G.R.A.S. Sound &Vibration A/S

Artificial Ear Dilemma

Historical

IEC 60318

IEC 60711

Anatomical variations

Combined coupler and pinna

Closed-coupler testing

Free-field testing

Zwislocki to IEC correction

G.R.A.S. Sound &Vibration A/S

Historical

French Artificial Ear made by CNET

G.R.A.S. Sound &Vibration A/S

Historical

Swiss Artificial Ear made by the Swiss P.T.T.

G.R.A.S. Sound &Vibration A/S

NBS 9-A Earphone Coupler

Historical

G.R.A.S. Sound &Vibration A/S

The IEC 60318-1 ear. The impedance and lumped parameter electrical network is shown in the IEC 60318-1 standard.

IEC 60318

G.R.A.S. Sound &Vibration A/S

IEC 60318

Frequency response obtained by a ½”condenser microphone receiver and transmitter mounted concentrically at the top and bottom of the variously shaped coupler volumes. Valid for the range 500-20000 Hz. All coupler dimensions are given in millimeters. Vertical scale 2dB per line, 50dB full scale.

G.R.A.S. Sound &Vibration A/S

IEC 60318

Detailed measurements to determine the optimum dimensions for the best possible linearity over the widest frequency range. 10dB full scale. 0.4 dB per line.

G.R.A.S. Sound &Vibration A/S

IEC 60711

G.R.A.S. RA0045 occluded ear simulator as used in KEMAR

G.R.A.S. Sound &Vibration A/S

Ear moulds from same person. Right and left ears. The width at the most narrow passage is 6mm for the left ear and 9.6mm for the right ear.

Anatomical variations

G.R.A.S. Sound &Vibration A/S

Combined coupler and pinna

Type 43AG Ear and Cheek Simulator with IEC 60711 Coupler

G.R.A.S. Sound &Vibration A/S

Closed-coupler testing

Telephone Test Head Type 45AA showing:

Left; fitted with a G.R.A.S. Mouth Simulator & IEC 60318 Ear Simulator Type 43AD.

Right; computer rendering outlining its chief components

G.R.A.S. Sound &Vibration A/S

Speaking positions according to current recommendations

Closed-coupler testing

Speaking Position Recommendation

LRGP ITU-T Rec. P76

AEN ITU-T Rec. P76

HATS ITU-T P58

REF OREM A

G.R.A.S. Sound &Vibration A/S

Closed-coupler testing

Showing where the Lip-ring of the Mouth Simulator (Type 44AA or 44AB) should be for both AEN and REF positions. The angular distances of 39° and 13° (in that order) will move the handset from the AEN position to the LRGP

G.R.A.S. Sound &Vibration A/S

Free-field testing

KEMAR with positioning device

G.R.A.S. Sound &Vibration A/S

Free-field testing

KEMAR with reference microphone for linearization

G.R.A.S. Sound &Vibration A/S

Free-field testing

Auricle Measures used in KEMAR

G.R.A.S. Sound &Vibration A/S

Free-field testing

Mean values of frequencies of pressure maxima and minima at the open ear canal entrance for 12 male and female subjects; sound incidence from 90; loudspeaker source at 1m.

Equivalent lengths based on c=354 m/sfor l1 and l3, c=349.5 for L1 and L3.

G.R.A.S. Sound &Vibration A/S

Free-field testing

Ear canal entrance sound pressure, 12 females (above), 12 males (below), sound source at 90º azimuth angle, 1m.Free field is the reference pressure condition

G.R.A.S. Sound &Vibration A/S

Free-field testing

KEMAR Ear drum sound pressure for a free sound field with source azimuth angles of 0°, 90°, 180°, and 270°.

G.R.A.S. Sound &Vibration A/S

Zwislocki to IEC correction

15 IEC Modulus values of the acoustic transfer impedance function from IEC 711-1982 relative to the ANSI modulus values of the acoustic transfer impedance function.