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vibro veritas, measuring our IEMs like a pro with amateur budget.

Discussion in 'Sound Science' started by castleofargh, Aug 12, 2015.
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  1. castleofargh Contributor
    I was planning on doing this as a reviews, but there really isn't a review section for that kind of gizmo. so if there is a more fitting place for this, please moderator wherever you are, move it there [​IMG].
     
     

     
    what is it? A little acoustic coupler with a cone opening.
    Wait what? Ok, a little microphone to record the sound from your IEM. ^_^

     
    is it complicated? yes and no.
    -to do A measurement, you stick your IEM in it, plug the jack into your computer amp or headphone out. Plug the 3.5mm jack of the microphone in the mic input of your computer, get ARTA or whatever software that will let you fool around with measurements in a loop, select the proper input and output in the software, and there you go. If you're using ARTA, there is a pretty effective video on Vibro's website to show you how to do a measurement in no time.
    -to do a calibrated measurement that looks like online graphs, it might take more efforts.

     
    "So if I buy it, can I become the next Tyll with my blog outerfidelity.com?" Well not just yet no. sorry.
    without having much information about the microphone, and with no high end ADC, it's a little hard to do more than just frequency response measurement. and even then it's recommended for a limited frequency range.
     
     
     
     
     

     
    I bought the Veritas after reading about it on innerfidelity. TBH my mindset at the time was “oh that looks like a fun geeky toy, it costs the same as the last cheap copter I crashed in my room after 10mn of first charging it”. I really didn't expect much and while I was a little disappointed not to get a reliable calibration file(more on that later), I ended up spending more than a week wasting all of my free time and most of my sleep time(which is usually a lot!) Making measurements and learning a few things about IEMs in the process.
    So somehow,to me it's worth it. But that's because I'm a geeky nerd, and because I had about 10 IEMs, many many tips and a few resistors to play around with.
    I imagine the guy with 1 IEM doing a measurement, maybe a few more to see how reliable it is, maybe still a few more with different tips, and "… ok what's on TV?".
    So my take on this, it's a fun toy, it might even be used for seriouz bizznezz (within reason), but it's not for everybody and would bore many.

     
    I made no picture because there really isn't much to show. Just go there http://vibrolabs.com/pages/veritas-guide and check the videos, you'll see all you need to see.
     
     I believe the best way to give an idea about what you can do, is by showing examples of a few ideas I got. I used room EQ wizard instead of ARTA, simply because I already knew the basics of that software(yeah lazy reason). But I did use ARTA a few times and got the very same measurements so it doesn't change what you do on the measurement side of things(both can be used for free BTW).

     
    1/ making a measurement:
    I did just like the video on how to use ARTA is showing, and measuring my etymotic HF5 gave this:
    nocalib.jpg
    when I was expecting something like this:
    graphCompare.png
     
    Not the best first impression.
     
     
     
     
    After trying a lot of IEMs, it was clear that I needed to make a calibration profile on my own for the microphone. And did it using headroom or innerfidelity or M.R.O as references for what my final measurement should look like with different IEMs(funky stuff when they all have a slightly different graph of the same IEM).
    So I made a .TXT file like a boss with values like this
    10,-5.2
    12,-3.8
    13.5,-2.8
    15,-2.5
    18,-1.3
    20,-1
    22,-0.7
    25,-0.5
    etc
    each time with the frequency and then the “gain” difference. As you can guess it's not the funniest thing to do with one's life, but you can take comfort in thinking that it's not the kind of stuff you'll do everyday.

     
    And after messing around I ended up with the compensated measurement that looked like this:
    calib.jpg
    pretty happy with this because it fits reasonably in with most IEMs I've measured vs online graphs, I can now get on to do the real "fun" stuff:

     
     
    Measuring different tips:
    etymotictips.jpg
    What a mess! you can mask some in REW, that's only to show you how strong I am in tips :wink:
    First surprise to me, even if it was to be expected, I prefer and tend to use mostly the T100 and etymotic olives(the sport comply foam just doesn't isolate enough). And they show about the same signature. But now I also know that I could try to use other tips and EQ the signature a little.

