Introduction - Martin Audio ASX User Manual

5

Introduction

The Martin Audio ASX subwoofer is a revolution in ultra-efficient, low frequency sound
reproduction – achieving the highest ever SPL from a single low frequency enclosure
housing a single drive unit.
At the heart of the ASX is a unique, patented* 21" (530mm) transducer/Class D
amplifier/DSP combination which provide double the output capability of a conventionally
driven loudspeaker driver of the same size. When incorporated into a Martin Audio Hybrid®
horn design, the complete system can deliver an unsurpassed 152dB peak output
(measured) from a single enclosure.
This is typically greater than can be achieved by two 2 x 18" (460mm) conventionally driven,
reflex subwoofers.
Additionally, the adaptive control loop technology maintains linearity up to the maximum
output level and power compression is virtually eliminated. The dynamic, low distortion sonic
signature of the ASX at full power is a revelation.
Hybrid® horn
Martin Audio's trademark Hybrid® horn design marries the very high efficiency of a large
folded horn with the low frequency extension of a bass reflex enclosure.
With a path length of 2.13 metres (7ft), the horn dominates the output down to 40Hz. The
reflex ports take over below the horn cut-off frequency, extending output down to 30Hz. The
Hybrid® design maximises both the efficiency and bandwidth within the practical limits of
enclosure size and has the fast transient performance long associated with Martin Audio
bass horns.
The chamber housing the 21" (530mm) transducer is ported to the front of the enclosure,
with special attention given to the cross-section profile of the ports to equalise the air
pressure at the port entry and exit and reduce the air velocity at the inner and outer port
edges to reduce air noise. The port profile also minimises the acoustic resistance to
maximise the output from the ports.
Extensive bracing is employed throughout the 18mm birch ply enclosure and aluminium U-
channel bracing is incorporated into the access door to resist the unusually high pressures
generated within the driver chamber.
The ASX is ground stackable in letterbox orientation, with interlocking skids. Handles and
removable castors assist positioning during installation.
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.
All material © 2009. Martin Audio Ltd. PRELIMINARY