MiniDSP EARs measurement rig

Discussion in 'Measurement Techniques Discussion' started by dBel84, Nov 9, 2017.

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  1. cskippy

    cskippy Creamy warmpoo

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    I got mine on Wednesday. There are a couple issues and REQ Wizard doesn't play nice dince it doesn't take the compensation curve for sistortion so there is a huge distortion spike at ~5kHz.
     
  2. SineDave

    SineDave Friend

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    Yes I got a tracking number via email
     
  3. bartzky

    bartzky Acquaintance

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    A first glance at some measurements would be nice. Also I'm very curious how those compensation curves look like and which target they aim for.
     
  4. Tyll Hertsens

    Tyll Hertsens Grandpappy of the hobby - Special Friend

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    Bob Katz and I are both getting one to evaluate. I'll be looking in particular at how it deviates from my measurement rig, and how those deviation vary from headphone to headphone. Regardless, nice to see something so affordable appear in the market.
     
  5. Serious

    Serious Inquisitive Frequency Response Plot

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    Are you using the harmonic frequency as a reference? Should help
     
  6. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    I got tracking, was supposed to get it yesterday, but it's still overseas and majorly delayed vs estimated delivery date. Oh well. Can play with it after holiday travels.
     
  7. cskippy

    cskippy Creamy warmpoo

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    That did help some. I'll see what it looks like in ARTA and will post comparisons to flat plate coupler vs MiniDSP H.E.A.R.S
     
  8. Serious

    Serious Inquisitive Frequency Response Plot

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    You can't change physics, so SNR is obviously gonna vary a lot when there's something with 15db of gain at a certain frequency in between the mic and headphone. And the mics have to be quite low distortion which I'm not sure the UMIK is. Mine does start to distort a bit at higher levels.
     
  9. Koth Ganesh

    Koth Ganesh Friend

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    Guys,

    my first measurements ever so go easy on me. I just got the miniDSP H.E.A.R.S. The HP used was the Audez'e LCD 2c. So here goes....
     

    Attached Files:

  10. Mayor D

    Mayor D New

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    Does it do raw measurements?
     
  11. Cspirou

    Cspirou They call me Sparky

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    I suspect those are raw measurements. Otherwise the LCD2 is really bass heavy.

    Edit:

    I dont know what im talking about
     
  12. Hrodulf

    Hrodulf Prohibited from acting as an MOT until year 2050

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    Good job! Can you measure the HD650 or 600? Something which everyone knows.
     
  13. purr1n

    purr1n Desire for betterer is endless.

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    I've got some raw measurements coming in. The L and R channels do not match on this $199 ChiFi POS. Channels are off quite a bit below 2kHz. I haven't downloaded the calibration files on my unit's serial #, so cannot attest how good MiniDSP's provided calibrations are.

    I'm getting a little spike in the upper mids, presumably because the microphone in the ear canal does not appear to be flush mounted. Think of a can sticking out of a surface, with the microphone also sunk into the can. Anyone who has measured speaker drivers knows what happens when the lip of a driver basket sticks out without flush mounting.

    Will take pictures and plots when I get home, but so far not pleased because of it's wild inaccuracy.
     
  14. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    I'm thinking about starting a community development thread. Yes, no? The default compensations are...weird. I am disappointed the ear canal is just a straight pipe, but I guess you get what you pay for...I would rather it be at the canal opening.

    I too have yet to see if calibration files help L/R balance. If it does, it's not too hard to take the relative differences in those and apply to custom curves.
     
  15. purr1n

    purr1n Desire for betterer is endless.

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    That indeed is a sucky element from my limited time playing with it. The ear provides a lot of gain, and this forces me to record at lower input levels, with corresponding higher noise floor.

    Distortion measurements might still be better from the flat coupler. I am assuming the ear will not change non-linear distortion.
     
  16. purr1n

    purr1n Desire for betterer is endless.

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    I am getting the feeling they wanted to rush the product out and pulled off a Singularity 7.
     
