Audio Basics

Ways to get audio into your computer for
your creative projects
 

by Tweak

 So, then how do we get our sounds into the computer?  On this page we get into digital audio.  Yep, the same kind of audio, consisting as ones and zeros, with which your CDs are made.  But fear not my friend, its not that complex. I am here to deliver to you all the advanced concepts of digital audio you need to start your own studio, and when I am done with you, you will be able to hang with today's studio wizards and hold your own.  When you have the right tools, recording digital audio is not harder than using a cassette recorder. 

To start, I'm going to get your head on straight so you can make some good decisions for your future rig.   There are 6 common approaches here, and we'll talk about each briefly.   

Shorthand for "In the Box" is ITB.  This means the piece was recorded and mixed inside the computer.  OTB, or out of the box, means the song was mixed outside the computer, most likely on a hardware mixer or console.

6 Ways to get your sounds into "the Box"
(erm..that means into the computer, dude, from your microphones, electric guitars and other electronic instruments)
 

1.  Use your onboard Sound device

A cheap sound card, like the one that comes with your PC that only has 1/8"  MIC and LINE ins poses a problem right away.  You'll have to use a cheap mic to connect to the little 1/8 inch phone jack, and you'll need a little adapter (1/4" to 1/8") to connect the guitar to the MIC in.  (be careful to keep you guitar at very low volume).  If you have a direct box or a pedal, connect that to the LINE IN.  You also connect your synths to the Line In, again, with the 1/4" to 1/8" adapter.  As you might guess, this is not a very good solution.  The Mic preamps are often hissy, usually worse than an old cassette deck. The DACS are poor on these cards and the cables are always falling out of the jacks due to the weight of the adapters. Also you will find yourself always plugging and unplugging stuff in this very inaccessible area behind your computer.      
 

2. Mixer/Soundcard  

The classic solution here is to get a small mixer that lets you connect the mixer output to the LINE IN jacks on the soundcard.  The Mixer will let you use better microphones with XLR jacks and will have better clearer sounding preamps.  Also a Mixer will be able to boost the guitar signal just right, making it easy to use pedals and all the cool guitar gadgets you might have.  I call this the Mixer/Soundcard approach.  The little mixer shown to the left may be of great benefit to those who record one track at a time to audio.  Its the Mackie 402 VLZ3.  A decent soundcard for a computer with an open PCI slot is the M-Audio 2496.

You should know that as PCI slots start to disappear from the modern PC, Firewire and USB 2.0 approaches are becoming the favored approaches. Yet if you already have a decent soundcard you like, adding a mixer is easy, cheap and convenient.

3. Audio Interface Only-- The "Mixerless" Approach

 A third way to connect audio sources to a computer is with an audio interface, which 100% replaces all the functions of a soundcard, with mixer-quality mic preamps and line inputs and outputs.

The Presonus Firebox is an example of an inexpensive firewire audio interface that has Mic Preamps and line ins and outs.  It also has MIDI i/o.

Some audio interfaces come with PCI cards and others with Firewire or USB2.0 interfaces. You don't need another soundcard if you have an audio interface--it is your soundcard.  If you get one with Mic preamps, you don't need a mixer.  We will call this the "mixerless" approach. 

There are many different Firewire and USB audio interfaces available, and they are not all small like the one above.  To get an idea of the options available to you, take a look at my PCI and Firewire comparison charts.  They give you a good rundown of what features you get at the different price points.

4. Mixer with integrated audio interface

A fourth way to connect your audio sources to a computer is to get an analog mixer that has a firewire port or USB port.  You don't need a soundcard or an audio interface with these devices. 

The Onyx 1220 is a full function analog mixer, when equipped with the optional firewire card, does not need a soundcard. A similar approach, but with USB 2.0 as the format, it the linme of Alesis MultiMix USB Mixers.  There are also many inexpensive analog mixers with simple USB 1.1 interfaces tacked on, like with the Behringer XENYX 2442FX, which is OK to get you started, and at the high end a professional console like the Allen and Heath ZED R16 which connects by Firewire.

