and uninterrupted power during the update.
Updating ERX Firmware with a ZMT4-X Transmitter
Instructions guide updating ERX firmware using the ZMT4-X as a programmer, requiring specific ZaxNet settings and SD card preparation. A warning emphasizes battery and power continuity.
Updating QRX Firmware with a ZMT4-X Transmitter
Details the process for updating QRX firmware using the ZMT4-X, including SD card preparation and specific QRX settings. A warning highlights the importance of not powering off the QRX during the final firmware burn process.
OPERATING FREQUENCIES
ZaxNet - Remote Control and Time Code: Operates between 2.403 GHz and 2.475 GHz.
UHF - Audio:
- ZMT4.5: Operates from 512.0 MHz to 614.0 MHz (Blocks 20 through 23).
- ZMT4.6: Operates from 596.0 MHz to 698.0 MHz (Blocks 23 through 26).
Antenna Cutting Chart
This chart provides guidance for cutting antennas for SMA/SSMA connectors, listing various blocks and their corresponding recommended antenna lengths in inches. It also indicates compatibility with specific Zaxcom models such as TRX-2.5, TRX-2.6, and QRX200.
ZAXCOM branding and social media links are present.
PRODUCT SUPPORT
Zaxcom offers various support resources:
- Register your product: http://zaxcom.com/support/product-registration/
- Download latest Firmware: http://zaxcom.com/support/updates/
- Download latest User Manuals: http://zaxcom.com/support/updates/
- Submit Technical Questions: http://www.zaxcom.com/submit-a-technical-question
- Submit for Repair Services: http://www.zaxcom.com/support/repairs
- Zaxcom User Forum: http://www.zaxcom.com/forum/forum.php
- Zaxcom Face Book User Group: https://www.facebook.com/groups/682199065139938/
SPECIFICATIONS
Transmitter
- Power output: 25 / 50 mW – Firmware Selectable
- RF Modulation: Proprietary Digital Method
- RF Frequency Step: 100 KHz
- RF Bandwidth (ZHD48 Mode): 100 KHz
- RF Bandwidth (ZHD96 Mode): 200 KHz
- RF Bandwidth (XR Mode): 400 KHz
- RF Frequency Range: ZMT3.5 Flex: 512 - 614 MHz; ZMT3.6 Flex: 596 - 698 MHz
- Antenna Connector: 50 Ω SSMA Female
- Emission Designator: 180 KV2E, 100 KV2E, 50 KV2E
- FCC Part: 74.861
Audio
- Dynamic Range: Mono: 128dB; Stereo: 108dB
- Mic input Impedance: 6.8 k Ohms
- Distortion: 0.002%
- Frequency Response: Mode 0: 20 Hz to 16 kHz
- Microphone Power: 3.3V
- Mic Connector: Microdot X 2
- Input Range: -60 to -30 dBu
- ADC Bit-Depth: 24 Bits
- ADC Sampling Rate: 48kHz
Time code Reader/Generator
- Clock Accuracy: 1.54PPM (1 Frame Out in 6 Hours)
- Time code Type: SMPTE
- Time code Frame Rates: 23.98, 24, 25, 29.97NDF, 29.97DF, 30NDF, 30DF
Recording
- Media: Micro SD Card (Flash Memory)
- File Format: .ZAX convertible to BWAV, MP3
- Recording Time: Up to 216 Hours (16 GB card)
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
All Specifications are subject to change without notice.
ZAXCOM WARRANTY POLICY AND LIMITATIONS
Zaxcom Inc. provides a one (1) year standard warranty period from the date of delivery. This warranty covers defects in material and workmanship. Zaxcom disclaims other warranties, express or implied. For warranty service, products must be returned to Zaxcom Inc. or an authorized dealer. Basic troubleshooting with the dealer is recommended before returning a product. Repair services can be initiated via the Zaxcom Repair Services page. Zaxcom covers return shipping within the US via two-day delivery; overnight service requires a FedEx or UPS account number.
Warranty Limitations: Remedies are limited to repair or replacement. Zaxcom's liability for any defective product shall not exceed the purchase price. Zaxcom is not liable for consequential, incidental, or special damages, including loss of recorded data.
Use of the Product: Zaxcom is not liable for returned products that are stolen, have non-existent defects, or have been damaged due to misuse, improper installation, alteration, accident, or mishandling.
Additional Limitations: Warranty does not cover products received improperly packaged, altered, or physically abused.
NOTICES
Most users do not need a license to operate a wireless microphone system, but must adhere to restrictions regarding harmful interference, low power levels (not exceeding 50 milliwatts), and protection from interference. Purchasers should be aware that FCC rules are subject to change. For more information, contact the FCC or visit their website. Operation with radiated power greater than 50mW requires Part 74 user qualification and licensing.
RF Exposure: The equipment complies with FCC radiation exposure limits for uncontrolled environments and should not be co-located or operated with other antennas or transmitters.
Industry Canada Regulations: Transmitters must use approved antenna types and gains. The device complies with Industry Canada license-exempt RSS standards, provided it does not cause interference and accepts any interference received.
The document lists specific FCC and IC identifiers (PR6ZMT3, IC:12755A-ZMT3) and Zaxcom's patent numbers, with a link for full patent information.
EU Declaration of Conformity
Zaxcom Inc. declares that the listed wireless microphone transmitters (including ZMT4, ZMT3, ZMT3-X, ZMT4-X, etc.) and receivers (including MRX214, MRX414, QRX200, etc.) conform to essential European directives: RoHS, Human Exposure, Radio Directive 2014/53/EU (RED), EMC (EN301 489-1v1.9.2 and EN301 489-9v2.1.1), and Safety (EN62368-1 2014).
Dated 07/24/2023, signed by Glenn Sanders, President, Zaxcom Inc.