     

     
    Then I measured my etymotic MK5(you'll see a lot of etymotic in there, they're cheap and isolate like crazy so I have them). I use the MK5 with a white damping filter added in it because I find it tames the mids a little, but I could never really see what it really did to the sound:
    MK5vsaddedwhitefilter.jpg
    White line is the original MK5, and the cyan line is with the white filter(who's in first base who). clearly the white damping filter goes right back on! my eyes agree with my ears ^_^.

     
     
    I also checked my 2 pairs of HF5 to see if they were identical:
    HF5duo.jpg
    L and R are the left and right earpieces. I've arranged them like this to make the difference obvious. But you may notice that the differences are pretty consistent on the left and right of the same IEM. Pseudo burn in(they're both more than a year old and both were used a lot so...) or simply that etymotic tries to match the drivers even on the hf5? or random luck? IDK
    But now I know better than to just blindly believe that all IEMs of one model will sound exactly the same.

     

     
    Then I played with a few resistor adapters I had to see how it would affect the signature depending on the impedance response of the IEM. I already know the electricity behind it, and have made a little excel file to estimate changes when I have both the FR graph and the impedance graph. But now I can test it for myself:
    hf5o2-5ohm-30ohm-130ohm.jpg
    so now I can say with both theory and practice how my HF5 will become brighter with added resistor. The same way the ER4 becomes brighter when turned into the ER4S by adding a resistor to the cable.

     
    BUT being an EQ junky, of course there was one thing I really had wished to be able to do for a long time, and I suspect a few of you would like to do it too. Making sure my left and right earpieces are matched:
    MC5withoutEQ.jpg
     not too bad, but could be better. I don't know for ARTA but REW let you simulate the use of an EQ and estimates in real time(or not) the changes in frequency response(and phase but not very relevant for this use). So I used that and trying to keep the EQ minimal not to create more of a mess than there is to correct, I ended up with this:
    MC5withEQ.jpg
     
    could be still improved but I'm very happy with this already. And that's measured while using easyQ vst(also free) in foobar. It has a left and right EQ so I went for that one, and have converted a few albums with the VST in it so that the balance would be on my DAPs. I'm still trying and TBH I can't really tell the difference. And that doesn't take care of the imbalance of my own ears, but I do feel like I've conquered audio in my head and can drop the mic like a boss.

     

     

     
    You could do those stuff with any microphone and some duck tape to try and seal the space for the IEM to keep its bass. It would surely need some work but it would work. So the Vibro Veritas product isn't a revolution or anything, but it can simplify things. for a guy like me that has no ties with audio professionals doing recordings, knowing what kind of microphone I should have, what device to plug it in etc, that was simply too much for me. so while I had wanted to do some measurements for a long time, I clearly owe it to the vibro veritas this time.
    And as you can see, all you need are some IEMs and strange ideas to enjoy and maybe benefit from it.
    I'm very glad I bought one.

     

     

     
    + Let you actually measure your very own IEMs!
     
    + 99$ expensive for a toy, cheap for a measurement tool.
     
    + The mini jack works into a basic computer mic plug, so no need for recording equipment.


     
    - Will most likely need calibration so you must have at least 1 IEM that has online measurements available. Else that may limit what you can do with your measurements. Like using them to make an EQ, it can make sense only if you know what the graph is showing. I went to try copying RAW measurements(I'm used to that), so I readily know what I need to change to get the kind of signature I love. If I was stuck to the first measurement without calibration, it would need a lot of time and a good deal of experiments to achieve the same kind of EQ.

    - The jack works into a computer mic plug, but doesn't work on my focusrite 2i2 when it's a device specifically built to record microphones and instruments, oh irony ^_^.

    - Some silicone tips just wouldn't stay in place, so you need to find the right size of tip, or maintain it in place with the play-doh smurf paste provided when you buy a Veritas.

    - For customs, it might not always be possible to measure the sound at the right distance from the eardrum/microphone. Like if your ear canal turns a lot then you may not be able to push the shell as deep as you would want to. It's a minus, but maybe I should blame the ear canals that bend too much? Still very much manageable to get a measurement, just not THE measurement at perfect distance to see how the trebles really are.
     
