What note is my gong?

Pluck a guitar string and it makes a low tone, plus quieter tones at exactly 2, 3, 4 and 5 times that frequency. Because they line up so neatly, the ear joins them into one note.

A gong is a plate of metal, not a string. It also makes many tones, but they sit at uneven distances from each other: perhaps 1.5 times the lowest, then 2.1, then 2.6. The figures differ from gong to gong. They do not line up, so the ear does not join them. You hear several pitches at once, and a shimmer on top.

The separate tones are called partials. When they line up in whole numbers they are called harmonics. A gong has partials. It does not have harmonics.

Not every gong is like this. Gongs with a raised dome in the middle, such as those of Thailand and Java, are made to sound one clear note. Large flat gongs, often called tam-tams or symphonic gongs, are not.

With a large flat gong the sound is not finished when the mallet leaves it. The low tones come first. Over the next second or two the high shimmer builds, as the metal passes energy from its slow movements to its fast ones. A reading taken just after the strike and one taken three seconds later will differ. Both are right.

A tuner looks for a pattern that repeats, and reports how fast it repeats. With a string that gives the note. With a gong there may be no clean pattern, or the pattern the tuner finds may repeat at a speed that matches none of the tones in the sound.

This site tested a single-pitch method of that kind on a modelled metal bowl whose lowest tone was 200 Hz. It reported 68 Hz, steadily. There was no 68 Hz in the sound. That is why the analyzer has a separate way of listening for gongs and bowls.

1. Open the Frequency Analyzer on a phone or laptop and choose Gong or bowl.
2. Find a quiet room. Put the device about an arm’s length from the gong.
3. Allow the microphone when the browser asks.
4. Strike the gong gently, in the place you usually strike it. Let it ring.
5. The analyzer lists the strongest tones, each with its frequency, its nearest note, and how far it is from that note in cents. Press Hold to keep the list.
6. Strike again, a little harder, and then near the edge. Watch which tones grow.

The lowest strong tone is the one makers usually mean when they name a gong’s pitch. The others are what make it sound like your gong and no other.

• Hear the interval inside your gong. Put the two strongest tones into Compare two tones. It names the interval between them and plays them together.
• Choose a second gong or a bowl. Compare your gong’s lowest tone with the pitch of the instrument you are thinking of buying. An octave, a fifth or a fourth will sound settled. Two tones a few hertz apart will pulse.
• Keep a record. Save the reading. If the gong is ever damaged or retuned, you will know what it was.

Paiste states a lowest tone for each of its planet gongs. For most of them it is the tone in Cousto’s tables one octave lower, which means half the frequency: the Earth gong’s lowest tone is 68.05 Hz, and the tone in the table is 136.10 Hz. They are the same note. Pluto and Chiron are the exceptions: Paiste’s pitch for them differs from Cousto’s current table. Your analyzer reading for the lowest strong tone should be close to the figure here.

Where those numbers come from is explained in Planet gongs explained.

A metal singing bowl behaves like a small gong in this respect: its tones sit at uneven distances, and a tuner can be fooled by it in the same way. Bowls also tend to beat. A hand-made bowl is not perfectly even, so it makes pairs of tones a few hertz apart, and the ear hears each pair as one tone that slowly pulses.

A quartz “crystal” bowl is different. Its sound is close to a single pure tone, and a tuner reads it well. For a crystal bowl, use the analyzer’s Single note view.