HMS II.3 HEAD Measurement System with Ear Coupler and Artificial Mouth
HMS II.4 HEAD Measurement System with Ear Coupler
HMS II.5 HEAD Measurement System with Artificial Mouth
Type 3.3 and 3.4 Pinnas
For testing handsets, headsets and hands-free telephones, telecommunications test engineers and international standards bodies have recognized the need for acoustic transducers that replicate real use situations. Important considerations are the acoustic properties of the ear, the physical properties of the pinna and an accurate means of clamping a handset to the ear. The overall geometry of the head, ears and mouth are also critical.
The HMS II.3 HEAD Measurement System is a Head And Torso Simulator (HATS) in accordance with ITU-T P.58, which specifies the geometry of the head and the acoustic output of the mouth, and IEC 711 which describes an occluded-ear simulator, to which is added an ear canal extension terminated with a simplified pinna. Standard delivery includes the IEC 711 ear coupler on the right side only; the left side ear coupler is optional.
HHP II HEAD Handset Positioner clamps a telephone handset according to ITU-T P.57. A precision force gauge measures the exact force against the pinna. When the HHP II is ordered with the HMS II.3, a pinna according to ITU-T P.57 Type 3.4 is standard delivery. The Type 3.4 pinna is a more flexible version of the simplified pinna which closely models the mechanical impedance of a human pinna.
Measurements of handsets coupled to the HMS II.3 using the HHP II were compared to measurements coupled to human ears, using a probe microphone in the subjects¹ ear canals. Tests were conducted over the range of forces that a handset would press against the human ear. These tests showed excellent correlation between the HMS II.3 and human subjects over the entire range of forces. Likewise, tests of headsets also showed good correlation.
The MFE VI with the Binaural Equalizer software option works with HMS II.3 to digitize and equalize ear signals for binaural recording and measurement. The HEADphone Playback Systems comprising of the PEQ IV Programmable Equalizer, PVA IV.3 Power Voltage Amplifier, and HA III Electrostatic HEADphones reproduce binaural recordings with proper level and equalization over high quality electrostatic headphones for aurally accurate listening. Furthermore, the Free Field equalization provided by the Binaural Equalizer option is required by newer measurement standards for hands-free, handset, and headset measurements.
For a data sheet, please select the "downloads" area from the HEAD acoustics GmbH site www.head-acoustics.de
The HMS II.4 is a simplified version of the HMS II.3 that comes with the IEC 711 ear coupler, ear canal extension and simplified pinna on the right side only, and no artificial mouth.
For a data sheet, please select the "downloads" area from the HEAD acoustics GmbH site www.head-acoustics.de
The HMS II.5 is a simplified version of the HMS II.3 that comes with the artificial mouth only and no ear coupler.
For a data sheet, please select the "downloads" area from the HEAD acoustics GmbH site www.head-acoustics.de
The ITU-T P.57 Type 3.3 Pinna - meeting the latest ITU-T standard - is a human-like pinna which is suitable for measuring headsets and handsets. It is an option for both the left and right ears of the HMS II.3 and II.4 heads.
The ITU-T P.57 Type 3.4 Pinna is a thin-walled simplified pinna which is suitable for measuring headsets and handsets, particularly for applications where the pressure dependent characterization of those devices is needed. The right side pinna is standard delivery when HMS II.3 or II.4 is ordered with HHP II; otherwise, it is an option for both the left and right ears of the HMS II.3 and II.4 heads.
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