SST-251 - Loudspeaker ROLAND - Free user manual and instructions

Product Type	Loudspeaker, full-range, passive
Model	SST-251
Brand	Roland
Enclosure Type	Bass-reflex
Speaker Configuration	15" woofer + horn tweeter
Power Handling (Rated)	200 W (EIA RS426A)
Power Handling (Max)	600 W
Frequency Response	52 Hz – 20 kHz
Nominal Impedance	8 ohms
Sensitivity (1 W/1 m)	100 dB
Crossover Frequency	1.5 kHz
Connectors	Parallel Inputs x 2 (1/4" phone), Direct Input x 1 (Speakon NL4MP), High Freq Output x 1 (Speakon NL4MP)
Dimensions (W x D x H)	572 x 407 x 762 mm (22.5" x 16" x 30")
Weight	31.8 kg (70 lbs)
Enclosure Material	3/4" plywood cabinet with metal speaker grill
Design Features	Trapezoidal shape for array clustering, oversized steel carrying handles
Tweeter Protection	Auto-reset protection circuit against input overload
Compliance	EIA RS426A (power handling)
Accessories Included	Owner's manual
Maintenance	Clean with soft dry cloth; mild detergent for stubborn dirt; avoid solvents
Safety Notes	Do not open or modify; avoid moisture, extreme temperatures, vibration; use stable surface

Frequently Asked Questions - SST-251 ROLAND

What is the nominal impedance of the Roland SST-251 speaker?

The nominal impedance is 8 ohms. Ensure your amplifier supports this load.

How do I connect multiple SST-251 speakers?

Use the Parallel Inputs (1/4" phone) to daisy-chain speakers. When connecting two speakers in parallel, the combined impedance becomes 4 ohms.

What is the purpose of the Speakon connectors?

The Speakon NL4MP connectors provide high-reliability connections for the Direct Input and High Freq Output. They are recommended for professional use.

Does the SST-251 have tweeter protection?

Yes, it features a built-in auto-reset protection circuit that guards against excessive input. If triggered, lower the amplifier volume; the tweeter resumes normal operation after 5–10 seconds.

What is the frequency response of the SST-251?

The frequency response is 52 Hz – 20 kHz.

How should I clean the SST-251?

Use a soft, dry cloth for everyday cleaning. For stubborn dirt, use a cloth slightly dampened with mild detergent. Never use benzine, thinners, alcohol, or solvents.

What safety precautions should I observe when using the SST-251?

Do not open or modify the unit. Avoid exposure to moisture, extreme temperatures, dust, and vibration. Ensure the speaker is placed on a stable, level surface. Use at least two persons to lift due to weight.

Can the SST-251 be used as a floor monitor?

The SST-251 is not specifically designed as a monitor (the SSM-151 serves that purpose). However, it can be placed on its side if needed, but ensure stability.

What is the maximum power handling?

The rated power handling is 200 W (EIA RS426A) and maximum is 600 W.

What connectors are available on the SST-251?

It has two Parallel Inputs (1/4" phone), one Direct Input (Speakon NL4MP), and one High Freq Output (Speakon NL4MP).

USER MANUAL SST-251 ROLAND

Thank you, and congratulations on your choice of the SST/SSW/SSM Speaker System.

Before using this unit, carefully read the sections entitled: "USING THE UNIT SAFELY" (p. 2) and "IMPORTANT NOTES" (p. 3). These sections provide important information concerning the proper operation of the unit. Additionally, in order to feel assured that you have gained a good grasp of every feature provided by your new unit, this manual should be read in its entirety. The manual should be saved and kept on hand as a convenient reference.

Features

Roland's SST/SSW/SSM speaker systems, designed, developed, and manufactured in the U.S.A., offer the ideal combination of excellent sound, superb design, and outstanding value.

• The enclosures (except for the SSM-151) feature a trapezoidal design, allowing them to be arrayed in radiating clusters.
• The metal speaker grills and 3/4" plywood cabinets are designed to withstand the rigors of professional use.
• The tweeter features a built-in auto-reset protection circuit to prevent problems from input overload before they start (not featured on the SSW-351).
• The SSM-151 can be oriented at two different floor angles (35 and 55 degrees), allowing selection of the most appropriate angle for your particular stage environment.
• The crossover network components have been carefully selected to ensure high input capacity and precise impedance characteristics.
• Speakon® NL4MP (speaker connectors) are featured to allow high-reliability connections.
• Oversized steel carrying handles help to provide exceptional portability.

* Speakon® is a registered trademark of NEUTRIK.

USING THE UNIT SAFELY

INSTRUCTIONS FOR THE PREVENTION OF FIRE, ELECTRIC SHOCK, OR INJURY TO PERSONS

About ⚠️ WARNING and ⚠️ CAUTION Notices

	Used for instructions intended to alert the user to the risk of death or severe injury should the unit be used improperly.
	Used for instructions intended to alert the user to the risk of injury or material damage should the unit be used improperly.* Material damage refers to damage or other adverse effects caused with respect to the home and all its furnishings, as well to domestic animals or pets.

