How to estimate SPL from a microphone output ?
14 October 2025
When developing audio devices involving microphones, knowing the actual Sound Pressure Level (SPL) hitting your sensor is crucial. It…
When developing audio devices involving microphones, knowing the actual Sound Pressure Level (SPL) hitting your sensor is crucial. It…
The BU Series piezo-ceramic accelerometer has output from 20 Hz to above 10 kHz, and is used primarily as a contact microphone for high noise environments. It may also be used as an accelerometer with lightweight structures. As a contact microphone, the BU may be worn on the throat, or touching a bony part of the head (top, temple, or mastoid bone). BU has been integrated into helmet designs for radio communication for military and emergency services.
| Image | Name | Description | Diameter / length [mm] | Width [mm] | Thickness [mm] | Directivity | Impedance [Ohm] | Nominal Voltage [V] | Sensitivity @ 1kHz [dBV re. 1V/Pa] | Sensitivity Tolerance [± dB] | SNR [dB] | AOP [dB] | Connection | Product status |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| BU-27135-141 | Accelerometer | 7.87 | 5.54 | 2.24 | Single Axis | 19000 | 1.5 | -11.5 | 3 | NA | NA | 3-Wire | Active |
|
| BU-21771-000 | Accelerometer | 7.87 | 5.54 | 4.06 | Single Axis | 5200 | 1.5 | -25 | 3 | NA | NA | 3-Wire | Preferred |
|
| BU-23173-000 | Accelerometer | 7.87 | 5.54 | 4.06 | Single Axis | 5200 | 1.5 | -19 | 3 | NA | NA | 3-Wire | Preferred |
|
| BU-23842-000 | Accelerometer | 7.87 | 5.54 | 2.24 | Single Axis | 5200 | 1.5 | -20 | 3 | NA | NA | 3-Wire | Active |
The BU Series piezo-ceramic accelerometer has output from 20 Hz to above 10 kHz, and is used primarily as a contact microphone for high noise environments. It may also be used as an accelerometer with lightweight structures. As a contact microphone, the BU may be worn on the throat, or touching a bony part of the head (top, temple, or mastoid bone). BU has been integrated into helmet designs for radio communication for military and emergency services.
| Image | Name | Description | Diameter / length [mm] | Width [mm] | Thickness [mm] | Directivity | Impedance [Ohm] | Nominal Voltage [V] | Sensitivity @ 1kHz [dBV re. 1V/Pa] | Sensitivity Tolerance [± dB] | SNR [dB] | AOP [dB] | Connection | Product status |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
| BU-27135-141 | Accelerometer | 7.87 | 5.54 | 2.24 | Single Axis | 19000 | 1.5 | -11.5 | 3 | NA | NA | 3-Wire | Active |
|
| BU-21771-000 | Accelerometer | 7.87 | 5.54 | 4.06 | Single Axis | 5200 | 1.5 | -25 | 3 | NA | NA | 3-Wire | Preferred |
|
| BU-23173-000 | Accelerometer | 7.87 | 5.54 | 4.06 | Single Axis | 5200 | 1.5 | -19 | 3 | NA | NA | 3-Wire | Preferred |
|
| BU-23842-000 | Accelerometer | 7.87 | 5.54 | 2.24 | Single Axis | 5200 | 1.5 | -20 | 3 | NA | NA | 3-Wire | Active |
When developing audio devices involving microphones, knowing the actual Sound Pressure Level (SPL) hitting your sensor is crucial. It…
When developing audio devices involving microphones, knowing the actual Sound Pressure Level (SPL) hitting your sensor is crucial. It…
The BU Series piezo-ceramic accelerometer has output from 20 Hz to above 10 kHz, and is used primarily as a contact microphone for high noise environments. It may also be used as an accelerometer with lightweight structures. As a contact microphone, the BU may be worn on the throat, or touching a bony part of the head (top, temple, or mastoid bone). BU has been integrated into helmet designs for radio communication for military and emergency services.
| Image | Name | Description | Diameter / length [mm] | Width [mm] | Thickness [mm] | Directivity | Impedance [Ohm] | Nominal Voltage [V] | Sensitivity @ 1kHz [dBV re. 1V/Pa] | Sensitivity Tolerance [± dB] | SNR [dB] | AOP [dB] | Connection | Product status |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
| BU-27135-141 | Accelerometer | 7.87 | 5.54 | 2.24 | Single Axis | 19000 | 1.5 | -11.5 | 3 | NA | NA | 3-Wire | Active |
|
| BU-21771-000 | Accelerometer | 7.87 | 5.54 | 4.06 | Single Axis | 5200 | 1.5 | -25 | 3 | NA | NA | 3-Wire | Preferred |
|
| BU-23173-000 | Accelerometer | 7.87 | 5.54 | 4.06 | Single Axis | 5200 | 1.5 | -19 | 3 | NA | NA | 3-Wire | Preferred |
|
| BU-23842-000 | Accelerometer | 7.87 | 5.54 | 2.24 | Single Axis | 5200 | 1.5 | -20 | 3 | NA | NA | 3-Wire | Active |