Meyer Sound Documentation

All components in an audio system (self-powered loudspeakers, mixing consoles, and processors) must be properly connected to an AC power distribution system, ensuring that AC line polarity is preserved and that all grounding points are connected to a single node or common point using the same cable gauge (or larger) as the neutral and line cables.

120V AC, 3-Phase Wye System (Single Line) — Line-Neutral-Earth/Ground

The figure below illustrates a basic 120V AC, 3-phase Wye distribution system with the loudspeaker load distributed across all three phases, with each loudspeaker connected to a single line and common neutral and earth/ground lines. This system delivers 120V AC to each loudspeaker.

120V AC, 3-Phase Wye System (Single Line to Loudspeakers)

Line-Line-Earth/Ground

The figure below illustrates a 120V AC, 3-phase Wye distribution system with each loudspeaker connected to two lines and a common earth/ground line. This configuration is possible because the 900-LFC tolerates elevated voltages from the ground line and does not require a neutral line. This system delivers 208V AC to each loudspeaker.

120V AC, 3-Phase Wye System (Two Lines to Loudspeakers)

Tip

The 120V AC, 3-phase Wye system with two lines is recommended because it allows loudspeakers to draw less current than with single-line systems, thereby reducing voltage drop due to cable resistance. It also excludes the potential of varying ground to neutral voltages producing an audible hum.

230V AC, 3-Phase Wye System (Single Line)

Line-Neutral-Earth/Ground

The figure below illustrates a basic 230V AC, 3-phase Wye distribution system with the loudspeaker load distributed across all three phases, with each loudspeaker connected to a single line and common neutral and earth/ground lines. This system delivers 230V AC to each loudspeaker.

230V AC, 3-Phase Wye System (Single Line to Loudspeakers)

Caution

For 230V AC, 3-phase Wye systems, never connect two lines to the AC input of the 900-LFC, as the resulting voltage would exceed the upper voltage limit (275V AC) and will damage the loudspeaker.

The 900-LFC user panel includes two powerCON 20 connectors, one for AC Input (blue) and one for AC Loop Output (gray), as shown in the figure below.

AC Input (Left) and AC Loop Output (Right) Connectors

AC Input (Blue)

The blue AC Input connector supplies power to the

900-LFC. The 3-conductor powerCON 20 is rated at 20 A and uses a locking connector that prevents accidental disconnections. A 10-foot AC power cable, rated at 15 A, is included with each loudspeaker. If you replace the included AC power cable, make sure to use a cable with the appropriate power plug (on the other end) for the area in which you will operate the loudspeaker. The 900-LFC requires a grounded outlet. To operate safely and effectively, it is extremely important that the entire system be properly grounded.

The AC Input connector also supplies power to any additional loudspeakers connected to the loudspeaker’s gray Loop Output connector.

Caution

When looping AC power for loudspeakers, do not exceed the current capability of the AC Input connector (20 A) or the included AC power cable (15 A). Consider the total current draw for all loudspeakers on the circuit, including the first loudspeaker. See AC Loop Output (Gray) for more information.

AC Loop Output (Gray)

The gray AC Loop Output connector allows multiple 900-LFCs to be looped and powered from a single power source. The 3-conductor powerCON 20 is rated at 20 A and uses a locking connector that prevents accidental disconnections. For applications that require multiple 900-LFCs, connect the AC Loop Output of the first loudspeaker to the AC Input of the second loudspeaker, and so forth.

The maximum number of loudspeakers that can be looped from the AC Loop Output connector is determined by the voltage of the power source, the current draw of the looped loudspeakers, the circuit breaker rating, and the rating of the AC power cable connected to the first 900-LFC loudspeaker (see the table below).

