AH 252

Hearing protector test head frame
AH 252 is a hearing protector test head frame that meets the requirements of GB/T 7584.3-2011/ISO 4869-3:2007 Acoustic Hearing Protectors Part 3. Different configurations can be selected to test the sound insulation effect of head mounted or in ear hearing protectors according to IEC 60318-1 or IEC 60318-4 standards. The built-in artificial ear can also be used for acoustic performance testing of head mounted or in ear headphones.
The main body of AH 252 is made of aluminum alloy, which not only achieves good sound insulation effect, but also controls the overall weight well.
Paired with IEPE signal conditioners such as MegaSig PM 0083, achieve optimal testing results.

Specification parameters

AH 252-A
Compliant with standards	Compliant with IEC 60318-1 (applicable for head mounted)
Pressure field microphone frequency response	20Hz - 16kHz±1dB
Sensitivity	12mV/Pa（-38.5dB±2dB）re 1V/Pa
Dynamic range	33dB（A）- 143dB（1000Hz THD＜3%）
Noise floor	＜33dB（A）
Isolation degree	80 - 250Hz：＞40dB, 300 - 4000Hz：＞65dB, 4500 - 16000Hz：＞55dB
Material	Stainless steel
Operation temperature	-20℃ - 60℃
Relative temperature	10% - 90% not condensing
Storage conditions	Temperature: 25 ℃± 5 ℃, Temperature: 50% ± 15RH (to maintain long-term stability of the sensor)

AH 252-B
Compliant with standards	Compliant with IEC 60318-4 (applicable to in ear type)
Pressure field microphone frequency response	20Hz - 10kHz±0.5dB 10Hz - 16kHz±1dB
Sensitivity	12.5mV/Pa（-38dB±2dB）re 1V/Pa
Dynamic range	33dB（A）- 143dB（1000Hz THD＜3%）
Noise floor	＜33dB（A）
Isolation degree	80 - 250Hz：＞40dB, 300 - 4000Hz：＞65dB, 4500 - 16000Hz：＞55dB
Material	Stainless steel
Operation temperature	-20℃ - 60℃
Relative temperature	10% - 90% not condensing
Storage conditions	Temperature: 25 ℃± 5 ℃, Temperature: 50% ± 15RH (to maintain long-term stability of the sensor)