d&b M4 Loudspeaker

General Information

Version: 2.3 en, 11/2021, D2990.EN.02

Copyright © 2021 by d&b audiotechnik GmbH & Co. KG; all rights reserved.

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d&b audiotechnik GmbH & Co. KG, Eugen-Adolff-Str. 134, D-71522 Backnang, Germany. T +49-7191-9669-0, F +49-7191-95 00 00.

Safety Precautions

Potential Risk of Personal Injury

Never stand in the immediate vicinity of loudspeakers driven at a high level. Professional loudspeaker systems are capable of causing a sound pressure level detrimental to human health. Seemingly non-critical sound levels (from approx. 95 dB SPL) can cause hearing damage if people are exposed to it over a long period.

In order to prevent accidents when deploying loudspeakers on the ground or when flown, please take note of the following:

• When setting up the loudspeakers or loudspeaker stands, make sure they are standing on a firm surface. If you place several systems on top of one another, use straps to secure them against movement.
• Only use accessories which have been tested and approved by d&b for assembly and deployment. Pay attention to the correct application and maximum load capacity of the accessories as detailed in our specific "Mounting instructions" or in our "Rigging manuals".
• Ensure that all additional hardware, fixings and fasteners used for deployment are of an appropriate size and load safety factor. Pay attention to the manufacturers' instructions and to the relevant safety guidelines.
• Regularly check the loudspeaker housings and accessories for visible signs of wear and tear, and replace them when necessary.
• Regularly check all load bearing mounting devices.

Potential Risk of Material Damage

Loudspeakers produce a static magnetic field even if they are not connected or are not in use. Therefore make sure when erecting and transporting loudspeakers that they are nowhere near equipment and objects which may be impaired or damaged by an external magnetic field. Generally speaking, a distance of 0.5 m (1.5 ft) from magnetic data carriers (floppy disks, audio and video tapes, bank cards, etc.) is sufficient.

M4 Loudspeaker

Product Description

The M4 is a high performance stage monitor employing an integrated 15"/1.3" exit coaxial driver design with neodymium magnet and constant directivity horn loading. Its dispersion of 50° x 70° (hor. x vert.) provides an accurately defined coverage area on stage. Used upright, the M4 serves as a powerful front PA speaker (70° x 50°) for various applications.

The M4 is a two-way design with a built-in passive crossover network. It can optionally be operated in two-way active mode by changing the configuration of the applicable amplifier without any modifications to the loudspeaker. Its frequency response extends from 55 Hz to above 17 kHz.

The cabinet is constructed from marine plywood and has an impact resistant paint finish. The front of the loudspeaker cabinet is protected by a rigid metal grille in front of an acoustically transparent foam. Each side panel incorporates a handle, while four M10 threaded inserts allow connection to different rigging devices and brackets. A pole mount is incorporated in one side panel to accept a loudspeaker stand. Two runners recessed in the bottom panel prevent cabinet movement and protect the bottom panel against scratching.

A diagram shows the M4 loudspeaker, a rectangular cabinet with a prominent circular grille on the front, and a rear panel with connector inputs.

Connections

The cabinet is fitted with NLT4 F/M connectors. All four pins of both connectors are wired in parallel using the pin assignments 1+/1- (LF) and 2+/2- (HF). Using one connector as the input, the second connector allows for direct connection to a second cabinet.

The cabinet can be supplied with NL4 M or EP5 connectors as an option.

A wiring diagram illustrates the pin assignments for NLT4 F/M and EP5 connectors. For NLT4 F/M, pins 1+/1- are for LF and 2+/2- are for HF. For EP5, pins 1/2 are for LF and 3/4 are for HF, with pin 5 being not connected (n.c.).

Operation

NOTICE! Only operate d&b loudspeakers with a correctly configured d&b amplifier, otherwise there is a risk of damaging the loudspeaker components.

Applicable d&b amplifiers: D80/D40/D20/D12/D6/40D/30D/10D.

