FitEar custom Iems , why do some have 2 bores and some have 3 bore holes? - Rudi0504

I would like to share About FitEar custom Iems , why some have 2 bores and some have 3 bores nozzle?

Please read the womderful knowledge explanation from Keita Suyama San about 2 bores or 3 bores on his Fut Ear Custom Iem as follow :

for Rudi-san

音導孔（Sound Hole/Bore）に関するお問い合わせがありましたので、ちょっとご説明を。

3-unitのものですと基本音導孔を3つに設定する事が多いのですが、この理由は「そっちの方が作りやすいから」です（笑）。

3-unitで音導孔が2つと3つでは3つの方が良いんじゃないか？と心配される方もいらっしゃるかと思いますが、安心して下さい！変わりませんよっ！！

じゃあ、なんで2つになることがあるかというと、ひとつにはその方の耳穴のサイズや形状で、物理的に3つの音導孔を設定するのが難しい場合などが該当します。

「以前作ったのは3つだったのに今回は2つなんだけど・・・」。というのが今回のお問い合わせだったのですが、まず条件としては元々3つの音導孔を設定するにはあまり良く無いということ、そして2つにした方がより良い結果が得られるという判断から音導孔を設定しています。

ここでポイントとなるのが「高域ユニットの音導孔をなるべく独立させる」事です。低域〜中域にかけては、音導孔の長さや複数ユニットの混在による影響はほとんどありません。しかし高域になるにつれ、共鳴や干渉により再生結果に大きな影響が生じてきます。

それゆえ3-unitを2つの音導孔で製作する場合、高域は音導孔を専用に1本設け、低、中域をひとつにまとめます（これ、実は作業上とても面倒です）。2つの音導孔が確保できる場合には高域の音導孔を他の周波数帯を担当するユニットと共用することはありません（1本しか音導孔を設けることができない耳穴が極めて細い人などはゴメンナサイ）。

なんとか3つの音導孔を設けられるのに2つの音導孔とする場合の判断ですが、以前は出来る限りなんとか3つに分けようというアプローチを取っていました。しかしこれも使い方や皮脂のタイプにもよりますが、シェル厚が薄くなってしまった所に応力が集中してスジのようなヒビが入ってしまう、音導孔出口の角が欠けやすくなってしまうといった耐久性への影響が出るケースがありました（出ない場合もあるんですが）。

また、理想的な高域再生のため、音導孔長8〜10mmを基準として先端方向に高域ユニットをシェル内に配置する上で、3つの音導孔ではスペースが取れずに音導孔を長くひきまわさなければならないケースも出てきます。こうした際にはあえて3つではなく2つの音導孔とし、適正な位置に高域用ユニットを納めるよう製作アプローチを改善しています。

手元に届いた製品を見た時「あれ？なんで3つじゃなくて2つしかないの？！」と心配になる方もいらっしゃるかもですが、上で説明した通り「あなたの耳の条件でより良い音が得られるため」ですので安心してご愛用下さいませ♡

Translation in English :

for Rudi-san

Otoshirubeana (Sound Hole / Bore) because there was inquiry about, a little .. explanation.

3-unit and is a thing of when I often set the basic sound guide hole in three, but the reason is "because easy to make a person over there" (laughs).

Whether the sound guide hole not it be better of three two and three Tsudewa in 3-unit? Do you think is whether some people are worried, do not worry! It does not change the Tsu yo! !

So, if say whether it may become why two, the size and shape of the ear of the one person that, for example, when it is difficult to set a physical three sound guide holes are true.

"... I'm 2 Tsunan this time though was the three of previously made was". From the But was this inquiry because, first the fact that not so good to originally set up three of the sound guide hole as a condition, and determined to be that the person 2 was Tsunishi better results We have set the Otoshirubeana.

Here's to the point that "cell as much as possible independent of the sound guide hole of the high-frequency unit." When it comes to low-frequency to medium range, the influence of the mix of length or multiple unit of Otoshirubeana rarely. But as it goes to the high-frequency, it has caused a significant impact on the reproduction result by the resonance and interference.

When fabricating hence 3-unit with two sound guide hole, high frequency is provided one the Otoshirubeana to a dedicated, low, is summarized in one mid-range (which, in fact, is very troublesome on the work). It is not possible to share the high frequency sound guide hole and unit in charge of other frequency bands in the case where the two sound guide hole can be ensured (one only ear that can not be provided Otoshirubeana extremely thin person such as I'm sorry to).

This is the judgment of the case managed to be two sound guide hole is to be provided three sound guide holes, but previously had somehow taken the approach that will Wakeyo into three as much as possible. But although this also depends on the type of usage and sebum, the stress is concentrated in the place where the shell thickness has become thinner would cracked like streaks, making it easier missing corner of Otoshirubeana exit impact on the durability such as put away there was a case that exits (I sometimes does not go out but).

Furthermore, since an ideal high-frequency reproduction, Otoshirubeana a high frequency unit in the distal direction to Otoshirubeana-cho 8~10mm as a reference in order to place in the shell, without taking space in three sound guide hole also came out long and routed unless should not the case. Such a case is the dare instead of three two sound guide hole, we have to improve the production approach so as to pay the high frequency unit in the proper position.

When I saw the product that arrives at hand, "there? Why In No only two it 's not three?!" And is also is be some people to become worried, more as described in the above "in your ear conditions ♡ not please patronize with confidence because it is good for sound can be obtained. "