VIDEO ANALYSIS

How to proceed

Once the entire setup was assembled, I was able to start shooting video. In order to obtain the desired videos, it is necessary to obtain the most stable vibration of the reed possible. Adjust the frequency of the strobe to a value very close to a multiple of the vibration frequency of the reed. This proved to be no small challenge with my setup. I found that the most stable average vibration frequency in my setup is between 284 and 286 Hz. However, the reed tends to gradually change its frequency and increase over time over the course of a few seconds. For this reason, I decided to vary the strobe pulse frequency to three different values for each recording: 71, 71.25, 71.5 Hz. These values are a quarter of the values between 284 and 286. My goal was to get as close as possible to a multiple of the reed's frequency and let its instability create the small difference needed to generate the slow-motion effect.

Second Closure

The opening between the blades closes again. This movement is limited. The reduction of the opening from its natural resting position is minimal.

Third Opening

The opening between the blades increases again. This movement is also minimal like that of the previous closing.

End of Cycle

The suction force created by the vacuum between the blades now reaches its maximum intensity and causes the reed to close completely in a new closed phase.

3) Reed #81 - This is a finished reed but played very little. It has an unsymmetrical opening with a defect in the profile of the opening on the left side (in this video). It is an easy reed to play, with a brilliant sound and agile articulation. I find it a little too light for my taste.

Closed pahse

The reed is completely closed. In this situation the air flow does not pass through the reed.

First opening

The elastic forces of the reed push the blades to open again in order to return to the reed's rest position. The inertia of the movement exceeds the rest position by separating the sides of the reed blades.

First Closure

With the reopening of the blades, airflow can pass through the reed and its speed creates a zone of low pressure between the two blades. These are sucked inward and begin to close. The elastic forces of the reed greatly slow the movement and the opening only narrows by a small amount.

Second Opening

The elastic forces are at their peak intensity and push the blades outward creating the maximum opening that can be adjusted during the whole cycle. This opening can be observed up to a third of the entire length of the blades. The deformation at the sides is evident and significant.

More reeds to compare

I selected videos of five different reeds to compare.

To assist me in selecting the quality of the reed in the construction of the reeds I assign each reed a number so that I can trace which tube of cane I used.

1) Reed #7 - This is a reed that is not yet fully polished. It has a tip that is still slightly thick and the threads that control the vibration of the reed have not yet been adjusted. To play now, it is very tiring, tends to be wan and the vibration difficult to control. It has a very good potential as far as sound is concerned, both in color and sound. I expect that once refined it will become a good quality reed.

4) Reed B - This is a reed from another very skilled reed maker. I find it easy to play and balanced with a rich vibration. The sound is a little too bright. Sometimes it is too weak, especially in the high register.

5) Légère M plastic reed - This reed is the Medium model of the Légère plastic reeds. I find it very easy to play, but with a poor sound quality and too immediate a response that makes soft attacks difficult. The dynamic range in the forte is limited. Too weak for the high register.

Using a strobe light, it is not possible to observe the beginning of the vibration. Therefore, to describe the motion, it is necessary to arbitrarily establish a moment of onset. I decided to use the instant in which the opening between the two blades of the reed is completely closed as the beginning of the cycle of vibration. This moment is called closed phase and is easily recognizable, to simplify the observation.

2) Reed #76 - This is an excellent reed that I have already played for quite some time. It has a great sound and intonation. Good dynamic range in the piano. Due to long time use it has lost quality in the forte with smaller dynamics and clunkier articulation.

How the reed vibrates

I have performed several videos with different reeds. I decided to use the following video as a reference of the vibration motion and use it as a model. In this video, the frequency of the reed remained relatively stable for several seconds, which allowed me to get clear shots of its motion.

Reed #81 seen from 45° degree vibrating at 285.1Hz. Stobe Light at 71.25 Hz. Pressure inside the box around 75 mBar.

Shorter version with audio.

Reed #81 seen from 45° degree vibrating at 285.1Hz. Stobe Light at 71.25 Hz. Pressure inside the box around 75 mBar.

Audio removed.

Reed #7, reed #81, reed B and Légère reed side by side comparison. Audio removed.

0.3 speed.

Reed #7  seen from a frontal view. Audio removed

Reed #81 seen from 45° degree vibrating at 285.1Hz. Stobe Light at 71.25 Hz. Pressure inside the box around 75 mBar.

Closed Phase

Reed #76  seen from a frontal view. Audio removed

Reed #81  seen from a frontal view. Audio removed

Légère M plastic reed seen from a frontal view. Audio removed

Reed B  seen from a frontal view. Audio removed

Reed #81 seen from 45° degree vibrating at 285.1Hz. Stobe Light at 71.25 Hz. Pressure inside the box around 75 mBar.

Maximum opening

Reed #81 seen from 45° degree vibrating at 285.1Hz. Stobe Light at 71.25 Hz. Pressure inside the box around 75 mBar.

Only one cicle. HD version. Adudio removed. Slow-motion 0.2x speed.