Aftertouch on Musical Keyboards
Aftertouch is a feature on electronic music keyboards that lets musicians change how a note sounds after pressing the key down. It works by sensing how hard you press the key while holding it. This pressure control gives musicians more ways to shape their music, just like acoustic instruments can change their sound while playing.
How aftertouch Works
When you press a key on a keyboard with an aftertouch, special sensors inside track how much pressure you’re using. These sensors send this information to the keyboard’s computer brain. The computer then changes the sound based on how hard you’re pressing. You can make these changes while still holding down the key.
Types of aftertouch
Channel aftertouch
Channel aftertouch is the basic type. It looks at all the keys you’re pressing and uses the highest pressure level to change all the notes simultaneously. This type uses less computer power and is cheaper to make. Most keyboards with aftertouch use this type.
Polyphonic aftertouch
Polyphonic aftertouch is more advanced. It tracks the pressure on each key separately. This means you can press one key harder to make it louder while keeping the other keys soft. Very few keyboards have this feature because it’s harder to make and costs more money.
Uses of aftertouch
Making Music More Expressive
Musicians use aftertouch to make their playing more lively. They can make notes swell up or get quieter, add vibrato, or change the sound’s brightness. This helps electronic instruments sound more natural and emotional.
Common Sound Changes
The most common things aftertouch controls are:
Volume changes let you make notes louder or softer while holding them. This works like pressing piano keys harder or softer.
Vibrato adds a wobbling sound to notes. Instead of turning a wheel or lever, press the key harder to add more wobble.
Filter sweeps make the sound brighter or darker. Pressing harder usually makes the sound more colorful, like a trumpet player blowing harder.
Musical Styles
Aftertouch is big in many types of music. Jazz players use it to bend notes and add expression. Electronic musicians use it to create moving, changing sounds. Classical players use it to copy how acoustic instruments work.
Technical Details
MIDI and aftertouch
MIDI is the language electronic instruments used to communicate with each other. It has special messages for aftertouch. Channel aftertouch uses one kind of message for all notes, while polyphonic aftertouch needs separate messages for each note, which uses more computer power.
Pressure Sensors
Keyboards sense pressure in different ways. Some use special materials that change their electrical properties when squeezed, while others use springs and switches. The best ones feel natural and respond smoothly to pressure changes.
Control Settings
Most keyboards let you change how aftertouch works. You can make it more or less sensitive. You can also choose what it controls. Some keyboards let you control several things at once with an aftertouch.
History of aftertouch
Early Development
Aftertouch appeared in the 1970s and 1980s. Companies wanted to make electronic instruments more expressive. The first keyboards with aftertouch were very expensive, and only professionals could buy them.
Important Instruments
The Yamaha CS-80 from 1976 was one of the first keyboards with polyphonic aftertouch. It became famous because of its expressiveness. The Prophet T8 from 1983 also had a great aftertouch. These keyboards showed what was possible.
Modern Use
Today, many professional keyboards have channel aftertouch, but only a few expensive ones have polyphonic aftertouch. Some companies make special keyboard controllers just for aftertouch control.
Benefits and Drawbacks
Advantages
Aftertouch gives musicians more control over their sound. They don’t need extra controls like wheels or pedals. The pressure control feels natural and lets them focus on playing.
Players can make subtle changes to their sound. This helps electronic instruments sound more alive and interesting. It also lets one person control more parts of the sound at once.
Disadvantages
Keyboards with aftertouch cost more to make and buy. The pressure sensors can break over time. Some players find it hard to control and might accidentally press too hard.
Channel aftertouch can cause problems when you want to control notes separately. Polyphonic aftertouch fixes this but costs much more. Some players don’t like how aftertouch feels compared to acoustic instruments.
Learning to Use aftertouch
Basic Techniques
New players should use aftertouch for simple things like volume or vibrato. They should practice pressing keys with different amounts of pressure. This helps build control and stops them from pushing too hard.
Advanced Skills
Better players learn to use aftertouch while playing complex music. They might use it differently for each part of a song, and some learn to control several sound changes simultaneously with aftertouch.
Future of aftertouch
New Technologies
Companies are working on better ways to sense key pressure. Some are trying new materials that last longer. Others are making keyboards that can tell exactly where on the key you’re pressing.
Growing Use
More people want expressive electronic instruments. This might make aftertouch more common in cheaper keyboards. New ways to use computers might also make polyphonic aftertouch more affordable.
Choosing a Keyboard with aftertouch
What to Look For
When buying a keyboard with aftertouch, try it first if you can. See how the pressure control feels. Check if it’s easy to control and responds smoothly. Make sure it can control the sound changes you want.
Price Range
Basic keyboards with channel aftertouch start around $500. Professional ones cost $1000 or more. Keyboards with polyphonic aftertouch usually cost several thousand dollars.
Final Thoughts
Aftertouch makes electronic music more expressive and helps bridge the gap between electronic and acoustic instruments. While it has some problems, it’s an important tool for many musicians. Aftertouch will likely become more common and easier to use as technology improves.
