Introduction to Music Production 2 – Audio
As a music producer, understanding the fundamentals of audio, both analog and digital, is extremely important for a greater chance of success. There are great difference between analog and digital sound that must be addressed.
Analog audio is usually seen as a ‘pure’ form of sound because the waves are ‘smooth’ compared to digital recordings. To record and play back true analog forms of audio (vinyl records, tapes, and older forms), mechanical devices are required (record players, tape players, and others). In analog, the only limitation on quality is the quality of the devices doing the recording and playback. Unfortunately, with analog, it is possible to get noise generated by dust, electrical circuits, and poor equipment maintenance.
Photo Credit: Klipsch
The photo above, comparing digital and analog waves, may not make sense just yet. Digital audio, unlike analog, is made up of bits. You may have seen the term ‘sample rate.’ A sample rate is the speed at which samples are played to generate sound. For instance, a typical CD quality WAV file has a sample rate of 44,100 kHz. This means there are 44,100 samples played per second. Each one of those little boxes in the above digital wave image is a sample. Each sample has what is called a ‘bit depth.’ This is the amount of information each sample can hold. A typical CD quality bit depth is 16 bits. This means there are 16 spots for information per sample.
Let’s do some math! If a sound clip is 1 minute long (60 seconds), 16 bit, and 44.1 kHz, we can decipher the file size! There are 8 bits in a byte, and memory is measured in bytes. (16 x 44,100 x 60) / 8 = 5,292,000 bytes (5.292 MB).
To get sound from a physical medium to a digital one, you need an Analog to Digital Converter (ADC). An ADC processes the analog waves into digital samples. On the other hand, when you need to hear audio, (for instance, you created a song on the computer, but you want to hear it), you need a DAC (Digital Analog Converter). A DAC performs the operation of interpreting the information from digital samples into driving a speaker.
To record audio, you’ll need to use an audio interface. Interfaces usually contain both ADCs and DACs, which are necessary for both recording and audio playback. These devices will contain much higher quality sound cards than the ones typically found in computers, and they will have the industry standard inputs and outputs. They will likely be able to handle higher sample rates and bit depths, also.
Common cables and Inputs/Outputs
1/4 inch TRS (Tip Ring Sleeve) and TS (Tip Sleeve) – usually used for instruments, speakers, patch cables, headphones, and other applications
3.55 millimeter TRS and TS – usually used for headphones
XLR – usually used for microphones and speakers
S/PDIF – high fidelity digital audio
Optical – high fidelity digital audio