CD Quality Music?
I remember that I used my cd player to play CDs when I was a student. Now, CD became old legacy and most people enjoy a streaming service such as Spotify, Apple Music, TIDAL, and etc.
Like I mentioned on previous post, Apple Music started their streaming service with lossless music. I think that people will start enjoying to listen high quality music and the market will be bigger.
So, what is a relationship between lossless music and CD quality?
Apple Music’s lossless audio ranges from 16-bit/44.1 kHz (CD Quality) up to 24-bit/192 kHz. CD Quality indicates that the audio has been recorded in 16 bit-depth and 44.1 kHz sample rate. Now, I would like to talk about the sample rate and bit-depth.
In digital audio, the sample rate describes how many samples are sampled in one second. If the sample rate is 44.1 kHz, for example, the audio is sampled 44,100 times per second during recording. But, Why does CD use 44.1 kHz sample rate? This can be related to the Nyquist theorem. The theorem indicates that the sampling frequency must be greater than twice the maximum frequency. Many people are aware that the human hearing range is from 20 Hz to 20 kHz, so the sampling rate had to be greater than 40 kHz.
How about bit-depth?
Bit depth is the number of bits of information (0 or 1 ) in each sample, and it directly corresponds to the resolution of each sample. So, if the bit-depth is 16, 16 bits are used in one sample. If the audio file has a higher bit-depth, the resolution is higher. Also, we can calculate the dynamic range of the audio from the bit-depth. The dynamic range describes the difference between the quietest and the loudest volume and the equation is 20 * log10(2¹⁶), which is approximately 96 dB.
Reference: Apple Music, Adobe, Wikipedia