What's The Difference Between Audio and Midi?
What's The Difference Between Audio and Midi?
So, you’ve opened Ableton, Logic or FL Studio and you face the daunting choice of selecting either a MIDI channel, or an Audio channel to start your track…
… and you’re here… trying to work out the difference.
Let me help by explaining what the difference is between Audio and Midi. Knowing the answer is crucial for any beginner music producer!
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What is a channel?
A channel is something you will find in every DAW. A Digital Audio Workstation (DAW) is a music production software program used by music producers to present audio data in a visual manner. The channel is where the DAW stores the audio data for an individual stream of sound.
An individual stream of sound could be : a vocal, a recorded live instrument, a sample from some form of media, a ready-to-use drum loop, a digital drum, a VST plugin, or any one of a number of sound generating digital items.
Multiple channels can then be layered to allow different streams of sound to play at the same time, which in turn, will form an entire, completed song.
Each channel should be granular enough that different types of sounds can be treated in their own bespoke way during the mixdown stages - allowing an audio engineer to highlight the positive aspects or minimise the negative aspects of each sound.
What is an Audio Channel used for?
An Audio channel is used for storing “Audio” - a type of digital data that is gathered when real sounds are recorded using a microphone.
When recorded audio is displayed you will see a waveform. A wave form is a graphical representation of the sound waves.
Audio recording has been around since the late 1800's, and works through use of a microphone diaphragm (a thin sheet of material stretched tight and attached to vibration sensors) which detects changes in atmospheric pressure (the vibrations we call sounds) and converts this information into digital signals. The resulting output will look like a typical sound wave that most people imagine when they “visualise a sound”
What can an Audio channel do?
Audio is a computers way of interpreting an analogue signal, and it allows a music producer to capture sound information with no limitations on frequency or sound type. Audio can be used to record any sound that can be heard by a human and as such is a useful tool for creating unique songs.
Audio recordings are useful as the information is discrete which means that it does not rely on any specific software to be listened to and as such an audio file can be copied and pasted into one of the channels of your song very quickly and sometimes with minimal need for processing.
Audio also allows for the capturing of spoken dialogue which enables the (very much necessary) recording of vocals, and as the file operates as an independent item, consistent playback quality is offered regardless of the device it is being processed on.
What can an Audio channel not do?
Audio channels offer less control than a MIDI channel - as once the audio is recorded - you’re stuck with it. You can tinker and modify the sound, you can chop and cut it, and you can add effects, however once this is recorded, the only way to truly take the sound back to basics and to have complete control is to re-record it. As such, when recorded sound is modified and edited repeatedly to achieve a clean mix for the song - the quality of the file will slowly degrade, meaning there is a limit to the amount of editing that can be performed before the file requires re-recording.
Processing audio files also takes up a (relatively) large amount of storage space when compared to MIDI as it is a standalone file containing all the information required to produce a sound.
What Hardware do you need to work with Audio?
To record and work with audio, two pieces of hardware are required : a microphone, and the correct cabling to allow it to transfer data to a computer.
Microphones have a vast array of applications and quality levels, as such, there are many different styles and brands - each aiming at different areas of the audio recording market. Examples of different areas of audio capture could be: live vocals, studio vocals, live instruments, and spoken word, such as podcast recording. They can range from models such as the bedroom producer’s standard: Blue Yeti all the way to the Neumann U87 Ai which will set you back rather a few thousand pounds.
Each microphone will then require the correct linking cables to either connect directly to your PC via USB, or through a dedicated Audio receiver via an XLR cable.
What Software do you need to work with Audio?
Microphones do not require any unique software other than the drivers to allow them to communicate with your PC, and as such, with a few tweaks to the digital settings, it is very simple for a producer to record audio into their DAW.
What is a MIDI Channel used for?
MIDI stands for “Musical-Instrument Digital-interface” and it is the type of data created when any MIDI enabled instrument (an instrument which has the right electrical connections to connect and send data to a computer) is used to play and record a melody or drum pattern for a song. Unlike an Audio file, a MIDI file does not contain any sound of its own - it is simply a piece of data that a computer can store.
MIDI data is generated when sensors within an instrument detect tactile information - the force created when something touches something else - which in this case would be the force applied when musician's hands touch a MIDI Keyboard or MIDI Drum-pad. The computer then measures which key on the keyboard or pad on the drum pad was pressed, how hard it was pressed down, and how long it was pressed for.
This information is then recorded into your music production softwares piano roll - meaning all appropriate information about the way the notes were played (note, length, octave, velocity) on the instrument is captured.
Once MIDI notes are stored on the system - a sound (essentially just a short clip of Audio information) can be assigned to each of the notes, allowing the computer to play out the melody the producer created in MIDI, using any Audio-file sound.
What can a MIDI channel do?
