In 2015, the Telos Alliance and 25-Seven Systems launched the original Voltair. This groundbreaking system was really two products in one, combining both watermark-monitoring and processing capabilities.  For the first time, Voltair  gave broadcasters visibility into the quality of their watermark encoding and also allowed them to process signals, often dramatically improving watermark robustness. 

What many do not know is that the original Voltair development was conceived of as 2 separate, companion products; a monitor and a processor. The introduction of the Voltair M Watermark Monitor basically splits the great diagnostic features of Voltair into a monitor-only box that does not affect the original audio in any way. This makes Voltair M ideal for facilities that want visibility into their encoding system, but don't currently need or want Voltair’s full processing capabilities. 

Voltair M runs on the same hardware platform as its namesake, and is priced at roughly half the cost of a full Voltair Watermark Monitor and Processor. Voltair M can be upgraded to a full, processing-capable Voltair with an optional field software upgrade. 



  • Monitors the robustness of watermark encoding across all program content.

  • Offers visibility into how listening environments may influence watermarking, using models of acoustic spaces where listeners are wearing or carrying their devices.

  • Empowers programmers to make informed decisions to address potential weaknesses in either encoding or decoding by offering encoding confidence information (both on the front panel and via comprehensive data exports) without altering the original signal.

  • Expanded audio monitor output capabilities let users switch between the raw feed, encoded feed, or the raw watermark tones. This gives them an auditory understanding of how encoding and processing interact.

  • Calibration tests are included that provide noise measurements for both Layer 1 and 2 encoders.

  • ‘Encode Failure’ detection: Voltair Monitor features GPIO output alerts in the event that encoder signals fail. A detection sensitivity “grace period” is user selectable to prevent false alarms

  • A lifetime Data Export License is included, giving programmers access to minute-by-minute confidence histories. This allows them to better analyze programming by correlating it to other data sources, such as ratings information and audio log files.

  • By connecting Voltair M to your backup encoder, it can also serve as an off-line production tool to identify content with low encoding confidence. This can help stations produce programming elements—liners, promotions, etc. with greater confidence that comes from strong encoding.

  • Voltair M can be upgraded to a full Voltair model, which includes watermark enhancement processing. 


Ratings. Confidence.

It’s all about your listeners. Your people, your programming, your gear…they’re all focused on building and retaining your audience. 

We don’t have to tell you about the direct link between the size and composition of your audience—as measured and reported by your ratings—and your advertising revenue. That’s why it’s vital to you that every panelist in your market is accurately measured and that every station is playing on a level field.

Just like the classic Voltair, Voltair M is designed to give you greater confidence that every listener is counted when it counts the most.


Ratings, Programming & Technical Operations

Radio ratings have been called “a game of inches,” where winners and losers are sometimes decided by the thinnest of margins. Station management teams have always carefully monitored their markets’ listener data and taken action to maximize ratings and revenue.

With changes in rating survey methodologies, many program directors report making more dramatic changes than ever before. For example, dayparts have been moved, local breaks have been reduced, and programming clocks have become more rigid in response to the hard, quarter-hour boundaries of ratings credit. Likewise, the industry has seen changes in audio processing practices, airchain device order, and other station engineering procedures—all in service to optimal performance of watermark-based ratings technologies.

Because ratings performance data is provided on a delayed basis, stations lack the means to conduct real-time analysis of audience response. Programmers have had limited insight into what efforts are of benefit and why. Hence, most stations' efforts to optimize their performance in ratings have been trial and error, with little insight into what may or may not be effective.


Understanding the Current Ratings Ecosystem

25-Seven has been following the deployment of watermark-based rating methodologies since they were introduced. We’ve spoken with many program directors and engineers, getting their perspectives on the overall system architecture and the results of their optimization efforts.

After researching the publicly available data on the technology, our team of broadcast and audio experts uncovered the variables that contribute to watermark integrity. More importantly, we developed Voltair and now Voltair M, to provide you with the tools you need to monitor and analyze these variables, providing you with data to inform your technical and programming decisions.


What Did We Find?

Audio Content—The spectral characteristics of your audio content—music, announcer voices, etc.—may negatively impact the robustness of your watermark encoding. Simply put, some audio content encodes well while other content does not.

