CHANGSTAR: Audiophile Headphone Reviews and Early 90s Style BBS
Lobby => IEM Measurements => Topic started by: speakerphone on February 10, 2015, 02:48:24 AM
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(http://lh3.googleusercontent.com/-_BwoXaIY2vE/VW02ORXaMFI/AAAAAAAAAxs/kMjhmmHPyZk/s1600/Screenshot_2015-06-02-13-48-44.png)
(http://lh3.googleusercontent.com/-1nXWnotMzlk/VW02bVA48GI/AAAAAAAAAx0/-o0bDGJlmJo/s1600/MDtrumpetraw.png)
(http://lh3.googleusercontent.com/-BNHtwbB2rzo/VW02b_CHoNI/AAAAAAAAAx4/6ur6jcG5LF8/s1600/MDtrumpetDF.png)
(http://lh3.googleusercontent.com/-ut0D-utmMXo/VW02cT0U_HI/AAAAAAAAAyA/bS4sPkxNkW8/s1600/MDtrumpetOW.png)
(http://lh3.googleusercontent.com/-H9wihup2N0s/VW02cmV-2BI/AAAAAAAAAyE/1rXqv3WSOLA/s1600/trumpetCSD.png)
(http://lh3.googleusercontent.com/-Ijh9wLNsuUo/VW02dJF_jNI/AAAAAAAAAyM/DUj3-wqWa8k/s1600/trumpetTHD.png)
(http://lh3.googleusercontent.com/-YrN_qMs5338/VW02dsrrIaI/AAAAAAAAAyQ/SyCB5eXrkdc/s1600/trumpetIMP.png)
I measured only left channel, because right channel was broken.
This is the best designed IEM I'd every seen. It really looks like trumpet.
My artificial Ear (Coupler) follows IEC 60318-4 (former IEC 60711), ITU-T Recommendation P.57, ANSI S3.25 standards.
About the measuring standards
I mostly follow the IEC 60268-7 standard. I use O2 Amp for Lower the output impedance close to 0ohm. (In IEC standard, amplifier output impedance should be 120ohm.)
Also I use [1/24 octave smoothed Pink periodic noise] for frequency response analysis, and [1/6 octave stepped sine] for harmonic distortion analysis.
Diffuse Field Compensation Target follows the ISO 11904-2 standard, and Olive-Welti Target follows latest In-Room research. (Olive, Sean; Welti, Todd; McMullin, Elisabeth at AES).
But, as we know, frequency range of ISO 11904-2 standard is 20~10000Hz. So I dealt [-6dB/Oct.] at 10000Hz~20000Hz.
References
IEC 60318-4 : Electroacoustics - Simulators of human head and ear - Part 4: Occluded-ear simulator for the measurement of earphones coupled to the ear by means of ear inserts
http://webstore.iec.ch/webstore/webstore.nsf/artnum/043703!opendocument
ITU-T Rec. P.57 : Series P: Telephone transmission quality, Objective measuring apparatus : Artificial ears
http://www.itu.int/rec/T-REC-P.57
ANSI/ASA S3.25 : Occluded Ear Simulator
http://webstore.ansi.org/FindStandards.aspx?SearchString=s3.25&SearchOption=0&PageNum=0&SearchTermsArray=null%7cs3.25%7cnull
IEC 60268-7 : Corrigendum 1- Sound system equipment - Part 7: Headphones and earphones
http://webstore.iec.ch/webstore/webstore.nsf/artnum/043714!opendocument
ISO 11904-2 : Determination of sound immission from sound sources placed close to the ear
http://www.iso.org/iso/catalogue_detail.htm?csnumber=32439
Olive-Welti Target : Listener Preferences for In-Room Loudspeaker and Headphone Target Responses
http://www.aes.org/e-lib/browse.cfm?elib=17042