Equal temperament and just intonation are two distinct tuning systems employed in music. The equal temperament system divides the octave into twelve equal parts, which results in all notes being slightly out of tune with their natural harmonics. This system was developed for keyboard instruments such as the piano, which can be played equally well in any key. On the other hand, just intonation employs pure intervals based on the natural harmonics of a note. This system produces smooth and pure chords but necessitates tuning the instrument for a specific key. Just intonation is frequently used by ensembles like orchestras and choirs, where players match pitch with one another "by ear."

In contrast, equal temperament produces rough-sounding intervals because the notes are slightly out of tune with their natural harmonics. Just intonation, however, results in pure and smooth chords, but it can sound out of tune when playing melodies in different keys. Just intonation is a more "pure" way of tuning that employs small whole number ratios to determine the intervals between notes. This produces a more spontaneous pitch space in music that can be advantageous for certain musical styles.

Singing bowls can be purchased in either equal temperament or just intonation, depending on the desired sound. Singing bowls tuned to just intonation offer greater timbral and sonic possibilities, producing smooth and pure chords based on the natural harmonics of a note. This can create a more harmonious and therapeutic sound that reduces heartbeat, improves focus, and uplifts the mind to a higher consciousness.
In contrast, modern Western music commonly employs equal temperament, which allows for playing in any key but sacrifices the purity of the intervals. Singing bowls in equal temperament tuning may not be marketed as such, but they may produce rough-sounding intervals to the attentive ear. If you have a musical ear, there is a slight chance you may be able to discern the difference between just intonation and equal temperament by listening to the sound of the singing bowls. To determine if a singing bowl set is tuned to just intonation or equal temperament, you can consult the product description or inquire with the manufacturer or seller. Singing bowls tuned to just intonation are often marketed as such and may have a C note based on either 440hz or 432hz tuning.

Choosing between equal temperament and just intonation depends on the context and desired sound. If you seek a more pure and harmonious sound, just intonation may be the preferable choice. If you require flexibility and the ability to play with numerous styles of instruments, equal temperament may be the better option. It's important to choose a singing bowl set that produces the desired sound and fits the intended musical context.
The most popular alternative tuning systems for singing bowls are based on specific frequencies and tones. Quartz crystal singing bowls are typically very specific in frequency, making it simple to construct mathematically harmonized sets based on the frequency. Singing bowls can be tuned to specific notes and arranged using either equal temperament or just intonation, which employs pure intervals based on the natural harmonics of a note.

Crystal singing bowls are known for producing pleasing and comfortable sounds, and specific intervals are often used to achieve this effect. Some of the most commonly used intervals in crystal singing bowls include unison, perfect fourths, and perfect fifths. However, the tuning of the bowls can also greatly impact the perceived pleasantness of these intervals, as different tunings can produce varying emotional and therapeutic effects. For instance, some people prefer the 432Hz tuning, which is believed to be more in tune with the natural harmonics of the universe, over the standard 440Hz tuning. Ultimately, the choice of interval for crystal singing bowl notes depends on personal preference and the desired musical and therapeutic effects, and there is no one-size-fits-all solution for achieving the most pleasant sounds.

The perfect fifth is the most popular interval purchased in crystal singing bowls. For beginners, it's recommended to select bowls with natural harmonic intervals that blend well together, and the perfect fifth is a popular choice. In Crystal Vibes' frosted or Empyrean style bowls, the ideal example of the perfect fifth is the 14” C-10” G note and size combination. The perfect fifth is a musical interval that is seven semitones above the root note and is considered to be one of the most consonant and harmonious intervals in music. It's also commonly used in guitar chords and vocal harmonies. However, crystal singing bowls are available in different scales or tuning concepts, which include various frequencies and tones. Additionally, the size of the bowl corresponds to its pitch, with larger bowls producing lower pitches and smaller bowls producing higher pitches.

The Frosted or Empyrean bowls come in different sizes, and each size has certain notes that are best suited for it. The notes follow a scale, starting with the largest bowl which is the 14" C note in the 4th octave, and ending with the 7" C note in the 5th octave, completing the octave in whole notes. The sizes and corresponding notes are: 14" C, 13" D, 12" E, 11" F, 10" G, 9" A, 8" B, and 7" C. The sharp notes also follow this order, with the 14" C#, 13" D#, 11" F#, 10" G#, 9" A#, and 7" or 6" C#. By arranging the bowls in this way, a player can create a set that covers all 12 tones of the 12-tone equal temperament using the following notes: 14" C, 14" C#, 13" D, 13" D#, 12" E, 11" F, 11" F#, 10" G, 10" G#, 9" A, 9" A#, 8" B, and 7" C.
A harmonic set of crystal singing bowls typically includes 2-5 bowls that are specifically tuned to notes and intervals that complement each other and produce harmonious sounds. A great starter set for beginners could include a 14" C, 12" E, and 10" G bowl, as these notes are in a harmonic relationship with each other. Additional bowls that are also in harmonic relationship with these notes can be added to the set to create a more diverse range of sounds. Ultimately, the choice of which notes to add to a crystal singing bowl set will depend on personal preference and the desired musical and therapeutic effects. For instance, one could complement the existing G bowl in the 4th octave with a 14" G note in the 3rd octave frosted quartz crystal singing bowl. Adding a 5th octave C bowl would also complete an octave with the 14” 4th octave C note bowl.

In conclusion, the choice of tuning system for singing bowls can greatly impact the sound, emotional response, and therapeutic effects that they produce. Just intonation and equal temperament are two distinct tuning systems commonly used in music, with just intonation producing smooth and pure chords based on the natural harmonics of a note, and equal temperament allowing for flexibility and the ability to play in any key. Singing bowls can be purchased in either tuning system, with just intonation offering greater timbral and sonic possibilities and a more harmonious and therapeutic sound. Crystal singing bowls are popular for producing pleasing and comfortable sounds, and specific intervals like the perfect fifth are commonly used. The choice of interval and tuning system for crystal singing bowls ultimately depends on personal preference and the desired musical and therapeutic effects, and selecting a set that produces the desired sound and fits the intended musical context is crucial.