    - from the webpage you can read this warning:
    In practice you can do better than that, but I would still suggest not to get your hopes too high about the precision in the trebles. With rather short frequency wavelength like trebles, any kind of change can make several DB of difference, pushing the IEM slightly deeper, your ear canal being bent in a particular way. Or simply because the manufacturer's confidence stops at 10khz on the microphone you're using.
    So while I can get readings at 20khz or even above, when I'm trying to show how an IEM really measures I will mostly use the measurements I've done up to 10khz. maybe 15khz at times just to show if a massive roll off is final or just a short blip. but that's probably it. And I recommend like Luke on his webpage to keep the 100hz-10khz accuracy in mind.
     
    james444, earthpeople, Brooko and 4 others like this.
  2. ForceMajeure
    Thank you. Very interesting.
    By the way how much was the international shipping?
     
  3. USHI
    99$ is way overprice imo. You can get the dayton imm6 for way less than this ( and i think better mic too) plus a pvc tube and some blutack.
     
  4. castleofargh Contributor
    I paid 10bucks for shipping.
    sorry for the delay, lightning decided to use my modem(and most of my neighbors) so I was stranded on that desolated place called IRL for a few days. ^_^
     
    that's exactly what I'm talking about, I know nothing about those things, and I'm most certainly not alone. I had no idea something like the IMM6 existed, else I would have bought one eons ago(ok I bought one now so I'll test them side by side. thanks for the tip^_^).
    some "all in one" solution at 100$, for lazy guys like me it's very fair. with a reliable calibration or a convenient way to create one(anything to serve as reference like a cheap IEM and the precise curve of the IEM) I would have been in paradise for 100$. but indeed it might seem a little expensive for what it is if people have to go through all the effort of creating a calibration file on their own. at that point it's not better than any other microphone and a little mc gyvering. but at least one guy using the vibro veritas had a very usable calibration right from the start. so it's hard to make a definitive judgment on this. maybe mine didn't like the delivery trip or something?
     
    anyway for people a little curious about audio, I find that it is an eye opener. using a mic brought me much more questions than it brought answers, but they were all very healthy questions about audio. most certainly cured me of audiofoolia, and more than ever made me appreciate what a proper EQ can do.[​IMG]
     
    USHI likes this.
  5. ForceMajeure
    Waiting for your comparisons, though I don't know how accurate they can be with different calibration.
     
    By the way I checked the Vibrolabs site for a calibration file for the Veritas and couldn't find one.
     
    Apparently Dayton audio provides you a txt calibration file according to the serial number on the product. 
    http://www.daytonaudio.com/index.php/imm-6-idevice-calibrated-measurement-microphone.html
     
  6. castleofargh Contributor

    veritas started with 4 calibrations profiles, and the mic came with a letter corresponding to one of those calibrations. so while not super individual calibration, it was supposed to put you in a ballpark of the proper settings.
    but in practice it clearly didn't work for me, I mailed them about it and soon after the calibrations were removed and we all got a mail telling us he had a problem with his calibration gear and we should not use the calibration files.
     
     a IEC 711 coupler is not something new and even I remember reading about it for ear simulation somewhere. TBH the calibration is really the only thing I have to complain about, else my measurements over the last 3 weeks are very consistent(when I check the raw graphs), so at least the main purpose of making direct comparison works perfectly for me.
    I'm personally very happy to have bought one and have IMO already EQed a few IEMs in a way that is well worth the money I paid for the vibro veritas. but I'm afraid people with only one or 2 IEMs may have a really hard time making a reliable calibration by themselves. that's really my only concern.
     
  7. arnyk
     
    This paper may shed some light on where IEC 711 couplers sit in the universe of ear simulators:
     
    http://www.aes.org/technical/documentDownloads.cfm?docID=177
     
    castleofargh likes this.
  8. higbvuyb
     


    A PVC tube wouldn't have the correct acoustic impedance. An IEC 711 coupler is much more complex than a tube. As long as you're measuring IEMs you don't need a pinna simulator or a head and torso simulator.
     
  9. briskly
    Veritas isn't a 711 simulator, but more a simple package to get people to start performing measurement with IEMs. No proper IEC 711/60318-4 spec canal simulator is going to be made for 100 dollars, that's for sure. castleofargh is taking a coupler and performing his own unique RECD correction on measurements from it.
     
    Of course, acoustic Z of Veritas is not equal to the 711. For anyone who has a Veritas coupler, do you have a large and ventilated dynamic driver IEM to play around with?
     
