Touched by an IEM guru, running the SBAF Dick Gauntlet, and why target curves for IEMs won't work

Discussion in 'IEMs and Portable Gear' started by purr1n, Oct 21, 2017.

  1. TomHP

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    I have no interest really in this back and forth but this caught my eye. Differences in FR between KEMAR with old and new ears are very minor (<1dB). Purposely so. The goal was not to get a more accurate FR with the new ear canal. The goal was to get earphones to fit properly and on ear headphones to seal better (softer pinna). KEMAR with or without new ears also comply to all the same standards.

    HRTFs will measure slightly differently between different Hats though, cause all their ears are based on different data sets. There's a good AES paper somewhere showing the differences between all of them. I'll see if I can dig it up.
     
  2. purr1n

    purr1n Desire for betterer is endless.

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    No a big deal, but would be curious how maybe the Kemar differs from what Olive uses.

    In reference to the image that @k.e posted above, the superimposed "flat curve", the green line, looks very similar to Olive's research flat-in-room response (see dotted green line) - see below. The issue with this is that flat-in room EQ does have the 1db/octave slide or B&K behavior (as I said before, an in-room response that is flat at the listening position would sound unbearably bright.) It would be pretty easy to derive the B&K curve or 1db/octave slide from the dotted green line below or green line above.

    [​IMG]

    I also noticed the words "B&K 2.txt" in orange on the bottom with an unchecked box in the photo that @k.e. posted? Is that the B&K target?
     
    Last edited: Oct 23, 2017
  3. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    Ahahahahaha...hahahaha...ha, a picture of a monitor, for times when print screen or the snipping tool are too tough. Now THAT'S someone with a very, very good brain!
     
  4. purr1n

    purr1n Desire for betterer is endless.

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    We are horrible.
     
  5. insidious meme

    insidious meme Ambivalent Kumquat

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    It hard to find any good "silent observer" help these days.
     
  6. bartzky

    bartzky Acquaintance

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    Seems like I am the mysterious "silent observer". Well, I didn't want to join this discussion, but apparently my highly professional screenshot had already found it's way into this thread. Anyway!

    First of all (normalized @500 Hz):
    [​IMG]

    The yellow curve is taken from @TomHP 's second PP8 measurement (sorry for stealing it). More details in his original post.

    About the blue curve:
    That's exactly what I did.

    The green curve is the curve Olive, Welti and McMullin came up with by measuring a pair of Revel Performa F208 equalized flat at the primary listening position (small spatial average by using a 3 x 3 array of omnidirectional microphones) in the Harman International reference listening room by using a "GRAS 45 flush mounted to a head".

    [​IMG]

    It's the same curve Marvey posted here. For more details please refer to Olive's paper: http://www.aes.org/e-lib/browse.cfm?elib=17042

    The red curve obviously is the B&K 1974 room curve that can be found in their paper: https://www.bksv.com/media/doc/17-197.pdf

    The blue curve is a simple multiplication of the green and red curve in the frequency-domain. It's pretty certainly what Olive would have measured when he would have EQ'd to the B&K curve instead of a flat line.

    If anyone's curious, here are a few filters that will EQ the PP8 to the blue curve. They can directly be imported with EQ Apo. Mind that the pregain needs to be reduced to prevent clipping.
     
  7. purr1n

    purr1n Desire for betterer is endless.

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    The results are interesting, but I would say that the something with is very wrong the data, because what it suggests is that a "neutral" sound would actually be even leaner and even more shrill than the PP8, and I know that is most certainly not right! Heck, these results also makes @k.e. claims of the PP8 being neutral also quite incorrect - but in the other way from my position.

    Although both Olive and Tom use the same coupler, I am not sure if mixing datasets from different measurement apparatus would lead to meaningful results. The Jude Z1R gate is a good example of this.
     
  8. TomHP

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    @bartzky now do the same graphs for the Andro and we have ourselves a real dick swinging party.

    In all seriousness, this is very valuable info and I need to absorb and analyse it all a bit more. Tbc.
     
  9. purr1n

    purr1n Desire for betterer is endless.

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    So this doesn't make much sense as the result here doesn't seem consistent with the plots @bartzky provided - since the Harmon curve is similar to the flat curve with a bass lift. We can derive the
     
    Last edited by a moderator: Nov 12, 2017
  10. TomHP

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    @bartzky can you send me the blue curve in excel format?
     
  11. TomHP

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    The harman target I used is the one with the bass lift and treble shelf, the outcome of the study. Not the blue curve Bartzky used.
     
    Last edited by a moderator: Nov 12, 2017
  12. TomHP

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    @Marvey also, don't stare too much at my compensated curve, it's not exactly the one from the paper.

    I will update this thread later in the week with the B&K room response Harman (aka the blue curve above) compensation.
     
  13. purr1n

    purr1n Desire for betterer is endless.

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    Throw up some JBLs or Mackies in front of your Kemar!
     
  14. TomHP

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    No proper IEC listening room in my office unfortunately.
     
  15. purr1n

    purr1n Desire for betterer is endless.

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    This is a good point. I've been thinking about this for a while - years now. I didn't want to go into it, but I guess I will now.

    Let's start with this and chew on it.
    IMG_20171024_100837.jpg
    • We know that HRTFs can differ. Different people will have different HRTFs. Different dummy heads will have different HRTFs. @james444 already posted some "HRTFs" measured in a few different ways (http://www.superbestaudiofriends.or...-hear-different-thread.2535/page-2#post-67954) and @TomHP mentioned some AES papers showing the differents among the hats.
    • The question I have is do the "inverse HRTFs", that is the brain processing, also differ from individual to individual? If the inverse HRTFs are the same for every individual, then there will be no doubt that people will not hear the same. If the inverse HRTFs mirror the HRTF, then people will probably hear the same. I don't think there will every be an answer to this. Perception is a tricky thing to study. Note that the illustration above assumes the inverse HRTF is will mirror the HRTF for the sake of simplicity.
     
    Last edited: Oct 24, 2017
  16. purr1n

    purr1n Desire for betterer is endless.

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    IMG_20171024_103207.jpg

    Ten points to anyone who knows where I am going with this.
     
  17. jowls

    jowls Never shitposts (please) - Friend

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    Oh shit. My brain is exploding. Jude was right; Ether C is actually ‘neutral plus’. And perhaps those people rolling in ‘mountain dew’ lamborghini’s actually perceive them to be my yellow?
     
  18. purr1n

    purr1n Desire for betterer is endless.

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    IMG_20171024_105008.jpg
     
    Last edited: Oct 24, 2017
  19. Kunlun

    Kunlun cat-alyzes cat-aclysmic cat-erwauling - Friend

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    So, if I'm reading the last posts correctly, anyone who uses the Olive Welti to critique iems needs to "do the dew" which means being doused in a mixture of warm Mountain Dew and urine.
     
  20. purr1n

    purr1n Desire for betterer is endless.

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    It's actually not a direct criticism of the Olive-Welti target*, it's a criticism of the methodlogy in regards to IEM measurements! See next post...

    * Which is altogether a different issue. You guys already know that I take issue with it because it is more marketing research.
     

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