Surround Yourself

Surround

by Marshall Such

Will it happen? It’s now 2006 and the radio industry is still “taking a close look” at surround sound broadcasting. I say “still” because the ability to broadcast in surround sound is already here. On December 31, 2004 a public radio station in Denver, KUVO-FM, broadcast their New Years Eve celebration in 5.1 surround with great success. (Search www.radioworld.com for details.) Will commercial radio see this as a pioneering breakthrough that needs to be emulated and taken to the next level? Or will the suits in San Antonio and elsewhere sit and wait. And wait. And wait.

Quick Catch-up

If you’ve been living in a cave on an island in the South Pacific (or you work at an AM station), you may not be familiar with surround sound. Never fear, techno guy is here.

The most common type of surround sound is 5.1. (There are also 6.1 and 7.1 surround systems — more later.) Simply put, this means there are 5 speakers and a subwoofer (the “.1”). The configuration is Left and Right (your basic stereo) Center, LFE (Low Frequency Effects, a.k.a. subwoofer), Surround Left and Surround Right.

If you receive HDTV broadcasts at home, you are most likely receiving a 5.1 surround broadcast as well. Good examples are “CSI,” “Lost” or any prime time network program. You will see the HDTV and 5.1 surround logos in the lower right corner of the screen as the show begins.

So riddle me this, Batman. Why in the world is our biggest competitor, television, sounding better than radio?!? For example, I have pretty basic analog cable — no pay channels, but I do have an HDTV box which tunes in some music radio channels. I also have the cheapest of the cheap Yamaha receivers (an HTR 5830 for those of you with scorecards) with a set of low end Onkyo speakers.

The other night I was flipping through the local FM channels just to see what I could pick up. (A good punch line would be: static, hiss and an overcompressed signal.) When I popped the receiver into DTV/cable input and A-B’d my local FMs with the sound from the cable equivalent, I was floored! To say the cable music was cleaner, more defined and less fatiguing to listen to would be an understatement.

Another example: At Thanksgiving dinner our hosts had XM Satellite on their home stereo playing an Oldies channel. Talk about clean, quiet and defined! My big question: Why can’t terrestrial radio sound this good?

Current Situation: HD Radio & Surround

It can with HD Radio. What I’m about to tell you is my take on HD Radio. I am not a broadcast engineer (although I’ve always wanted to play one on TV), so the information will not be presented the way an egghead might.

As I understand it, HD Radio can broadcast on up to eight “channels.” These channels can be divided into “multicasting” (broadcasting more than one station at the same time on the same bit stream) with text messages transmitting the song and artist, call letters, etc. Alternatively, a station can broadcast a 5.1 surround signal (6 channels) along with an adjacent stereo mix (2 tracks).

For those of you who are thinking “Why not just broadcast in 5.1 and use 2 channels for messages/text?” the answer is this: (again, from my limited knowledge) The FCC requires that if a song is broadcast in a different format (i.e. 5.1 surround) it has to be broadcast in a compatible format as well, namely stereo. So there are your eight tracks.

Do any of you see the old cattlemen/farmers (read: programming/sales) brouhahas coming home to roost? Where the esoteric programmer wants to blow listeners away with something as cool and innovative as 5.1 surround, the practical sales managers see those extra channels as new real estate to sell.

To compound an already complex situation: Your current Alpine in-dash receiver with the deluxe CD player and fancy schmancy DX tuning doodads will not pick up HD Radio. As with XM and Sirius, you need a whole new radio -- in your home as well as your car.

In his article, “The Premature Death of HD Radio,” Mercury Radio Research President Mark Ramsey asked a very sobering question. Will people be willing to buy new radios just to get better audio quality? Look at your kid’s i-pod. If anything, we’re “dumbing down” the quality of our music. Crappy commercials are still part of the soundscape, and just like your granddad’s radio, the new HD Radio will have a limited broadcast radius.

Does that mean that HD is dead without even having suffered a difficult birthing? That’s truly a billion+ dollar question. A recent blurb in Radio Daily News said that Clear Channel will have 200 stations broadcasting in HD by the end of 2005 and that by 2007, 95% of their 1,200 stations will be broadcasting in HD. So how will they promote these stations?

The developers of HD Radio, iBiquity Digital Corporation (www.ibiquity.com), are trying promotions like “trade in your old radio for an HD radio.” This might grab a person or two, but the cost of HD Radios ain’t cheap. A company called radi•osophy has a portable receiver that starts at $269.00. The most inexpensive in-dash HD receiver is currently $450.00. In fact, with $450.00 in hand, you could buy a thoroughly respectable 5.1 surround system for your home theater to enjoy movies and super clean music from your cable or satellite dish!