About the Symbols

[4340]	The △ symbol alerts the user to important instructions or warnings. The specific meaning of the symbol is determined by the design contained within the triangle. In the case of the symbol at left, it is used for general cautions, warnings, or alerts to danger.
[4271]	The ⊙ symbol alerts the user to items that must never be carried out (are forbidden). The specific thing that must not be done is indicated by the design contained within the circle. In the case of the symbol at left, it means that the unit must never be disassembled.
[W884]	The ● symbol alerts the user to things that must be carried out. The specific thing that must be done is indicated by the design contained within the circle. In the case of the symbol at left, it means that the power-cord plug must be unplugged from the outlet.

ALWAYS OBSERVE THE FOLLOWING

WARNING

- Before using this unit, make sure to read the instructions below, and the Owner's Manual.

- Do not open or perform any internal modifications on the unit.

- Do not attempt to repair the unit, or replace parts within it (except when this manual provides specific instructions directing you to do so). Refer all servicing to your retailer, the nearest Roland Service Center, or an authorized Roland distributor, as listed on the "Information" page.

- Never use or store the unit in places that are:

• Subject to temperature extremes (e.g., direct sunlight in an enclosed vehicle, near a heating duct, on top of heat-generating equipment); or are
• Damp (e.g., baths, washrooms, on wet floors); or are
• Humid; or are
• Exposed to rain; or are
• Dusty; or are
• Subject to high levels of vibration.

- When using the unit with a rack or stand, the rack or stand must be carefully placed so it is level and sure to remain stable. If not using a rack or stand, you still need to make sure that any location you choose for placing the unit provides a level surface that will properly support the unit, and keep it from wobbling.

WARNING

- This unit, either alone or in combination with an amplifier and headphones or speakers, may be capable of producing sound levels that could cause permanent hearing loss. Do not operate for a long period of time at a high volume level, or at a level that is uncomfortable. If you experience any hearing loss or ringing in the ears, you should immediately stop using the unit, and consult an audiologist.

- Do not allow any objects (e.g., flammable material, coins, pins); or liquids of any kind (water, soft drinks, etc.) to penetrate the unit.

- Immediately turn the power off, remove the power cord from the outlet, and request servicing by your retailer, the nearest Roland Service Center, or an authorized Roland distributor, as listed on the "Information" page when:

• Objects have fallen into, or liquid has been spilled onto the unit; or
• The unit has been exposed to rain (or otherwise has become wet); or
• The unit does not appear to operate normally or exhibits a marked change in performance.

- In households with small children, an adult should provide supervision until the child is capable of following all the rules essential for the safe operation of the unit.

- Protect the unit from strong impact. (Do not drop it!)

CAUTION

- The unit should be located so that its location or position does not interfere with its proper ventilation.

- Try to prevent cords and cables from becoming entangled. Also, all cords and cables should be placed so they are out of the reach of children.

- If you need to move the instrument, take note of the precautions listed below. At least two persons are required to safely lift and move the unit. It should be handled carefully, all the while keeping it level. Make sure to have a firm grip, to protect yourself from injury and the instrument from damage.

• Disconnect all cords coming from external devices.
• Remove the unit from the speaker stand.

Important Notes

In addition to the items listed under "USING THE UNIT SAFELY", please read and observe the following:

Connection

• Before making any connections, be sure all units in the system are OFF. Also be sure that all amplifier and mixer volume controls are at MINIMUM.
• Before connecting SST/SSW/SSM Speakers to an external crossover read the specification chart carefully.

Maintenance

• For everyday cleaning wipe the unit with a soft, dry cloth or one that has been slightly dampened with water. To remove stubborn dirt, use a cloth impregnated with a mild, non-abrasive detergent. Afterwards, be sure to wipe the unit thoroughly with a soft, dry cloth.
• Never use benzine, thinners, alcohol or solvents of any kind, to avoid the possibility of discoloration and/or deformation.

Additional Precautions

• To avoid disturbing your neighbors, try to keep the unit's volume at reasonable levels (especially when it is late at night).
• To avoid possible breakdown, do not use the unit in a wet area, such as an area exposed to rain or other moisture.

Making Connections

1. Before you make connections, make sure that the power of all equipment is turned off. Also make sure that the volume controls on your amplifier and mixer are turned to the minimum position.
2. Use speaker cables to connect the output terminals of the amplifier to the inputs of the speakers.

When connecting speakers, pay attention to the polarity (+/-) of the amplifier.

The SST/SSW/SSM speakers have a nominal impedance of 8 ohms. Check the recommended load impedance of your amplifier.

When connecting speakers in parallel, make sure that the polarity matches. Since the total impedance of all speakers will decrease if they are connected in parallel, check the recommended load impedance of your amplifier once again to make sure.

In order to get the best sound quality, please use thick and sturdy speaker cables. Avoid using cheap cables, or shielded cables intended for use with a guitar. In order to achieve high-reliability connections, we recommend that you use Speakon® connectors (speaker connectors). When making Speakon® connections, refer to the network circuit diagram in the specifications.

