Introduction
The VU1 PRO is a multifunctional device serving as both a VU meter and an audio switcher. It features microphone, RCA, and XLR inputs. The device supports AGC and DB audio signal processing methods, manual adjustment of gain and pointer swing range, and offers an ultra-wide input signal range up to 5Vrms, combining practicality with aesthetic appeal.
Parameters
- Audio Input: Stereo RCA / XLR / Microphone
- Audio Output: XLR / Stereo RCA
- Sensitivity Adjustment: Supported
- Gain Adjustment: Supported
- Display Mode: AGC / DB
- Environment Noise Filter Function: Supported
- Working Voltage: Micro USB DC 5V (above 1A)
- Backlight Filament Voltage (Tungsten Lamp): DC 9-12V
- Settings Saved After Shutdown: Supported
- Diameter of VU Meter: 35mm / 0.11in
Important Notes
- The VU1 PRO requires a separate USB power supply. Do not use USB ports from computers or other equipment to power it, as this may cause the VU meter pointer to move erratically or introduce noise due to audio input common ground issues.
- The USB power supply must be 5V single voltage, with a current of at least 1A. Fast charging sources with dual voltages are not recommended.
- Audio input signals should only be connected from the audio output of ordinary players such as CDs, computers, mobile phones, MP3s, etc. Do not connect the VU1 PRO's input to the output of an amplifier or speaker, as this may damage the device.
How to Use
- The VU1 PRO will automatically power on when connected to a USB power cable.
- Connect Inputs and Outputs:
- Microphone Input: Press the MIC/LINE button until the MIC indicator lights up. In this mode, the VU1 PRO functions solely as a VU meter. Position it near your speaker to pick up music.
- LINE Input: Press the MIC/LINE button until the LINE indicator lights up. Select the correct input and output based on your other audio devices. The VU1 PRO can also act as an audio switcher: RCA input to XLR output, or XLR input to RCA output.
- Switch between AGC and DB audio signal methods. Adjust the falling speed of the VU meter pointer (DELAY), the swing range of the VU meter pointer (GAIN), and the environment noise filter function as per your usage requirements.
- After use, long press the MIC/LINE button to turn off the device, then disconnect the USB power cable.
Display Modes (AGC vs. DB)
AGC Mode
In ACG (Automatic Gain Control) mode, the VU meter is driven by a dynamic square root audio compression algorithm. This means the relationship between input volume and pointer swing is not proportional. When input volume is low, pointer swing is large; as volume increases, swing amplitude gradually decreases. This mode allows for good display effects over a larger audio input range without gain adjustment. It's recommended to adjust GAIN for a pointer swing close to 70% (0dB). Due to the compression algorithm, it doesn't display the true current input level, making it unsuitable for professional recording but good for regular listening habits.
Graph Description (AGC Mode): This graph illustrates the relationship between Input voltage (Vrms) on the Y-axis (0-2.0) and VU meter pointer swing range (%) on the X-axis (0-100%). The curve shows a non-linear, decreasing relationship, where higher input voltage results in a smaller pointer swing, characteristic of AGC compression.
DB Mode
In DB mode, the data is presented without compression changes. The swing of the VU meter pointer is directly proportional to the input signal. This mode is suitable for occasions requiring knowledge of the real music level, such as in a recording studio or when testing specific sound levels.
Graph Description (DB Mode): This graph illustrates the relationship between Input voltage (Vrms) on the Y-axis (0-2.0) and VU meter pointer swing range (%) on the X-axis (0-100%). The line shows a proportional, linear relationship between input voltage and pointer swing, indicating DB mode.
Environment Noise Filter
The environment noise filter function helps to filter out ambient noise.
- After making all connections, play music normally and set the pointer to jump within the proper range (approximately 50% to 90% position) by adjusting the GAIN knob. Pause the music, then long press the DB/AGC button for 3 seconds until all 4 LED lights (MIC/LINE/DB/AGC indicators) illuminate. Release the DB/AGC button. The environment noise filter function will then activate. The system sets a fixed threshold based on the actual environmental noise intensity collected to filter out the highest noise. This setting process takes about 3 seconds. The VU1 PRO will automatically exit the setting mode when completed, and two of the 4 LED lights will turn off. You can then play music again.
Important Note for Setup: Before exiting the setting mode, avoid making any other sounds such as talking or playing other music, as this can affect the setting accuracy.
- The environment noise filter function can only filter up to 50% of the maximum pointer swing value; noise beyond this position cannot be filtered. It is recommended to adjust GAIN to reduce the pointer swing range if necessary.
- Once set, the environment noise filtering function works in both LINE and MIC modes. To restore the default value without restarting, adjust GAIN to the minimum and re-enter the environment noise filtering function setup.
- The setting of the environment noise filtering function does not support saving after power off. If the device is in a soft shutdown condition (turned off by pressing the button but not disconnecting the USB power cord), the set value can be temporarily stored. However, if the device is powered off by unplugging the USB power supply and then turned on, the VU1 PRO will restore its default value.
Front and Back Panel
The VU1 PRO features controls and indicators on the front panel and connection ports on the rear panel.
Front Panel Controls & Indicators:
- DB/AGC Button:
- Short press: Switches between AGC and DB display modes.
- Long press (3 seconds): Turns on the function of environment noise filter.
- MIC/LINE Button:
- Short press: Switches between MIC and LINE input modes.
- Long press (3 seconds): Turns off the device.
- LED Indicators: MIC, LINE, DB, AGC lights indicate the current mode and status.
- DELAY Knob: Adjusts the falling back speed of the VU Meter pointer.
- GAIN Knob: Adjusts the swing range of the VU Meter pointer.
- Backlight Brightness Adjustment: A knob or potentiometer (located on the back panel) to adjust the brightness of the VU meter backlight.
Rear Panel Ports:
- Input Switch: Selects between RCA and XLR inputs.
- Output Switch: Selects between RCA and XLR outputs.
- RCA Input/Output: Standard RCA connectors for audio signals.
- XLR Input/Output: Professional XLR connectors for audio signals.
- DC 5V IN: USB Type-C port for power supply (5V, at least 1A).
Diagram Description (Front/Back Panel): Visual representation of the VU1 PRO unit. The front panel displays two VU meters, several buttons (MIC/LINE, DB/AGC), knobs (DELAY, GAIN, Backlight Brightness), and LED indicators (MIC, LINE, DB, AGC). The rear panel shows input/output connectors (RCA L/R, XLR) and the DC 5V IN power port.
Frequently Asked Questions
Q: The pointer of VU Meter is moving even when there is no music input.
A:
- The quality of the USB power supply might be poor, with large ripples causing significant interference. It is recommended to change to a better USB power supply.
- The VU1 PRO might be sharing a USB power supply with the player's audio source, leading to common ground interference. Please use a separate USB supply to power the VU1 PRO.
Q: The backlight brightness of the VU1 PRO's two VU meters is not the same.
A: Because the VU1-PRO uses a tungsten bulb as the backlight for the meter, during transportation, the tungsten filaments in the bulb may become entangled and shortened due to vibration. This can cause the internal resistance to become smaller, resulting in different brightness levels. You can manually adjust the backlight brightness of the two meters by adjusting the resistance located on the back panel of the VU1 PRO.
Contact Information
Address: Room 1329, Wang Cheng Building, Long Guan street, Long Hua new District, Shenzhen, Guang Dong, China
Contact: LIU CHENXI
Tel: +86-18570015672
Email: nobsound@doukaudio.com
