USER MANUAL
MASS1015
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USER MANUAL
1. IMPORTANT NOTE 04
1.1. Precautions and recommendations 04
2. INTRODUCTION: CONCEPT AND DEFINITION OF A LINE ARRAY SYSTEM 04
2.1. Historical introduction 05
2.2. Sound propagation 05
2.3. LINE ARRAY systems as sources of cylindrical waves 06
2.4. Directivity of LINE ARRAY systems 06
3. THE LINE ARRAY BET ACOUSTICS MASS1015 10
3.1. General description of the system 10
3.2. Amplification and processing 13
4. ASSEMBLY AND CONNECTIONS 14
5. CONFIGURATIONS 19
6. TECHNICAL CHARACTERISTICS 20
All numbers subject to variation due to production tolerances. BET ACOUSTICS reserves the right to make changes or
improvements in manufacturing or design which may affect specifications.
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1. IMPORTANT NOTE
Congratulations! You have just become the owner of the result of careful design and painstaking
manufacturing. We thank you for placing your confidence in us by selecting our Line Array MASS1015
system.
To obtain maximum use and performance it is VERY IMPORTANT that you read this manual
carefully before using the system and that you take notice of the indications presented in it.
To ensure optimum functioning of the system we recommend that maintenance be carried out by
technical service personnel authorised by us.
1.1. Precautions and recommendations
The Line Array BET ACOUSTICS MASS1015 system is capable of delivering levels of sound
pressure that are capable of damaging the human ear. Protect your hearing when working with high
sound levels near the system.
The BET ACOUSTICS MASS1015 systems are designed to work only with your signal
amplification and processing system, thus providing well-balanced sound together with perfect
functioning. The use of components that differ from those specified can lower the performance of the
system and cause loudspeaker rupture.
All BET ACOUSTICS products are tested and checked before leaving the factory and should
therefore be in perfect condition on delivery.
Carefully unpack the product and observe its condition. If it has been damaged during transport
please check the damage so that you can send a report to the haulage contractor and return the product
immediately. Only consignees can initiate a claim against a haulage contractor if damage has been
caused during transport. The claimant is responsible for keeping all packaging parts for later inspection.
Please ensure that the system is not exposed to sunlight or rain.
2. INTRODUCTION: CONCEPT AND DEFINITION OF A LINE ARRAY SYSTEM
LINE ARRAY: “A group of emitting elements placed close together in a straight line, emitting with
the same phase and amplitude”. As per Harry F. Olson in his work “Acoustical Engineering and
Dynamical Analogies” (New York, 1940
Currently the advantages of line array systems over conventional sound equipment are common
knowledge: greater control of auditive coverage level, increased performance, greater projection,
optimisation of frontal emission and also lower weight and volume to handle.
The purpose of the following sections of this user manual is to provide a simplified view of the
behaviour of line array systems and familiarise the user with the basic concepts of acoustics and
electroacoustics.
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2.1. Historical introduction
Although the commercial development of Line Array systems began to expand in the 90s, the
acoustic principles that govern the behaviour of line array systems date back to observations made and
parallelisms introduced more than 150 years ago in the field of acoustics after the study of the behaviour
of polarised light.
The analogy between the behaviour of both types of radiation, light and sound, makes it possible
to establish the basic theories on which are based the minimum requirements that define the behaviour
of sound amplification systems such as the line array.
To understand the advantages of a line array system over a conventional sound system it is
important to keep in mind how sound behaves from the point of view of propagation.
2.2. Sound propagation
There are three basic natural forms of propagation of sound in air, each of which has its own
characteristics as regards form and pressure level attenuation as a function of the distance of the
listener from the sound source:
a) Spherical waves
These are emitted by a point source of sound which sends out a
spherical wave front, which therefore obey the inverse square law:
In this case, the level of sound pressure is attenuated by 6dB SPL for
each doubling of the distance between the listener and the sound
source in open air.
b) Cylindrical waves
These are emitted by a line of juxtaposed sound sources. The sound
emission of the group behaves as a cylindrical wave front with
attenuation with respect to the sound source of 3dB SPL.
Basically with a line array system the behaviour of the wave front for
a given range of frequencies follows this type of propagation so long
as the listener is located within the so-called near field (see section
2.3.).
The propagation of cylindrical waves is clearly advantageous as compared with the type of
propagation of spherical waves.
c) Plane waves:
These are generated, for example, in the interior of pipes with a given length and diameter in which
the acoustics are maintained independently of distance covered by the wave front with respect to the
source of sound emission.
In this case the level of sound pressure is not attenuated with distance. This type of wave is
synthesised in the so-called Kundt tubes, but are infrequent in nature.
