Threshold of detectionThreshold of detectionEstablished according to some criterionEstablished according to some criterion

Other terms related to thresholdOther terms related to threshold

dB HL: Hearing leveldB HL: Hearing level

dB RETSPL: Reference equivalent dB RETSPL: Reference equivalent threshold sound pressure levelthreshold sound pressure level

dB SL: Sensation leveldB SL: Sensation level

Frequency Frequency (Hz)(Hz)

dB HL dB HL dB RETSPL; ANSI, 1996dB RETSPL; ANSI, 1996(for TDH 49 (for TDH 49

headphones)headphones)250250 00 26.526.5500500 00 13.513.510001000 00 7.57.520002000 00 11.011.040004000 00 10.510.580008000 00 13.013.0

HL to RETSPL conversion HL to RETSPL conversion (Table 3.2 in (Table 3.2 in textbook)textbook)

What is the What is the SPLSPL value corresponding to a 20 dB value corresponding to a 20 dB HLHL 4000 4000 Hz tone?Hz tone?

Is this the same for other types of headphones/sound field Is this the same for other types of headphones/sound field measurements?measurements?

InstrumentationInstrumentation

AudiometerAudiometer

Pure tonePure tone

SpeechSpeech

Pure tone generator Amplifier Attenuator

Headphone/Insert earphone

Bone conduction vibrator

Interrupter

Pure tone audiometerPure tone audiometer

Microphone/CD/

TapeAmplifier Attenuator

Headphone/Insert earphone

Loudspeaker

Interrupter

VU Meter

Amplifier

Speech audiometerSpeech audiometer