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Reverse engineering IEMs and design topics

  1. synesthesiac
    I recently demoed some really high-end IEMs (top of the line Ultimate Ears, Noble, and Aurisonics) and they raised a lot of questions in my head. Here are some of those questions:
     
    1) What parts to they use? That is, do different manufacturers use the same drivers and whatnot? If so, I'd like to create a list here.
    2) Has anyone reverse engineered these high-end IEMs? These improvements seem pretty well-known and don't seem to be secrets (adding drivers for various freq ranges, adding extra holes for different frequencies, etc).
    3) I'm wondering how hard it really is to manufacture/build an IEM those features
    4) It seems like the width, length, and precision of the bass travels through makes a huge difference. These "ports" or whatever you call them is one design characteristic of IEMs that I'm interested in.
     
    I'm also truck by the huge difference in sound between, for example, the low-end model Noble makes versus the Kaiser 10. I wonder how much more the Kaiser 10 really is to manufacture than their lowest end model. The top-end model is ~$1500, while the low-end $300.
     
    Anyway, if you all know of any places which has reverse engineered and taken about some of these high end IEMs, then I think everyone would find their internal design interesting. Then it might be more apparent which physical features of the IEMs map to our perception/preferences.
     
    Would love to hear from any of you.
     
  2. TwinQY
    There are many pre-existing models of armature drivers one can order from Knowles and Sonion. Those drivers compromise the internals within the majority of high-end armature-wielding universal offerings. Some of the bigger outfits can order existing driver models to be custom-specced in order to fit their specific design requirements. Of course they are other companies who manufacture armature drivers (Sony does their own) but the majority market belongs to Knowles and Sonion. When it comes to dynamic drivers unless you use existing models as driver donor candidates they are produced in-house or outsourced so it would be very difficult to DIY.
     
    With crossover parts and circuitry they are your run of the mill stuff (caps, resistors) that you can find through any electrical parts source. Tubing on a custom is PVC.
     
    With regards to your question on cost, take the Kaiser 10 you mention as an example . Having not seen one I can only go by the information on the spreadsheets and see that they use 2 CI-22955s and 2 different sets of 2 TWFKs. The TWFKs are a WBFK and a FK wired together, therefore the TWFKs are a dual driver unit. If you were to go by cost of drivers alone, on Mouser the TWFK-23991 and the TWFK-30195 go for $49.86 each. The cost for the CI-22955 is $29.76. Keeping in mind that you need a set for each ears, this comes down to 4 TWFK-23991s, 4 TWFK-30195s, and 4 CI-22955s. The total would come to $518.
     
    This is not keeping in mind that as a DIYer there is still a minimum order quantity you have to meet when ordering on Mouser, Digikey, Newark, etc. IEM manufacturers usually have a lot of costs cut in that they order much larger quantities.
     
    And of course, all of this is not taking into account the sheer amount of time, effort, and workmanship it would take to create a custom. To create a mold with the impressions, UV cure the acrylic shell by pouring it in the mold, coming up with the crossover design, putting in the electrical components with respect to distancing the tubing among other things, sealing the unit with the faceplate, polishing off the shell, and the piles upon piles of work, a staggeringly inordinate amount, for the logistics of the company to be worked out.  All of this needs to be factored in. In the end, while the driver costs might not make much of a difference to compensate for the price, they need to tier their offerings accordingly in order to keep some semblance of of having healthy margins. This results in what you see where the 10-driver unit costs more than the two-driver.
     
    Many companies, who are capable of manufacturing universals along with their customs, such as UE, make their margins off of the high-production universals. As you can imagine, some will outsource the housing to some factory that does injection molding and the likes, while sending them the approximate designs and details to give to the Knowles/Sonion factories to assemble. Or they will assemble them in-house. This process would be less time-consuming. The exceptions would be the customs-to-universal offerings UM, FitEars, etc, produce.
     
    There is a great chart of the driver models used on this thread, documented by a local Head-Fier tomscy2000. A Japanese enthusiast also keeps a spreadsheet here with his own additions.  In addition, the Home-Made IEM thread documents much of the process it takes to work with armatures, along with other things that you might be looking for.
     
    SilverEars likes this.
  3. earfonia
     
    Got a chance in the last local meet to try Noble 3, 4, and 5. I would say, not to my liking. Despite our personal preferences, observing real performance and speakers, I don't buy the idea of the multi BA drivers IEM, where the sound is channeled through small pipes from each BA drivers to reach the ear canal.  Would anyone do that in speaker world? Put the drivers in the box, and then channel out their sound using pipes?
    So far there are only a handful of BA IEMs with sound signature that meet my sonic preferences. They must have done a really good engineering to make it sounds good.  Many multi drivers BA IEM just so expensive but sound inferior to my ears.
     
