XIEGU GNR1 Digital Audio Noise FilterIntroducTIon

GNR1 digital audio noise filter is an audio processing device integraTIng digital noise reduction and digital filtering. It can be widely used in the external audio processing sector of all types of wireless receiving equipment such as radio transceiver, receiver, radio, to effectively reduce the background noise, improve the signal-to-noise ratio, and improve the signal identifiable degree. GNR1 supports to connect external passive speaker, which can provide 3W audio output power; support independent adjustment of input/output sound volume; support selection of high/low input impedance; support audio double output ports (3.5mm stereo output, RCA output); support headphone output and automatic switch of headphone/speaker output.

Basic Indicators

Operating Instruction

Description of Panel
Front panel

Rear panel

1. Wiring
   The input is a mono channel, and its interface is a 3.5mm stereo jack. Two tracks are connected by the internal wiring. Do not use the mono channel jack, or you will cause a short circuit and no sound to the input!
   The output is also a mono channel, with two jacks: RCA jack, 3.5mm stereo jack. This stereo interface also connects two channels in the device. Do not use the mono channel jack, or you will cause a short circuit and no sound to the output! The external power is DC 12V ± 15%, you can directly use the 13.8V power of the radio equipment to supply power for this.
   1. Do not use it under over-voltage! Do not directly power with 220VAC!
2. Selection of input impedance
   Reasonably select the high/low input impedance level for GNR1 according to the audio output impedance of the device you are using. You may turn down the output sound volume if you select it improperly.
3. Adjustment of input sound volume
   You can adjust to the appropriate sound volume to keep a proper output sound volume and distortionless sound quality. You can adjust it in cooperation with the output sound volume. If the input audio amplitude is so high that the input is overloaded, the CLIP indicator on the panel will be on, so you should turn down the input sound volume at this time.
4. Adjustment of output sound volume
   The knob controls the output sound volume of the speaker and headphone. You can adjust to an appropriate output sound volume without distortionless sound quality. If you need to use headphones to monitor the output, it is recommended to turn the knob leble to the lowest sound volume, and then insert the headphones to avoid damage to your hearing due to too loud sound.
   After inserting the headphone, the speaker output will be automatically cut off.
5. NR noise reduction adjustment
   This knob controls the NR noise reduction switch, and the 200-level noise reduction degree. Turn  to the end to turn off the NR. Turn to right to turn on NR noise reduction and increase the noise reduction degree by levels.
   1. NR noise reduction will cause slight volume loss, so please reasonably adjust the noise reduction degree to get a comfortable listening experience.
6. Adjustment of the digital filter
   The digital filter can be adjusted by L and R, indicating the L-CUT low cut and H-CUT high cut adjustment. Turn the L knob  to the end, and the L-CUT low cut will be turned off. Turn the H knob right to the end, and the H-CUT high cut will be turned off.

Schematic Diagram of Filter Composition

As shown in the figure on the right, the filter consists of L-CUT and H-CUT, and both work together to form an effective filter bandwidth.
L-CUT controls the low boundary frequency, which can effectively cut off the low-frequency component;
H-CUT controls the low boundary frequency, which can effectively cut off the high-frequency component;
In daily use, adjust according to your own listening preferences, subject to geting the best listening effect.

Note: If the actual bandwidth of the filter is less than the useful bandwidth of the useful signal,

Documents / Resources

XIEGU GNR1 Digital Audio Noise Filter [pdf] Instruction Manual GNR1, Digital Audio Noise Filter, Audio Noise Filter, Noise Filter

References

• User Manual