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Wednesday, February 6, 2013

Final Audio Design FI-BA-SS part 2 & 3: General analysis / In-depth analysis

[A special thanx goes to James. He sent me a brand-new pair, directly routed from Japan! I'd like to personally salute his commitment and passion, as he is truly doing a lot of favor for the headphile community.]

Final Audio Design's FI-BA-SS is a flagship model with the pinnacle of their proprietary BAM(Balanced-Air-Movement) technology implemented. Initially priced at eye-popping ¥100,000, it is known to have the best acoustic tonality among other models with BAM.

Previously, three different Final Audio Design's heaven series models, which are also BAM-driven, have been analyzed: Heaven A, Heaven C, and Heaven S. They indeed all exhibit very unique electroacoustic characteristics, but it turns out their overall performances are more or less the same in spite of huge differences in pricing.

In order to verify such acoustic superiority FI-BA-SS is known to have over its lower end models, as claimed by many of the owners, its electroacoustic properties will be assessed & compared.

PRO: As expected, FI-BA-SS shares the same funkiness that the heaven series models have. The distortion is still there, and the polarity is still inverted.

CON: Unfortunately, FI-BA-SS is not even close to hi-fidelity. Then again, once funkiness goes extreme, the basic principle of electroacoustic engineering diminishes, and the judgement of good/bad sound turns into the matter of personal preference, as FI-BA-SS users find such distortion to be euphonic.

ON SECOND THOUGHT #1: As expected, as FI-BA-SS gets further away from the reference plane, the sound becomes more peaky. This characteristic is universally applicable for the Heaven models as well.

ON SECOND THOUGHT #2: As expected, adding a resistor in series changes the IEM's sound signature radically, even with 33-Ohm.

ON SECOND THOUGHT #3: A simple dust filter, such as HiFiMAN's stock filter, does not change the sound of FI-BA-SS. Even a microfiber cloth for eyeglasses yields only about 3 dB of damping in the high frequency range. However, the sound signature of FI-BA-SS is finely modifiable, once this acoustic damping tweak is combined with electric damping. Although this experiment has not been carried out with the Heaven models, it shall be equally applicable too.

ON SECOND THOUGHT #4: There are total of eight rear vents on FI-BA-SS's housing, and they are claimed to be directly related to the working principle of BAM technology. However, just like the Heaven models, the electroacoustic effect of the vents are extremely minimal. In addition, the opening at the strain relief is completely blocked.

ON SECOND THOUGHT #5: Heaven-A yields slightly less amount of output above 10 kHz. Other than that, it turns out the only difference between the Heaven models and FI-BA-SS is the housing material.

ON SECOND THOUGHT #6: Here is my two cents for FI-BA-SS users: equip a 33-ohm resistor in series, and use an eyeglass cleaning cloth + a HiFiMAN filter as an acoustic damper. Still funky in distortion, but the spectral balance becomes very linear! Vents may be blocked, but I'd recommend to keep them open for better sub-bass reproduction.


  1. Where can I get the 33-ohm resistor and the HiFiMAN filter? How do I apply the eyeglass cleaning cloth?

    1. Some DIYers sell impedance adapters. Such filter can be substituted with any type of thin-layered material. Simply cut out a small piece, maybe in 1cm x 1cm , and stick it in between the sleeve & the headphone unit.

  2. Rin, I was curious about your thoughts of the Vsonic GR07 vs the FI-BA-SS

    1. Such an interesting question. Hmm.. It is hard to tell, but GR07 is more neutral, thus suitable for wider range of usage, whereas FI-BA-SS is more unique, thus suitable for certain kind of music such as female vocals or Shibuya-kei. I can definitely tell you though that FI-BA-SS is definitely not for classical music!