Potential Delivery Formats

If radio can overcome the HD hurdles, then the viability of surround sound becomes much more likely. Call me silly, but I see surround sound as the ONLY vehicle capable of saving terrestrial music radio — there are just too many other options for music these days. Talk Radio will do just fine; the new HD spec for AM lifts the quality all the way up to the 15kHz bandwidth now employed by FM.

So the next issue is how to send those 6 channels of music across the great digital divide. Going back to our episode of “CSI,” the audio signal being sent is not true discrete 6 channel audio. Instead, it’s a hybrid format developed by Dolby Labs called Dolby Pro Logic which sends the signal as pseudo-stereo, Lt-Rt, to be exact. When this Lt-Rt signal is picked up by your receiver, it is converted it into a 5.1 surround sound mix, sounding very close to the original 5.1 mix.

In my experiments thus far, I have not been able to get an exact replication of my 5.1 mixes, but I can get a fairly close representation. It’s sort of like working with those old Orban processors that would take a mono signal to create a stereo mix. Bizarre as those Orban splits would sometimes be, they would produce stereo. While Dolby Pro Logic does work, it doesn’t do anything weird like putting a kick drum in the lower left hand corner of the sound spectrum.

To create a Dolby Pro Logic track, you simply drag your six discrete tracks (more on mixing later) into a very-easy-to-navigate program (available for both the PC and the Mac from www.minnetonka.com). You can then further “mix” your six tracks into a 2 channel Lt-Rt mix. The program allows you to check the sound of the mix in stereo as well as a decoded Dolby Pro Logic mix. And in the battle for top dog honors of all that is 5.1 surround, Dolby boasts having something like 20 bajillion Pro Logic decoders in various receivers. Even my cheap Yamaha decodes Pro Logic into 5.1.

To paraphrase an old Norm McDonald bit when he anchored SNL’s “Weekend Update,” the Germans love the Fraunhofer mp3. That’s right. The company that revolutionized audio now has “mp3 surround.” You can even download a very basic encoder and player for free! (www.iis.fraunhofer.de/amm/download/mp3surround/downloadpage.html) This is where the battle gets interesting.

While the 800 lb. gorilla named Dolby is attempting to corner the HD Radio surround market, we all know what mp3 (and now mp4) has done for audio over the past 10 or more years. In my estimation, this mp3 surround actually does it better than Dolby! Testing the same 5.1 mixes that I encoded as Dolby Pro Logic, I found the Fraunhofer mp3 surround tracks came back as true discrete channels. Fraunhofer even has a simple test file for you to download and encode on the above-mentioned web site.

Then there is DVD-Audio. (SACD is for the Big Boy Record Companies and won’t be examined here.) Again, www.minnetonka.com has software for both the Mac and PC to create DVD-Audio disks. While this is by far the most hi-fi of the 5.1 formats, it uses a ton of hard drive/DVD space. It will be interesting to see if radio uses these disks from players or if the music to hard drive will be compressed via mp3 surround or Dolby Pro Logic.

Finally, there is Dolby Digital. This is the 5.1 audio you hear on your DVD movies. It is an mp4 format that compresses the audio tracks about 10 to 1. While it works great with video, it must have video accompanying it; it cannot record/play without it. While we know how good this audio sounds, the hassle of dealing with adding video makes this seem quick impractical.

Setting Up Your Room

From all the reading I’ve done, the general consensus in acquiring monitors for 5.1 production is to purchase from the same manufacturer but not necessarily all the same models. The more I work in surround, the more sense that makes. I chose to go the active monitor route with a Hafler system. I set up the L-R stereo speakers with the larger 8" monitors and the center and surround speakers with the similar 6" models. I chose a 10" subwoofer versus the 12" due to the small area of my studio.

I strongly recommend purchasing an inexpensive reference system as well. As we will discuss, mixing in surround is a whole new experience. If you have a pedestrian system and your mixes sound good on it, chances are you’ve nailed it.

For you Pro Tools guys/gals, Pro Tools LE currently doesn’t support surround mixing. Since I’m not a Digi kinda guy, I don’t know if they are going to offer this capability in a software update. I do know that you can mix in surround on the more expensive Pro Tools HD system.