Passive Operation ("Dual Channel" Mode)

Selecting "Dual channel" mode with the M4 setup enables up to two M4 cabinets to be driven by the respective channel. In "Dual channel" mode, each amplifier channel drives all output pins of its respective output connector, thus driving the cabinet's HF and LF sections via their passive crossover networks. Pins 1+/2+ of the NL4 output connector (EP5: 1/3) carry the positive and pins 1-/2- (EP5: 2/4) carry the negative components of the signal.

A schematic shows an amplifier channel (AMP A) connected to the loudspeaker's LF and HF sections via a passive crossover. Input A is routed to both. The output connector carries both positive and negative signals for LF and HF.

Passive Operation ("Mix TOP/SUB" Mode)

With its standard connector wiring, the M4 requires 4 wires to be driven and therefore cannot be used in "Mix TOP/SUB" mode. However, for permanent passive use with dedicated 2-wire cabling, the M4 setup is also available in "Mix TOP/SUB" mode. For passive operation with a 2-wire loudspeaker cable, pins 1+/- and 2+/- have to be bridged on the loudspeaker side of the cable.

A schematic shows two amplifier channels (AMP A for TOP, AMP B for SUB) connected to the loudspeaker. This mode requires specific 2-wire cabling with bridged pins on the loudspeaker side.

Active Operation ("2-Way Active" Mode)

Selecting "2-Way Active" mode with the M4 setup enables up to two M4 cabinets to be driven actively by the respective amplifier. In "2-Way Active" mode, separate LF and HF signals are routed to the amplifier channels. Pins 1+/1- of both NL4 output connectors (EP5: pins 1/2) carry the LF signal, pins 2+/2- (EP5: 3/4) carry the HF signal.

For D80 and D12 amplifiers, the output connector pin assignment is set automatically when "2-Way Active" mode is selected. For all other applicable amplifiers, a dedicated socket for active operation is available. The input signal can be fed either to INPUT A or to INPUT B and is routed (linked) to both amplifier channels internally.

A schematic shows two amplifier channels (AMP A for LF, AMP B for HF) connected to the loudspeaker. Input A and B are routed to the respective amplifier channels, which then send separate LF and HF signals to the loudspeaker.

Controller Settings

CUT Mode

Set to CUT, the low frequency level is reduced. The cabinet is now configured for use with actively driven d&b subwoofers.

HFA Mode

In HFA mode (High Frequency Attenuation), the HF response of the system is rolled off. HFA provides a natural, balanced frequency response when a cabinet is placed close to listeners in near field or delay use. High Frequency Attenuation begins gradually at 1 kHz, dropping by approximately 3 dB at 10 kHz. This roll off mimics the decline in frequency response experienced when listening to a system from a distance in a typically reverberant room or auditorium.

A graph shows frequency response correction in HFA mode. The X-axis represents frequency in Hz (from 20 Hz to 20 kHz), and the Y-axis represents dB level. The line shows a gradual roll-off starting around 1 kHz, with approximately -3 dB at 10 kHz.

CPL Function

The CPL (Coupling) function compensates for coupling effects between the cabinet and close boundary surfaces or when the cabinet is used as a stage monitor. CPL begins gradually around 1 kHz, with the maximum attenuation below 400 Hz. To achieve a balanced frequency response, the CPL function can be set to dB attenuation values between 0 and -9.

Positive CPL values create an adjustable low frequency boost (0 to +5 dB) and can be set when the system is used in full range mode without subwoofers. For a single cabinet in free space conditions, a value of +3 dB is recommended.

A graph illustrates frequency response correction for the CPL function. The X-axis is frequency in Hz (20 Hz to 20 kHz), and the Y-axis is dB level. It shows how CPL values affect low-frequency response, with options for attenuation (0 to -9 dB) or boost (0 to +5 dB).

Operation with E-PAC

Selecting the M4 setup enables the E-PAC to drive one M4 loudspeaker. LO IMP mode configures the E-PAC to drive a maximum of two M4 loudspeakers with a 6 dB reduction in input level to the loudspeakers.

