Skip to content
USA and AUSTRALIA customers. Please note there are longer than normal delays with the tracked airmail postal delivery service due to Covid disruption to flights leaving the UK. If you want your order urgently please select UPS or DHL.
USA and AUSTRALIA customers. Please note there are longer than normal delays with the tracked airmail postal delivery service due to Covid disruption to flights leaving the UK. If you want your order urgently please select UPS or DHL.

Tuning Fork Quality

Sound Therapy Shop sells top quality aluminium tuning forks manufactured in America and India.

We have carried out our own tests to compare 2 types of tuning forks from the different manufacturers:

  • 136.1 Hz (mid-Om) weighted tuning fork 
  • 256 Hz (note C) unweighted tuning fork

ACCURACY

Biosonics tuning forks are guaranteed to an accuracy of +/-0.5.  This allows for temperature changes and testing variations.

The Indian tuning forks are guaranteed to an accuracy of +/-0.25%

We have found that both makes of fork normally fall within the accuracy range of +/-0.25%

Testing Results

Mid Om forks - both makes tested as exactly 136 Hz which is accurate to 0.07%

Unweighted C tuning forks (256Hz) - Biosonics tested as 256 Hz (spot on) and Indian fork to 256.5 Hz so the accuracy was 0.18%. This is within the guaranteed range. 

SPECTOGRAM COMPARISON: MID-OM WEIGHTED TUNING FORKS

The forks were tapped using the same mallet at similar velocities and held in a similar position close to the microphone of an iPhone 12 Pro, one minute apart, thereby maintaining similar environmental conditions.

HARMONICS

The 2 images below provide a comparison of the harmonics of the 2 types of tuning forks.  The harmonics are shown by the thin white lines in each image.

136.1 Hz MID-OM WEIGHTED AMERICAN (BIOSONICS) TUNING FORK

OM weighted Biosonic tuning fork

136.1 Hz MID-OM WEIGHTED INDIAN TUNING FORK

OM weighted tuning fork India

Comparison of harmonics and sustain:

Both brands of tuning forks display the same 10 frequencies and the sustain pattern for each harmonic is similar.

Conclusion:

For this type of tuning fork the spectogram comparison shows that there is little difference between the two brands of tuning forks.

 

SPECTOGRAM COMPARISON: 256 Hz UNWEIGHTED TUNING FORKS

The tuning forks were tapped using the same mallet at similar velocities and held in a similar position close to the microphone of an iPhone 12 Pro, one minute apart, thereby maintaining similar environmental conditions.

HARMONICS

The 2 images below provide a comparison of the harmonics of the 2 types of tuning forks.  The harmonics are shown by the thin white lines in each image.

256 Hz UNWEIGHTED AMERICAN (BIOSONICS) TUNING FORK

256 Hz unweighted biosonic tuning fork

256 Hz UNWEIGHTED INDIAN TUNING FORK

256 Hz unweighted Indian tuning fork

Results: 

The Indian tuning fork displays more harmonics - 9 harmonics with the Indian tuning fork compared to 7 harmonics with the Biosonic tuning fork.

3 of the higher harmonics of the Biosonics tuning fork are shown to be more audible with a greater amplitude and to have a longer sustain than the Indian tuning fork.

SUSTAIN

Audible sound:

We tested how long each fork could be heard after activation.

Mid Om forks:- Biosonics: 48 seconds and Indian: 39 seconds

Unweighted C fork:- Biosoncis 42 seconds and Indian: 32 seconds

Felt Vibration:

We tested how long the vibration of each mid-Ohm tuning fork could be felt after activation.

Each fork was activated and placed on Jane's sternum and timed to discover at what point the vibration died away.

The felt vibration of the Biosonic tuning fork lasted 18 seconds, while the Indian tuning fork lasted 14 seconds.

The 2 images below provide a comparison of the length of sustain of the 2 types of unweighted tuning forks using a spectrogram analysis - see the lowest thin white line.

256 Hz UNWEIGHTED AMERICAN (BIOSONICS) TUNING FORK

256 Hz unweighted biosonic tuning fork 

The fundamental tone of the Biosonics fork (256 Hz) has an audible sustain that lasts about 42 seconds.

256 Hz UNWEIGHTED INDIAN TUNING FORK

256 Hz unweighted Indian tuning fork

The fundamental tone of the Indian fork (256 Hz) has an audible sustain that lasts about 32 seconds.

OVERALL CONCLUSIONS

Both makes of tuning forks had a high level of accuracy.

The harmonics are similar in both makes. 

There are slightly more harmonics in the Indian tuning fork.  However the American tuning forks displays a slightly higher amplitude (louder sound) of audible harmonics.

The main difference we found is in the sustain which is longer in the Biosonics tuning forks. This is in both audible sound (approximately 10 seconds longer) and felt vibration (4 seconds longer).

The Indian tuning forks perform very well compared to Biosonics.   We have been using Indian forks successfully for ten years and they are great value.  There is a wide range of tuning forks available.

Biosonics tuning forks are a premium product and they do have the edge in terms of sustained note and a higher amplitude of audible harmonics.