When deciding which set of headphones or earphones you want to buy, you are faced with a seemingly endless number of choices. They uniformly promise great sound quality and come packaged inside of boxes with large numbers written all over them. If you’re a casual buyer limited by the amount of money you are able to spend on headphones, you probably won’t pay much attention to them.
Some audio equipment stores will allow you to test the headphones before purchasing them, which is a benefit you should definitely use. In most cases, though, you will have to buy them based solely on the specifications highlighted on the outer packaging. In this article, we’ll explain what these specs mean and why they should play an important role in deciding the headphones that are best suited for your needs.
A driver is an integral part of every set of headphones – by turning electrical signal into sound pressure (measured in decibels), it effectively produces sound. Driver size (measured in millimeters) indicates the diameter of the woofer surface – the common rule is that the larger the driver, the better the sound.
Because earphones are too small to fit a large driver inside, many manufacturers use the dual driver technology. This means that one ear bud houses two drivers instead of one in order to deliver better sound quality. One driver is in charge of bass, while the other takes care of mid and high frequencies.
Drivers rely heavily on magnets, which facilitate the electromagnetic current that affects the electrical flow delivering the sound waves to the woofers. Different models make use of different types of magnets (ferrite, alnico, samarium cobalt), but neodymium magnets are becoming increasingly popular despite their considerably higher price. Due to neodymium’s inherent qualities, a smaller magnet can be used to deliver the strength equal to that produced by larger magnets made from other materials.
Frequency response denotes the range of frequencies (measured in Hertz) headphones can reproduce. The human audio spectrum is commonly given as 20hz to 20,000hz (although this does vary from person to person): the lower number indicates the amount of bass, while the higher number indicates the amount of treble (highs). Frequency rates lower than 20 hz usually mean your headphones/earphones are better suited for lower frequencies, so all your bass heavy music may sound deeper and richer. Frequency rates higher than 20,000 Hz mean that the headphones will deliver better highers and mid range frequencies, which is great for most genres but especially so for audio books, folk/country music and orchestral music.
Impedance (measured in Ohms) is the resistance of an electric circuit to alternating current. The rule here is that smaller woofers should have higher impedance in order to deliver optimum sound quality. Because they are most commonly used to listen to music on a phone, the majority of earphones today are made with lower impedance (below 32 Ohms), which results in lesser sound quality. Check out this video here for more information.
In simple terms, sensitivity and Sound Pressure Level (SPL) denote how loud your headphones can go. Sensitivity is a measure of the effectiveness with which electrical signal is converted into an acoustic signal. This measure is usually expressed in decibels of SPL per milliwatt (dB SPL/mW).
Most headphones nowadays range from 85 to 120 dB SPL/mW. Another important thing to consider is that the pain threshold for noise is widely considered to be around 120 dB. Furthermore, prolonged exposure to Sound Pressure Levels higher than 85 dB can put you in danger of damaging your hearing.
Before you purchase new headphones, you have to be sure that the connector on your device is the same size as the headphone jack. Most connectors have a diameter of 3.5 millimeters, though older phones used a model with a 2.5 mm diameter. Headphone jacks can go up to 6.5 millimeters in diameter, but you can buy an adapter to make them fit the device you will be using your headphones on.