OK, so by now most of you are saying, "Who the @#$% is this 'Frank G' guy and why does he keep popping up everywhere?"  The rest of you have been hanging around WAY too long...but I digress.  

For the first timers (and read it fast, because this information will not be repeated next week....)  "Frank G" was created in 1991 when I first began working for the Recording Institute Of Detroit.  Things were a lot different then, digital recording was reserved for those with hundreds of thousands of dollars to spend, and "aligning the tape machine" was not something we learned about on a trip to the museum, but a daily (and occasionally, hourly) reality in what was at that time RID's Sidestick Recording.  

4 years and many personnel mixups later, I somehow wound up in charge of the damn thing, as I was now chief engineer AND studio manager of the recently renamed "Golden Section Recording."  Anyone still around from then?  OK, stick with me...  I decided to branch out on my own and wound up touring North America and having a wild time for a few years, then returning to work at the world's prissiest video studio.  As you may be able to determine from my picture, I do not fit in well amongst 'prissy' things...  

So after they kicked me out, I ran into Bob and a couple of "Sir!..."s later, here we are....whew!  Didn't think I'd be able to fit 10 years into one paragraph, let alone one big run-on sentence.  [if you've never read my stuff before, I'd like to take a moment to inform you that I'm quite fond of run-on sentences.  Sometimes it's just not practical to stop yourself mid-rant and correct punctuation, not to mention the fact that while ranting, I probably wouldn't include the damned commas out loud, either...] The fact that anyone bothered to read this far down is worth rewarding, so enough of my nonsense, and on with my bull@#$%! 

Hey Frank, what's all the fuss over this 5.1 stuff?

That's the #1 question I hear from my more techno-savvy friends (yes, I also hate the fact I used that term, but it was less offensive than calling my other friends "electromoronic")

Anyway, the point is, a lot of people have been hearing about the benefits of 5.1 surround sound lately.  Hopefully,  it's from a cool friend who's got a home theater setup, not one of those damned ads for that store I won't mention that advertises the "5.1 surround setup in one box!" deal (which you should avoid at all costs, this is the modern equivalent of a drive-in speaker).  Either way, it's safe to assume there's a lot of misinformation floating around out there, so I'd like to take this opportunity to properly misinform you.   I feel obligated to note, there are several competing formats of 5.1 surround for the home and theater at the moment.  The most widely used, and therefore the system covered in this article is Dolby Digital 5.1    Advocates of DTS (Digital Theater Sound) boast of its crisper highs and more spacious rear field, but like Beta in the 80's, the software just isn't there yet.  Now then, officially speaking:

What is Dolby Digital (AC-3) ?

Dolby Digital AC-3 delivers six totally separate (discrete) channels of sound. Like Dolby Surround Pro Logic, it includes Left, Center and Right channels across the front of the room. Dolby Surround Pro Logic provides a single limited-bandwidth (100 Hz to 7,000 Hz) Surround channel which is typically played back in the home through two channels of amplification and two speakers. In comparison, Dolby Digital AC-3 provides separate (discrete) Left Surround and Right Surround channels, for more precise localization of sounds and a more convincing, realistic ambiance. And, with Dolby Digital AC-3 (A format found on all DVD players in North America), all five main channels are full range (3 Hz to 20,000 Hz). A subwoofer could be added to each channel, if desired. The sixth channel, the Low Frequency Effects Channel, will, at times, contain additional bass information to maximize the impact of scenes such as explosions, crashes, etc.

All six channels in a Dolby Digital AC-3 system are digital, which means that they can be transferred without loss from the producer's mixing console to your home playback system.

Amazingly, Dolby Digital AC-3 packs all six channels into less space than a single channel on a Compact Disc. This advanced approach to coding digital audio data is what makes it possible for multiple Dolby Digital AC-3 soundtracks to be added to conventional laser discs, DVDs, and a host of other sources.

These technologies give you a dramatic improvement in extremely wide dynamic and frequency range, with low-distortion reproduction in your home.

In case you didn't notice, much of the above section was scammed directly from a Dolby press release from a few years ago.  I do this because they explain their technology far better than I'd ever be able to.  I tried to modernize it where necessary.  Does that diagram make sense?  You need 6 speakers in all: 

1) Front Left [L]

2) Front Right [R]

3) Front Center [C]

4) Rear Left [RL]

5) Rear Right [RR]

6) Subwoofer [S]

Some people (mostly salesmen who wear red vests at work) will tell you that you don't need a subwoofer, you can add one later.  While technically true, this would be like buying that car you've always wanted and convincing yourself that you can get an engine for it later...

A properly setup subwoofer can convinces even the oldest of fogeys that they need a system in their house.   Try this at your convenience:  Invite a bunch of the people over who say things like "Oh, what do you need all THAT crap for?  There's nothing on TV worth hearing anyway..."  and throw in, oh, let's say...The Matrix.  Now, I thought the movie was OK at best, but as a surround demo, it's amazing.  The kicker is, once you've selected the scene you want to watch (may I suggest starting where they storm the building for maximum surround potential?)  TURN DOWN your surround setup.  Yes...all the way.  Now, turn UP the volume on your TV.  I know many of you may not have done that for years, but do it now.  

