1. Introduction
This manual provides detailed instructions for the proper use and maintenance of your GAIN EXPRESS Digital Sound Level Meter, Model SLM-269. This device is designed for measuring sound levels in various environments, offering accurate readings from 30dB to 130dB with A/C frequency weighting. Please read this manual thoroughly before operation to ensure safe and effective use.
2. Safety Information
- Do not attempt to repair or modify the device. Refer all servicing to qualified personnel.
- Avoid exposing the device to extreme temperatures, humidity, or direct sunlight.
- Remove batteries if the device will not be used for an extended period to prevent leakage.
- Keep the device away from strong electromagnetic fields.
- Always use the included windscreen to protect the microphone and ensure accurate readings, especially in windy conditions.
3. Package Contents
Verify that all items listed below are present in your package:
- 1 x Digital Sound Level Meter (SLM-269)
- 1 x Sponge Ball (Windscreen Filter)
- 1 x AC Output Wire
- 4 x 1.5V AA Alkaline Batteries
- 1 x Carrying Case
- 1 x Instruction Manual
Image 3.1: The GAIN EXPRESS SLM-269 Sound Level Meter, including the carrying case, windscreen, and batteries.
4. Product Overview
4.1. Components and Controls
Image 4.1: Front and back views of the SLM-269 Sound Level Meter with key components labeled.
- Windscreen: Protects the microphone from wind noise and dust.
- Electret Condenser Microphone: Captures sound waves for measurement.
- LCD Screen: Displays measurement readings and settings.
- Power Button (⏻): Turns the device on or off.
- MAX Value Hold Switch (MAX): Toggles the maximum value hold function.
- Level Range Control Switch (LEVEL ▲/▼): Adjusts the measurement range (30-80dB, 50-100dB, 60-110dB, 80-130dB, 30-130dB).
- Timeweight Switch (FAST/SLOW): Selects fast or slow response time.
- Equivalent Weight Switch (A/C): Selects A or C frequency weighting.
- Tripod Mounting Screw: Allows mounting the device on a tripod (tripod not included).
- Battery Compartment: Houses the AA batteries.
4.2. LCD Display Elements
Image 4.2: Detailed diagram of the SLM-269 LCD display and its indicators.
- UNDER/OVER: Indicates if the current measurement is below or above the selected range.
- FAST/SLOW: Shows the selected response time weighting.
- Level Range Indicator: Displays the active measurement range.
- Bar Graph: Provides a visual representation of the sound level.
- Measuring Value: The primary digital display of the sound level in dB.
- Frequency Weight A/C: Indicates the selected frequency weighting (A or C).
- Measuring Unit (dB): Denotes decibels as the unit of measurement.
- Low Battery Indication: Appears when battery power is low.
- MAX: Indicates that the maximum value hold function is active.
5. Setup
5.1. Battery Installation
- Locate the battery compartment on the back of the device.
- Slide the battery compartment cover downwards to open it.
- Insert four (4) 1.5V AA alkaline batteries, ensuring correct polarity (+/-).
- Replace the battery compartment cover, sliding it upwards until it clicks into place.
Image 5.1: The battery compartment located on the back of the sound level meter.
6. Operating Instructions
6.1. Powering On/Off
- To turn on the device, press the ⏻ (Power) button.
- To turn off the device, press and hold the ⏻ (Power) button for approximately 2 seconds.
6.2. Selecting Frequency Weighting (A/C)
Press the A/C button to toggle between A-weighting and C-weighting.
- A-Weighting: Simulates the human ear's response to sound, commonly used for environmental noise measurements.
- C-Weighting: Provides a flatter response, suitable for measuring peak sound levels or noise from machinery.
6.3. Selecting Response Time (FAST/SLOW)
Press the FAST/SLOW button to switch between fast and slow response times.
- FAST: (125ms) Suitable for capturing rapidly changing noise levels.
- SLOW: (1 second) Provides a more averaged reading for stable noise levels.
Image 6.1: The FAST/SLOW button for adjusting response time.
6.4. Adjusting Level Range
Use the LEVEL ▲ (Up) and ▼ (Down) buttons to select the appropriate measurement range. The available ranges are:
- 30dB to 80dB
- 50dB to 100dB
- 60dB to 110dB
- 80dB to 130dB
- 30dB to 130dB (Auto-ranging)
If the display shows 'UNDER' or 'OVER', adjust the range until the reading falls within the selected range.
6.5. MAX Hold Function
Press the MAX button to activate or deactivate the maximum value hold function. When active, the display will show 'MAX' and hold the highest sound level recorded since the function was enabled.
6.6. General Measurement Tips
- Hold the meter at arm's length, pointing the microphone towards the sound source.
- Ensure the windscreen is properly installed to minimize wind interference.
- Avoid blocking the microphone with your hand or other objects.
Image 6.2: The sound level meter being used to measure sound in a professional setting.
7. Calibration
The SLM-269 is factory calibrated. For professional applications requiring certified accuracy, periodic calibration with a standard acoustic calibrator is recommended. The device features a calibration control accessible via the battery compartment (refer to Image 5.1).
Note: Adjusting the calibration control without a proper calibrator may lead to inaccurate readings. Consult a qualified technician for calibration services if needed.
8. Maintenance
- Cleaning: Wipe the device with a soft, dry cloth. Do not use abrasive cleaners or solvents.
- Storage: Store the meter in its carrying case in a cool, dry place when not in use. Remove batteries for long-term storage.
- Microphone Care: Always keep the windscreen on the microphone to protect it from dust and physical damage.
9. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Device does not power on. | Dead or incorrectly installed batteries. | Replace batteries with new 1.5V AA alkaline batteries, ensuring correct polarity. |
| Display shows 'UNDER' or 'OVER'. | Measurement is outside the selected range. | Adjust the Level Range using the ▲/▼ buttons until the reading is within range. |
| Inaccurate readings. | Incorrect frequency/time weighting, microphone obstruction, or device needs calibration. | Check A/C and FAST/SLOW settings. Ensure microphone is clear and windscreen is properly fitted. Consider professional calibration if issues persist. |
| Low battery indicator appears. | Batteries are low. | Replace all four AA batteries. |
10. Specifications
Image 10.1: Key technical specifications of the SLM-269 Sound Level Meter.
- Measuring Range: 30 ~ 130dBA, 35 ~ 130dBC
- Accuracy: ±1.5dB (under reference conditions)
- Frequency Range: 31.5Hz ~ 8.5KHz
- Level Ranges: 30-80dB, 50-100dB, 60-110dB, 80-130dB, 30-130dB (Auto)
- Linearity Range: 50dB / 100dB
- Frequency Weighting: A and C
- Time Weighting: FAST (125ms), SLOW (1s)
- Microphone: 1/2 inch Electret Condenser Microphone
- Digital Display: 4 digits, Resolution 0.1dB
- Power Supply: 4 x 1.5V AA Alkaline Batteries
- Operating Temperature: 0 to 40°C (32 to 104°F)
- Operating Humidity: 10 to 80% RH
- Storage Temperature: -10 to 60°C (14 to 140°F)
- Storage Humidity: 10 to 70% RH
- Dimensions: Approximately 16 x 12 x 2 inches (Package)
- Weight: Approximately 1 Pound (Package)
11. Warranty and Support
GAIN EXPRESS products are manufactured to high-quality standards. For warranty information, technical support, or service inquiries, please refer to the contact information provided with your purchase or visit the official Gain Express website.
Please retain your proof of purchase for warranty claims.
