Tuning Fork Quality
The 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 different manufacturers:
- 136.1 Hz (mid-Om) Weighted Tuning Fork
- 256 Hz (note C) Unweighted Tuning Fork
ACCURACY
Biosonics tuning forks are guaranteed an accuracy of +/-0.5. This allows for temperature changes and testing variations.
The Indian tuning forks are guaranteed 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 make 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.
SPECTROGRAM 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
136.1 HZ MID-OM WEIGHTED INDIAN TUNING FORK
Comparison of harmonics and sustain
Both brands of tuning forks display the same 10 frequencies and the sustained pattern for each harmonic is similar.
Conclusion
For this type of tuning fork, the spectrogram 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 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 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
The fundamental tone of the Biosonics fork (256 Hz) has an audible sustain that lasts about 42 seconds.
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 display 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.