Organ characteristics

Registers

• Bass Coupler
• Diapason (rear row of reeds)
• Principal (front row of reeds)
• A vibrato knop which is broken off
• Dulcet (front row of reeds)
• Vox Celeste (front and rear rows of reeds)
• Melodia (rear row of reeds)
• Treble Coupler 

Keyboard lay-out

The organ has a 61 keys F keyboard.

Current tuning

After going through all notes I realized that the organ is tuned with a 455 Hz reference instead of 440Hz. This is almost exactly a quarter of a note higher.

When googling "tuning with A4 = 455 Hz", it seems that is has been the standard tuning pitch in England until in 1953 a worldwide standard was defined at A4 = 440 Hz.

Since my organ originates from England, this explains its tuning reference at 455 Hz.

Here a sample from the book "Physics and music"

For several hundred years, the pitch of (the notes of the musical scales has been determined by specifying A4 as the standard of pitch. The frequency of this standard note has varied widely and changed so frequently that no set value could really be called standard.

In Handel's time (1685-1759), A4 was determined by his personal tuning fork, which had a frequency 422.5 Hz. Since the brilliance of string instruments, like the violin family, appears to increase with higher frequencies, the standard A4 gradually went up in value until ar the end of the nineteenth century it had reached 461 Hz in the United States and 455 Hz in England. Since a change in standard pitch imposes major problems on musicians and

instrument manufacturers, a fixed value became more and more essential. Finally in 1953, the International Standards Organization recommended that A4 = 440 Hz be adopted as the standard frequency for music throughout the

world. Unfortunately, not all musicians followed the recommendation, and (here still exist some orchestral groups that tune their instruments to A4 = 442 Hz or A4 = 444 Hz.

Opera singers today are singing Beethoven and Mozart arias about a semitone higher than the pitch for which they were written.’ This necessitates tuning the accompanying string instruments by increasing their string tensions by nearly 12 percent. To do this. some of the violins made by the old Italian masters have had to be strengthened, which means that their tone quality is not the same. 

Some years ago a scientific scale was developed that was based upon C being given by integral powers of the number 2, On this scale, middle c has a frequency of 256 Hz. There are many of such tuning forks still around and

commercially available, and many high school and college science teachers still like middle C at 256 Hz

The standard of pitch for most symphony orchestras today is taken to be A4 = 440 Hz. The oboist usually carries a tuning fork or pitch pipe to sound the correct pitch. The other musicians then tune to the oboe.