  17. TheIceman93

    TheIceman93 El pato-zorro

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    Any plans to test the rig with Mini DSP's calibration files? I'm curious to see if that improves things at all.
     
  18. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    Yes, their emails about delays stated they were overwhelmed with orders as well, so couple that with a rushed product...

    I am thinking about taking headphones with known excellent channel matching and using that to compensate for channel imbalances in the mics. Can even use some headphones, like HD650, and measure both channels on both ears to see what the differences are. May need to combine that a bit with their own compensation curves, but working with mic and other material imbalances is not the end of the world.

    I am also contemplating a way to leave the ears on the rig, because I like those, but bring the mic flush with the canal opening. Not sure if the mic can be moved, i.e. if it's just attached with wires that have slack, or if I'd need to get out the knife, cut the ear off, and mount it flush. :)
     
  19. cskippy

    cskippy Creamy warmpoo

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    Sad to see I wasn't the only one with matching/calibration issues. I measured the HE-5, Code Sex, HD650, and Andromeda on the rig with poor results. Debating about returning it.
     
  20. Hands

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    So, I've gone through a few mics before for my in-ear setup, and they all vary to some degree. Sometimes more than I'd like. I'm not sure what is considered within spec with the MiniDSP stuff, but my understanding is that there's a reason why companies provide compensation curves tailored to each individual mic. Then you have companies like Cross Spectrum that go even further with that. All mics have variances, and I'd assume two mics in a $150 product aren't going to have the tightest tolerances, nor should we expect MiniDSP to have done a superb job calibrating them with the compensation curves. These issues are easy enough to work around if you know your way around Excel. I expected this when I pre-ordered the product. We'd have to spend a ton of money to have these problems figured out for us out of the box, or so I see it.

    Maybe I'm being too nice and optimistic, but I like to make things work if at all possible. Plus, I'm a believer that there are benefits to using rigs that get us closer to actual ears and ear canals. Nothing will ever be perfect, sure, and trying to figure out compensation curves for each rig is the worst part. But, in theory, it's possible this could take us a step further than flat couplers with some patience. In theory...Yeah, it's a big maybe. Channel imbalances you can iron out easier than you can trying to do mental gymnastics figuring out how a flat coupler translates to what we hear all the time. More good for comparison within those types of measurements, which is fine for what it is. In-ear has problems too. It's all just a big mess anyway that we're trying to figure out, and I expect it will take a lot of work no matter what we do. That's just my dumb opinion, and I'm not as well read on this as many of you.

    Honestly, I'm more worried about the width of the rig, or lack thereof. A large rubber band might be needed here to add some force to the back of cups and simulate a fatter head. On-ear headphones are going to be really tricky, though.

    Anyway! Here are some of my very preliminary results.

    This is my personally modded HD650, worn pads, with and without the provided compensation curve.

    It's pretty obvious the ear canal on this setup causes a ton of gain right around 4KHz. There also appears to be a bit of treble loss beyond that as well.

    The compensation curve they provide basically takes a nuke to everything above 2KHz. That is no good. But, still, the raw results look to me like something I can mold into what I want. Eventually. I look at this, what Tyll gets, and even what Serious did with his own compensation curve for Tyll's results, and I think I can make something of this.

    HD650 MiniDSP EARs.png

    I didn't get a chance to do raw vs. compensated results on the LCD-2C, but here are the raw results. Things look really good up till about 1KHz, give or take a couple hundred hertz. We would expect the LCD-2C to measure flat here. Given my ADC and what appears to be a bit of natural bass roll-off on the rig itself, I need to bump that up a wee bit till about 30-40Hz. Just a bit.

    LCD-2C MiniDSP EARs.png

    Here is the Aeon Open for your viewing pleasure. The cheap way they did the ear canal really screws up that whole 4KHz area in general, as is becoming a trend. Still, given the relative differences seen here and vs the HD650, I see promise based on what I actually heard myself on these two. I think I can work with this.

    AFO MiniDSP EARs.png
     
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