WM2 is the first watermarking-only product designed by SOUND4. It is a dedicated hardware platform, specifically developed for the Kantar Media watermarking standard, with no hidden PC inside.

It can tag one stereo program (I/O: Analog, AES3, AES-67/Livewire) but also provides the option of adding five more stereo channels using AES-67/Livewire I/O only. This means that the WM2 can watermark simultaneously six stereo channels for a breakdown price.

SOUND4 WM2 is a standard 1U rack-mountable tool, fully controllable through the user-friendly HTML5 GUI.


About Kantar Media watermarking technology:

SNAP audio watermarking technology by Kantar has been designed for TV and Radio audience measurement. In addition, it can also be used for the synchronization of a second screen application. SNAP watermarking carries 2 types of information, a channel identifier and a timestamp for linear content and a timecode for non-linear content.

The audio watermarking technology can be described by 3 main properties: the inaudibility of the watermarking, the amount of data carried by the watermarking and the robustness of the watermarking.

The SNAP technology remains inaudible thanks to a very complex acoustic model and preserves the quality of the sound. This is a crucial property for TV channels and Radio stations that invest time and money into getting the best quality for their sound. Regarding the amount of data, the SNAP technology proposes a single payload for Channel and Content identification. The robustness of SNAP watermarking in the broadcast chain is also a key element. SNAP is robust to low encoding bitrates, and to adaptive bitrates. Don’t hesitate to contact Kantar support to get bitrate recommendations depending on the audio codec.


  • Watermarking capacities:
    • 1 stereo channel, I/O: analog, AES/EBU, AES-67/Livewire
    • In Option: up to 3 more stereo channels, I/O: AES-67/Livewire only
  • Stereo Inputs: 1 AES/EBU 32 to 192 kHz, 1 analog, 1 AES-67/Livewire + 3 additional AES-67/Livewire available as Option
  • Stereo Outputs: 1 AES/EBU 32 to 192 kHz, 1 analog, 1 AES-67/Livewire + 3 additional AES-67/Livewire available as Option
  • Digital wordclock synchronization input from AES/EBU or AES67 (PTP1588)
  • 1 Ethernet port: Admin & AES-67/Livewire
  • GPIO: 4 inputs, 4 outputs, advanced management with scripts
  • 1 USB ports: rear side (for upgrade loading and other functionalities)
  • Routing management: Each output is able to deliver a watermarked signal or a replicated input
  • Relay switch for automatic by-pass (analog in to analog out & digital in to digital out)
  • SNMP traps
  • Fully controllable from front Panel
  • HTML5 GUI: for all configurations
  • Single Power Supply
  • Analog Input
    Quantity1 stereo
    Level2 ranges (+12 or +24 dBu - software selectable)
    Impedance10 kΩ
    Connectors1 pair of XLR female balanced, EMI suppressed
  • Digital Input
    Quantity1 stereo
    StandardAES3 (EBU)
    Sampling Rate32 to 192kHz, 24 bits
    ConnectorsXLR female balanced , EMI suppressed
  • Analog Output
    Quantity1 stereo balanced (with automatic unbalancing)
    Level2 ranges (+12 or + 24 dBu - software selectable)
    Load Impedance10 kΩ typ. (> 300 Ω)
    Connectors1 pair of XLR male balanced, EMI suppressed
  • Digital Output
    Quantity1 stereo
    StandardAES3 (EBU)
    Sampling Rate32 to 192kHz, 24 bits
    ConnectorXLR male balanced, EMI suppressed;
  • Audio Over IP (I/O)
    CompatibleAES-67, Ravenna, Livewire; 48kHz, 24 bits, stereo, 48 samples/packet (1ms),
    Quantity of channels1 for the WM2 without options and up to 6 with options
  • Audio Specifications
    Watermarking Delay???ms
    Frequency Response30Hz - 20 kHz +/-0.2dB
    Signal to Noise>90 dB
    Distortion Analog<0.006% THD
    Separation>70 dB
  • Bypass Relay
    AES/EBUAES in => AES out
    AnalogAnalog in => Analog out
  • Power Supply
    Voltage100 – 260 Volt AC, < 25W
  • Operating Conditions
    Operational between0 – 50°C
  • Power Up Boot
    For analog and AES/EBU25s
  • Other Interfaces
    USB 2.0for upgrades
    GPIO4 inputs, 4 outputs (opto-isolated) with 5V supply (DB15 male)
  • PC To Client Communication Interface
    HTML5All parameter are accessible
    SNMPSupervision with Trap Feature
  • Size And Weight
    Dimensions (WxHxD)483 x 44 x 180 mm
    Shipping Weight540 x 115 x 300 mm / 2.465 kg
    HS Code8517620000