Table 1. Maximum 900-LFCs that Can Be Looped with AC Power

Circuit Breaker/ Connector Rating	115 V AC	230 V AC	100 V AC
15 A / 16 A	2 looped (3 total)	5 looped (6 total)	1 looped (2 total)
20 A	3 looped (4 total)	7 looped (8 total)	2 looped (3 total)

Note

Current draw for the 900-LFC is dynamic and fluctuates as operating levels change. The indicated number of loudspeakers that can be looped assumes that operating levels are normal and not such that loudspeakers are constantly limiting.

The 900-LFC ships with a gray powerCON 20 cable mount connector, rated at 20 A, for assembling AC looping cables. Assembled AC looping cables are also available from Meyer Sound.

Caution

When looping AC power for loudspeakers, do not exceed the current capability of the AC Input connector (20 A) or the included AC power cable (15 A). Consider the total current draw for all loudspeakers on the circuit, including the first loudspeaker ([→ _bookmark9]Table 1).

The 900-LFC ships with a gray powerCON20 cable mount connector (Figure10), rated at 20A, for assembling AC looping cables. The pins on the powerCON20 cable mount connector are labeled as follows:

powerCON 20 Cable Mount Connector

How AC power cables are wired is determined by the type of AC power distribution system used ( see AC Power Distribution). When wiring AC power cables for single-line systems, use one of the wiring schemes described in the table and illustrated in the figure below:

AC Wiring Scheme, illustrated

The 900-LFC operates as intended when receiving AC voltage within the following range:

If the voltage drops below 90 V, the loudspeaker uses stored power to continue operating temporarily; the loudspeaker powers off if the voltage does not return to its operating range.

If the voltage rises above 275 V, the power supply could become damaged.

Current draw for loudspeakers is dynamic and fluctuates as operating levels change. Because different cables and circuit breakers heat up at varying rates, it is important to understand the following types of current ratings and how they affect circuit breaker and cable specifications.

Use the information provided in the table below as a guide for selecting the gauge of cables and the circuit breaker ratings for the system’s operating voltage.

The minimum electrical service amperage required by a loudspeaker system is the sum of the maximum long-term continuous current for all loudspeakers. An additional 30 percent above the combined Maximum Long-Term Continuous amperages is recommended to prevent peak voltage drops at the service entry.

The 900-LFC’s Intelligent AC™ power supply automatically selects the correct operating voltage (allowing the loudspeaker to be used internationally without manually setting voltage switches), eliminates high inrush currents with soft-start power up, suppresses high-voltage transients up to several kilovolts, filters common mode and differential mode radio frequencies (EMI), and sustains operation temporarily during low-voltage periods.

Powering on the 900-LFC

When powering on the 900-LFC, the following startup events take place over several seconds.

1. Audio output is muted.

2. Voltage is detected and the power supply mode is automatically adjusted as necessary.

3. The power supply ramps up.

4. On the user panel, the Active/Status LED flashes multiple colors successively.

   • Make sure the AC power cable for the loudspeaker has the appropriate power plug (on the other end) for the area in which you will operate the loudspeaker. In addition, the AC power cable must be rated for the total current draw of all loudspeakers looped from the power source.

   • Do not operate the loudspeaker if the power cable is frayed or broken.

   • Keep all liquids away from 900-LFC loudspeakers to avoid hazards from electrical shock.

   • Use the cable rings (Cable Rings) on the rear of the 900-LFC cabinet to reduce strain on the AC power cable (and audio cables). Do not use the cable rings for any other purpose.

5. The Active/Status LED turns solid green, indicating the loudspeaker is unmuted and ready to output audio.

Caution

If the Active/Status LED does not turn solid green, or the 900-LFC does not output audio after 10 seconds, remove AC power immediately and verify that the voltage is within the required range. If the problem persists, contact Meyer Sound Technical Support.

Make sure to observe the following important electrical and safety guidelines.

The 900-LFC is available with XLR 3-pin, as shown in the first figure below, or 5-pin connectors, shown in the second figure, for audio Input and audio Loop output. XLR 5-pin connectors accommodate both balanced audio and RMS signals.

