New portable headphone measuring setup

Discussion in 'Measurement Setups, Systems, and Standards' started by La Cenric, Dec 13, 2018.

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  1. La Cenric

    La Cenric Friend

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    Straight to the point, I'll be attempting to head into the headphone measuring game. A bit of new territory for me so looking for some additional pointers/advice from the measuring heads here (@Hands, @purr1n, @cskippy, @ultrabike etc. feel free to chime in).

    Current setup with HD800:
    01b7c6b94e0e560359fa359d8e64e136a402bef3fc.jpg

    Reusing my IEC microphone to mimic the input/transfer impedance of the inner ear per Bruel & Kjaer's researched recommendations. Can't find a ITU-T P.57 compliant ear (or relevant clone) so I've resorted to using the MiniDSP EARS for now. A bit of a placeholder in that regard, at least until I can find something more accurate.

    Additional purpose is to be portable hence the foldability:
    014322b143fe7926ab9c4045eec52b01e7893f83ec.jpg

    Procedures and settings are similar to that of my IEM measurements (also shameless plug to my subreddit where I'm updating measurements/impressions more frequently) though I will be running the headphones off of a iFi Micro iDSD BL for power and SPL reasons. Due to the equipment (literally a phone) and the environment, I'll only be taking frequency response measurements. Also, probably only right-channel measurements due to ear used.

    FR graphs acquired, processed from raw data gathered by an iPhone 7 Plus on the AudioTools app and subsequently generated with REW:

    HD600.png
    Sennheiser HD600

    HD650.png
    Sennheiser HD650

    Sennheiser HD800 with SDR

    The data should be closer to that of Innerfidelity's raws, Rinchoi's raws, Stereophile's data, Clarity Fidelity's rig or RTing's stuff. Looks pretty good with the HD650, though the HD800 graph has me scratching my head a little.

    I'll be heading out tomorrow to get more measurements of other headphones for testing and calibration (feel free to request any) but once all my hardware and settings are finalised, I'll go out full-force with the data collection.

    Raw data can be provided if needed, just ask.
     
  2. purr1n

    purr1n Finding his inner redneck

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    Are you mounting the microphone flush with the EARS or using some of the canal? Taking a wild guess here that the microphone you are using is mounted flush.

    The HD800 measurement looks like the microphone may have shifted. The EARS when used with the included microphone as-is in the canal has a high Q resonance around 4.5kHz. When the microphone is flush mounted, this resonance goes away (per @Hands' results). I would expect that if the microphone fell back a little creating a canal, but of shorter length, the resonance would come back at a higher frequency, i.e. 6kHz per your HD800 results.
     
  3. La Cenric

    La Cenric Friend

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    I did some extra measurements if anyone needs a reference point for where I'm going with this. Some are unusual/niche models since I just wanted to try them, but again just request for something and I'll get right to it.

    Audio Technica ATH-ADX5000
    ADX5000.png

    Final Audio D8000
    D8000.png

    Focal Utopia
    Utopia.png

    Klipsch HP-3
    HP3.png

    Meze Empyrean
    Empyrean.png

    Sennheiser HD800
    HD800.png

    Sennheiser HD800S
    HD800S.png

    Stax SR-L700
    L700.png

    @purr1n I am using the IEC-provided external canal simulator so the EARS canal is effectively bypassed in this case. The only "component" of the EARS I'm using is its artificial pinna. The 6k spike on the HD800 measurement doesn't seem to be a consistent resonant artifact of the system (as shown in the re-measurement above) and should be part of the transducer. Also seems to be consistent with current reports of the HD800S having a lower 6k spike, per the comparison plot I made below:

    HD800 vs HD800S
    HD800vHD800S.png
     

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