Now, start playing the scene through that one crappy TV speaker, and watch as your guests remain unimpressed and begin to smirk at you and your wasted time and money.  Just as hell is about to break loose, unmute your system and let bullets explode around you in sparkling 5.1 goodness.  As that first earth shattering KABOOM goes off and the subwoofer kicks in, you may want to be the guy running the underwear concession stand, and as everyone knows, anything good enough to make you do THAT is worth having in your house.  This is a slightly underhanded trick, but it IS a surefire way to convert to most unwilling participant.

That's nice...but how does it work?  We want to create our OWN 5.1 mixes!  OK, OK...let me see what I can dig up from ol' Dolby Labs about this, and maybe catch up on a bit of history while we're at it --

The principles of Dolby Digital follow from the analog noise reduction work that Dolby has been engaged in for more than 30 years. Dolby noise reduction works by lowering the noise when no audio signal is present, while allowing strong audio signals to cover or mask the noise at other times. Thus it takes advantage of the psycho acoustic phenomenon known as auditory masking. Even when audio signals are present in some parts of the spectrum, Dolby noise reduction reduces the noise in the other parts so the noise remains imperceptible. This is because audio signals can only mask noise that occurs at nearby frequencies.

When moving from analog recording to a digital recording medium like the compact disc, one finds that the digital audio coding used on CDs yields an amount of data often too immense to store or transmit economically, especially when multiple channels are required. As a result, new forms of digital audio coding - often known as "perceptual coding" - have been developed to allow the use of lower data rates with a minimum of perceived degradation of sound quality. Dolby's third generation audio coding algorithm (AC-3) is such a coder.

This coder has been designed to take maximum advantage of human auditory masking in that it divides the audio spectrum of each channel into narrow frequency bands of different sizes optimized with respect to the frequency selectivity of human hearing. This makes it possible to sharply filter coding noise so that it is forced to stay very close in frequency to the frequency components of the audio signal being coded. By reducing or eliminating coding noise wherever there are no audio signals to mask it, the sound quality of the original signal can be subjectively preserved. In this key respect, a coding system like AC-3 is essentially a form of very selective and powerful noise reduction.

Indeed, Dolby Laboratories' unique experience with audio noise reduction is essential to AC-3's effective data rate reduction: the fewer the bits used to describe an audio signal, the greater the noise.

It's true...having all those mixes available comes at a cost:  Data Compression!  Pretty damn good data compression but noticeable enough if you're an audio guy and you're dwelling on it.  (DTS offers less compression, which may account for its percepted increase in "spaciousness").  DD (AC-3) sounds at least as good as a top quality MP3, (with DD having an average data rate of 448k while MP3's max out around 320) which is far nicer sounding than any audio contained on a MiniDisc.   If everything's set up properly, and fine tuned by someone who knows what they're doing (and not someone who's working from a sheet that came in the box) everything should sound great.  Can you tell the difference between raw uncompressed PCM audio and DD 5.1 (or DD 2.0, which would be a more fair comparison)?  Sure, but again, only if you know what you're listening for, and I think we're all guilty of over-examining everything we like.

What's the point of all this?  Someday soon, this is going to be standard technology in everyone's home, and you're going to have to know how to mix for it (or some other multichannel standard they may settle on in the future)  Besides, how cool is it to think that someday you'll be able to do what Pink Floyd accomplished 30 years ago and make someone turn their head around and go "What the...?" while one of your mixes plays back.  They had drugs and Alan Parsons, you have a computer...start playing with this as soon as possible. 

Once upon a time I had a recipe for a home brewed 5.1 cd-r.  This assumes you have a DVD player capable of reading a cd-r, but many of the newer models do.  Basically, you could take your 6 tracks, set their volumes, encode them into 5.1 using Sonic Foundry's Soft Encode 5.1, then burn the resulting file using either DVD authoring software that allows you to burn test cd's, or by using something like VCD creator and simply burning the file to a vcd.  In theory, the player should recognize the stream as being DD 5.1 and everything should be cool.  It's late and I probably screwed that up, so if anyone actually cares to know about this (or anything else), drop me an email.

Hey, I need your help!  This article was written with the beginning recording student in mind.  I'm wondering who my audience really is.  I don't want to appear as though I'm talking down to anyone, nor do I want to leave anyone in the dust scratching their head wondering what happened.  Feedback would be appreciated, and will ensure I provide you guys with the stuff you want to know about instead of just babbling like an idiot.   We try to answer all questions posted in our "Recording Q&A" message forum (at my other home, www.fatthaxx.com,) but it does require you to register (for free) before you can post.  Small price to pay for such a wealth of information... Come on over and check it out!.

OK, folks, it's been lovely, but it's approaching 8AM and Mrs. Frank G gets cranky if I'm not there before she wakes up....Remember, send those emails and post those questions!

I made it through the whole thing without making any Spinal Tap references...

TOP SEVEN USES FOR 5.1

7. Convince the neighbors there's bad weather so you can watch Twister without interruptions.

6. Drive your dog crazy trying to find the animals he hears on the Crocodile Hunter

5. The thing Howard Stern got his listener to do with the speaker in Private Parts

4. Give yourself an excuse to stretch your legs as you get up to answer the phone that's ringing in the movie you're watching.

3. Create a bunch of new jobs for people like us as demand for experienced mix engineers goes up

2. Constantly knock stuff off the walls in your home theater

1. Scare the hell out of your wife at 5:30 AM when the automatic machine guns go off in the hallway in Aliens and you were just listening to that quiet scene with the volume cranked up....

*DOLBY and the double-D symbol and all other references to Dolby Digital are trademark of Dolby Laboratories Licensing Corporation.