Home-Made IEMs

  1. Dellwolf
    I would think the distance would be to help with phasing.
     
  2. rellik
    Sorry, but the distance is to tune to a different resonant mode. The chamber length and diameter become the dominant resonant frequencies as the driver is stored outside the ear.

    Adding a horn or waveguide creates additional oscillation modes which throws off phase often considerably. Changing diameter can help to spread the response range of a driver from its Thiele/Small Fs Free air resonance parameter. This will give the driver a more even amplitude at different freuqencies. Its focal dispersion is also spread, creating a larger sweet spot.

    Another benefit to adding a ramped phase is to reduce ringing and amplifier load by playing different notes at different times thus maximizing power output. Ramped phase is quite easy to get accustomed to as it is constant and a simple delay.

    OFF Topic: ------

    Opamps such as the recently discontinued LM Overture series shift tune to a maximal frequency and delay other frequencies (in a nutshell). The more recent LM chip amps actually will choose "random" dominant frequencies that shift between a bucket of maximal frequencies after a certain time, they will also include delay to support other frequencies. This "random" function is based on power line noise to maximize output power and minimize output noise. Shifting faster allows for the amp to "cool" from the maximal frequency just alittle more. Can be distracting as hell though. Both chips support a set of these concepts, but how many tones and more importantly how quickly is based on their design specs.

    The OPA541 tends to just include a basic monotonic wave(s) added to the signal to allow for chip to cool. This is why it can only output 10W vs 35-45W in the same TO-220 power package. The aforementioned LM amps include this as well.

    All of these designs are strictly different from the Class D(varying square wave duty cycle based on loading) or Tripath(varying duty cycle pulse(sine,saw,square) generated via simple internal DAC) amps yet include some form of "audible" Duty Cycle to maximize output. Tripath amps and Class D amps can also use a function of the above techniques based on their design.

    Basic discrete transistor amplifiers tend to use a duty cycle outside of their "audible" range due to separate component function and significant heat sinking of the output drivers. The larger external traces also act as much better heat sinks than tiny internal lithographed traces.

    The tones of certain standard OP Amps can become quite familiar and pleasing thus restricting the use of Discrete Op Amps. Why swap it when its designed for it??? AKA DAC chip output. Pure amps are a different bag o worms.
     
    Last edited: Jun 2, 2017
  3. briancortez2112
    Sorry never posted a while, ive been super busy!
    Everyone on here seems to be doing a great job figuring out these things! Thats awesome!
    Here are just a few i have recently done, hope it fires up everyone to continue there passion. :L3000:


    2yerye.jpg gffggfhtr.jpg u5y434.jpg
     
    Last edited: Jun 4, 2017
    Mogol, MuZo2, tomekk and 1 other person like this.
  4. yomogi
    SR 32453 (full range) + dynamic driver (woofer).
    Face plate is fluorescent color.
    The sound quality is very warm.
    SR series are low cost and high performance.

    [​IMG]

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  5. jbr1971
    Nicely done. What is the purpose of the holes in the faceplates? Bass ports?
     
  6. tomekk
    Metaphysical question. Why are weekends so short? :cry: :beyersmile:

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    JorgePantalones and Mogol like this.
  7. bartzky
    tomekk likes this.
  8. jbr1971
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  9. yomogi
    It is to prevent the air spring effect of the dynamic driver.
     
  10. tomekk
    You need some mesh there. Nothing so irritates as stains and dust in shells.

    Maybe a small tube and a damper of wool?
     
  11. yomogi
    thank you for the advice.
    But I am not worried.
    Because other earphones were okay as well.
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  12. Spinnerauto
    How did you put graphic on faceplate? Can you explain?
     
  13. Shilohsjustice
    There are a couple methods I use based on the graphic and need. The ones pictured I used a cameo vinyl cutter to cut the image into vinyl then applied and used clear Fotoplast over top.
     
    Wei Khai Lim likes this.
  14. J-breezy
    A friend of mine has a pair of iems from Alclair and his right iem is a bit loose and he is already past the 30 day re-fit time limit. He was wondering if I could add something to it to build it up and I was wondering if you guys would just use something like lack 3 to add some buildup? Also, I'm guessing it's best to just cover the entire iem, instead of just the canal to avoid the difference in layers ones it hardens?
     
  15. Shilohsjustice
    First and foremost Alclair is a fantastic company with exceptional customer service. My recommendation would be to reach out to them and rule that completely out first.

    Second, I would have them try to be more specific as to where the fit issue is;
    Canal
    Base Canal
    Cymba

    Then I would apply a small amount of Lak3 in that area only. You only need to to get to a point where it completely seals, if you do that you done a good job adjusting fit.
    IMG_3002.PNG

    Just my 2 cents...... I wouldn't coat the entire IEM.
     

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