My colleagues and I are working with Digital Performer because it also offers an awesome MIDI sequencer as well as audio recorder/mixer. I believe Steinberg’s Cubase and Nuendo offer surround mixing as well. I’m sure there are other programs for both the Mac and PC that will become available as 5.1 gathers strength.

My Mackie 24•8 was replaced by a Tascam FW-1884 which connects to my Mac G5 via firewire. I think just about any analog board can be configured to act as a 5.1 surround playback system by hard-wiring six channels directly to your speakers, but a digital console makes everything a lot easier, and for you prod pros on the go, a lot faster.

The two biggest challenges facing this new medium are placing the speakers in a correct configuration (the subwoofer can reside just about anywhere) and managing the LFE channel. I chose to set up my speakers in a fairly tight near-field monitoring configuration. Audio guru Chris Green asked as he was tuning my system, “You’re mixing for the automobile, right?” The issue of managing the low end is addressed further on in “Bottoming Out.”

Surround For Profit: A New Business Model?

If I may, I would like to mosey down a side road for a moment. For those of you who know me, I’ve bitched and bellyached for years about radio’s propensity to give away our creativity for free. Newspapers charge for layout design, television spots sure don’t grow on trees, and I’ve yet to meet a webmaster who maintains a site gratis.

But good ol’ radio: “Yes sir, of course the spot is free! It’s part of the whorish image we’ve been perpetuating for years. Sure we can have that spot written by this afternoon, have it voiced by our very recognizable morning man and Ace Roland, our production genius, can have it together for you by tomorrow morning. No problemo. And we really appreciate your $1,500 in business. Yes sir, we sure do!”

PLEASE, if surround becomes as big as I think it might, would you please make a last gasp attempt at breaking the Herb Tarrlick image of radio? Could you at least tell Mr. Flame Throwing Screaming Voice Car Dealer that his spot would sound terrific in 5.1 surround, but it will cost an additional $150 (or whatever) to produce that way? (Let him price it at a Pro Tools HD studio if he thinks that’s too much.) Once he hears his laser shots fire from the front to the back speakers and hears his screaming announcer’s voice fed into the subwoofer, you will have an ongoing 5.1 surround client who is at least paying something for his crappy spots. Now, back to the story.

Bottoming Out

Listening to commercial DVD-Audio and SACD (Super Audio Compact Disks), I hear a wide range (no pun intended) of options in addressing the low end of a mix. Disks that are mixed as true 5.1 surround tracks (versus quick and dirty re-mastering), tend to ride the wave of being just a hair too close to overdoing the sub-sonics. Most home theater subwoofers have a gain control, but who wants to reach behind himself to adjust levels from one DVD to the next?

In my studio I have found that if I get the LFE to just barely speak at moderate volumes, then when the mix is cranked everything seems to be in pretty good balance.

Again, that’s why I recommend a plain-Jane system to check your mixes. I’ve been really surprised that what sounds great on my fairly expensive Hafler system sounds way too bassy on the Onkyos. If you’re going to spend time playing in your room when you get it set up, I strongly urge you to mix something familiar and experiment with what you’re feeding the subwoofer. I would also recommend picking up a Mannheim Steamroller DVD-Audio, not only to test your system but to hear how 5.1 audio can be mixed in a very cool manner.

Surround Basics

The first thing you must know, as far as I can tell, is that the only way to get DVD-Audio or a SACD audio track off the disk and into your computer is via a special player dedicated to both formats. While both disks say they will play on conventional DVD or CD players respectively, the only way to access the 5.1 audio tracks is from these players. The good news is that manufacturers such as Toshiba make commercial units for under $200.

The bad news, however, is that these six audio tracks are delivered through six hi-Z RCA connectors. I don’t get it: 48 Khz or 96 Khz digital audio fed through hi-fi connectors. Be prepared to adjust your trim pots as you dub material to your hard drive. There seems to be no unity gain among the various DVD-Audio/SACDs I’ve purchased.

Special note: On many DVD-Audio disks you can also play the audio through the digital output into a home receiver. However, this audio is basically “file shrunk” mp4 audio that you cannot separate out of the digital port. (At least I haven’t learned how it can be done.)

DVD-Audio and SACD vary in quality from knock-your-socks-off boffo-neat-cool, to ho-hum just-barely-passable, especially with SACD’s. Be sure the CD says “mixed in 5.1”. Sometimes all that is done is as follows: Cancel out the vocal on the original stereo file to create the L-R front. Sum the original to mono for the Center speaker. Feed some low info to the LFE. Put a slight short delay on the L-R tracks and bring the returns back on the Left and Right Surround speakers. Heck! You could do that yourself!

