Many of our clients, simple music fans or professionals in the sector, constantly seek perfection. Some are willing to spend even thousands of euros to assemble a high-quality hi-fi system. Many come to us for advice, and we are happy to accommodate them. First, however, it is good to gain some (really few) insights into the world of music and the media through which we generally hear it.
We will start from the beginning.
Digital music is distributed in many formats. Some are compressed, others are not compressed. However, all files are nothing more than a sequence of bits whose value can be 1 or 0. These bits are grouped into bytes, that is, words of 8 bits each. A series of bytes forms a file or an audio track that we can listen to.
High resolution audio: recording and playback
Once recorded, to be played by us, this digital music file is sent to an analog-to-digital converter (DAC), converted to an analog signal, and finally sent to an output circuit, either a preamplifier or analog output
The quality of the file to be reproduced is given by two factors: resolution and sampling frequency.
Resolution is expressed in bits, while the sampling value is expressed in kilohertz (kHz).
Word length (bit)
= resolution Dynamic range Reproducible tones
12 bit 72 dB 4,096
16 bit (CD) 96 dB 65,536
24-bit (DVD) 144 dB 16,777,216
32 bit 192 dB 4,294,967,296
In simple terms, all this means that the denser the digital information, the closer the “digital” version of the signal gets closer to the original analog signal.
“The highest possible quality is the closest to the original as it was produced.”
For example, if you have digital music on CD in 16 bit / 44.1 kHz, this corresponds to a dynamic range of 96 dB with 65,536 gradations. However, music is rarely written to CD under these conditions, because the recording was originally made in only 16 bits (other recording defects may further reduce the signal).
Today, however, recordings are made at 24-bit / 192 kHz (in part also at 32-bit / 384 kHz), which means that the length of the information is significantly longer (and therefore has a greater dynamic range) and a higher sampling rate thus increasing the bandwidth.
The higher the resolution of the audio file, the higher the sample rate and the better the final audio signal.
Please note that the increase in “information content” resulting from higher resolution / sampling is exponential: consequently, the qualitative difference between a 16-bit audio file and 24-bit recordings could be so subtle that only be perceived by a trained ear and obviously well equipped.
HIGH DEFINITION: COMPRESSED AUDIO FORMATS AND UNCOMPRESSED AUDIO FORMATS
Audio files can be compressed (with or without loss of quality) and uncompressed (without loss of quality).
Some examples:
Uncompressed audio formats
WAV – Waveform Audio File Format (.wav)
AIFF – Audio Interchange File Form (.aiff, .aif or .aifc)
Compressed audio formats (no quality loss)
ALAC: Apple Lossless Audio Codec (.mp4 or .m4a)
FLAC: Lossless Audio Codec (.flac)
Compressed audio formats (with loss of quality)
MP3: MPEG-1 or MPEG-2 Audio Layer III (.mp3)
AAC: Advanced Audio Coding (.aac, .mp4, or .m4a)
To make a “visual” example and clarify the concept, let’s take a photograph: on the left, the original version, in good resolution; On the right, the same photo, saved in compressed format, which reduces its quality:
music in high definition, example of maximum quality
In summary: CDs (compact discs) offered good quality (not maximum) and a certain “portability”, but their capacity was limited.
Mp3 files certainly helped share music over the network, at the price of a substantial loss in terms of playback quality.
HIGH DEFINITION SOUND: A SMALL GLOSSARY TO BETTER UNDERSTAND
Bit rate
The bit rate is the amount of data per second required for a transfer from A to B. The bit rate is always expressed in kilobits (Kbps) or megabits (Mbps) per second. For example, an mp3 plays an audio track from 96 to 320 kbps; a FLAC file can exceed 5000 kbps.
Bit depth (resolution)
This value describes the number of bits recorded in a single audio sample. Therefore, it is equivalent to termination. An example: the quality of a CD (compact disc) supports up to 16 bits; An audio DVD supports up to 24 bits.