XLR 5-Pin Audio Connectors, Input and Loop Output

XLR 3-Pin Audio Connectors, Input and Loop Output

Audio Input (XLR 3-Pin or 5-Pin Female)

The XLR 3-pin or 5-pin female Input connector accepts balanced audio signals with an input impedance of 10 kOhm. The connector uses the following wiring scheme:

• Pin 1 — 1 kOhm to chassis and earth ground (ESD clamped)

• Pin 2 — Signal (+)

• Pin 3 — Signal (–)

• Pin 4 — RMS (polarity insensitive)

• Pin 5 — RMS (polarity insensitive)

• Case — Earth (AC) ground and chassis

Note

Pins 4 and 5 (RMS) are included only with XLR 5-pin connectors.

Pins 2 and 3 carry the input as a differential signal. Pin 1 is connected to earth through a 1 kOhm, 1000 pF, 15 V clamped network. This circuitry provides virtual ground lift for audio frequencies while allowing unwanted signals to bleed to ground. Make sure to use balanced XLR audio cables with pins 1–3 connected on both ends. Telescopic grounding is not recommended and shorting an input connector pin to the case may cause a ground loop, resulting in hum.

Tip

If unwanted noise or hiss is produced by the loudspeaker, disconnect its input cable. If the noise stops, there is most likely nothing wrong with the loudspeaker. To locate the source of the noise, check the audio cable, source audio, AC power, and electrical ground.

Audio Loop Output (XLR 3-Pin or 5-Pin Male)

The XLR 3-pin or 5-pin male Loop output connector allows multiple loudspeakers to be looped from a single audio source. The Loop output connector uses the same wiring scheme as the Input connector (see Audio Input (XLR 3-Pin or 5-Pin Female)). For applications that require multiple 900-LFCs, connect the Loop output of the first loudspeaker to the Input of the second loudspeaker, and so forth.

Note

The Loop output connector is wired in parallel to the Input connector and transmits the unbuffered source signal even when the loudspeaker is powered off.

Calculating Load Impedance for Looped Audio Signals

To avoid distortion when looping multiple loudspeakers, make sure the source device can drive the total load impedance of the looped loudspeakers. In addition, the source device must be capable of delivering approximately 20 dBV (10 V rms into 600 ohms) to yield the maximum SPL over the operating bandwidth of the loudspeakers.

To calculate the load impedance for the looped loudspeakers, divide 10 kOhms (the input impedance for a single loudspeaker) by the number of looped loudspeakers. For example, the load impedance for ten 900-LFCs is 1000 ohms (10 kOhms / 10). To drive this number of looped loudspeakers, the source device should have an output impedance of 100 ohms or less. This same rule applies when looping 900-LFCs with other Meyer Sound self-powered loudspeakers.

Note

Most source devices are capable of driving loads no less than 10 times their output impedance.

Tip

Audio outputs from Meyer Sound’s Galileo GALAXY Network Platform have an output impedance of 50 ohms. Each output can drive up to 20 Meyer Sound (10 kOhm) loudspeakers without distortion.

Caution

Make sure that all cabling for looped loudspeakers is wired correctly (Pin 1 to Pin 1, Pin 2 to Pin 2, and so forth) to prevent the polarity from being reversed. If one or more loudspeakers in a system have reversed polarity, frequency response and coverage will be significantly degraded.

Two cable rings are provided on the rear of the 900-LFC cabinet (Figure 15). Power and audio cables should be tied off to the rings to reduce strain on the cables and prevent damage to them during installation. The cable rings should not be used for any other purpose.

Cables Tied Off to Cable Ring

The 900-LFC employs Meyer Sound’s advanced TruPower® limiting. Conventional limiters assume a constant loudspeaker impedance and set the limiting threshold by measuring voltage alone. This method is inaccurate because loudspeaker impedances change as frequency content in the source material changes, and as thermal values for the loudspeaker’s voice coil and magnet vary. Consequently, conventional limiters often begin limiting prematurely, which reduces system headroom and dynamic range.