Mixing Basics

I just completed a 5.1 demo of a new surround radio format using DVD-Audio and SACDs as my source for music. The announcer, Matt Rawlings, was recorded in mono and all the effects were from stereo sources.

Since this was going to be a first for radio, I wanted to put some “wow factor” in the production. And yes, being a prod guy at heart, I just had to “spin” Matt around the speakers a couple times.

There are a few things I have picked up on in 5.1 production so far that may be of help to you guys/gals in creating tasteful work. (And these include not spinning Matt Rawlings voice around your speakers.)

1. Put anything that’s real important in the center speaker. If you have a 5.1 system hooked up at home to your DVD movies, you know that your dialog comes out of this speaker.

2. If you want to make a stereo music track really shine in a 5.1 mix, buss the music to an “Ambient” reverb and bring the returns up in your Right and Left Surround speakers.

3. The same goes for the voice: maybe pan a phrase left-to-right across your front speakers, but dial in an effect that is returned to the rear speakers.

4. You can also send particular words to the LFE. For example, in a concert promo you might have:

ANNCR: “Tonight!”

ANNCR: (Voice pitched down overlay) “Tonight!”

The overlaid pitched down track could be automatically assigned to the LFE or you could quickly dial it in, like a crescendo.

5. For promos, use the Right and Left Surround speakers for surprises. You know how you do a montage of voices that goes bam, bam, bam! back and forth across your left and right speakers? Do the same thing, but throw a voice every once in a while to a hard Left or Right Surround speaker.

6. What makes 5.1 surround so cool is that you can REALLY create concert spots that jump. When you mix in a cheering crowd and stomping feet, try finding two different but similar stereo crowd effects. Assign one pair to L-R and the other to LS-RS. Take a stomping crowd and mix judicially in the Center channel while feeding the low stuff to the LFE.

7. Back to the LFE thing again. If you do send something like a foot-stomping crowd to this speaker, I suggest rolling off everything above 120 or 80 Hz. (Depending on how you have your subwoofer set up.) It seems to clean up the definition in the bottom end and avoids the “muffled rumbling” effect you get if you don’t clean the signal prior to sending to the LFE.

Archiving and Sharing

The “official” spec for 5.1 surround audio is 24 bit, 96 Khz. (The “audiophile audio” spec for stereo is 192 Khz.) You will however find that 48 Khz is also being used in DVD-Audio and SACDs. For practical reasons, hard disk space being the primary one, I’m doing my production in 24 bit/48 Khz. To my (admittedly abused) ears, this sounds pretty darn good.

As you do your first 5.1 mixing, realize that your file sizes have more than tripled. What used to be a 10 Mb per stereo minute is now a whopping 30+ Mbfile. And your final mixes won’t truly be “final” until you encode them into one the above-mentioned formats.

Whatever route radio takes with surround, you will want to mix in two different configurations: WAV multitrack and discrete SD II files. Perhaps if Dolby or Fraunhofer prevail, only one mix will be necessary in the future. Currently, I use the WAV multitrack (it looks like a standard wav but contains all 6 tracks) to make DVD-Audios and for my experiments with the Fraunhofer mp3 surround files. To create a Dolby Pro Logic file, I need the separate Sound Designer II files. I then have to convert these SD II files into wavs or aiffs for Dolby Pro Logic encoding.

Can you begin to see how massive – literally — these files can get? If you were to work in 24 bit/96 Khz, all these mixes/encodings could add up to nearly 250Mb for just a :60 spot! The recordable CD only holds 750 to 800 Mb. Can you say, “massive storage?”

An Exciting Future

As I mentioned earlier, there are already 6.1 and 7.1 surround systems. These allow for more surround speakers, further increasing the depth of field. Conceivably, surround could expand to 9.1 or beyond, allowing for more “up/down” imaging. Manufacturers are beginning to market surround mics that can truly capture a live setting and then reproduce it via a surround sound system.

Could radio grow into an even more expansive surround system? At this juncture, it’s doubtful. Just getting the 5.1 specs ironed out and finding a happy hunting ground for this exciting new medium appears to be taking forever. And quite honestly, it may be forever before surround sound graces the American airwaves. Until then, I can happily work in surround sound with television stations and video producers.

Comments (0)

There are no comments posted here yet

Leave your comments

  1. Posting comment as a guest. Your post will be moderated. Your email address will not be shown or linked. (If you have an account, log in for real time posting and other options.)
0 Characters
Attachments (0 / 3)
Share Your Location