For acoustic adjustment, the CUT and HFA modes are available. The characteristics are described in the previous section.

Dispersion Characteristics

The graphs below show dispersion angle over frequency of a single M4 cabinet plotted using lines of equal sound pressure (isobars) at -6 dB and -12 dB. The characteristics refer to monitor operation. When used as a front-of-house system, the horizontal dispersion corresponds to the vertical plot and vice versa.

Two isobar diagrams illustrate the dispersion characteristics of the M4 loudspeaker. The X-axis represents frequency in Hz (125 Hz to 16 kHz), and the Y-axis represents dispersion angle in degrees. Lines of equal sound pressure (isobars) at -6 dB and -12 dB are plotted, showing horizontal and vertical coverage patterns for monitor operation. When used as a front-of-house system, the horizontal and vertical plots are swapped.

Altering the HF Horn Dispersion

The HF horn can be rotated through 90° for dedicated installation applications.

Tools required: Torx wrench (#TX25).

1. Disconnect the loudspeaker.
2. Undo the 10 screws holding the front grille and remove the front grille.
3. Undo the screws holding the horn flange and the two opposite screws at the 15" driver for the desired orientation.
4. Rotate the horn to the desired orientation.
5. Refit all screws and tighten them using a torque setting of 2 N-m.
6. Refit the front grille and tighten all screws using a torque setting of 4 N-m.

Technical Specifications

M4 System Data

Frequency response (-5 dB standard): 55 Hz - 17 kHz

Frequency response (-5 dB CUT mode): 95 Hz - 17 kHz

Max. sound pressure (single cabinet, 1 m, free field):

• with D6/10D/E-PAC passive mode: 134 dB
• with 10D active mode: 135 dB
• with D80/D40/D20/D12/40D/30D passive mode: 138 dB
• with D80/D40/D20/D12/40D/30D active mode: 140 dB

(SPLmax peak, pink noise test signal with crest factor of 4)

A graph displays the M4 frequency response in standard and CUT modes. The X-axis is frequency in Hz (20 Hz to 20 kHz), and the Y-axis is dB level. It shows the frequency response curve for both modes, indicating the -5 dB points.

M4 Loudspeaker

Nominal impedance: 8 ohms

Power handling capacity (RMS / peak 10 ms): 400/1600 W

Nominal dispersion angle (hor. x vert., monitor setup): 50° x 70°

Components:

• 15" LF driver with neodymium magnet
• coaxial 1.3" exit compression driver with 3" coil and CD horn
• Passive crossover network

Connections:

• NLT4 F/M (optional 2 x EP5)
• WR option: Faston type connector (2 x 6.3 mm), female

Pin assignment:

• NLT4 F/M: 1+: LF+/1-: LF- | 2+: HF+/2-: HF-
• EP5: 1: LF+ | 2: LF- | 3: HF+ | 4: HF- | 5: n.c.
• WR option: Brown: (+) / Blue: (-)

Weight: 20 kg (44 lb)

A diagram shows the external dimensions of the M4 cabinet in millimeters and inches. Key dimensions include width (505 mm / 19.88 in), height (363 mm / 14.3 in), and depth (360 mm / 14.17 in).

Manufacturer Declarations

Conformity of Loudspeakers

This declaration applies to: d&b Z0800 M4 loudspeaker, manufactured by d&b audiotechnik GmbH & Co. KG.

All product variants are included, provided they correspond to the original technical version and have not been subject to any later design or electromechanical modifications.

We herewith declare that said products are in conformity with the provisions of the respective directives including all applicable amendments.

Detailed and applicable declarations are available on request and can be ordered from d&b or downloaded from the d&b website at www.dbaudio.com.

WEEE Declaration (Disposal)

Electrical and electronic equipment must be disposed of separately from normal waste at the end of its operational lifetime.

Please dispose of this product according to the respective national regulations or contractual agreements. If there are any further questions concerning the disposal of this product, please contact d&b audiotechnik.

WEEE-Reg.-Nr. DE: 13421928