5. Audio Interface with Integrated Control Surface

These are not mixers.  They are control surfaces with an integrated audio interface.  The faders control the software mixer inside your computer sequencer application.  These typically have microphone preamps, analog and digital ins and outs and MIDI ins and outs. There is a lot going on development wise in this area.  One trend is towards the hardware box that does everything you need and works seamlessly with your DAW (computer).  We are not quite there yet, but we are moving closer. These are usually Firewire interfaces.  The Tascam FW1884 is popular.  Others that are similar is the Digi 003 (for Pro Tools LE), the Project Mix and Alesis Master Control.  The most inexpensive of this group is the Tascam FW1082 which is popular among those starting out.

6. Multi-Track Recorder   

A final and fifth method is an alternative to the computer midi and audio sequencer for those who don't want to mess with computers that much.  It is the dedicated standalone multi-track recorder.  You basically do all your work on the recorder, not on the computer, but can use its built in interface (usually USB) to port files over to the computer for editing or whole songs over after the mix.

Today there are multi-track recorders you can slip in your pocket like the Zoom H4n and those like the Tascam X48 designed for professional installations and many in between at nearly every price point.

OK, I've showed you the 6 basic approaches to getting audio recorded in your studio. While some of these approaches may seem consumer-friendly and inexpensive, the principles carry over to the ultra high end of gear.  There are mixer-based approaches that may cost upwards of $100,000, massive multi track studios featuring cascaded 48 track recorders and more common today, large computer-based rigs with expanded audio interfaces and outfitted with extremely high end preamps and converters that may cost upwards of $2,000 a single mono channel.  We will get into some of the high end stuff later, but for now, we just want to get started painlessly.  So start thinking about which way you want your studio to take form.  If you are to have a recording studio, you'll need to go down one of these paths.  When we get to the coming Rigs page, you'll read about many different rigs that fall into these 5 approaches.

What is Digital Audio

Regardless of which approach you use, after you connect your sources and make noise, the sound will go through a  microprocessor called the digital audio converter (DAC) which contains 2 parts.  1) Analog to digital conversion (a/d) and 2) Digital to analog (d/a) conversion.  Some call the DAC an ad/da converter.  The analog audio Signal goes to the a/d, where it is converted to digital data, then to the CPU, memory, and storage.  The stored digital audio (often formatted as a .WAV file) goes back to the memory, CPU, then out the d/a where it is converted back to an analog signal.  Simple enough.  Yep!

The digital audio/MIDI sequencer allows you to record the analog output of your synths, guitars and microphones as digital audio .wav files.  Regardless of what method you choose to get audio to the computer it goes through the DAC to computer memory and hard disk. This type of data is correctly called digital audio data. If you record at "CD quality" (which, by the by, is one of the lowest quality recordings you can make now) each second of sound is divided into 44,100 slices.  What is this data?  It's just numbers, man. But unlike MIDI data, which is just numbers that represent what notes you played, digital audio data is a numerical representation of the actual soundwave.  It "is" the sound, captured in numbers. So you should be digging that audio data is thousands of times larger than midi data, right?  It is.  

How MIDI becomes Audio

You might be asking now, so how does MIDI become audio, is there some "conversion" utility?  Heh, if I could count how many times I have had to answer this.  No utility is needed.  Its simpler than that.  You just connect the analog outputs of your synth to the soundcard (or audio interface, or mixer with firewire, etc.,) and then press record.  The analog waveforms stream in from the synth, goes through the DAC, turns into numbers, and viola! you have digital audio data.  The cool thing about the sequencer is first you record the MIDI track, then perfect it in the editors, and then record it as audio so you have the "perfect" track.  (Well maybe not perfect, nothing ever is).  If you are using software synths, the process is called "bouncing" but it is the same.  The computer generates the sound of the track from the MIDI data and records it as audio.

Now it's time to process these perfectly synced wave files with plugins or effects.  Or you can keep your synth tracks in the MIDI domain (where they are always freely editable) and add your voice, or guitars, or whatever else you want as audio tracks.   Getting the idea?  In the sequencer, you can have MIDI and Audio tracks side by side. 
 