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2.3. LINE ARRAY systems as sources of cylindrical waves
As was shown in the previous section the conditions under which a line array behaves as a
source of cylindrical sound waves depend on factors such as array length and the frequency used, and
can be expressed in a simplified way with the following formula:
D<H
2
f/2c
Where
H: array length (determined by the number of sound enclosures
used)
f: frequency
c: sound speed
D: frontal distance between the near region (Fresnel region) and the
far region (Fraunhofer region)
For distances greater than D the wave front emitted by a line array ceases to be cylindrical and
tends to become spherical, with a consequent attenuation of the sound pressure level of 6dB SPL on
doubling the distance from the array.
It is important to keep in mind that the behaviour in the near field of a line array system is in
actual fact qualitatively more complex given that each point located in this region is affected by the
pressure level contributions related to the distance to each one of the components that constitute each
of the acoustic enclosures that make up a line array.
This is why line arrays require suitably adjusted sound signal equalization and processing.
2.4. Directivity of LINE ARRAY systems
The efficiency of line array systems is based on constructive and destructive interference. The
pattern of any sound wave front begins to behave directive when the wavelength () of the sound is
comparable with the dimensions of the emitting surface.
If two acoustic boxes that emit the same frequency, phase and amplitude (see section 2) are
grouped, the resulting pattern of sound emission is different than when they emit separately:
At points along the axis between them there will be constructive interference with a resultant sound
level 6dB greater than with only one sound source.
At points outside the axis between them the difference in the distance travelled by the wave fronts
will cause cancellations, resulting in a lowered sound pressure level. This is the so-called
phenomenon of destructive interference or combing.
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The graphs included below depict the sound pressure level maps resulting from grouping 8
generic point sources of sound, the centres of each separated by 56 cm.
As can be seen, the directivity of the group of 8 sources differs as compared to that of one single
source, varying as a function of frequency.
Eight point sources of sound emitting in phase with the same amplitude.
Comparison of the vertical coverage as compared with one single point source as a function of frequency.
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Eight point sources of sound emitting in phase with the same amplitude.
Comparison of the vertical coverage as compared with one single point source as a function of frequency.
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Eight point sources of sound emitting in phase with the same amplitude.
Comparison of the vertical coverage as compared with one single point source as a function of frequency.
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As is to be expected, each of the acoustic enclosures that make up the line array consists of
different transducers, each of which is perfectly adapted to a range of frequencies to be reproduced and,
in general, with directive behaviour that varies with frequency and differs notably from the directional
behaviour of a point source.
The vertical directivity of a line array is determined using the following mathematical expression:
According to this mathematical function, the vertical response of a line array group is more
directive as frequency increases, low frequencies being almost omnidirectional.
The number of acoustic enclosures in a line array is related to resultant vertical directivity and is
therefore an important parameter on designing equipment for specific applications.
BET ACOUSTICS makes available to you the simulation program EASE FOCUS with the
corresponding library for predicting the behaviour of the MASS1015 system. EASE FOCUS allows rapid
and efficient determination of the number of acoustic enclosures needed as well as the optimum angle
between them to obtain sufficient and homogeneous sound pressure levels in the entire audience area.
EASE FOCUS can be downloaded free from www.betacoustics.com
3. THE LINE ARRAY BET ACOUSTICS MASS1015
3.1. General description of the system
The BET ACOUSTICS MASS1015 is a three-way line array system consisting of:
1 15" bass loudspeaker
1 10" middle frequency loudspeaker
2 1" compression motors for treble frequencies equipped with waveguides and a 90º diffusor for
horizontal coverage
The system is capable of reproducing an extensive bandpass range, (35 Hz – 18.000 Hz)
sufficient to make it a full range system which makes it possible to do without woofer or subwoofer
support systems. In this manner, a more coherent wave front is obtained as the entire information
bearing frequency range (80–18.000Hz), in addition to the most dense mass motion range (35–80 Hz),
proceed from the same source.
The acoustic enclosures that constitute the system are made from 18-mm thick laminated
phenolic birch wood with sufficient internal reinforcements to prevent undesirable mechanical vibrations,
providing the required robustness for the intended type of application.
With a textured black paint finish, each acoustic enclosure contains a flying system, 4 lateral
handles for transport as well as a frontal protective grille with acoustically transparent foam that protects
loudspeakers from splatter and against entry of foreign objects that occasionally can damage them.
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The components and architecture used for each of the ways of the system are described below:
BASS FREQUENCIES
The MASS1015 system uses a 15" bass frequency loudspeaker. As is shown in the diagram, the
loudspeaker is inclined. Thus the distance between the axes of the various stacked acoustic enclosures
is reduced, achieving a greater resultant sound pressure level.
