Introduction
Thank you for choosing the Onkyo D-509C Center Speaker. This speaker is designed to deliver clear and dynamic dialogue and central sound effects, enhancing your home cinema experience. This manual provides essential information for the proper setup, operation, and maintenance of your speaker to ensure optimal performance and longevity.

Image: The Onkyo D-509C center speaker shown with other speakers in a home cinema setup. The center speaker is typically placed horizontally below or above the television.
Setup
1. Speaker Placement
The center channel speaker is crucial for dialogue clarity in a home theater system. Place the D-509C directly above or below your television or projection screen, centered horizontally. Ensure it is on a stable, flat surface, such as a TV stand or shelf, and positioned at approximately ear level when seated for the best listening experience.
2. Connecting Speaker Cables
Before connecting, ensure your AV receiver or amplifier is turned off and unplugged from the power outlet. Use high-quality speaker cables for optimal sound performance.
- Prepare the speaker cables by stripping approximately 1/2 inch (12-15 mm) of insulation from the ends of each wire. Twist the bare wire strands tightly to prevent short circuits.
- Identify the positive (+) and negative (-) terminals on both the D-509C speaker and your AV receiver. The positive terminal is usually red, and the negative terminal is black.
- Connect the positive (+) terminal of the D-509C speaker to the positive (+) center channel output terminal on your AV receiver.
- Connect the negative (-) terminal of the D-509C speaker to the negative (-) center channel output terminal on your AV receiver.
- Ensure all connections are secure and that no bare wire strands are touching each other or any other metal parts, which could cause a short circuit.

Image: Rear panel of the Onkyo D-509C center speaker, highlighting the speaker wire binding posts. Note the red (+) and black (-) terminals for correct polarity connection.
3. System Configuration
After connecting the speaker, refer to your AV receiver's manual for instructions on configuring speaker settings. This typically involves setting the center speaker to "Small" or "Large" depending on your system's subwoofer presence and crossover frequency. Run any automatic calibration features your receiver may have (e.g., Audyssey, MCACC) for optimal sound balance.
Operating Your Speaker
The Onkyo D-509C is a passive speaker and does not have its own controls. Its operation is managed entirely through your connected AV receiver or amplifier. Ensure your receiver is set to the correct input source and that the center channel volume is appropriately balanced with other speakers in your system.
- Volume Control: Adjust the overall system volume using your AV receiver's remote control.
- Channel Levels: If dialogue sounds too quiet or too loud, adjust the center channel level in your AV receiver's speaker setup menu.
- Listening Position: For the best sound, ensure your primary listening position is centered relative to the speaker and TV.
Maintenance
To maintain the appearance and performance of your Onkyo D-509C speaker, follow these simple guidelines:
- Cleaning: Gently wipe the speaker cabinet with a soft, dry cloth. For stubborn marks, slightly dampen the cloth with water, then wipe dry immediately. Avoid using abrasive cleaners, solvents, or chemical sprays, as these can damage the finish.
- Grille: The speaker grille can be carefully removed for cleaning if necessary. Use a soft brush or a vacuum cleaner with a brush attachment to remove dust.
- Placement: Avoid placing the speaker in direct sunlight, near heat sources, or in areas with high humidity, as these conditions can affect its performance and lifespan.
- Handling: Do not press on the speaker cones or tweeters, as this can cause damage.
Troubleshooting
If you experience issues with your Onkyo D-509C speaker, consult the following common problems and solutions:
| Problem | Possible Cause | Solution |
|---|---|---|
| No sound from center speaker |
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| Distorted or unclear sound |
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| Dialogue sounds muffled or too quiet |
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If the problem persists after trying these solutions, please consult your AV receiver's manual or contact Onkyo customer support.
Specifications
The following are the technical specifications for the Onkyo D-509C Center Speaker:
- Brand: Onkyo
- Model Name: D-509C
- Model Number: D-509C(B)
- Speaker Type: Center Channel
- Speaker Maximum Output Power: 150 Watts
- Max Power Handling: 150W (from product image label)
- Impedance: 4 Ohms (from product image label)
- Mounting Type: Tabletop Mount
- Item Weight: 16.09 Pounds (approx. 7.3 kg)
- Connectivity Protocol: Bluetooth (Note: This specification is typically for active devices; the D-509C is a passive speaker.)
- Power Source: Corded Electric (Note: This refers to the amplifier/receiver power, not the passive speaker itself.)
Note: Specifications are subject to change without notice.
Warranty Information
Onkyo products are manufactured to the highest quality standards. For specific warranty terms and conditions applicable to your region, please refer to the warranty card included with your product or visit the official Onkyo website. Keep your proof of purchase for warranty claims.
Customer Support
For further assistance, technical support, or service inquiries, please visit the official Onkyo website or contact your local Onkyo dealer. You can find contact information and FAQs on the Onkyo support page:





