1. Introduction
The Amprobe SM-CAL1 is a precision sound meter calibrator designed to ensure the accuracy and reliability of your sound level measurements. This device generates two fixed sound pressure levels, 94 decibels (dB) and 114 dB, at a frequency of 1,000 hertz (Hz), allowing for precise calibration of sound meters with microphones up to 1/2 inch in diameter. Regular calibration is crucial for maintaining measurement integrity and compliance with relevant standards.
This manual provides detailed instructions for the proper use, maintenance, and troubleshooting of your SM-CAL1 Sound Meter Calibrator.
2. Safety Information
Please read and understand all safety instructions before operating the SM-CAL1. Failure to follow these guidelines may result in injury or damage to the device.
- Do not expose the calibrator to extreme temperatures, humidity, or direct sunlight.
- Avoid dropping or subjecting the device to strong impacts.
- Do not attempt to open or modify the calibrator. Refer all servicing to qualified personnel.
- Ensure the battery compartment is securely closed during operation.
- Dispose of batteries according to local regulations.
3. Package Contents
Verify that all items are present in the package:
- Amprobe SM-CAL1 Sound Meter Calibrator
- One (1) 9V battery (installed)
- User Instructions (this manual)
4. Setup
4.1 Battery Installation
The SM-CAL1 comes with a 9V battery pre-installed. If replacement is needed:
- Locate the battery compartment cover on the bottom of the unit.
- Remove the cover.
- Connect a new 9V battery, observing correct polarity.
- Replace the battery compartment cover securely.
4.2 Preparing for Calibration
Before calibrating your sound meter, ensure its microphone is clean and free of debris. The SM-CAL1 is designed to fit microphones with a diameter of up to 1/2 inch.
Figure 1: Amprobe SM-CAL1 Sound Meter Calibrator. The image shows the top face of the cylindrical calibrator, featuring the 'AMPROBE' logo, 'SM-CAL1' model number, a three-position slide switch labeled '94', 'OFF', and '114' (referring to dB levels), and text indicating 'db at 1kHz', 'IEC 942 1988 CLASS 2', and 'Sound Calibrator'. A red power indicator light is also visible.
5. Operation
5.1 Calibrating a Sound Meter
- Gently insert the microphone of your sound level meter into the opening on the top of the SM-CAL1 calibrator. Ensure a snug fit to minimize sound leakage.
- Select the desired calibration level using the slide switch on the calibrator:
- Slide to '94' for a 94 dB signal.
- Slide to '114' for a 114 dB signal.
- Observe the reading on your sound level meter. Adjust your sound meter's calibration settings until its display matches the selected output level of the SM-CAL1 (either 94 dB or 114 dB). Refer to your sound meter's user manual for specific calibration adjustment procedures.
- Once calibration is complete, slide the switch to 'OFF' to conserve battery life.
- Carefully remove the sound meter's microphone from the calibrator.
5.2 Low Battery Indication
The SM-CAL1 is equipped with a low-battery indicator. When the battery voltage drops below a certain level, the indicator light will dim or not illuminate, signaling that the 9V battery needs to be replaced.
6. Maintenance
6.1 Cleaning
To clean the exterior of the calibrator, use a soft, dry cloth. Do not use abrasive cleaners or solvents, as these may damage the casing or internal components.
6.2 Storage
When not in use, store the SM-CAL1 in a cool, dry place, away from direct sunlight and extreme temperatures. If storing for extended periods, it is recommended to remove the 9V battery to prevent leakage.
6.3 Recalibration of the SM-CAL1
While the SM-CAL1 is designed for stable output, periodic verification of its accuracy by a certified calibration laboratory is recommended to ensure continued compliance with standards and optimal performance. The frequency of such recalibration depends on usage and regulatory requirements.
7. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| No sound output / Power indicator off | Battery is dead or incorrectly installed. | Replace the 9V battery, ensuring correct polarity. |
| Inaccurate calibration readings on sound meter | Microphone not properly seated; Calibrator needs recalibration; Sound meter issue. | Ensure microphone is snugly fitted. Consider sending SM-CAL1 for professional recalibration. Check your sound meter's functionality. |
| Sound meter reading fluctuates | Ambient noise interference; Loose microphone connection. | Perform calibration in a quiet environment. Re-seat the microphone firmly. |
8. Specifications
- Model: SM-CAL1
- Output Sound Pressure Levels: 94 dB and 114 dB
- Output Frequency: 1,000 Hz (1 kHz)
- Microphone Compatibility: Fits microphones up to 1/2 inch diameter
- Accuracy: Meets IEC 942 1988 Class 2 standards
- Power Source: One (1) 9V battery
- Low Battery Indicator: Yes
- Operating Temperature: 0°C to 40°C (32°F to 104°F)
- Storage Temperature: -10°C to 50°C (14°F to 122°F)
- Dimensions (H x D): Approximately 4.9 x 1.9 inches (125 x 48 mm)
- Weight: Approximately 0.6 lb (285 g)
- Certifications: CE compliant, ANSI, IEC standards
9. Warranty and Support
9.1 Warranty Information
Amprobe products are warranted against defects in material and workmanship for a specified period from the date of purchase. For detailed warranty terms and conditions, please refer to the warranty card included with your product or visit the official Amprobe website. This warranty does not cover damage resulting from misuse, accident, neglect, alteration, contamination, or abnormal conditions of operation or handling.
9.2 Customer Support
If you encounter any issues or have questions regarding your Amprobe SM-CAL1 Sound Meter Calibrator, please contact Amprobe customer support. Before contacting support, ensure you have reviewed the troubleshooting section of this manual. You can find contact information on the official Amprobe website or through your local distributor.
