Tibetan Singing Bowl in C

There is no single standard diameter. Diameter alone determines neither the note nor the octave; the wall thickness and shape must also be considered, since a thicker bowl produces a higher note, while an open shape produces a lower note than a closed shape. When the size changes, the note may remain the same while the octave shifts. As a general guideline, a hammered metal bowl that produces a low C measures about 22 to 27 cm (8.7 to 10.65 in), compared with about 17 cm (6.7 in) for a C one octave higher. A frosted crystal bowl that produces middle C is often around 30 cm (12 in), while the rarer high C is found at around 20 cm (8 in).

These figures should be viewed as guidelines rather than rules. Size and weight vary from bowl to bowl. Metal bowls sold as C bowls are usually selected for that note from among many others.

You can check your bowl's note with a tuner, but ideally, you should use a spectrum analyser app installed on your phone. First, check whether the note is marked on the bowl or the receipt, either as “do” in solfège, the letter C in letter notation, or the number 1. Then follow these steps to take the measurement:

• Find a quiet room.
• Next, produce a steady sound by gently rubbing the rim, since a single strike may cause the app to display an overtone.
• Repeat the measurement and note the frequency that appears consistently.
• On the spectrum, the fundamental is the first peak from the left. You can then compare it with the frequency of C.

Keep in mind that deviation from the centre of a note is measured in cents. This means that a bowl listed as 20 cents above C or 30 cents below C is still a C. However, the reading remains approximate. A phone's microphone is not a measuring instrument, and a tuner may identify the wrong octave for very low sounds. Finally, this instrument may also produce two different notes depending on whether it is struck or rubbed.

A C bowl is most commonly paired with a G bowl to form a perfect fifth, an interval perceived for centuries as stable and open. Here are other combinations you can create starting with C:

• C, E, and G: These three bowls form a major chord with a bright, pleasant sound.
• Two Cs in different octaves: The note is the same.
• Adjacent notes a tone or semitone apart, such as a C bowl and a D bowl: Together, they produce a darker, more ethereal sound.

However, the bowls must share the same reference pitch for the interval to sound in tune. For example, bowls tuned to A = 440 Hz and those tuned to A = 432 Hz are approximately 32 cents apart. Furthermore, their deviations from the centre of each note must be similar. In other words, if your C is 25 cents sharp, you will also need an E that is 25 cents sharp. Different deviations do not necessarily make a poor combination, but they give it a distinctive character that some people seek.

A hammered metal bowl is not forged to an exact frequency. Therefore, when a bowl is described as tuned to C, it means that its fundamental is close to C rather than exactly centred on it. Achieving a precise note through hand-hammering is extremely difficult, and that is also part of the instrument's richness.

A quartz crystal bowl, on the other hand, holds its note more precisely, although its pitch is likewise determined after it is made.

C is the starting note of the C major scale, the best-known scale, which has no sharps or flats, making it the logical first bowl in a set. The seven bowls in a set follow the seven notes of this scale and span one octave. In a metal singing bowl set arranged this way, C corresponds to the largest bowl—the lowest-pitched one—while B corresponds to the smallest. According to tradition, C is also associated with the root chakra, Muladhara. For general use without a specific purpose, the Instruments du Monde store recommends a singing bowl tuned to C at A = 440 Hz.

You can then gradually expand your set without needing all seven notes. A first bowl close to the centre of its note will give you a clear foundation, making it easier to establish the relationships between notes. You will simply need to listen to each new bowl alongside those you already own.

You can absolutely accompany a voice or another instrument with a C singing bowl, provided that they are all tuned to the same reference pitch.

C is a reference note for singers and pianists and the note used to begin music theory lessons and choir warm-ups. Over a sustained C, you can sing the degrees of the scale one after another and adjust each interval. Simply rub the bowl's rim to sustain the sound. A bowl close to the centre of its note will be better suited to singing or recording. However, metal is less precisely tuned than crystal because of its overtones, so you should listen to your bowl alongside your instrument or voice before getting started.