Axient® Digital PSM Transmission Modes: Versatile Solutions for Every Application

• Axient Digital PSM offers five transmission modes, giving engineers the flexibility to prioritize what matters most for every show, venue, and RF environment.
• Patented Spatial Diversity technology works with OFDM-based modes (Multi-Channel Wideband and Narrowband) to mitigate signal fades caused by multi-path interference and maximize range without increasing RF output power.
• Multi-Channel Wideband mode packs more channels into less spectrum, ideal for high-density setups where RF coordination is a constant challenge.
• SC Narrowband and Analog FM deliver dependable performance when conditions get tough or ultra-low latency is the priority.
• From global tours to broadcast studios, Axient Digital PSM adapts to the demands of any show and gives engineers the confidence to deliver every time.

Shure introduced its first flagship digital IEM system, Axient Digital PSM, in October 2024 to overwhelming rave reviews and industry acclaim (and a few awards!). Features include patented Spatial Diversity transmission and True Digital Diversity reception that significantly improves reception while defending against interference, an exceptional wide tuning range to cover more regions with one system, ShowLink® for real-time remote control over the ADXR bodypack receiver from the monitor mix position, scalable channel count with optional perpetual licenses, and more channels per system than ever before thanks to Shure WMAS innovation.

At launch, Axient Digital PSM offered four transmission modes to choose from, allowing users to customize their in-ear monitoring solution to meet modern needs and challenges. Since then, we’ve added an additional transmission mode, bringing the total to five. Axient Digital PSM is the most flexible, powerful, expandable wireless system we’ve ever designed. Let’s talk about each of these five transmission modes to give you an idea of when each might solve problems in today’s demanding world of touring and performing.

OFDM Transmission Modes and Spatial Diversity
Orthogonal Frequency-Division Multiplexing (OFDM) is a digital, multi-carrier modulation technique that divides a data stream into multiple, closely spaced, orthogonal subcarriers utilized by Multi-Channel Wideband and Narrowband transmission modes. OFDM specifically enables the use of Spatial Diversity in both while opening the door to never-before-achieved spectral efficiency through Shure WMAS in the Multi-Channel Wideband transmission mode.

Developed by Shure, patented Spatial Diversity transmit technology employs two transmit diversity antennas, each sending an identical signal on the same frequency to an ADXR True Digital Diversity bodypack receiver, which employs two receiver channels, combining and totaling four discrete RF signal paths from RF transmitter to receiver. The resulting benefits Include mitigated signal fades caused by multi-path interference and greater range without having to increase RF output power.

Spatial Diversity is critical for maximizing both Multi-Channel Wideband and Narrowband transmission modes. Using either of these OFDM-based transmission modes without Spatial Diversity is not recommended.

Multi-Channel Wideband

OFDM - Achieve greater spectral efficiency with Shure WMAS innovation.

With Shure WMAS innovation, Multi-Channel Wideband transmission mode enables highly efficient use of spectrum by supporting multiple stereo audio channels on a single frequency. As a result, it achieves exceptional spectral efficiency, accommodating up to 28 channels per 6 MHz in the U.S. and 40 channels per 8 MHz in Europe. The Multi-Channel Wideband transmission mode streamlines everyday RF coordination in crowed RF environments since there are fewer total frequencies to coordinate and less intermodulation that would otherwise further crowd the RF environment. However, since RF output power is shared across the multiple subchannels per RF carrier, the spectral efficiency comes at the cost of range. Spatial Diversity is designed to gain back range performance at these lower compromised RF output power values per channel.

Using Multi-Channel Wideband without Spatial Diversity is never recommended due to compromised RF output power. 

Narrowband

OFDM - Access more RF output power for even better range performance with traditional narrowband wireless technology.

Combining Narrowband with Spatial Diversity will provide the greatest overall range performance of all the available transmission mode options. However, since Narrowband with Spatial Diversity requires double the radio resources per channel, it reduces the channel count per device by half. Spectral efficiency remains strong, supporting up to 17 channels per 6 MHz in the U.S. and 23 channels per 8 MHz in Europe. 

Narrowband is ideal for mission critical events that require extreme RF performance across vast distances or within busy, complex RF environments. 

SC Narrowband 

Non-OFDM – Perfect middle ground of both impressive spectrum efficiency and more predictable performance across the stage.

SC Narrowband is a new digital wireless transmission mode for Axient Digital PSM, utilizing advanced single carrier modulation to enhance RF stability and adaptability in challenging environments. SC Narrowband delivers the perfect middle ground of both impressive spectrum efficiency and predictable performance across all parts of the stage. It’s not only more spectrally efficient than Analog FM, but also more resilient to EVM noise (a phenomenon that occurs when scraping metal instruments, such as hi-hats, etc. onstage are within line of sight between the bodypack receiver and the transmit antenna) when compared to the available OFDM transmission mode options.

Like OFDM-based Narrowband, SC Narrowband supports 17 channels per 6 MHz in the U.S. and 23 channels per 8 MHz in Europe with the same respectable 2.8ms of latency.

Analog FM

Non-OFDM - Achieve ultra-low latency performance with updated hybrid technology that combines high quality digital audio with traditional analog RF.

Analog FM transmission mode delivers high-quality digital audio with exceptionally low latency (1.29 ms!) by combining digital audio processing and traditional analog RF. While Analog FM offers lower spectral efficiency—accommodating 9 channels per 6 MHz in the U.S. and 11 per 8 MHz in Europe—it provides the most available RF output power over all other transmission modes. This transmission mode is ideal for when low latency performance is required or when combining very high amounts to transmitter signals down to a single transmit antenna. 

Axient Digital Standard (PTP)

Non-OFDM - Send long-distance audio to any Axient Digital receiver.

Axient Digital Standard (PTP) is a point‑to‑point transmission mode that enables Axient Digital PSM transmitters to deliver high‑quality, long‑distance mono wireless audio to Axient Digital microphone receivers. Designed to replace PSM 1000 and UHF‑R for fixed‑power applications, it transmits audio identical to a portable microphone transmitter. With support for up to 17 channels per 6 MHz in the U.S. and 23 channels per 8 MHz in Europe. Its compatibility across Axient Digital systems makes setup simple, while its powerful signal transmission allows for clear audio even in demanding environments. This flexibility and reliability make it an ideal choice where distance from transmitter to receiver is the challenge.

Flexible Transmission Modes for Every RF Challenge
Global tours, large festivals, broadcast studios, houses of worship. professional theater, etc. present different challenges related to RF congestion, latency tolerance, and channel count. By offering five distinct transmission modes, Axient Digital PSM delivers the solutions monitor engineers need in a one-size-DOES-NOT-fit-all world. By offering flexible transmission options, Axient Digital PSM empowers engineers to prioritize what matters most in each scenario, whether that’s maximum spectral efficiency, ultra‑low latency for performers, enhanced robustness in crowded RF conditions, or pristine audio fidelity. This adaptability not only future‑proofs the system against evolving RF landscapes but also reinforces Shure’s commitment to giving audio professionals the control and confidence needed to deliver consistent, reliable monitoring, each and every time.