31. Vibration intensity (2-4, order by PIN weight)

[ 01/31/2018 ]     Labels: 31..Intensity-TopPlate

 
Measured vibration intensity data(from 'on floor') were sorted in order of endpin weight.
There seem to be some tendencies:

(1) The behavior of top plate rather shows the similarities in the pattern between 'without pin' data and 'carbon'(:the lightest endpin).

(2) The heavier endpin selected, to the lower area shifts the vibration-center of the top plate slightly, and moreover, the mechanical vibration seems getting integrated along the whole length including the endpin.

エンドピン重量順に測定データを並べてみると、最も軽いカーボンの場合はエンドピンなしのパターンに似ており、エンドピンが重くなると最大振動中心が胴体の下方向へ少し移動して、さらにエンドピンを含めた全身振動にシフトしていくように見受けられる。

31. Vibration intensity [ Measurement 2-3 ]

[ 01/28/2018 ]     Labels: 31..Intensity-TopPlate

Vibration intensity data of cello on the top-plate, tailpiece and endpin were measured using a '8mmD' iron rod (iron alloy rod) endpin. The length of the endpin is 535mm, weight 224g(..rather heavy).

(1) Like as the previous measurements(10mmD endpin), when the tip of endpin is placed on the floor and restricted to vibrate, the vibration intensity/pattern of endpin or tailpiece changes remarkably.

(2) Cello without an endpin vibrates using its whole wood body, however if an endpin is added, the mechanical vibration seems to shift along the whole length including the endpin.

(3) Advanced Endpin Holder(AEH-011) can create the mitigated situation from the alliance vibration of endpin, tailpiece and the floor.

8mmφの鉄(棒)のちょっと重いエンドピンでの振動挙動を調べました。先般の10mmφエンドピンとよく似た傾向。エンドピンなしでは当然チェロ胴体全体で振動しますが、ピンを付けるとピンを含めた全身振動にシフトしているかのようです。
Advance Endpin Holderはこれらの乖離の中間状態を実現しているように見えます。

Device : Vibration meter VB-8205SD
Cello  : 110-year-old German cello
Endpin : 8mm(D) iron alloy rod, 28cm(11in) below tailpin
Data   : 10 data by pizzicato were averaged at each measurement point

81..Advanced Endpin Holder Developer Notes

[ 01/20/2018 ]     Labels:  81.Solution & Study1

[Video :] Moonlight Sonata (by Beethoven) -Youtube free background music-

A1. AEH Instruction Manual

[ 12/30/2017 ]     Labels: A1..AEH

BGM : Piano Y.Kawano 2017

31. Vibration intensity -Measurement 2_2-

[ 12/14/2017 ]     Labels: 31..Intensity-TopPlate

Vibration intensity of cello on the top-plate, tailpiece and (this case -->) carbon endpin:

When the tip of endpin is placed on the floor and restricted to vibrate, the vibration patterns of endpin and tailpiece change remarkably and the vibration intensity increases. As a result, the influence seems to extend over whole cello.
There seems to be some difference between the result from a steel pipe endpin and a carbon-fiber, but this phenomenon probably comes from the essential mechanical/structural issue of the endpin-built-in-cello.
エンドピン材質により若干の違いはあるものの、床置きしてエンドピン先端の振動が止められると、チェロの振動は大きく影響を受けて変化します。

Device : Vibration meter VB-8205SD
Cello  : 110-year-old German cello
Endpin : 10mm(D) carbon, 28cm(11in) below tailpin

82..Cello -Response and Resonance 4-

[ 11/18/2017 ]      Labels:  94.Video & Study

 

This exaggerated simulation suggests a simple and important truth.
The sound speed in the air is far faster than the speed of top-plate vibration. Actually it is probably 100 times or more.
If so, cello's all sound color/quality and even overtones might be created by the top-plate(or body)'s mechanical vibrations rather than acoustic resonance.
Furthermore the top-plate/body reflects the influence from tailpiece, endpin and the floor.
Players encounter poor resonance at rainy day. It will be because the resonance is generated by wood plate.

空気中の音速はチェロの表板の振動速度より遥かに速い。
これは楽器の音色・響き・倍音さえも表板自体が創り出していることを示唆しているように見えます。床やエンドピンの影響も反映されます。
雨の日に響きが悪くなるのはなぜでしょうか。楽器のディメンションや音響構造の話ではなく、単純に響きや音を造るエンジンが木製であることに起因すると考えられます。

BGM: YouTube free sound

82..Cello -Response and Resonance 5-

[ 12/02/2017 ]     Labels:  94.Video & Study

 
Cello takes 10-20 Hz slow swing(/vibration) along its whole-length.

BGM:
Brandenburg Concerto No4-1 BWV1049 - Classical Whimsical by Kevin MacLeod is licensed under a Creative Commons Attribution license (https://creativecommons.org/licenses/by/4.0/)
Source: http://incompetech.com/music/royalty-free/index.html?isrc=USUAN1100303
Artist: http://incompetech.com/ 

31. Vibration intensity -Measurement 2-

[ 11/24/2017 ]     Labels: 31..Intensity-TopPlate

 
Top-plate's vibration intensity was measured again including tailpiece data.

MEMO:
When the tip of endpin is placed on the floor and restricted to vibrate, the influence seems to extend over whole cello. 

(1)Endpin changes its vibration patterns remarkably.
(2)Tailpiece increases its vibration intensity.
(3)Top-plate slightly weakens the vibration in general or shifts to the flat(/even) vibrations at least along the vertical direction.

Device : Vibration meter VB-8205SD
Cello  : 110-year-old German cello
Endpin : 10mm(D) steel pipe, 28cm below tailpin
Data   : each 10 measurements averaged