    Front mounted micro drivers is the design that I like most.  Like the following IEM:
    JVC HA-FXD80, and many other models in their FXD and older FXC series (I have some of them).  Also the famous Yamaha EPH-100.  And less known TDK CLEF-Premium.  I'm not saying their sound always better than the multi BA drivers IEM, no.  Many BA IEMs sounds better than them. But instead of spending more time and research on tuning the multi BA drivers with sound pipes, I prefer manufacturer to research and develop more IEM using Front Mounted Micro Driver design.  I call it FMMD design.
     
    Combining the FMMD design with dual driver push-pull technology like on the ATH-CKR9 and ATH-CKR10 I reviewed a while ago, or ATH-IM50 and ATH-IM70 type of Symphonic driver, IMHO would be the design closer to the Holy Grail of IEM world.
     
     
     
    Thanks a lot for the information!
    I'm also a fan of the Knowles Twin BA. I have both DUNU DN-1000 and DN-2000, and liking them a lot. A good design of combining 2 BA drivers in one unit, and channel both through only a single port.  And many of the Hybrid design using Knowles put this twin driver at the front, direct to the ear canal, so sound pipe is not necessary.
     
    Anyway, it's a very interesting topic, thanks for starting! [​IMG]
     
  4. TwinQY
    Historically, armatures have had more output per size/volume than convientional dynamics drivers of this size. With the advent of microdynamics the tide might start turning. A similar, albeit flawed in that analogies often are, parallel is between that of the hard drive industry. Where as HDDs have continued to show platter density increases among other I/O-related things, SSDs have an edge in performance by the sheer nature of their underlying technology. With armatures they continue to advance incrementally but dynamics are ultimately more stable, can be more easily free of distortion, have more bandwidth as a standalone unit, and do not suffer the phase problems that multi-armature units are afflicted with via their crossovers.
     
    I'm not very understanding of the hesitancy towards acoustic tubing. There are stranger things still done with crossovers in the speaker world.
     
    Actually the TWFK does have design compromises. Essentially the WBFK and the FK are wired out of phase and this results in the infamous bandwidth gap between 2-4k. However there are a couple of ways to resolve this. And there are other factors that contribute to the brittle nature up top but the most thorough write-up that describes why this is happens to be on a forum where we dare not link. Nevertheless I'm sure you can just PM the member himself to ask for details if he has the time. All in all, it's a great tweeter, great for housings and applications limited in size, like hybrids but nothing is perfect.
     
    earfonia likes this.
  5. synesthesiac
    I love this kind of discussion! Thanks you two!
     
    Earfonia, I also did not like the low end nobles at all. I assume they use similar design and parts as the higher-end nobles, but I found the Kaiser 10 to be awesome! 
     
    I'm going to find a book or something on armatures and completing technologies.
    (this video has some basic details https://www.youtube.com/watch?v=1uzFhlpKIvM#t=216 )
     
    I'm mostly curious about the limits of cost production of armatures of this type, and the various designs people have tried. I imagine the output holes, for example, have some micro-acoustic affects. What if the output tube was metal vs plastic vs some sound dampening material...
     
    After hearing the differences between a bunch of high-end and low-end IEMs now, I get the feeling there is a lot of design freedom here and room to innovate.
     
  6. TwinQY
    FitEar does a lot of work on titanium tubing on their models - customs and universals. Any significant difference I would not be so sure on since not many companies have the precision that a company with dental background like FitEar does to pull it off. Generally when something is reshelled to a custom it has been stated that the change from whatever tubing the universal uses to the PVC tubing would have an impact. For their universals they have also utilized an acoustic horn made of titanium.
     
    Again, costs can come down to things other than performance.
     
  7. SilverEars
    There isn't details on benefits of the titanium material, but the gradual narrowing of the housing to the horn is the magic according to Rin.  The gradual transition creates a more stable treble because of minimal loss of acoustic energy.  The problem with 111 is that it rolls too early compared to ER4.  Maximum boost of treble can be done with minimum of 33ohms according to Rin which Fitear did not add.
    I'm curious if the titanium material creates less impedance at around 10k. Once again, I didn't see anything about the material.  Anybody know what the titanium does?
     
  8. synesthesiac
    It feels like there is enough knowledge between members of this forum to create an amazing "open source" IEM. I'm down!
     

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