Instructions for Preventing Feedback in a Sound System

Feedback is an unwanted whistling or humming sound that occurs when the sound amplification system is used at high volume. It happens when the microphone picks up sound from the speaker instead of the instrument, creating a self-sustaining loop of amplification.
While the physical principles behind feedback cannot be changed, their effects can be minimized through proper equipment setup.

To prevent feedback, it is essential to position the microphone and sound system correctly and adjust the audio settings accordingly.

1. Optimal Microphone Placement
   •   Place the microphone as close as possible to the guitar strings inside the instrument. The closer the sound source, the stronger the signal and the lower the chance of feedback.
   •   Use a microphone with a flexible gooseneck to find the optimal position and reduce unwanted resonances.
   •   Each guitar has unique wood density, dimensions, and acoustic properties, so it is important to experiment with the microphone’s direction, depth, and height to achieve the best balance of low and high frequencies.

IMPORTANT!

For large-stage performances, we recommend using the NV-Tone Swan NT (Integrated) microphone model and mounting it entirely inside the guitar while sealing the soundhole with a rubber suppressor.

To securely attach the microphone inside the guitar:
1. Attach a 3M Dual Lock fastener (available at hardware stores) to the base of the NV-Tone Swan mount.
2. Fix the second part of the fastener to the bottom of the guitar body.
3. Connect the NV-Tone Swan mount to the fasteners.
4. Firmly secure the microphone mount on the 3M Dual Lock fastener inside the guitar, and route the cable inside, securing it with construction tape to prevent unwanted noise.
5. Adjust the gooseneck microphone, directing it towards the lower or upper strings depending on the guitar’s wood density.
6. Keep the microphone and mount inside the guitar, then close the soundhole with a rubber suppressor.

2. Positioning the Acoustic Amplifier or Speakers
   •   Place the acoustic amplifier slightly behind and to the side of you, so your body partially blocks the sound, preventing it from feeding back into the microphone.
   •   If the amplifier is placed in front of you and directed toward the audience, the sound will be cleaner, reducing the need for excessive volume adjustments.
   •   The 16.4-foot (5-meter) cable allows you to maintain a safe distance from the amplifier and speakers.

3. Volume Balance
   •   Playing slightly quieter helps avoid excessive signal amplification and reduces the risk of feedback.
   •   If possible, lower the overall gain level to minimize feedback risk.
   •   Keep in mind that the 16.4-foot (5-meter) cable allows you to stay at a safe distance from the amplifier and speakers.

4. Equalizer Settings
   •   If feedback occurs at a specific frequency, adjust the equalizer to cut the problematic range.
   •   Use a preamp with a feedback suppression function and configure it to eliminate unwanted noise.
   •   If low-frequency hum appears, gradually reduce the bass level on the mixer or amplifier until the effect disappears.
   •   High-frequency squealing can be removed by lowering the treble level on the amplifier.

5. Equipment Placement
   •   If the amplifier is placed on the floor or near a wall, low frequencies may become amplified, increasing the risk of feedback. Position the amplifier higher (e.g., on a stand) and farther from walls.
   •   When using monitors, try angling the instrument slightly away from them and avoid increasing monitor volume too much.
   •   In small rooms, feedback is more likely due to sound reflections from walls. If possible, perform in larger rooms or open spaces.

Reminder: The 16.4-foot (5-meter) cable allows you to keep a safe distance from the amplifier and speakers.

6. Using Pickups
   •   Pickups (piezo or magnetic) are less prone to feedback than microphones. For a balanced sound, combine the microphone and pickup signals (a 50/50 mix is ideal).

   •   To minimize feedback, send the pickup signal only to monitor speakers and the microphone signal to the main loudspeakers.
   •   In the mixer, increase the monitor level in the pickup channel and lower its fader while doing the opposite for the microphone channel. This allows the performer to hear themselves clearly without unwanted noise.

7. Filter Adjustments
   •   Activate the low-cut filter on the mixer to eliminate low-frequency feedback.
   •   For acoustic and classical guitars, banjos, and bass guitars, set the filter to 80 Hz.

Conclusion

Our NV-Tone Swan microphones are equipped with built-in settings to minimize feedback, a long cable for flexible positioning, a gooseneck microphone for precise adjustments, and a secure mounting system to keep the microphone and cable firmly in place.

However, if feedback occurs in specific conditions, following these recommendations will help you achieve clear and high-quality sound while completely eliminating unwanted noise and feedback.