These speakers are equipped with self-recovering protection circuitry designed to guard the tweeters from excessively high input and abnormal signals. The circuit is tripped when the speaker is presented with excessive input, thus preventing sound output from the tweeter; this does not indicate a malfunction. In such instances, lower the amp volume; the tweeter function is restored automatically after 5–10 seconds. Contact a Roland Service Center if the speaker function does not recover properly.

The Roland SST/SSW speakers are designed to allow multiple units to be combined to create high-output spaker clusters. The SSW-351 speaker system can be driven with a single amp when using its built-in crossover network, or driven with a multi-amp system when an external crossover is used, and is also the ideal subwoofer system for use in conjunction with a SST-151/251. In order to take full advantage of its performance and to protect the speakers, please read the following explanations carefully.

SST-151/251/SSM-151

Connect the inputs of the SST-151/251/SSM-151 directly to your amplifier. If you wish to add an additional SST-151/251/SSM-151, connect it in parallel. To connect the additional SST-151/251/SSM-151, use the second PARALLEL INPUTS an an output.

Basic Connection

(input impedance: 8 ohms)

Parallel Connection

(combined input impedance: 4 ohms)

SSW-351

The SSW-351 contains a built-in crossover network.

There are several ways in which an additional speaker can be connected to the SSW-351.

1. Since the HIGH FREQ OUTPUT is routed through the internal crossover network, a signal from which the low range has been cut will be sent to the connected speaker.

In this case, the combined impedance will be 8 ohms.

1. The speakers can be driven by multiple amps very simply with the internal crossover network. When driving the speakers with two power amps (bi-amping), connect the speakers using the parallel input jacks.

The volume balance between the subwoofers (SSW-351) and full-range speakers (SST-151/251) and be adjusted with the power amp level settings.

Using two power amps provides greater headroom when driving the speakers.

1. The PARALLEL INPUTS can be used as an output to connect an auxiliary woofer or a full range speaker. A full frequency range signal will be sent to the connected speaker.

In this case, the combined impedance will be 4 ohms.

A method to increase low-range sound pressure levels.

1. If you wish to use an external channel divider (crossover network) instead of using the built-in crossover network, make connections to the DIRECT INPUT. Pay attention to the crossover frequency of each speaker that is connected.

Carefully read the specifications before connecting an external channel divider (crossover network).

For the crossover frequency, we recommend frequencies between 100 Hz and 200 Hz.

Setting Up the SSM-151

When used as a stage floor monitor, the SSM-151 can be set at two different floor angles.

When setting up monitor speakers, be sure to observe the following points in order to prevent the speakers from falling over (exercise caution particularly when using the 55-degree setup, as the speakers may topple more easily in this orientation than when set up 35 degrees).

* Do not sit or place feet on the speakers.
* Do not place the speakers on unstable or inclined surfaces.
* Do not use the speakers as steps.

Specifications

Model	SST-151 SST-251 SSW-351 SSM-151
Enclosure	Bass-reflex	Bass-reflex Bass-reflex Bass-reflex
Speakers	12" Woofer + Horn Tweeter	15" Woofer + Horn Tweeter 18" Woofer 12" Woofer + Horn Tweeter
Power Handling (rated) *1 150 W 200 W 200 W 150 W (max)	450 W	600 W 600 W 450 W
Frequency Response	58 Hz–16 kHz	52 Hz–20 kHz 45 Hz–1.5 kHz 58 Hz–16 kHz
Nominal Impedance	8 ohms 8 ohms 8 ohms 8 ohms
Sensitivity (1 W/1 m)	98 dB	100 dB 97 dB 98 dB
Crossover Frequency	4 kHz	1.5 kHz 200 Hz 4 kHz
Connectors (1/4" phone)	Parallel Inputs x 2 Parallel Inputs x 2 Parallel Inputs x 2 Parallel Inputs x 2
		Direct Input x 1
		High Freq Output x 1
(Speakon® NL4MP)	Parallel Input x 1	Parallel Input x 1 Parallel Input x 1	Parallel Input x 1
		High Freq Output x 1
Weight	20 kg/44 lbs	31.8 kg/70 lbs	39.5 kg/87 lbs	14.5 kg/32 lbs
Dimensions	407 x 407 x 642 mm	572 x 407 x 762 mm	572 x 559 x 838 mm	620 x 400 x 360 mm
(W x D x H)	16 x 16 x 25-1/4 inches	22-1/2 x 16 x 30 inches	22-1/2 x 22 x 33 inches	24-7/16 x 15-3/4 x 14-3/16 inches
Accessory	OWNER'S MANUAL	OWNER'S MANUAL	OWNER'S MANUAL	OWNER'S MANUAL

*1 EIA RS426A
* In the interest of product improvement, the specifications and/or appearance of this unit are subject to change without prior notice.

Pin Diagram of Speakon® NL4FC

* A Speakon® male connectors used by this device is sold separately.