In contrast, TruPower limiting anticipates varying loudspeaker impedances by measuring both current and voltage to compute the actual power dissipation in the voice coil. This approach improves performance, both before and during limiting, by allowing the driver to produce the maximum SPL across its entire frequency range, while also retaining signal peaks. TruPower limiting also eliminates power compression at high levels over lengthy periods, which helps regulate voice coil temperatures, thereby extending the life of the driver.

LF Limit LED

The low-frequency driver for the 900-LFC is powered by separate amplifier channels, one for each voice coil, that are routed to a single limiter. When a safe power level is exceeded in either channel, limiting is engaged for both channels and the LF Limit LED lights on the user panel (the HF Limit LED is disabled for the 900-LFC), as shown in the figure below..

900-LFC Limit LEDs (HF LED Disabled)

When engaged, the limiter not only protects the drivers but also prevents signal peaks from causing excessive distortion in the amplifier channels, thereby preserving headroom and maintaining smooth frequency response at high levels. When levels return to normal, below the limiter threshold, limiting ceases.

The 900-LFC performs within its acoustical specifications at normal temperatures when the LF Limit LED is unlit, or when the LED is lit for 2 seconds or less and then turns off for at least 1 second. If the LED remains lit for longer than

3 seconds, the loudspeaker enters hard limiting where:

• Increases to the input level have no effect

• Distortion increases due to clipping

• Drivers are subjected to excessive heat and excursion, thereby compromising their lifespan

Caution

The Limit LED indicates when a safe, optimum level is exceeded. If a 900-LFC loudspeaker system begins to limit before reaching the desired SPL, consider adding more loudspeakers to the system.

The 900-LFC is convection cooled. The amplifier’s heat sink provides natural convection cooling from the air flowing near its fins. When exposed to high ambient temperatures or when driven continuously at high output levels, a variable-speed fan circulates air internally to ensure that the 900-LFC remains operational.

During normal operation, when the 900-LFC is powered on, the Active/Status LED is solid green. If the loudspeaker encounters a hardware fault, or the loudspeaker begins to overheat, the LED flashes red. In some instances, the loudspeaker will continue to output audio while the LED flashes red, though with a reduction in the limiter threshold and acoustic output to protect the loudspeaker.

If a loudspeaker is overheating (for RMS-equipped loudspeakers, you can verify this situation in Compass RMS), a reduction in SPL may be necessary. If, after a reduction in SPL and an appropriate cooling period, the Active/Status LED continues to flash red (does not return to solid green), contact Meyer Sound Technical Support.

If the Active/Status LED flashes red and the loudspeaker does not output audio, contact Meyer Sound Technical Support immediately.

When installing Meyer Sound loudspeakers and subwoofers, the following precautions should always be observed:

The table below summarizes the available rigging options for the 900-LFC.

Rigging Example, Mixed Array with 900-LFCs and LEOPARDs

900-LFCs can be ground-stacked up to three cabinets high, with or without the MRK-900-LFC rigging kit, as shown in the figure below.

Protective plastic skids are included on the bottom of the 900-LFC cabinet that align with the slots on the cabinet top. Loudspeakers can be stacked normally or reversed for cardioid configurations. When ground stacking 900-LFCs, make sure the skids for each cabinet align with the slots in the cabinet tops. When equipped with the MRK-900-LFC rigging kit, the 900-LFC can be ground-stacked on the MG-LEOPARD/900-LFC grid with LEOPARDs for mixed groundstacks.

900-LFC Groundstack (Without Rigging)

The 900-LFC can be configured in cardioid arrays to reduce output heard behind the loudspeakers, as shown in the figure below. The loudspeaker’s linearity ensures that cardioid patterns behave accurately even at very high levels. Cardioid arrays are achieved by placing three loudspeakers coplanar to each other (in either a groundstacked or flown array) with one loudspeaker facing the opposite direction. Polarity and delay processing is applied to the rear-facing loudspeaker, which yields output that cancels output from the other loudspeakers normally present behind the cardioid arrays. For example, on the rear-facing unit, reverse the polarity relative to the front-facing loudspeaker and add 3.8 ms relative to the front-facing units.

900-LFC Cardioid Groundstack (With Rigging)

The optional MRK-900-LFC rigging kit allows the 900-LFC to be flown and groundstacked with the MG-LEOPARD/900-LFC multipurpose grid. The kit also allows 900-LFCs to be flown and ground-stacked with LEOPARD with no transition hardware. The rigging kit is available as a factory-installed option or as a field upgrade and uses rugged GuideALinks and intuitive quick-release pins to securely link adjacent loudspeakers in flown and ground-stacked array configurations.

When equipped with the MRK-900-LFC rigging kit, the 900-LFC includes six captive GuideALinks and six mating link slots that link to adjacent loudspeakers in flown and groundstacked arrays. Located at the top of the cabinet,

GuideALinks extend up and into the link slots of the cabinet above it, as shown in the following two figures, or into the link slots of the MG-LEOPARD/900-LFC grid, making it easy to link cabinets when they are stacked. GuideALinks extend and retract with knobs and are secured with two quick-release pins: one each in the top and bottom cabinets. GuideALinks accommodate reversed loudspeakers for cardioid arrays.

The MRK-900-LFC rigging kit includes eight 5/16 x 0.63-inch quick-release pins (black button) (PN 134.024).

900-LFCs with MRK-900-LFC Rigging Kit, GuideALinks, Exploded View

The 900-LFC’s GuideALinks accommodate both 900-LFCs and LEOPARDs without transition hardware. The front and rear GuideALinks are used when flying the 900-LFC below the MG-LEOPARD/900-LFC grid, or when flying it below another 900-LFC, as shown in the figure below. The configuration of the 900-LFC’s GuideALinks, front and rear, determines its splay angle.

Flown 900-LFC with GuideALink Attachments

The 900-LFC’s four corner link slots on the bottom of the cabinet accept GuideALinks from flown 900-LFCs. The front and middle link slots accept LEOPARD GuideALinks when flying LEOPARDs below the 900-LFC, as shown in the figure above. The configuration of LEOPARD’s GuideALinks, front and rear, determines its splay angle.

The 900-LFC’s front and middle link slots also accept links from the MG-LEOPARD/900-LFC grid when groundstacking the 900-LFC, as shown in the figure below. The configuration of the grid’s links, whether set to A or B, determines the angle of attachment for the groundstacked 900-LFC.

Groundstacked 900-LFC with GuideALink Attachments

The 900-LFC’s front and middle GuideALinks are used when attaching a LEOPARD groundstack on top of the 900-LFC, as shown in the figure above.

900-LFC Splay Angles

The front and rear GuideALinks attach at angles of 0.00, 1.25, 2.50, 3.75, or 5.00 degrees, thereby allowing curved arrays for the 900-LFC. Because the cabinet and front and rear GuideALinks are symmetrical, the curved arrays can also include cardioid configurations.

The labels next to the front, as shown in the figure below, and rear GuideALinks indicate the splay angle between cabinets (when the opposing links are set to 0 degrees). As the links are moved up, the splay angles increase. To stow the GuideALinks, move them all the way down to STOW and pin them.

900-LFC Front GuideALinks Label

Note

Curved 900-LFC arrays do not provide directionality for low-frequency content. The curved array capability of the 900-LFC is provided for aesthetic reasons, to complement, if desired, the curvature of LEOPARD, LYON, and LEO-M arrays and to not potentially shadow the HF output of an adjacent array.

You can mount a Meyer Sound loudspeaker on top of the 900-LFC with a third-party heavy-duty pole and pole-mount

adapter, shown in the figure below. The 900-LFC includes a 38 mm (1.5 in) (U.S.) or 35 mm (1.38 in) (E.U.) pole-mount receptacle.

