How Do Singing Bowls "Sing"?
- Nov 23, 2025
- 5 min read
Singing bowls may look simple, but the way they create sound is a surprisingly elegant piece of physics. In this article, we’ll explore how the bowl vibrates, where the mallet actually makes the sound happen, and what’s really going on when a bowl begins to “sing.”
Thrumming, Not Rubbing
To make a singing bowl sing, gently run the mallet around the outside edge of the rim. This motion isn’t really “rubbing,” but called a strike-slip phenomenon that I call Thrumming, As the mallet moves around the bowl’s rim, it briefly sticks to the metal, then slips away, over and over very fast. It's this unique repetitive motion that I call Thrumming and is the action that can make a singing bowl "Sing"
Thrum Transitive Verb Tenses: Thrum, Thumming, Thummed The action of producing sound on a friction idiophone by utilising the stick-slip phenomenon along the objects rim, which generates continuous vibration and sustained tone. Expanded: Thrum refers specifically to the controlled motion used to make instruments like singing bowls “sing,” where a mallet alternately grips and releases the rim in rapid cycles rather than smoothly rubbing it. Example: “I thrum a singing bowl to make it produce a steady, resonant tone.”
What Does "Singing" Look Like To The Bowl?
When a singing bowl “sings,” it vibrates in several patterns at the same time, each producing its own frequency a number of times the bowl’s surface moves in and out per second (these are illustrated below). As you thrum the rim, these vibrations travel through the metal and push against the air around the bowl, creating sound waves with different wavelengths—longer waves for the lower, deeper tones and shorter waves for the higher, shimmering ones. What we hear as the bowl’s rich, resonant “singing” is the blend of these multiple frequencies and wavelengths interacting at once, producing the warm, evolving character that singing bowls are known for.
Where Does The Mallet Go?
When you thrum a singing bowl, the vibration pattern you create doesn’t stay in one place; it actually travels around the rim, following the motion of your mallet. As the mallet grips and releases the metal in rapid stick–slip cycles, it continually re-energizes the same vibration mode. This causes the sound wave; its frequency and wavelength, to move with you, circling the bowl like a ripple that keeps being pushed forward. To a listener, this makes the tone feel alive and slightly shifting, because the bowl’s vibrating shape is literally rotating around its edge as you play.
Understanding The Fundamental Note
A singing bowls' Fundamental Tone is the lowest and typically the loudest frequency it produces when you begin thrumming—the deep base note created by the bowl’s (2,0) vibration mode (See earlier illustrations of modes). This is the most commonly recognised frequency to the listener when you begin thrumming. Different Mallets produce different fundamental notes within a bowl too, a mallet too small would raise the frequency, a mallet too Large would create a much lower bass. The size and shape of the bowls does not guarantee its fundamental note whenever used.
Learning The Bowls Overtones
A spectrograph chart shows sound as a series of vertical lines, each one representing a different frequency. The tallest, strongest line is the fundamental tone—the bowl’s main note. But if you look to the right of that line, you’ll see several smaller lines at higher frequencies. These are the overtones. Each overtone corresponds to a different vibration mode of the bowl, meaning the metal is bending and flexing in additional patterns beyond the main one. On the spectrograph, these overtones appear as evenly spaced or sometimes unevenly spaced lines, stacked higher and higher in frequency. Even if some lines are faint, they still contribute to the bowl’s richness. So, when you listen to a singing bowl, you’re not hearing just one pitch, you’re hearing a whole set of frequencies at once, and the spectrograph below reveals this mix through multiple lines rising from the chart. This layered pattern of lines is what gives a singing bowl its warm, complex, and shimmering sound.
What Do Overtones Look Like?
When a singing bowl produces sound, its rim doesn’t vibrate as one solid piece, it bends and flexes in several patterns at the same time. Each of these patterns is called a vibration mode, and every mode is what the listener would hear as an overtone, or higher-pitched frequency.
In one mode, the rim may bulge outward in a few spots while pulling inward in others, creating alternating high and low points around the bowl. In another mode, there may be more of these bending areas, spaced closer together, causing the rim to flex in a more complex pattern.
As higher overtones are activated through thrumming or striking, these bending shapes become more intricate, with the rim twisting and rippling in finer, faster motion with several of these overtones happening at the same time. What we hear as the bowl’s shimmering, layered sound is actually the metal bending in multiple vibration patterns at once—each overtone adding its own shape to the bowl’s constantly flexing rim.
Authors: Beena S. Limkar a∗ and Gautam S. Chandekar
What Are Double Overtones?
Double overtones occur when a singing bowl produces two overtone frequencies that sit very close together on the spectrograph, almost like a pair of neighboring lines. Because these frequencies are similar but not identical, they interact with each other through constructive and destructive interference; sometimes reinforcing each other and sometimes cancelling out. To the listener, this creates a familiar “wah-wah” sound, a pulsing effect that feels like the tone is breathing. A skilled musician can bring out this double-overtone wobble by using a steady mallet technique and a focused ear, gently adjusting their thrumming technique to emphasize the two modes that sit close enough to beat against each other. This controlled interaction is what gives singing bowls their hypnotic, wave-like shimmer.
The Bowls Note
Even though most of the visible movement happens at the rim of a singing bowl, the entire bowl is actually vibrating when it produces sound. The research shows that different vibration modes, especially the ones involving the bowl’s bottom; send waves of motion through the metal much like ripples spreading across water.
Shared below is a graphical view of some of these deeper vibration patterns, showing how energy travels in curved, circular paths from the rim toward the center, creating repeating peaks and valleys of motion. This is why, when you hold a singing bowl, you can feel it buzzing or pulsing through your fingers: the whole bowl is flexing in complex wavelength patterns, even if only the rim is making the dominant audible tones.
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