A virtual instrument is software that can sound exactly like the real thing.
Professional sounding audio recording is not as dependent on money (for good gear, studio musicians, commercial studios, etc.) like it was for so many years. Now you can produce pro audio right from your computer without having to spend much (or any) money at all. This new technology has also made it possible to record instruments for your music that you don't actually have. You can have drums, piano, trumpets, guitars, etc. playing in your song without knowing how to play these instruments or without having someone else play them. Sounds impossible, right? Well that's the magic of virtual instruments.
I'm sure you're familiar with the typical sounds a computer plays when a MIDI file is launched (for a review of what MIDI is, see our article: MIDI Recording – What Is It And Why Is It Awesome?). These are computer-y sounding cheesy "instruments" that come built into most sound cards. Technically these are virtual instruments. Let me state right up front that these are NOT the sounds I refer to when I say "virtual instrument." Oh no. What I want you to know about is the host of real-sounding software instruments available to load up on your computer and then play with your MIDI keyboard (or depending on the software, your computer keyboard). If you can think of an instrument, odds are you can find a virtual version on-line somewhere.
What is the difference between the cheesy sounds on your sound card and the virtual instruments I'm talking about? The major difference is that a virtual instrument can (usually does) sound indistinguishable from the "real" version of the instrument. At least to most people. that's because the instrument is created by taking lots of recordings of an actual instrument. These are called sampled instruments.
Try this experiment (for which you won't even need the keyboard). Find a simple MIDI file on the internet. They are everywhere, just type "MIDI file" into a search engine and download one for a tune you know. Nursery rhymes work well...just something simple. Double-click that file (MIDI files have a ".mid" extension) and listen to it play through your sound card's piano sound.
Now we'll listen to the same MIDI file played through a free virtual instrument. There are several types of virtual instruments out there, the most popular of which is probably a "VST" (virtual studio technology) type of instrument. To play one of those, we need to download something called a "VST host" from the web. There are several free ones to choose from (yup, type "free VST host" into a search engine). Try VSTHost or MiniHost.
A VST host is just a piece of software that can play VST virtual instruments. If you already have recording software such as Pro Tools or Reaper, you can play VST instruments within the software and won't need a separate VST host. Either way, once you have the host program installed, you'll need to attach or "load" an instrument. For this let's use a free VST instrument called "4Front Piano Module" (which you can download here: http://www.yohng.com/software/piano.html).
Once that is downloaded, all you have to do is load the 4Front Piano from within your VST host program and you're ready to rock. Import the MIDI file you played earlier on your sound card into the VST host (with the 4Front piano loaded up) and hit "play."
Hopefully you'll notice that the piano sound coming from the virtual instrument, 4Front Piano Module in this case, sounds vastly superior to when you heard it coming from your sound card's factory instrument. And this was just a free instrument! For a few bucks, you can get an even better sounding VST piano to plug into your VST host and play that same MIDI file.
Want to hear the same notes on a different instrument? Trumpet, maybe? Or violin? Download some trumpet and violin VST instruments and try those in your host program. You can play that same MIDI file through any MIDI instrument you can find! The possibilities are just about endless.
Eventually you'll learn to create your own MIDI files to play back through a virtual instrument, and then mix that instrument in with actual audio files you've recorded to create a rich ensemble. Use virtual bass guitar and virtual drums along with real electric guitar and real vocals to turn yourself into a rock band. Are you starting to see how this can be life-changing if you are a musician?
If you don't already have a home music studio, this can be your start. If you do have one but didn't know about virtual instruments, this will take your productions to a whole new level. There is not reason (at least no monetary reason, since the example here used only free stuff) to give this a try right now! You'll be amazed and inspired. I know I was.
If you would like to learn more about MIDI and virtual instruments, check out our new tutorial video course The Newbies Guide To Audio Recording Awesomeness 2: Pro Recording With Reaper, which has a 3-part lesson (Lesson 11 - Intro to MIDI and Virtual Instruments) guiding you step-by-step through creating and playing virtual instruments.
Here is a video from the course: