Chapter 3.1: The Hosepipe Horn

Testing the Horn

The concept of a hosepipe horn is not a new one. It has long been used as an educational tool, particularly in demonstrations designed to introduce young children to musical instrument construction. During the global COVID-19 pandemic, many videos and online resources highlighted home-made instruments like the hosepipe horn as an accessible and engaging way for children to experiment with music. Additionally, musicians and educators have used hosepipe horns to illustrate the physics of sound production and the harmonic series. One of the key advantages of using a hosepipe is its affordability, making it a practical option for projects involving multiple participants.

As part of my research, I carefully charted the required lengths of tubing for each horn key to determine how long the hose should be to approximate the sound of a horn in F1. My primary concern was whether the resonant quality of the hosepipe would allow for accurate harmonic vibrations, as it lacks the structural and material properties of a traditional brass instrument. Unlike metal tubing, which is designed to enhance resonance and projection, a hosepipe might not produce the same level of clarity and tonal stability.

To put this concept to the test, I constructed my own version of a hosepipe horn. I spent some time ensuring it was cut to the correct length and, most importantly, capable of producing sound. I gathered insights from several educational videos by the Orchestra of the Age of Enlightenment2, the London Mozart Players3, and the Atlanta Symphony Orchestra4, where musicians demonstrated how to create a horn from simple tubing. Based on my findings, I determined that for the horn to approximate the key of F—the key most familiar to the students—it needed to be 3.7 meters in length. I purchased a small hose from a local hardware store, cut a 3.7-meter section, and attached a funnel as a makeshift bell. To connect my mouthpiece to the hose, I had to buy a narrower tube to serve as an adapter. While this extra step added some complexity, it ultimately improved the playability by making the instrument more comfortable to hold and blow into.

Upon testing the harmonic series, I observed an unexpected phenomenon. While the upper harmonics sounded as anticipated, the lower harmonics seemed to align more closely with a horn in E rather than F. This discrepancy left me questioning whether the issue stemmed from the bell's dimensions or the fact that the tubing remained cylindrical rather than conical. In a traditional brass instrument, the gradual flare of the tubing significantly impacts tone production, resonance, and tuning. The lack of this flaring in my hosepipe horn may have contributed to the unusual harmonic behavior. Despite these uncertainties, the instrument successfully produced sound—albeit quieter than expected. I suspect this was due to the thickness and material composition of the hose, which likely absorbed some of the sound energy rather than amplifying it as brass does.

When preparing hosepipe horns for my students, I was concerned that the lower-than-expected harmonics might create confusion. To mitigate this, I made a strategic adjustment by slightly shortening their tubes. This modification helped align the harmonic series more closely with their expectations, particularly since their repertoire emphasized lower notes rather than higher ones. The adjustment proved effective, as the students were less distracted by tuning inconsistencies and more able to focus on playing comfortably.

Overall, this experiment reinforced the importance of material properties and instrument design in sound production. While a hosepipe horn is a fun and cost-effective way to explore musical acoustics, its limitations highlight the critical role that structure, resonance, and shape play in traditional brass instruments.