Getting your Sounds Out of the Box

After you get done recording all your tracks, then you take off the composer's hat and put on the audio engineer's cap.   It's time for the mix, and in the modern sequencer you have a complete virtual mixing console with full automation at your command.  When it all sounds the way you like it you MIXDOWN to your format of choice.  You can do this internally in the sequencer, or ITB,  (if you recorded your MIDI tracks as Audio tracks).  This process is called "bouncing" or "audio mixdown" , where several sequencer audio tracks are combined to a single stereo track.  Or if you are using external keyboards and synths that you are not recording as audio tracks, you can blend them with the soundcard output in your mixer and route that to a tape deck, DAT, cd recorder or even to the unused inputs of your audio interface or to the inputs of a second soundcard. 
 

A good MIDI/Audio sequencer gives you the software you need to make a complete piece of music.  You can sing or speak over massive orchestras, hip-hop beats, trance tapestries, audio loops, sampled snippets ripped from your music collection, whatever you can get in there.  You should be getting an idea of how flexible a MIDI/Audio sequencer is, and how there is not a necessarily "best" way to go about making a final master.  If it sounds good and you can record it--that's the bottom line. 

The Recording process, Step by Step

Introduction to the Tracking and Mixing process with the Mixer/Soundcard Approach 

What?  You want me to draw you a picture?  OK I will.  Below you see a simple rig consisting of an entry level keyboard, a PCI soundcard, and a mixer with a recording bus with monitors.  Add a decent Mic and you can get started.  Yes it is that simple. 

The picture above may have you asking questions.  That's good.  To further clarify, lets go through the basic process of making a song.  Let's follow the recording path of a 1) Microphone or guitar, 2)the MIDI keyboard with sounds, and 3) a typical soft synth or drum sample playback program.  All of these examples are based on the Soundcard/Mixer approach.
 

Tracking Phase

The tracking phase is where material is recorded onto tracks, which play back together and are monitored while more tracks are are added, or "overdubbed".  Generally speaking, in a studio you do all your tracking first, then you start your mix.  

Audio Path with a Mic or Guitar

Studio Projects B1 Large Diaphragm Condenser Microphone Tweak: The B1 is a low cost condenser mic that sounds clear and clean.   It can be used for vocals and general instrument recording     Shure SM57 Cardioid Dynamic Microphone  Tweak: The SM57 is probably the most popular studio mic in the world.  It can do everything, but excels at recording guitar amps, drums and loud instruments.  Can also do hip hop vocals thanks to the rich proximity effect.   Emu 1212M 24-Bit/192kHz Balanced PCI Interface (Windows) Tweak: The Emu 1212M is a robust soundcard with excellent quality sound.  it will work well with the Mackie 1402 above

1. The guitar (or Mic) signal goes into the mixer through a preamp. 
2. The signal travels through the mixer and goes out your recording output (called an alt-3-4 bus, direct out, or group out). 
3. The signal goes into the soundcard and is converted to digital audio data.
4. The waveform appears on the screen in your sequencer.
5. You can cut and paste, chop up, move around, even reverse this waveform.  You now have one audio track.
6. The sound of this track goes back to the mixer and to the speakers.  You hear it and like it or don't like it.  If the latter, you go back to #1.
    

MIDI Path using a keyboard that has sounds

1. You want a bassline, so you call up a bass program on your keyboard
2. You press record on a MIDI track, play the part along with the guitar track.
3. The MIDI data (which notes you pressed and when) is recorded in the sequencer as a MIDI track. 
4. When you play back the track, this data goes back to the keyboard and triggers the notes.
5. The sound of the keyboard goes to the mixer, is mixed with the sound of the guitar track and you hear it on your speakers.
6. At this point you can record it as audio, or leave it as MIDI till later.  By leaving it as Midi data, you can always change the notes you played, time-correct them, add notes, remove notes or change the instrument from bass to bassoon if you want.
    

MIDI path using a software synth or drum sample synth

1. You call up another Midi track in the sequencer and assign (for this example)  a software drum sampler, like Battery.
2. The computer creates a virtual instrument and you assign it to an output in the sequencer.
3. You play notes on your keyboard.  You hear the drums and make a wack beat  The MIDI data creates a track in the sequencer.  The data plays the drum sounds on playback. 
4. You think it is so crappy you quantize all the timing to 8th notes and switch to 'yo coolest samples.  You can now live with it. 
5. You can "bounce"  these virtual tracks to audio tracks inside the sequencer.

