With the wealth of options in music, podcasts, gaming, and online content, most people find themselves wearing headphones for several hours each week. If you are thinking about buying a new pair for the holidays, the array of choices may be overwhelming. As a professional musician and professor of music technology who explores acoustics, I delve into how scientific, artistic, and human elements intertwine in sound. Selecting the best headphones requires attention to all these factors. So, what defines a great set of headphones?
In physics, sound is comprised of air vibrations that create patterns of high and low pressure, known as sound wave cycles. Measuring the number of these cycles per second determines the sound’s frequency, or pitch – higher frequencies correspond to higher pitches. Frequencies are expressed in hertz; for instance, a 500 Hz sound completes 500 cycles of alternating pressures each second. The amplitude, which denotes loudness, is influenced by the wave’s peak pressure levels: Greater pressure results in louder sounds. Headphones convert electrical signals into cycles of pressure, which ears perceive as sound.
Human hearing is remarkably sensitive, allowing us to detect a broad spectrum of pitches and sound intensities. But how do our ears function? Once sound enters the ear, the eardrum converts air vibrations into mechanical vibrations in the middle ear bones. These become fluid vibrations in the inner ear. The sensitive nerves then transform these into electrical signals that the brain interprets as sound. Although humans can hear from about 20 Hz to 20,000 Hz, we’re not uniformly sensitive across all frequencies. For instance, a low rumble and high-pitched bird sound may be equally loud, yet the rumble will seem quieter. Typically, our ears are more sensitive to mid-range frequencies than to extreme pitches, possibly due to evolutionary influences. While most aren’t aware of these nuances, headphone designers must consider perceptual differences beyond the physics of sound.
Headphones, whether large over-ear models or tiny earbuds, serve as small speakers, converting electrical signals from devices into air vibrations. Speakers usually consist of four parts: a stationary magnet, a wire coil that moves around it, a diaphragm to push air, and suspension for diaphragm support. According to electromagnetic principles, altering the current in a wire coil changes its magnetic field. When headphone wires carry the audio signal, this moves the magnet, which in turn moves the diaphragm like a plunger, creating pressure pulses—the sounds you hear.
In an ideal world, speakers would precisely convert electrical inputs into perfect sound outputs. Realistically, factors like the magnet and diaphragm size and material cause distortion, altering perceived loudness or softness. No headphones can flawlessly recreate the original signal, and different designs distort signals in unique ways. Even similarly priced headphones may sound different because of varying distortion techniques. Engineers must consider the distortion inherent in human hearing and speaker limitations when designing headphones. The listener’s preferences ultimately play a crucial role in what makes headphones “good.” Factors such as age, listening experience, cultural backgrounds, and musical preferences influence favored frequency distortions. Headphones cater as much to personal taste as to technical requirements.
For instance, people who enjoy hip-hop might prefer bass-heavy headphones, whereas classical music enthusiasts might seek fewer distortions. Beyond music preferences, practical considerations matter as well. Headphones for hearing impairment might emphasize frequencies from 1,000 Hz to 5,000 Hz to enhance speech clarity. You can play hip-hop through hearing-impaired headphones, but they likely won’t deliver the best sound quality. Selecting headphones that suit your intended use is key to ensuring an enjoyable listening experience.