Audiometry/Hearing Conservation

3M™ Bio-Acoustic Simulator Series

Audiometers should be regularly verified to help ensure accurate patient testing, and the 3M Bio-Acoustic Simulator series offers customers a flexible and simple solution for performing this procedure. They are highly reliable, durable devices that save time and money by eliminating the need for a test subject to help you perform a daily biological check of your audiometer.

The BA-202, BA-202-25 and BA-202-27 can be used with manual, automatic and microprocessor audiometers. They can be powered by battery or optional power adaptor, whichever is most convenient for your application. Two color coded LEDs help ensure that the earphone connections are fastened properly. The earphone cups are intended to be used with TDH-39, TDH-49 or TDH-50 earphones and can also be used with or without audio cups.

Testing a Manual Audiometer

Operation of the Bio-Acoustic Simulator is a very simple process.*

  1. After the audiometer is switched on and stabilized, the earphones are placed on the simulator.
  2. The hearing level (HL) value is increased on the left earphone until the appropriate indicator light appears. The HL value is then recorded. This is repeated several times to ensure consistency. Test all audiometer frequencies from 125 Hz to 8 kHz. The entire process is repeated for the right earphone.
  3. A biological log of the data should be kept. Always compare the new HL values to the original biological log that was established early in the calibration interval of the audiometer. All data should compare within ± 5 dB of the original biological log.

Reliable Audiometer Biological Testing

Daily audiometer functional checks are required, and the Bio-Acoustic Series of instruments make it easy to quickly perform this task. These instruments also reduce the cost and uncertainty of using a team member for daily checks.

  • Test Frequencies: 125 Hz to 8 kHz
  • Background Test Levels (BA-202-25): 40 dB at 500 Hz and 1 kHz, 47 dB at 2 kHz, 57 dB at 4 kHz, and 62 dB at 8 kHz (per OSHA, Fed. Reg. March 8, 1983)
  • Background Test Levels (BA-202-27): 35 dB at 125 Hz, 25 dB at 250 Hz, 21 dB at 500 Hz, 26 dB at 1 kHz, 34 dB at 2 kHz, 37 dB at 4 kHz and 8 kHz
  • Calibration: 60 dB HL +/- 1 dB at 1 kHz continuous tone with TDH-39, 49, or 50 earphone
  • Accuracy: Repeatable to within 2 dB when using an audiometer with a continuously variable HL control. When using automatic audiometers, the BA-202 will be repeatable within the HL step increments of the audiometer (usually 5 dB)
  • Transducers: Two electret microphones for checking earphones
  • Response Output: Normally open and normally closed relay contacts (SPDT 3 wire output)
  • Hysteresis: 10 dB +/- 1 dB between ON and OFF indication for the LEFT/RIGHT earphone indicators when used with continuous tone input
  • Relay Specifications: 250 mA current, 30 volts AC or DC, 20 million operations
  • Power: 9-volt alkaline battery (Optional 120-volt or 220-volt power adapter) Low battery indicator when used in battery mode
  • Size: 6.8" x 6.5" x 4.2" (173 x 165 x 107 mm)
  • Weight: 1.63 lbs. (739g); not including the remote microphone
  • Approvals: CE Mark


*Please refer to the user manual for more detailed instructions on how to perform a daily biological test on an audiometer.

Part Numbers

IQBA20225 Bio-Acoustic Simulator, W/ Octave Monitor, per OSHA Buy Online
IQBA20227 Bio-Acoustic Simulator, W/ Octave Monitor, per ANSI Buy Online