Add Vocals

1. Enlist the significant other for your first production.  He/she will will listen to the tracks playing back and then sing out "Oh BayeyayeeBeehe Baybay!" on cue. 
2. They listen to the tracks on headphones.
3. The signal passes through the Mic, through the mic preamp on the mixer, and into the soundcard where it is digitized into data.  The audio data shows up on the screen.
4. It sounds so godawful you decide to drench it in reverb, reverse it, split up each sylable into a sample and load it into a software sampler when you can play it slowed down in backwards syllables.  "yyeeebb,, eeyyyahh,  yeeb, yeeb, hhhhoooh" 
5. Someone suggests you are a genius. 

In a nutshell, that is the tracking process.  Lets move to the Mixdown process.

The  Two Basic Mixing Methods

From these simple 4 tracks you should be able to see how MIDI and Audio tracks work together to make music in a computer environment.  Add as many tracks as you want.  When the song is finished you can mix to stereo.  There are two basic ways to do this, the digital mix (in the box, typically) and analog mix (out of the box, typically).
 

Analog Mix

Here you simply route the mixer's total output to an external deck, like a CD recorder, or back to your audio interface inputs.  I call it the "analog" mix as the sounds are mixed in the analog domain on a mixer.  When you use a mixer you are mixing electrical voltages that are analogous (i.e., the analog of) to sound.  These voltages are made up of real electrons. 
 

Behringer SX4882 Eurodesk 48-Channel Mixer

This is part of Sonar's virtual mixer.  Once the signal is digitized, all the mixing processes are numerical.  There are no cables, hisses, hums or voltages in the digital domain and processes can be applied with incredible precision.  Hence, digital processing is "clean"

Digital mix

You record all the MIDI tracks as Audio then mix all the audio tracks to a stereo wave file.  Its called a digital mix because the sounds are combined using mathematical processes inside the computer sequencer.  The data is numerical and every process involves math.  You don't "see" this math because it is all going on underneath a graphical mixer.   

We will get into all these processes in great detail in the article Mixing in the Virtual Realm of the Sequencer

So above you see a typical simple midi/audio system and how the pieces connect and the process used when writing music.   If you have quality components, add a few soft synths and samplers, and if you work carefully, even this simple system below can rival the sound of the advanced system.  If you already have a good quality soundcard with a good mic preamp on it, all you need is a working midi keyboard (an old one will do), a sequencer like logic, cubase, digital performer or cakewalk, and a decent mic, and some form of MIDI interface.   Even with just one module or soundcard, an immense wealth of music power is under your control.  The more you learn about it, the better your music will be.  All you need is a musical imagination and some basic gear and you are on your way. 

OK, we are going to move on to the Rigs sections, where I will show you, in greater detail, how to configure your home recording studio to your needs.  I'll give you everything you need to know to make an intelligent choice, and I'll warn you about the horrific mistakes some people make.  But first, lets take on some noobie questions. 

Questions

 

Q) Tweak! Cool stuff.  Tell me about some of the other devices that can be used with a MIDI audio sequencer?

You can also add MIDI drum machines, hardware samplers, and effects processors and control them all from the sequencer.  There's plenty of keyboards and sound modules of all types around.   Soft synths are so popular these days that keyboards are sold that don't make sound of their own.  These are called Keyboard Controllers.  You can add other controllers too, like a Control Surface, which controls the functions of the virtual mixer in side the sequencer, but does not (at least not always) pass actual analog audio. You can even hook up V-drums or virtual drum kits you always see people banging on in music stores. Its becoming a virtual world more and more each year. There are also MIDI guitar controllers and MIDI wind controllers.  Oh yeah, you can record real instruments too, guitar, bass, sitar, tabla, hurdy-gurdy (everyone needs one  :)
 

Q) Tweak!  Help Me out!   Tell me what I need to get started!  I don't have a lot of cash but I really want to get going with my music! 

Hey there!  Believe me, I have been on the lowest of the low end.  Here's some Options:

The Really Really Cheap Studio (under $100 total)

You already have a soundcard and computer, right?  Go down to the local pawn shop and dig for an old keyboard--just make sure it has a MIDI out.  Probably find one for under $50 bucks.  Get the MIDI cable for the soundcard.  Find a cheap plastic mic with an 1/8 inch plug ($10 or so, maybe you already have one?).  Get a basic entry level sequencer here for about $30.  Yer Done.  For a hundred smackers you have a recording studio.  It'll work.  It'll be fun, and you can get really serious if you want.  If you have a Mac running OS X, you are in luck.  Just get Garage Band if its not on your computer already.

