Drive unit, Amplification and DSP | Martin Audio ASX specs

IPAL (Integrated Powered Adaptive Loudspeaker)

The IPAL principle maximises the efficiency of electro-acoustic conversion of a transducer i.e. the way in which the mains input power is converted into actual acoustic output.

Traditional transducer design is compromised by the need to present an amplifier with a load impedance that is as resistive as possible – which implies a loss of efficiency of the transducer and also sets a limit on the current in the voice coil because of thermal dissipation. A transducer that would minimise the voice coil resistance, maximise the Bl “force factor”, or that would present a more reactive load, would enable a significant increase in the conversion efficiency.

In the practical embodiment of the IPAL principle in the ASX, DSP controlled, active feedback topology “emulates” an ideal virtual “target” transducer to maximise efficiency and maintain linearity at maximum excursion. Distortion is reduced by up to 20dB and power compression virtually eliminated. The IPAL system in the ASX comprises a dedicated Class D amplifier module, a DSP system,

a 21" (530mm) transducer unlike any other and a differential pressure sensor.

the drive unit

A neodymium motor system of immense proportions, coupled with a voice coil impedance of less than one ohm enables the drive unit to generate an unprecedented force upon the air load presented by the enclosure. This ability dominates the rest of the driver’s electro-acoustic parameters thus creating the “virtual transducer”.

By adjusting the processing in the control loop, fixed parameters such as moving mass, resonant frequency and even cone area can be “virtually” adjusted and optimised.

To handle the unprecedented forces and resultant air pressures requires an extremely strong cone material. Made from a mix of cellulose and carbon fibres, the cone has excellent strength when in tension and compression – unlike woven aramid fibre cones, whose compressive strength is much lower than their tensile capabilities.

amplification and DSP

The efficient Class D amplifier topology in the ASX is capable of delivering a peak power of 8.5kW and dramatically reduces the amount of energy dissipated as heat, as well as being much smaller and lighter than other amplifier topologies. The switchmode power supply, with Power Factor Correction for worldwide operation, has very high voltage rails which can also provide high levels of current into the very low impedance of the 21" (530mm) drive unit.

The DSP system is programmed with a number of parameters which represent the model of the ideal “target” loudspeaker. The actual audio input signal is then processed, so that the real loudspeaker emulates this ideal target at all power levels. A differential pressure sensor is mounted close to the transducer and is part of a feedback loop which generates an error signal feeding the DSP system to compensate for the non-linearities of the acoustical load and of the transducer. DSP programming and firmware upgrades are performed using a PC via a single RS485 port on the rear of the enclosure. The same software also configures the onboard DSP to provide system delay, EQ and filtering as well as amplifier and driver excursion limiting.

*International Patents PCT/IT2006/00615, PCT/IT98/00031.

US Patent No. US 6,281,767 B1

ASX specifications

The Martin Audio ASX is a cutting-edge subwoofer that excels in delivering powerful and precise low-frequency performance for various audio applications. Designed to meet the demands of both portable and installed sound systems, the ASX stands out for its unique combination of advanced technologies and user-centric features.

At its core, the ASX utilizes a highly efficient, high-excursion 18-inch neodymium driver, which ensures high output levels while maintaining excellent sound quality. This driver is engineered to produce deep bass that is both impactful and articulate, catering to the needs of live music events, clubs, and venues requiring high-performance audio. The intelligent design of the ASX enables it to provide a flat frequency response down to the lowest frequencies, delivering an immersive listening experience.

One of the standout technologies integrated into the ASX is the proprietary DSP (Digital Signal Processing) engine. This advanced processing allows for precise tuning of the subwoofer’s performance, enabling users to shape the sound to suit the specific acoustics of the venue. With the ability to adjust parameters such as crossover points, EQ settings, and delay, the ASX allows sound engineers to achieve optimal sonic results with ease.

Additionally, the ASX features an innovative 'Array' mode, which enables users to deploy multiple units in a seamless array configuration. This feature enhances the subwoofer's collective performance, ensuring consistent low-frequency coverage across larger areas, making it ideal for festivals and large-scale events.

Portability is another critical characteristic of the ASX. With a robust yet lightweight construction, the subwoofer is easy to transport and setup, catering to the needs of touring professionals. The ASX is equipped with multiple rigging points, allowing for versatile deployment in various configurations.

In summary, the Martin Audio ASX represents a significant advancement in subwoofer technology. Its powerful driver, sophisticated DSP capabilities, and array compatibility make it a versatile choice for sound professionals seeking superior low-frequency performance. Whether used in touring setups or fixed installations, the ASX ensures an unparalleled audio experience that elevates any event. The commitment to innovation and quality in the ASX reinforces Martin Audio's position as a leader in the professional audio industry.