Bose 901 Series 5 Manual

The Bose 901 Series 5 is a legendary direct/reflecting speaker system designed to deliver a spacious, lifelike soundstage. It features nine full-range drivers per speaker (one facing forward, eight facing rearward), an active electronic equalizer, and is renowned for its unique approach to room-filling sound reproduction. Below are key sections for safety, features, installation, setup, operation, and troubleshooting.

Features at a Glance

Key components: Two 901 Series 5 speaker cabinets, Active Electronic Equalizer, Grilles, Spikes/Glides, Connection Cables.

Installation

Unpack and inspect contents. Choose a stable location away from heat sources and moisture.

1. Place Speakers: Position speakers on stands or floor, ideally 1-3 feet from rear wall and 2-8 feet from side walls. Angling may be required.
2. Connect Equalizer: Plug equalizer into AC power. Connect its OUTPUT to your amplifier's MAIN INPUT (or Tape Monitor loop as per manual).
3. Connect Speakers: Run speaker wire from your amplifier's speaker outputs to the INPUTS on the Active Equalizer. Then run wire from the equalizer's SPEAKER OUTPUTS to each 901 speaker.
4. Power On: Turn on your system components in sequence (source > equalizer > amplifier).

WARNING! The Active Equalizer MUST be connected and powered for the speakers to operate correctly and safely. Never connect the speakers directly to an amplifier without the equalizer.

First-Time Setup

Power on your entire system; set initial levels.

1. Set Equalizer Bypass: Initially set the EQ BYPASS switch to "IN" (engaged).
2. Adjust Level Control: Play music at a moderate volume. Adjust the equalizer's LEVEL control so the volume matches your other speakers (if any) or to a comfortable listening level.
3. Adjust Contour & Loudness: Use the CONTOUR control to balance direct and reflected sound for your room. Use LOUDNESS for low-volume listening enhancement.
4. Fine-tune Placement: Small adjustments to speaker placement and toe-in can dramatically affect soundstage and imaging.

CAUTION! Ensure all connections are secure and correct before applying power. Use an amplifier rated for 8-ohm loads.

Specifications

• System Type: Direct/Reflecting® loudspeaker system with active equalization.
• Drivers: Nine 4.5-inch (114mm) full-range drivers per enclosure.
• Frequency Response: 35Hz - 16kHz (±3dB) with equalizer.
• Recommended Amplifier Power: 10-450 watts per channel into 8 ohms.
• Nominal Impedance: 8 ohms.
• Sensitivity: Not applicable without equalizer.
• Dimensions (H x W x D): Approximately 25" x 14" x 12" (635mm x 356mm x 305mm).
• Weight: Approximately 48 lbs (21.8 kg) each.
• Equalizer Power: 120V AC, 60Hz.

Controls and Settings

All critical controls are located on the Active Electronic Equalizer.

Front Panel: LEVEL control, CONTOUR control, LOUDNESS switch (On/Off), EQ BYPASS switch (In/Out).

Rear Panel: AC Power Cord, INPUT from Amplifier, OUTPUT to Amplifier, SPEAKER OUTPUTS (Left & Right), FUSE holder.

LEVEL: Master volume/gain control for the equalized signal. CONTOUR: Adjusts balance between direct and reflected sound. LOUDNESS: Compensates for reduced bass perception at low listening volumes. EQ BYPASS: Removes equalization from the circuit for comparison; must be "IN" for normal operation.

Connecting to Your System

Connection is via the Active Equalizer only.

1. Turn off and unplug all system components.
2. Connect the equalizer's INPUT jacks to your preamplifier's or receiver's TAPE MONITOR OUTPUT jacks (preferred method) or MAIN OUTPUT/ PRE-OUT jacks.
3. Connect the equalizer's OUTPUT jacks to your power amplifier's INPUT jacks (or to the TAPE MONITOR INPUT on an integrated amp/receiver).
4. Connect speaker wires from the equalizer's SPEAKER OUTPUT terminals to the corresponding terminals on each Bose 901 speaker.
5. Plug in the equalizer's power cord.

Tip: Use high-quality, heavy-gauge speaker wire for best performance. Ensure polarity is consistent (+, -).

Equalizer Operation

The Active Equalizer is integral to the system's sound and protection.

1. Power Sequence: Always turn on the equalizer before the power amplifier.
2. Setting Level: With music playing, adjust LEVEL until desired volume is achieved at your amplifier's main volume control.
3. Using Contour: Adjust CONTOUR to suit room acoustics and personal preference. Higher settings increase reflected sound for a wider soundstage.
4. Loudness Compensation: Engage LOUDNESS when listening at very low volumes to restore perceived bass response.
5. Bypass for Comparison: Switch EQ BYPASS to "OUT" to hear the unequalized signal. Return to "IN" for normal listening.

WARNING! Do not operate the speakers without the equalizer engaged (BYPASS "IN"). This can cause poor sound and potential driver damage.

Placement & Acoustics

Placement is critical for optimal performance of the Direct/Reflecting design.

Ideal placement is with the speakers' rear panels facing and reflecting sound off the side and rear walls of the room. Experiment with distance from walls (1-3 ft from rear wall, 2-8 ft from side walls) and toe-in angle. The goal is a seamless, spacious soundstage with precise imaging. Room furnishings (carpets, drapes, furniture) will affect the reflected sound; the CONTOUR control helps compensate.

Care & Maintenance

Unplug equalizer before cleaning. Dust speakers with a soft, dry cloth. Vacuum grilles gently if needed.

CAUTION! Do not use liquids, solvents, or abrasive cleaners on the cabinets or grilles. Do not expose speakers to direct sunlight, excessive heat, or moisture. The foam grilles may degrade over time and are replaceable.

Regulatory Information

Complies with applicable FCC regulations. The Bose 901 Series V and Active Equalizer are trademarks of Bose Corporation. This product is protected by patents granted and/or pending. For technical support or service, contact Bose Corporation or an authorized Bose dealer.

Troubleshooting

Service: Do not attempt to repair speakers or equalizer yourself. Contact Bose Customer Service or an authorized service center.