How to select your music system ------ Pt I– A Basic Overview
Firstly id like to brush with some Fundas of Sound. Sound travels in waves and hence has to basic properties i.e. Frequency and Amplitude.
Frequency is related to pitch and tones and the range of sonic frequency which the human ear (the best ears ) can interpret to our brain is from 20Hz to 20, 000 Hz (20KHz) dogs , cats and most animals can go still higher. At very low frequencies (bass) below 60Hz the sound is also “felt” .
Amplitude is the loudness of the sound. Now the human ear responds logarithmically to the loudness hence measurement references are in decibel (dB) units .Now the threshold of hearing is referred to 0dB (ideally)and the threshold of pain is around 120 dB – which essentially means that if you are placed in an absolute quiet room you will hear a pin drop (about 2dB) and upto an aircraft takeoff from 100mts (about 120db), that means we can ideally have a range of 120 dB (referred as dynamic range or headroom of 120 db) – if you have a background sound or noise absolutely quiet as much as background sound or noise exits this will reduce headroom levels.
Now along with loudness there shud be clarity and the amount of clarity in which an amplifier reproduces is the distortion figure which mostly in amplifiers is referred as THD (Total Harmonic Distortion) percent, the human ear generally detects over upto 1% THD, although other types of sound distortions occur but are beyond the scope of this basics.
Ideally a music system then must
(a) Reproduce frequencies between 20Hz to 20 Khz equally, which means a tech spec – frequency response = 20Hz to 20 Khz flat , most end manage 45hz to 20Khz (some even from 20Hz !) . Psychological studies have shown that for an average music listener a response from 60 Hz to 16Khz would generally suffice .
(b) Power – the most important word .Now how much loudness you require will depend on how much headroom you require (maybe enough to tell the neighbors that you rule the world !!) . Most reputed manufacturer will quote the amplifier output in RMS (Root Mean Square) watts, please do not go by PMPO (peak music power output) as there is no standard of such calculation and the result is a multiplication factor of marketing the product.
Irrespective of the tech specs rating and price of the system the ultimate test is audition , your ears have to listen the system .Happy listening );