  10. arnyk
     
     
    As it stands the above seems to be a random collection of baseless opinions.  It seems like there must be some relevant observable and confimrable facts behind them. Do you know what they are?
     
  11. castleofargh Contributor
    it's not IEC711 compliant, Luke told me he tried to get as close as he could using components that would make it affordable. so I guess saying something like "modeled after IEC711" would be better?
     
     
    I don't have big vented dynamic drivers, I have the IE80 that has a super small back screw changing the size of a super small hole, or crap earbuds that are vented(the kind you get for "free" with a source and never use). I get IEMs for isolation so vented IEM isn't really my thing ^_^. but if there is something fun to try from it, I can always buy a cheap one. clearly curiosity is what got me here, so I can go another step into the unknown[​IMG].
     
     
     
     
    @ForceMajeure I've received the IMM6 and have fooled around with it. it seems to works pretty amazingly doing what it's intended for, but the IEM measurement conversion might not be as simple as I hoped. trying a few different sizes and materials to make a tube really makes some drastic changes(as expected TBH) and I will need to use my brain(not easy), and my mad DIY skill( that I never had) to make something that is at least somehow of ear canal length and doesn't vibrate too much for good measure(super pun).
    also I could only get it to work on my android table, so I have no way to make a loopback to use REW, I will have to mess with the TRRS(it's made for apple stuff so it's not a surprise) and see if I can get an adapter to stick it into at least my computer's soundcard if it's a no go wit the scarlet 2i2. so I don't know if it's such a good idea for IEMs. the veritas does make it look easy in comparison.
    but for speakers, it looks like a pretty cool portable low fi measurement kit. another kind of toy ^_^. I'll let you know if I end up with a simple method to use it for IEMs(but don't hold your breath, I have like a 10 page todo list right now and this isn't at the top of it).
     
  12. briskly
    Vibro Lab's product page stops short of claiming full IEC 711 compliance. See here.
     
    About the Veritas and 711 spec.
     
    If you look at the measurements of the HF5 raw (which is itself very similar to the ER-4P) on actual 711 spec simulators, the raw results are quite different from the uncorrected results presented in the first post.
     
    HF5/HF3 and ER-4P, from Headroom.
    graphCompare.png
     
    HF3 and ER-4P, taken from Rin Choi's blog/analysis.
    comp.png
     
  13. ForceMajeure
     
    Thank you for your reply.
    As far as I know the iec 711 have a 1.26cc volume between the entrance port and the mic so you could use the cylinder volume equation V=piR^2L   http://www.online-calculators.co.uk/volumetric/cylindervolume.php, make sure the radius is big enough so it doesn't restrain high frequencies. Of course there are other variables that can affect the sound like tube materials ...
     
    There are cheap trrs adaptor on ebay that should do the trick.
     
    Where did you buy the imm6? I am interested to get one for measurements, I want to build some DIY Custom IEM but I don't know if its a good reliable tool.
    I found on taobao (chinese ebay) some iec 711 equivalents http://world.taobao.com/item/37135316408.htm?spm=a312a.7700714.0.0.vu1I7U#detail
    but i think the imm6 is should be good enough, what do you think?
     
  14. castleofargh Contributor
    amazon ^_^.
     
    ok so I made an adapter compliant with the norm 1337wateva as seen on this picture showing that I didn't waste 3 years in a photography school:
    IMG_5836.jpg
    obviously built to last. and if you want, I can do one for you for 200euro. it really improves the soundstage of that microphone. [​IMG]
     
    then I went and just stuck the HF5 right on the mic with putty because F*** acoustic and I need to sleep at some point. here is what I get:
    imm6vsveritas.jpg

    purple is done with veritas, no calibration
    green is IMM6 no calibration
    yellow is IMM6 with the calibration file I downloaded.(let's just say it looks better when you measure speaker sound, because it's pretty useless for this usage).
     
    so when I find the right tube(pen cap or other professional grade material), I'm pretty sure I'll have to make up a compensation curve just like I did for the veritas.
     
  15. arnyk
     
     
    Ironically, the cost of that very interesting product on Taobao is under US$100.
     
    Looking forward to their eBay listing... :wink:
     
    BTW there are several IMM6 listings on eBay.
     
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