Hermann Von Helmolhtz: The Acoustics

Hermann Von Helmolhtz: The Acoustics of Speech

Hermann von Helmholtz was a German citizen of mixed European ancestry who developed into a brilliant and broadly knowledgeable scientist. He studied mathematics and made contributions in many areas of science, not the least of which was the study of sound in general and specifically how it applied to human hearing and speaking. He began his experiments with a simple observation that has delighted many children -- and adults -- since bottles have exited. Helmholtz notices that by blowing across the mouth of a glass bottle, he could produce a sound not unlike a human vowel. Even more extraordinarily, he noticed that by changing the amount of liquid in the bottle and using bottles of different size and shape, he was able to alter the pitch and sound of the vowels.

This began his interest in the physics of perception. He conducted research into how humans see and hear, as well, creating many new avenues for exploration with his discoveries and inferences. He also remained quite interested in the physics of sound, particularly sound created by humans and especially the mechanics of producing speech. Eventually, using more sophisticated means than blowing over the tops of bottles, he was able to mechanically reproduce most of the German vowel sounds. He first analyzed the sounds of the vowels, determining how he believed they were produced and the basic pitches required for them. His method for doing this was itself rather ingenious -- using wax to plug his ears so he wouldn't receive any interfering noise, he would listen to the human voice through a series of glass globes hose small ends would be place in the wax. The globes would only vibrate -- that is, resonate with sound, and so pass the vibrations of sound into his ear where he would hear them -- when the speaking voice matched the glass' natural frequency. By knowing the frequency of the glass, Helmholtz could determine the various pitches of the human voice and the resonance that created each vowel.

After determining the resonance of the vowel sounds, Helmholtz set about reproducing them. He was no less clever here than he was in figuring out how to analyze the pitches of human speech. After completing this analysis, he combined the sounds of various combinations of pitchforks until he achieved the same resonance as the human vowel. No one before had ever mechanically reproduced human speech sounds in such a conscious and accurate manner before, nor thought of vowels as purely interactions of different pitches. Helmholtz combined a very objective mind and ear to a fantastic and precise knowledge of the physics of sound in order to develop these reproductions. His knowledge and research into physics was essential to his study, as sound is ultimately a physical phenomenon. But his research into the human biological ability to produce sound was also groundbreaking, proving the breadth of his knowledge and worth as a scientist.