Martin Audio ASX User Manual

www.martin-audio.com

commercial installation

ASX

Ultra-High Performance Active Subwoofer

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.

commercial installation: ASX © Martin Audio Ltd.

features

✷ Ultra-efficient, with 152dB @ 1m half space

maximum output

✷ Hybrid® large folded horn and ported design,

-3dB @ 30Hz

✷ Single 21" (530mm)/6" (150mm) voice coil driver with

2.4" (60mm) peak-to-peak excursion

✷ DSP-based, adaptive control loop technology

maintains linearity up to maximum output level.
Power compression virtually non-existent

✷ Dedicated Class D amplifier with 8.5kW peak power
✷ Switched mode power supply with PFC (Power Factor

Correction) and global mains voltage operation

✷ DSP on board providing delay, EQ and filtering as well

as amplifier and driver excursion limiting

✷ PC based software application for parameter

configuration

applications

✷ Premium club installations
✷ Stadium installations
✷ Theme park special effects

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. Below this frequency the reflex ports take
over, extending output to -3dB @ 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 birch­ply 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.

ASX

Ultra-High Performance Active Subwoofer

commercial installation: ASX © Martin Audio Ltd.

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

www.martin-audio.com

Martin Audio Limited.
Century Point, Halifax Road, Cressex Business Park,
High Wycombe, Buckinghamshire HP12 3SL, England.

UK

Telephone: [phone]
Facsimile: [phone]
E-mail: [e-mail]

USA

Telephone: [phone]
Facsimile: 519 747 3576
E-mail: [e-mail]

All information is Copyright ©2008 Martin Audio Ltd.

Martin Audio and the Martin Audio Logo are trademarks of Martin Audio Ltd
and are registered in the United Kingdom, United States and other countries.

architectural and engineering specifications

The loudspeaker shall be a self-powered subwoofer with a
single 21" (530mm) diameter cone transducer with a rated
power of 2500W AES. The loudspeaker shall incorporate an
integral Class D amplifier module with a peak output power of
8500W, a DSP system and a differential pressure sensor.
Performance specifications of the complete system shall be as
follows: Frequency response 30-150Hz ± 3dB. Maximum peak
SPL 152dB, measured at 1 metre. The audio input connector
shall be an XLR type female, with an XLR type male link.

The power supply shall have global mains operation over an
operating range of 85V AC – 270V AC, 50/60Hz, with Power

Factor Correction. The AC power connector shall be a Neutrik

®

Powercon®.

All loudspeaker components shall be mounted in a
multi-laminate, birch ply enclosure with removable wheels.
Install dimensions shall be: (W) 1200mm x (H) 600mm x
(D) 1200mm, (W) 47.24ins x (H) 23.62ins x (D) 47.24ins.
Dimensions (inc. wheels) shall be: (W) 1328mm x (H) 600mm
x (D) 1200 mm, (W) 52.28ins x (H) 23.62ins x (D) 47.24ins.
Weight 160kg (353lbs).

The loudspeaker shall be the Martin Audio ASX active
subwoofer.

technical specifications

ACOUST ICAL

TYPE Hybrid

®

horn/reflex active subwoofer

FREQUENCY RESPONSE (1)

30-150Hz ± 3dB
MAXIMUM PEAK SPL (2) 152dB
RECOMMENDED CROSSOVER

60-120Hz

DRIVER

TYPE 21" (530mm) diameter/ 6" (150mm) voice coil
PEAK DISPLACEMENT ± 1.2" (30 mm)
MECHANICAL DAMAGE LIMIT

± 1.5" (38mm)
RATED POWER 2500W AES, 10000W peak

AUDIO INPUT

CONNECTORS Female XLR input, male XLR link output
INPUT IMPEDANCE 10kΩ, balanced to ground
NOMINAL SYSTEM GAIN 32dB
INPUT LEVEL FOR MAX SPL

3.5V rms
S/N RATIO >105dB
DISTORTION (100Hz) <0.05%

AMPLIFIER SECTION

TYPE Single channel switchmode, fixed frequency
PK-PK OUTPUT VOLTAGE

390V

PK-PK OUTPUT CURRENT

200A
AVERAGE EFFICIENCY 85%
PEAK OUTPUT POWER 8500W
COOLING 2 x temperature controlled, variable speed fans

1 x forced air blower, venting in to horn mouth

POWER SUPPLY SECTION

TYPE Switchmode, fixed frequency with PFC
AC INPUT OPERATING RANGE

85V AC – 270V AC, 50/60Hz
AC OVERVOLTAGE TOLERANCE

400V AC
POWER FACTOR > 0.95
AVERAGE POWER CONSUMPTION

300VA
MAINS CONNECTOR Neutrik®Powercon

®

DSP CONTROL INPUT

RS485 PORT RJ45 socket

GENERAL

ENCLOSURE Extensively braced, multi-laminate birch ply
FINISH Black textured paint
PROTECTIVE GRILLE Perforated steel
FITTIN GS 2 pocket handles on each side, 2 wooden skids on

top and bottom, 4 removable castors for transportation
INSTALL DIMENSIONS (W) 1200mm x (H) 600mm x (D) 1200mm

(W) 47.24ins x (H) 23.62ins x (D) 47.24ins
DIMENSIONS (W) 1328mm x (H) 600mm x (D) 1200mm
(INC. WHEELS) (W) 52.28ins x (H) 23.62ins x (D) 47.24ins
WEIGHT 160kg (353lbs)

Notes:

1. Measured in half-space

2. Measured in half-space at 1 metre with band-limited pink noise