What is Aftertouch on a synth?
The expressiveness of the keyboard is its way of reciprocating to a certain change from its normal functions. A keyboard is capable of using melodious sound by itself but with the addition of a synthesizer it can create music which is out of the box. The variations and twists incorporated to model the expressions produced by the keyboard is a remarkable leap in the music industry. The changes can be of three types:
Sensitivity to velocity: – Changes made to how fast the keys of the keyboard are struck.
Sensitivity to pressure: – Also known as Aftertouch, depicts the pressure exerted on the keys to create modulations.
Sensitivity to displacement: – To what depth the keys are pressed in order to create variations.
Clavichords and some professional keyboards are Aftertouch sensitive whereas acoustic pianos are velocity sensitive and pipe organs are displacement sensitive. Aftertouch on Synthesizer keyboards, composed of keys, are difficult when it comes to portraying expressiveness but some professional and new aged keyboards have this quality of Aftertouch which sets them apart from others.
What is Aftertouch?
Aftertouch in a way is a sensation which can be noticed once the key is depressed. It is basically triggered once a key is struck and then the associated filter is applied to it. Volume, vibrato, tone, pitch and other expressions can be controlled with the help of Aftertouch feature in synthesizers.Intonations can also be adjusted with the help of Aftertouch. This pressure sensing feature on the synthesizer has the versatility to change and customize music according to the needs of the player. By making modifications and deciding the amount of pressure required, voice modulations can be performed. With a customizable interface and editable format, Aftertouch has changed the face of recording and creating music.
Types of Aftertouch
Aftertouch produces MIDI control signals and the output depends upon the intensity with which the key is struck.
There are two types in which Aftertouch can be divided:
Channel Aftertouch: In this no special treatment is given to particular keys on a keyboard. The same amount of pressure is distributed throughout or to a subset of keys. It is the most common type of Aftertouch and produces a MIDI signal when the keys are pressed.
Polyphonic Aftertouch: This is a much more sophisticated and customizable form of Aftertouch. Each key has its own sensor which creates a different expression for keys when pressed down. The sensors involved identify if the key is pressed or not.
What is Aftertouch On A Midi Keyboard Synthesizer
The CS80– was the first synthesizer, introduced in the 70’s, facilitated with the Aftertouch feature. This synthesizer by Yamaha was so powerful in its own way that it could create an unbeatable experience. Featuring the polyphonic Aftertouch, CS-80 could apply filter on a single key even if multiple keys were pressed down. This vintage synthesizer could easily go for a prize of 10,000$ even today.
The Yamaha GX-1– keyboard creates a side to side motion in order to create the Aftertouch effect. This motion can be used to invoke vibrato. Aftertouch keyboards have a thin strip underneath it imparting the variations to the tones depending on which keys are struck and how.
The Yamaha EX-5- is a highly sophisticated and customizable synthesizer with the best features available. With the availability of pressure sensitivity it enables the player to pick and choose the effect that suits the music the best. Another unbelievable feature of this synthesizer is its versatility; it can replicate many non keyboard instruments like an electric guitar. By changing the pitch with the Aftertouch feature the player can create an illusion of a heavy metal guitar.
Applications of Aftertouch
Creating swells in music: By assigning Aftertouch to a lowpass filter, you can make the sound much bolder. A swell basically is a gradual increase and a sudden decrease in the sound. This can be achieved by cleverly using the Aftertouch and pressing the keys harder and softer as required.
Using Vibrato: A common and most used feature of Aftertouch is vibrato. It creates a depth in the music by changing the pitch of the voice. There are two aspects to vibrato, the amount of variation in pitch and the speed with which the variation is carried out.
Percussion effects: The beauty of Aftertouch is that with the help of it you can change a keyboard into any possible instrument. It may be violin, guitar or even drums, the possibilities are immense. All this can be possible by retouching the pitch and hitting the keys hard to get the maximum effect out of it.
Control signal processing: Few synthesizers do full justice when it comes to a signal processing feature. By controlling the MIDI signals one can customize echoes, harmonies and even random effects.
Guitar imitation: Pressing the keys of the keyboard can create the same effect of sticking the chords of a guitar by using Aftertouch. A good control over the pitch and correct sensitivity applied will create a harmonious guitar like sound just like the way you wanted it to be.
Problems faced with Aftertouch
No doubt that Aftertouch feature of a synthesizer has many applications but some things are still missing and problematic. Different synthesizers have different features and the Aftertouch is not capable of controlling all the parameters of sound. Pitch bend and velocity are common features for all synthesizers but rest of them vary. The interface is not very user friendly and difficult to grasp. This has to be updated for the players to have a better experience. The ease with which the Aftertouch works can vary from model to model. There are some problems issued with the smoothness with which the keys can be pressed. Another important issue is the portability of the patch of music from one synthesizer to another as the abilities and features of Aftertouch vary from one another. It is better to use common effects so that the patches can work on any synthesizer.