The Inexpensive Studio, but Decent under 5 bills

At the same pawn shop look for a keyboard that has MIDI and sounds good and is multitimbral.  Should be some there in the 200-300 range.  Spring for a better entry level sequencer like Cakewalk Home Studio, Cubase SE, or GarageBand or Logic Express if you are on a Mac.  Get a soundcard that has Mic and guitar inputs on it, or get a small mixer or preamp, and get a good XLR Mic. 

A Fine quality Budget Studio, under a grand

All the stuff is on this page except the sound card. Look at the M-Audio Delta Cards.  Get a fine digital audio sequencer like Sonar Home Studio, Cubase SE, Cubase SL (if on a PC) or Logic Express (if you are Mac-based). Sometimes the audio interface you choose will have basic versions of the top flight sequencers, like Cubasis and Sonar LE.   You have plenty of choices to go with the mixer/soundcard approach or with an audio interface "mixerless" approach.

Links to a Dream

Check out my Guide to Mixers page and Which Soundcard?" page which covers these options in more detail than we did here.   Find a new keyboard you like.   I also talk more about keyboards on m "Buy the Right Keyboard" Page.  Later on you can add a software synth or sampler, esoteric plugins and more. The sky is open with a pro sequencer and a clean way to get audio in it.  If you go this route, you'll enjoy excellent sound quality.  This is enough stuff to make music at CD quality, your own original MP3s you can upload to places on the internet and more than enough to experiment with many different forms of music from classical to drum N bass to Hip Hop.

Want to see more studio rigs?  Go there and take a peek, but come back here.  If you register at our forums, you can view some pics of the home studios of our members at studio-central. 

OK, my newbie friends, brace yourselves, I am going to call the pros back in.  But never let these guys intimidate whether you are at the music store or on the newsgroups looking for answers.  Instead, pay close attention to what they say. They can help you buy the right gear more than any store clerk can.  People that make music with MIDI and computers are usually passionate about what they do. That's what all the squabbling is about. The choice of sequencer, computer platform, synth, plugin is all hotly debated because the end product is something as indefinable as quality.  Electronic music is the most sublime of the arts!  The secrets to making music is all about having fun with sound.  The one warning is that when the music studio bug bites, it bites hard and you may find yourself in a lifelong pursuit of making dreams come true in music.

---Your First Test---

Think you understand MIDI and AUDIO? Here's a little test

OK, I promised you a test.  No cheating.  The TweakMeister will be watching.  The answers are here.

1.  True or False:  MIDI data is digital audio data

2.  True or False:  You can only have one synth on each MIDI port

3.   True or False:  You need an external keyboard or module to hear the midi events

4.  True or False:  Once you record MIDI tracks, the tempo cannot be changed

5. True or False:  You can use an audio plugin to add reverb to your midi track

6.  True or False:  All synths are GM compatible

7. True or False: You don't need to be a good keyboard player to write a great composition with MIDI.

8.  True or False: You can freely transpose or alter the timing of any note in an audio track.

9.  True or False:  You can Connect and XLR Microphone to a Soundcard directly

10. True or False:  If you have a Mic preamp, you don't need a Mixer

11. True or False: Digital audio refers to data created after an analog waveform goes through a DAC.

12. True or False:  Several Wave files can be combined in the sequencer to make one single wave file

13. True or False:  The MIDI Thru port has the same data as the MIDI OUT port

14. "Mixdown" is the art of combining several tracks to a stereo mix.

The answers

Best of Luck in your music making!

My Name is Rich, and I am the Ruling TweakMeister of TweakHeadz Lab and the Studio-Central forums

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Tweak's Guide
MIDI Basics
Audio Basics
Audio interfaces for your Mac
Choosing a Controller
Installing Sequencers
Keyboards: What you need to know
Consider Various Rigs
MIDI interfaces
The Signal Flow in a Basic recording studio
Choose a Mixer
How to Write a Song with a Sequencer
Multi track Recorders
The Concise History  of the Home Studio
What is a compressor?
Research Audio Interfaces and Soundcards
Constructing HH Beats
MIDI to Audio, Tracking, Premixing

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