CelloStone

Science of CelloStone™

CelloStones are made of two matched natural rock tiles, one cut to either a 10” square or 10” octagon and the other is a 12” square.

The CelloStones are matched so they select and dissipate the specific interfering energy found in a specific cello. The wolf note of the cello is where the interfering energy is audible. We at CelloStone can match cellostones to your cello from a recording of the wolf note.

Cellists normally play on wood, carpet, linoleum, or clay tiles. These substances do not dissipate the energy.  Concrete floors work some but the CelloStone is matched to your cello to dissipate nearly all of the interfering energy of your cello.

A Frequency-Amplitude Graph from a microphone placed about 3 feet (just under a meter) in front of the cello, shows the spectrum of the wolf note of a cello played on a carpeted floor and then the spectrum of the note with the exact same finger position but with the endpin on a CelloStone. 

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The fundamental frequency, the note you are playing, is a double peak when the endpin is on carpet and a single peak when the endpin on a CelloStone.  The double peak is the spectral representation of the characteristic “beating” sound of the note and of the physical stuttering of the bow. CelloStones remove the energy that interferes with the stick-slip motion of the bow giving faster bow response and reducing a feeling of drag on the bow. The spectrums from recordings of the wolf on a wood, tile or carpeted floor, all have the characteristic double peak. Only the CelloStone removes the interfering energy.

All of the string family of instruments suffer with the interfering energy. Though it is not in production at this point in time, a BassBoulder has been tested and will be available in the future. We are looking for a violin or viola luthier to work with on removing the energy from those instruments. Initial experiments show that this is possible.

The CelloStone must work in concert with the endpin and tailpiece of the cello to transmit the interfering energy into the CelloStone. This means that the tailpiece and endpin must allow the energy to travel through them. We have found that some carbon fiber endpins and some brands of tailpieces do not allow the energy to pass through them to the cello. Changing the length of the endpin can change the response of the CelloStone by changing the energy allowed through the endpin. Having more than 1/3 of the total length of the endpin inside the cello will not allow the endpin to transmit the energy to the CelloStone. If the wolf starts to return when the endpin is on the CelloStone, sometimes it can be eliminated by a slight change in endpin length.

If your cello has a tailpiece to endpin system that does not allow the energy to travel to the CelloStone, then the CelloStone is unable to work with your cello.

All wolf suppressors dampen or remove the frequencies of the wolf note. The CelloStone does not. This means that with a CelloStone your cello will resonate the frequencies of the wolf without the interfering frequencies. The frequency–amplitude spectrum shows the wolf note (double peak) overlain by the frequency-amplitude spectrum of the same cello playing the tones right near the wolf (slight lengthening and shortening of the string by rolling the finger). This is why we recommend that all wolf suppressors should be removed from the cello.

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Cellos with permanently attached wolf suppressors will still have the dampening of the voice of the cello though the bow should have smoother feel.

We have recorded the wolf note with the endpin on carpet or rubber mat and then the same note on a CelloStone from a number of cellos. The frequency-amplitude spectrums of the wolf note with the endpin either on carpet or on the CelloStone, show that:

  1. The wolf note in many different cellos, ranging from highest quality modern cellos to plywood or carbon fiber cellos have similar qualities.
  2. The CelloStone removes the double peak of the wolf note in a wide range of cellos.  (note that the tailpiece and endpin must be such as to allow the energy to travel to the CelloStone).

These amplitude spectrums from 9 different cellos, most of which are high end modern cellos, but also represent a student cello, a plywood cello and a carbon fiber cello.

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The slides are arranged:
  1. The amplitude-frequency spectrum of the wolf played with the endpin on carpet or rubber mat
  2. The amplitude-frequency spectrum of the wolf note (same finger location) played with the endpin on a CelloStone
  3. The two spectrum overlaid on each other. (note that the single peak on the CelloStone is at the mathematically correct frequency for the length of the string)

The double peak of the wolf is transformed into a single peak when the endpin is placed on a CelloStone.  This shows that the interfering energy creating the double peak is removed.
A cello’s sound post being loose or out of adjustment, will also cause a “wolf note”, but not from the interfering energy removed by the CelloStone.  This wolf note will not be eliminated by the CelloStone.  The sound post wolf, may be found on the D string as well as the G string.  We at CelloStone can differentiate between the spectrum of a sound post wolf and the spectrum of the normal G string wolf of the cello.

CelloStones are naturally occurring rocks that are cut into 12” tiles at the quarry. The specific type of travertine was chosen for its ability to dissipate the specific interfering energy.  The CelloStone is made of travertine tiles. Modern day travertine occurs in streams such as Havasu Creek near the Grand Canyon and in hot springs such as Mammoth Hot Springs. Each of these environments has a seasonal element which changes the travertine from year to year.

Mammoth Hot Springs
Mammoth Hot Springs
Havasu Falls
Havasu Falls


The travertine for CelloStones was picked with tonal parameters, so they would dissipate the interfering energy.  Each set of tiles is tested and then matched to each other. Each finished CelloStone is then matched to a cello.

The specific parameters that allow the travertine to dissipate the interfering energy are not found in other rocks such as Shale, Slate, Granite, Limestone, Marble and clays. Concrete floors have similar parameters to the CelloStone but the floor is not tuned to the cello. There are a few granites, sandstones and quartzites which could dissipate the energy, but due to mass considerations, they are not practical at this point in time.

Only a few rocks have the ability to dissipate the interfering energy of a cello in a size practical to carry around.