Listener Environment—A listener’s device may not detect particular content because of his or her current acoustic environment. A song or voice may not, for example, decode as well in a car as it does in a bedroom.

To address these issues, we needed to account for the highly complex set of interactions among the encoding and decoding processes, the audio properties of content, and listeners’ acoustic environments. We developed a totally new set of easy-to-use tools in Voltair and Voltair M to analyze and help you manage the consequences of these interactions.

Voltair M Data Export—You probably know that not all of your programming encodes equally well, and some content encodes downright badly. But you may not know which of your programming is problematic. In addition to simply watching the Voltair M front-panel screen and noting the areas that are and are not encoding via the color-coded indicators, Voltair M keeps a minute-by-minute history of encoding. Standard data export capabilities let you download this history in a color-coded spreadsheet for each broadcast day, with a confidence level for each minute of your programming. Programmers can then use this feature to identify the voices, commercials, and songs that don’t encode well. Visit our Voltair Data Export License FAQs for more information. All Voltair M units come with a free lifetime data export license. 


Voltair and 25-Seven are trademarks of TLS Corp. All other trademarks are the property of their respective holders.


Analog Line Inputs

  • Input Impedance: >40 k ohms, balanced

  • Nominal Input Range: +4 dBu

  • Input Headroom: 20 dB above nominal input

  • A/D Conversions: 24-bit, Delta-Sigma, 256x oversampling 


Analog Line Outputs

  • Output Source Impedance: <50 ohms balanced

  • Output Load Impedance: 600 ohms, minimum

  • Nominal Output Level: +4 dBu

  • Maximum Output Level: +24 dBu

  • D/A Conversions: 24-bit, Delta-Sigma, 256x oversampling 


Digital Audio Inputs and Outputs

  • Reference Level: +4 dBu (-20 dB FSD)

  • Impedance: 110 Ohm, balanced

  • Signal Format: AES3 (AES/EBU)

  • AES3 Input Compliance: 24-bit with sample rate conversion

  • AES3 Output Compliance: 24-bit

  • Digital Reference: Input

  • Internal Sampling Rate: 48 kHz

  • Input Sample Rate: 32 kHz, 44.1 kHz or 48 kHz

  • Output Sample Rate: matches Input Sample Rate  


Frequency Response

  • Any input to any output: +/- 0.5 dB, 20 Hz to 20 kHz 


Dynamic Range

  • Analog Inputs to Analog Outputs 108dB referenced to Full Scale, 111dB A-weighted

  • Digital Inputs to Digital Outputs 120dB

  • Be aware, some Encoders may have a lower dynamic range. This is a problem that exists whether or not you’re using Voltair, but does affect the total system performance.


Total Harmonic Distortion + Noise

  • Analog Input to Analog Output: < 0.005%, 1 kHz, +18dBu input, +18dBu output

  • Digital Input to Digital Output: < 0.0003%, 1 kHz, -20dBFs 


Crosstalk Isolation, Stereo Separation and CMRR

  • Analog Line channel to channel isolation: 90dB minimum, 20Hz to 20kHz

  • Analog Line Input CMRR: 80dB minimum, 20Hz to 20kHz


Power Supply AC Input

  • Auto-ranging supply, 100VAC to 240VAC, 50 Hz to 60 Hz

  • IEC receptacle, internal fuse, on/off switch

  • Power consumption: 55 Watts


Operating Temperatures

  • 0 degree C to +40 degree C, <90% humidity, no condensation


Dimesions and Weight

  • Chassis Dimensions (ex protrusions):

    • 19” (48.2 cm) wide

    • 3.5” (8.9 cm) height

    • 11.75” (30 cm) depth

  • Chassis Weight: 14.5 lbs. (6.57 kg)

  • Shipping Dimensions & Weight: Contact customer support



North America: FCC and CE tested and compliant, power supply is UL approved.

Europe: Complies with the European Union Directive 2002/95/EC on the restriction of the use of certain hazardous substances in electrical and electronic equipment (RoHS), as amended by Commission Decisions 2005/618/EC, 2005/717/ EC, 2005/747/EC (RoHS Directive), and WEEE.