900-LFC with Pole and Pole-Mount Adapter

The following Meyer Sound loudspeakers can be mounted on top of the 900-LFC. Make sure that the pole and pole-mount adapter can support the weight of the mounted loudspeakers

and that they are installed according to the manufacturer’s instructions.

Weather Protection is strongly recommended for all permanent outdoor installations where loudspeakers are directly exposed to the elements. This includes desert and semi-arid climates, where protection against dust and sand is important, and where infrequent rainstorms can contribute to deterioration of loudspeaker components.

Weather Protection is also recommended when the loudspeakers are sheltered from direct exposure to precipitation but are nevertheless exposed to prolonged high humidity, fog or mist. Examples would be installations on covered outdoor terraces or pavilions

Weather Protection is further advisable for portable or touring systems when any significant outdoor use is anticipated. Even though standard procedures may call for using external protective measures, these are often not implemented in time to prevent moisture intrusions that could lead to premature performance degradation of the loudspeaker.

The wear and tear on a loudspeaker will vary significantly with different climatic conditions. For example, a weather protected loudspeaker installed in a sunlight-exposed location on an ocean pier will experience much harsher conditions than a loudspeaker in a similar installation that is shaded by trees and exposed only to rainfall. The constant exposure to direct UV radiation and salt air environment will cause a loudspeaker to wear more quickly than one with partial UV shielding and exposed only to freshwater moisture.

Wear can eventually affect the performance of the loudspeaker. It also affects aesthetics. For example, in salt air environments, the exterior grille can quickly show signs of oxidation, causing unsightly discoloration.

Apart from selecting suitable weather protection, the progress of wear and tear on the loudspeaker can be slowed by a regular schedule of inspection and cleaning. This maintenance is particularly necessary in harsh environments. Inspection and cleaning should include routine removal of any visible oxidation or environmental particulates, as these can accelerate metal corrosion or decay of the cabinet. If installed loudspeakers are not in use for an extended period, exterior protection or temporary removal and storage of the loudspeakers should be considered.

There are several benefits to selecting the Meyer Sound Weather Protection option:

Meyer Sound assumes normal and accepted installation practices are used when installing Meyer Sound Loudspeakers outdoors. Deviation from such practices may cause weather protection to be ineffective and void the warranty for the loudspeaker.

Examples of unacceptable and acceptable installation practices include:

If in doubt about an installation method, contact Meyer Sound Technical Support for assistance.

Always discuss the environmental conditions of your Meyer Sound installation with your Sales Manager, and verify the availability of Weather Protection for your selected loudspeaker models. The Sales Manager, together with Technical Support, will verify the appropriate level of weather protection for the loudspeakers and related rigging hardware.

IP stands for "Ingress Protection." The current format for expressing an IP rating is a 2-digit code. The first digit of an IP rating represents protection from solid objects. The second digit of an IP rating represents protection from water or moisture. The table below provides a chart of IP ratings and the corresponding definitions of the rating.

The 900-LFC quick-clip removable rain hood is easily attached and removed with its two winghead studs, as shown in the figure below.

Another option for weather-protected 900-LFC loudspeakers is the collapsible rain hood.

The 900-LFC collapsible rain hood is easily attached and removed with its two screws.

900-LFC with Collapsible Rain Hood

The Ultra Weather Protection LEOPARD/900-LFC Rain Hood Kit includes the following parts:

Routing Cables and Attaching Rain Hood

Procedure. To route cables and attach the rain hood:

1. Install the necessary audio and power cables.

2. Attach the rain hood to the user panel, slipping it under the rain hood retainer flange at the top of the user panel.

3. Route the cables through the rain hood on either side of the baffle and through the bottom of the rain hood.

4. Push the rain hood flush against the loudspeaker.

5. Secure it to the loudspeaker by giving the two captive wing-head stud fasteners on either side of the rain hood a quarter turn, so they fully lock.

Routing Signal and Power Cables Through Rain Hood and Around Baffle

Note

• Ultra Weather Protected units using the LEOPARD/900-LFC UW Rain Hood are rated IPX5 for water intrusion.