Technical Specifications stated on Noise Isolating Earphones, and in fact all earphones, serve to differentiate themselves to the well-informed consumer ... and confuse the rest. So today, I will seek to explain the terms used by earphone manufacturers, so that you can become one of the well-informed consumers.
1) Frequency Response: This describes the range of frequencies that a earphone is able to reproduce. For example, if it says 30 Hz to 10 kHz, it means that the earphone can reproduce sounds that are in the frequency range of 30 Hz to 10 kHz.
What It Means to You: The human hearing range is generally around 20 Hz to 20 kHz. Therefore, you may want to find earphones that have that Frequency Response range at least. However, it is interesting to note that some earphones actually go way overboard and offer Frequency Response ranges of 10 Hz to 100 kHz. This is because some audiophiles claim that even though we cannot hear the sound that is out of our hearing range, it still enhances the music that we can hear.
2) Impedance: This is the resistance of the earphones (think electrical resistance), and is measured in Ohms. Basically, based on the mathematical equation of 'Power = Current X Resistance', a earphone with a higher Impedance value would have a smaller current flowing through it, compared to a earphone with lower impedance value, if the same amount of power was supplied to them.
What It Means to You: You should look for the highest Impedance values possible, as earphones with higher Impedance values are generally able to give higher quality music. However, the limiting factor here is whether your music will be audible to you. The smaller current flowing through high impedance earphones would mean that softer sound is produced. Buy earphones with too high impedance, and you cannot hear your music! A good guide would be to choose earphones below 100 ohms of impedance. (However, if you are going to use your headphones in the studio, it is a different story. Find headphones that have the same impedance as your amplifier that you are going to pluck into, or you will get echoing sounds.)
3) Signal to Noise Ratio: Ok this is an easy one to understand. It is a measure of the strength of the useful signal (your music) over the rubbish signals (noise) that are generated from connections, conversions, etc., and is measured in decibels. Based on the mathematical formula 'Ratio = 10 log 10 (Power of Signal / Power of Noise)', if your Signal and Noise have the same Power, you will get 0 dB. If the Power of the Signal is ten times the Power of the Noise, then you will get 10 dB.
What It Means to You: Simple. Find the earphones with the highest Signal to Noise Ratio.
4) Sensitivity / Sound Pressure Level (SPL): This is also an easy one. The Sensitivity is quoted in Decibels, and will something like '100 dB SPL/mW at 1 kHz'. This means that when 1 microWatt of power is passed to the earphone, it can produce a 1 kiloHertz musical note at 100 Decibels loudness.
What It Means to You: You should look for a high Sensitivity value for your earphone. This is because for the same power, it can produce a louder sound, thus saving you precious battery power.
Ok, I hope I have made you a better informed consumer, so that you can choose Noise Isolating Earphones that would be suitable for you. Do note that the terms listed here are the more common ones.
This article was extracted from my website: http://earphonesnoiseisolating.com
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