Download presentation

Presentation is loading. Please wait.

Published byJaylin Paulson Modified over 3 years ago

1
TR41.3.3-05-11-004a-Acoustic Impedance of Ear Simulators

2
This contribution consists of a brief PowerPoint summary of the following complete documents: TR41.3.3-05-11-004b-Acoustic Impedance Measurements B&K 2005.pdf TR41.3.3-05-11-004c-Acoustic Impedance Measurements B&K 2001.pdf TR41.3.3-05-11-004d-Equivalent Volumes of Ear Simulators B&K 2001.pdf

3
Why does the acoustic impedance of an ear simulator matter? “The fundamental purpose of an ear simulator is to test a receiver under conditions that most closely approximate actual use by real persons.” IEEE 269-2002 Please see next slide for illustration...

4
pSpS ZSZS Receiver ZEZE pEpE Ear Simulator Simplified Equivalent Circuit of Receiver & Ear Simulator High impedance source: Z S >> Z E and q constant, so p E Z E qq p S = source pressure p E = pressure at ear q = acoustic “current” Z S = source impedance Z E = ear impedance Low impedance source: Z S << Z E, so p E constant pepe qq pepe qq

5
IEEE/STIT: B&K 2001 Volumes of Historical Couplers Except as noted, equivalent volume of most couplers is about 6cc Volume of Type 3.4 is larger mostly due to a larger concha.

6
The Impedance Probe in Use IEEE/STIT: B&K 2001

7
Acoustic Impedance of 5 Human Ears at “Normal” force, with Parametric Average Human Parametric Average IEEE/STIT: B&K 2001 Note variation in real ears !! Notice M2 – average about 210dB at about 2.4kHz

8
Acoustic Impedance of Type 3.3 vs Human Average Human IEEE/STIT: B&K 2001 M2 of Type 3.3 is about 212dB at 2.6kHz

9
Acoustic Impedance of Type 3.4 vs Human Average Human IEEE/STIT: B&K 2001 M2 of Type 3.4 is about 206dB at 2.6kHz

10
Research & Graph: B&K 2005 Acoustic Impedance Measurements 2005 - New Procedures

11
Acoustic Impedance of 10 Human Listeners - 2005 Impedance measured with probe in form of cell phone. Subjects held probe in natural position, without further instruction, as they would normally hold a phone. Positions were generally different from HATS. Although the probe was held in positions different from HATS, 1.The “natural position” curves are well-grouped, considering human variation 2.Type 3.3 “35”pinna in HATS position at 10N simulates the group average well Research & Graph: B&K 2005 Note variation in real ears !! Notice M2 of Type 3.3 – about 210dB at about 2.5kHz M2

12
Conclusions: Human-like leakage is simulated by Type 3.3 or 3.4 Leakage is force and/or position dependent Both types generally require more handset force than humans use for equivalent leakage Acoustic impedance of M1 is similar Acoustic impedance of M2 is different Type 3.3 M2 is similar to humans Type 3.4 M2 is lower, generally resulting in underestimate of receiver response around 2.5kHz (most receivers) Comparison of Type 3.3, with Shore 35 Pinna, and Type 3.4

Similar presentations

Presentation is loading. Please wait....

OK

EXAMPLE 1 Apply the distributive property

EXAMPLE 1 Apply the distributive property

© 2018 SlidePlayer.com Inc.

All rights reserved.

To make this website work, we log user data and share it with processors. To use this website, you must agree to our Privacy Policy, including cookie policy.

Ads by Google

Ppt on punctuation in hindi Ppt on indian teachers day Ppt on world war 2 Ppt online compressor sales Ppt on paintings and photographs related to colonial period clothing Ppt on domestic robots definition Ppt on satellite orbit calculator Ppt on movie 300 Download ppt on civil disobedience movement in civil rights Ppt on 60 years of indian parliament members