What do all of these headphone specs mean and why are they important?
Answer: Headphone specs, like specs on any piece of audio equipment, provide valuable information about how the equipment is built, how it will perform and how it can be used.
Here’s a list that explains the various specs you’re likely to find cited for headphones:
Type – A description such as “closed-back dynamic” or “active noise-cancelling.” This may be the first spec you want to look at when selecting headphones because it indicates the style or function of the headphone.
Driver Diameter – Headphone sound quality depends to a great extent on the size of the diaphragm, which is indicated by the driver diameter: the larger the diameter, the better the sound quality tends to be. Most drivers for earbuds are 13.5–15.4 mm in diameter, with those for canalphones being 8.8–12.5 mm. Over-ear and On-ear headphone drivers lie in the 30–53 mm range.
Magnet – Sound quality can also be improved by the performance of the permanent magnet in the magnetic circuit. These magnets are often made of ferrite or cobalt, although sometimes more exotic material is used for stronger magnets.
Voice Coil – The voice coil fulfills a key role in converting electrical signals into sound. For better sound quality, voice coils are made of a variety of material besides ordinary copper wire, including PCOCC (Pure Copper by Ohno Continuous Casting) and Hi-OFC (a class of oxygen-free copper).
Frequency Response – The range of frequencies that the headphones can reproduce, from the lowest bass frequency to the highest high frequency, expressed as a numeric value. Although the typical audible range is 20–20,000 Hz, inaudible higher frequencies do affect the listening experience.
Maximum Input Power – Maximum input indicates the maximum supported power supply for the headphones, measured in mW. This is the peak instantaneous power that may be supplied. It should not be misunderstood as meaning that headphones rated at 2,500 mW (for example) can be continuously powered at 2,000 mW. Moreover, larger values are not necessarily better. As long as the value matches or exceeds the player’s maximum output value, any value is acceptable.
Sensitivity – The level of sound pressure produced by the headphones in response to a 1 mW signal. Measured in decibels per milliwatt (dB/mW). At a given input volume, headphones with greater sensitivity will produce a louder sound. A difference of 3 dB/mW or more is generally considered audible to most listeners.
Impedance – As a value indicating the degree of headphone electrical resistance, this specification mainly represents the voice coil resistance but also includes cable resistance. Measured in ohms (Ω). Choosing low-impedance headphones for low-voltage portable audio players ensures better efficiency.
Weight – This indicates the weight of the headphones and usually does not include the weight of the cable. This may be an important factor to consider for comfort, especially during extended use.
Cables – Cables come in various thicknesses and lengths to suit different listening needs. Cables are generally made of 99.5% pure copper wire, but for more efficient signal transmission they may be produced with exceptional material such as oxygen-free copper—whether Hi-OFC, PCOCC (Pure Copper by Ohno Continuous Casting, 99.996% pure copper), or other kinds. Additionally, the cable sheath may be cloth-wrapped or constructed of highly elastic elastomer to help prevent tangling and reduce “touch noise” when the cable is touched.
Active Noise Reduction – This is only provided for headphones with active noise-cancelling components. This indicates the amount of noise reduction at certain frequencies. This is measured in dB. Higher numbers indicate more noise reduction.
Connector – Plugs into the headphone jack of AV equipment or portable audio players. Comes in two main formats: standard (6.3 mm) and mini-plug (3.5 mm). Many headphones are equipped with a 3.5 mm mini-plug and include a 6.3 mm adapter.
Accessories Included – This is a list of all the additional items that are included when the headphones are purchased. This may include such things as additional cables, adapters, carrying case, batteries and so on. Checking this list is very important to ensure that you’ll have everything you need to use the headphones the way you intend. For example, if you plan to use the headphones with a professional audio device that has a 6.3 mm input and the headphones are terminated with a 3.5 mm connector, you’ll want to make sure that a 3.5 mm to 6.3 mm adapter is included.
Hopefully this review has given you a better understanding of headphone specs and will help you judge the quality and suitability of your next pair of headphones. If you have specific questions about A-T headphones, feel free to contact our Audio Solutions Department – they’re always here to help.
Check back next week for another “Question of the Week”!