By means of the aperture in the central partition wall of the enclosure the volumetric space is
optimized as regards loudspeaker rear load, creating a labyrinth that creates backward motion for
maximum improvement of the in-phaseness of front and rear emissions.
If access to the loudspeaker is required for maintenance purposes, the protective grille is
removed and the loudspeaker removed from the front of the enclosure.
Main characteristics of the 15" bass loudspeaker:
Loudspeaker: 15” with a neodymium magnet and 100 mm coil
Power: AES 1200W – 8 ohms
Program power: 2400 W
Sensitivity: 97dB SPL 1W/1m
Frequency response: 30Hz - 2kHz
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MIDDLE FREQUENCIES
For middle frequencies the system is equipped with a 10" loudspeaker with a neodymium magnet
that is hermetically sealed in its own rear chassis, which provides increased pressure that translates into
greater performance at middle frequencies. To support these pressures, the loudspeaker is equipped
with a curvilinear carbon-fibre cone.
As shown in the diagram, the system includes a corrector to reduce the distance between the
axes of the middle frequency wave fronts.
If access to the loudspeaker is required for maintenance purposes, the protective grille is
removed and the loudspeaker removed from the front of the enclosure. The corrector is fastened with
two screws to the loudspeaker itself, which maintains the cases separated.
Main characteristic of the 10" middle frequency loudspeaker:
Loudspeaker: 10” with a neodymium magnet and a 77 mm coil
Power: 400 W RMS – 8 ohms
Program power: 800 W
Sensitivity: 100dB SPL 1W/1m
Frequency response: 150Hz - 5kHz
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TREBLES
For the trebles 2 compression motors are combined as an optimum solution with a neodymium
magnet with waveguides, thus obtaining maximum coupling between both transducers. Both waveguides
are loaded with a diffuser with 90º horizontal coverage, projecting a wave front that is 10" high.
If the mobile treble motor groups need to be replaced, the protective grille is removed so that they
can be removed from the front of the system.
Main characteristic of the treble compression motor:
Compression motor with a neodymium magnet and 44.4 mm coil
Power: 40W AES – 8 ohms
Program power: 80 W
Sensitivity: 105dB SPL 1W/1m
Frequency response: 700Hz - 20kHz
Filter recommended: 1.5kHz
3.2. Amplification and processing
MASS1015 is a line array system which works straight out of the box. The basic configuration
includes 3 acoustic enclosures per channel. The corresponding amplification and processing of this
basic configuration is provided by a single flight case. This flight case consists of:
1 BET ACOUSTICS DPA1000 power amplifier (treble): 635W RMS / 4 ohms
2 BET ACOUSTICS DT6800 power amplifier (middle, bass frequencies): 1794 W RMS / 4 ohms
The BET ACOUSTICS power amplifiers are fully protected against subsonic frequencies, output
DC and overheating. Moreover, they include an efficient ANTICLIP circuit and forced, intelligent back
to front ventilation.
1 processor with 2 inputs and 6 outputs that provide the following functions:
o Values for cut-off frequencies and optimum slopes for each of the three ways
o Independent equalization for each of the three ways
o Phase-adjustment delays for the different transducer systems
o Limitation/compression needed to effectively control the dynamics of each of the three
ways.
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If more than three additional acoustic enclosures per channel are required for a given application,
it is sufficient to add a second flight case, and so on successively until the required final number of
acoustic enclosures has been obtained. In any case, 20 acoustic enclosures per flying column should
not be exceeded, given the load capacity of the system.
Please refer to section 5 for further information regarding BET ACOUSTICS MASS1015 line
array configurations.
4. ASSEMBLY AND CONNECTIONS
The acoustic enclosures of the MASS1015 system have been carefully studied and designed for
rapid, efficient and secure assembly, disassembly and storage of a line array:
Handling and operation of the BET ACOUSTICS MASS1015 system is simple owing to the 4
transport handles.
All of the units can be stacked together, forming easily handled, stored and transported clusters.
The reduced weight and compact size of each unit facilitates their handling.
The configurations can be kept assembled after events, both for transport as well as storage.
The flying system between enclosures contains only one type of connecting rod for easy
disassembly of units.
All fastenings are made with pins with magnetic heads for rapid handling.
The elevation mechanism is easily disassembled.
One single pin is used for all necessary functions as regards interconnection of units.
The STACK OUT output of each enclosure allows parallel connection of up to four acoustic
enclosures.
TRANSPORT, STORAGE
The most practical and usual way of transporting the BET ACOUSTICS MASS1015 system is in
configured clusters of 3 or 2x3 units. In this way the configuration of the vertical coverage of the system
can be maintained in addition to enabling transport of the iron elevation fittings installed in the same
cluster.