Once the “Piano roll” data is captured in MIDI, a producer then has the freedom to modify the played notes - moving them earlier or later in time, increasing or decreasing the length of the notes, moving them up or down octaves, up or down notes, and even completely deleting a re-adding notes using their computer mouse.
MIDI is useful as it is very easy to edit - as even when a MIDI channel has a lot of processing and effects placed upon it, the initial melody can be easily changed without causing issues.
MIDI takes up far less storage space than a whole audio file which reduces load on your computer's RAM, and in general MIDI tracks require less processing to get the sound to an acceptable level (as you will never get background noise or recording issues in a MIDI file)
What can an MIDI channel not do?
The issue with MIDI is that it is very hard to create certain sounds such as vocals or background ambiances, and as such this can very much detract from the realism of the music. An example would be the fact that a digitally created vocal will never take a slight breath between words like a human would, and a MIDI piano roll which is assigned a recorded guitar audio clip may not offer a distinctive resonance or acoustic noises that a real guitar string could offer.
What Hardware do you need to work with MIDI?
If you’re anything like me - you’ll want to keep making music as hassle free as possible - and as such, we’re only going to break down MIDI input devices into three basic categories : drum pads, keyboards and sequencers.
Drum Pads, such as the Novation LaunchPad Pro or Carlsbro CSD130 are tactile data input devices that are triggered to send data to your DAW when you hit either a drum pad or tap a square on a launchpad. Each pad can be pre-programed to either play a one-off short piece of audio, or trigger a continuous audio loop. In the case of the loop, this will commence when the pad is tapped once, and will stop when tapped again. These two methods then allow producers to either use the pads to spice up a production session by tapping out a beat as required, or to trigger loops to turn on and off during a live set to act like phrases in a song. These beats or loops are then recorded in MIDI into your DAW.
MIDI keyboards come in all shapes and sizes and can range from the bedroom producer's standard 25-key Akai MPK Mini (what I use) to the 88-Key Roland A-88 MK2. MIDI keyboards will have a basic piano roll as well as several other modulation dials that can be equipped to control parameters in your DAW in order to give you more control and some variance in your production process. A producer would then need to assign a VST synth plugin to the channel they wish to record a melody into, adjusting parameters as required, arming the correct channel in Ableton, and then setting their Ableton session to record as they play out required melodies.
Along the same lines as drum pads, sequencers act purely as a method of allowing producers to trigger audio clips on and off, however these are individual audio clips and not loops. These clips are played in a repeating pattern along the sequencer (... in a sequence) to generate an on-the-go loop. If the pads are pressed to light up, the sound will play at its point in the sequence, if not, the sound is not triggered to play.
Each of the three MIDI devices above will then need some form of MIDI interface, which is the electrical port that connects the device to your PC. Some devices are plug-and-play USB fed, however others require a standalone audio interface such as the FocusRite Scarlett. This is defined by the type of MIDI controller you use, however there are a vast array of options in the market regardless of what type of device you choose. This ensures you can make music just the way you want.
What Software do you need to work with MIDI?
MIDI instruments require 2 pieces of software to operate. Firstly they require a digital audio workstation in which to record their audio, along with all appropriate drivers for the software to read the data the MIDI device is outputting, and then they require some form of VST plugin or sample pack from which the data they output can be assigned a sound.
How to jump Between the MIDI and Audio
A vital piece of knowledge for any music producer is the ability to move sounds between the worlds of MIDI and Audio to allow for bespoke handling of the processing and mixing stages of any sound.
As required, any MIDI channel can be recorded into audio by opening up a new audio channel in Ableton, and mapping its input (in the channel settings) to come from the output of the MIDI channel you are now finished processing. This audio channel is then armed, and the record button is hit, writing all played midi sounds into an audio clip.
To jump from Audio to MIDI, a producer can right click any Audio loop in their arrangement view, and select “Slice to new MIDI track” before selecting the granularity of their slices. The software then breaks the MIDI clip into up to 32 equal sections and lays them out across a MIDI piano roll in the DAW - with each ~1/32nd of the Audio clip representing a note on the MIDI piano roll.
These MIDI notes can then be moved, duplicated or deleted essentially allowing these micro-sections of your audio clip to be treated like MIDI notes.
As Audio has the major benefit of being able to capture live sounds such as vocals, and MIDI offers the benefit of flexibility to edit the notes in your song throughout the entire production process it is clear that each is useful and holds a valuable spot in the music production medium. Without Audio - we would never hear a singer or get that oh-so-warming streak of an acoustic guitarist moving their fingers up the strings, and without MIDI - the entire recording process for an electronic song would be a nightmarish hellscape of constant re-recording of instruments or riffs every time you decided to make some change to the sound.
Both channel types are clearly valuable and have their own pros and cons, which poses the question : which will you choose to start your next track?
Thanks for reading this informative blog about the difference between audio and midi files! If you're a music producer looking to improve your production skills or learn how to mix and master click here to check out our range of music production courses in London and online.