CALIBRATION OF VERTICAL COVERAGE
The calibration of vertical coverage of the system is easily carried out prior to being flown. The
positions of the pins are altered as indicated on the silk-screen print on the lateral, frontal iron fitting, the
intervals of the positions being 1º.
The positions of the pins of the rear laterals are not changed as the rear mechanism is only
intended to serve as a hinge.
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DESCRIPTIVE DIAGRAMS
The following diagrams describe each of the acoustic enclosures of the BET ACOUSTICS
MASS1015 system as well as its various flying parts.
1- The system includes four handles, two on each side, both strategically placed for maintaining
equilibrium during individual transport. The orifices of the two handles on the right side of the system act
as bass resonators.
2- There are four rabbets at the top of each unit which serve to accommodate the skids of the unit
stacked on top.
3- At the bottom of each unit there are four skids that are inserted in the unit stacked below.
4- The lateral iron fittings together with the "strut" connecting rods serve as hinges.
5- The lateral, front iron fittings calibrated degree for degree determine the vertical angle between each
of the units.
6- Connecting rod that serves as a strut.
7- 9.8 mm diameter pin with magnetic head.
FRONT
LATERAL
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ASSEMBLY
1- MASS1015 units.
2- Elevation system.
3– Wheel transport system.
4– Lateral elevation system plate.
5– Central elevation system plate.
6– Beam for connecting the elevation cord.
7– Union beam for the lateral and central plates.
8– Rivet for fastening lateral plates to the beam.
9– Drill holes for lateral plates.
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1– Rear, bottom fastening pin of a unit for the connecting rod that functions as a strut between it and the
next unit below.
2– Top, rear pin to the connecting rod to avoid swaying of the system.
3– Fastening pin of the top rear of a unit that serves as a strut between it and the next unit above.
4– Fastening pin of the bottom front of a unit to the connecting rod that functions as a strut between it
and the next unit below.
5– Fastening pin of the top front of a unit that functions as a strut between it and the next unit above.
The position of pin no. 5 determines the angle of the opening between units (lower and upper) as
indicated by the silk print inscribed in the lateral, front iron fittings.
The maximum angular opening between two contiguous units is five degrees. It is possible to
calibrate this opening in intervals of one degree.
5º-
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1
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1– Cluster assembly of 3 units.
2– Cluster assembly of 3 units, with the “Bumper”.
3– The cluster is elevated and the wheel transport unit removed.
4– After elevating cluster no. 1, cluster no. 2 is positioned below it (cluster without “Bumper”).
5– After the skids of the lower unit cluster no. 2 have been inserted in the accommodations of the upper
unit cluster no. 1, the two are fastened with the connecting rods by inserting the magnetic pins.
6– After all of the units have been connected the system is elevated and removed from the wheel
transport system.
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5. CONFIGURATIONS
BET ACOUSTICS offers the following possible configurations for efficiently combining 6 or 12
acoustic enclosures, using the same power and processing rack.
Each of these configurations offers the possibility of adapting the equipment to the requirements
of the application, minimising the number of elements and providing MASS1015 with a flexibility that
makes it the optimum solution for a large number of needs…
In any case, BET ACOUSTICS places at your disposal the simulation program EASE FOCUS
with the corresponding MASS1015 system library for dimensioning the equipment rapidly and effectively
whatever the application might be.
EASE FOCUS can be downloaded free from www.betacoustics.com
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6. TECHNICAL CHARACTERISTICS
Frequency response ±3dB 45Hz÷18kHz
Maximum SPL continuous LF 133dB
Maximum SPL continuous MF 128dB
Maximum SPL continuous HF 130dB
Maximum SPL peak LF 139dB
Maximum SPL peak MF 134dB
Maximum SPL peak HF 136dB
POWER
Power AES LF 1200W
Power AES MF 400W
Power AES HF 120W
Power peak LF 4800W
Power peak MF 1600W
Power peak HF 640W
SENSITIVITY
Sensitivity LF 102dB
Sensitivity MF 102dB
Sensitivity HF 109dB
DIMENSIONS WEIGHT
Dimensions mm. (W) 1050
Dimensions mm. (H) 316
Dimensions mm. (D) 719
Weight (kg.) 53
DESCRIPTION
Drivers LF 1 x 15"
Drivers MF 1 x 10"
Drivers HF 2 x 1 in.
Nominal impedance (ohms) LF 8
Nominal impedance (ohms) MF 16
Nominal impedance (ohms) HF 16
Finish (textured paint) Black
Protective grille Steel
Connectors 2 x NL8
ECLER Laboratorio de electro-acústica S.A.
Motors 166-168, 08038 Barcelona, Spain
INTERNET http://www.ecler.com e-mail: [email protected]
50.0150.01.00
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