Setting Up a 5.1 StudioMixing 5.1 surround sound is no longer the preserve of the Hollywood dubbing theatre. TheAudioTechnology team thrash out some of the issues pertaining to setting up your own 5.1 room.

Well, I think we can now all but rule out the 5.1 revolution asa conspiracy perpetrated by monitor manufacturers to sellmore speakers! The most recent American AES exhibition

was awash with new surround sound technology. But what the AESexhibition also demonstrated in its seminars and workshops is thatthere’s almost a different opinion about how best to work withsurround as there are engineers doing it!

With this in mind, the following article isn’t intended to be adefinitive symposium of the pros and cons of multichannelsurround, or an investigation into the various file formats anddelivery media. Instead I’d like to look at the basics of getting yourstudio 5.1 equipped. I’ve outlined the basics, and perhaps we canexplore more sophisticated issues pertaining to working in 5.1studios in future issues.

From The BeginningMultichannel audio has its roots in film production. What’s peculiarabout film sound is that it’s traditionally mixed in a very similar envi-ronment to which it is reproduced – i.e. in big dubbing theatres. Thishas meant that for 5.1 surround, there are a number standards inplace dictating where you place your speakers, monitoring levels,etc. If you’re mixing for film then it’s best to adhere to the letter ofthe law as much as possible (although there will be exceptions),while in the world of multichannel music mixing there’s a little moreleeway. One reason for this is your mixes are being reproduced inpeople’s living rooms (and not standardised cinemas) where thepunter has much more control over the listening environment.

But still, it’s worth using certain 5.1 standards as a good founda-tion for putting your studio together. I know following a ‘rule book’mightn’t come as second nature to those us who have spent yearsworking in stereo. Setting up a studio with two speakers is often asscientific as banging a couple of nearfields onto the meterbridge,

and tinkering about with placement until it ‘feels’ right. Setting up a5.1 monitoring system is, as you’d expect, a little trickier.

Speaker SelectionStudios upgrading to 5.1 often think, “I’ve got two perfectly goodmonitors, all I need to do is buy three others and a sub”. That’s afine theory, just so long as you get more of the same monitors youalready have. Your aim is to achieve a consistent, uniform soundand the best case scenario is to install five identical full rangemonitors. Second best scenario is to have the three front speakersbeing identical and the two surround speakers being smaller modelsfrom the same manufacturer. Third best scenario is to have the frontleft and right speakers being identical and the centre speaker andsurround speakers being smaller models from the same manufactur-er. I don’t much care for the third scenario – whether you’re mixingmusic or to picture the centre speaker is pretty crucial.

The idea that the centre speaker isn’t so important emanatesfrom the days when home cinema salesmen attempted to keepcosts down by flogging cheaper centre speakers – but no self-respecting mix engineer would advocate an inferior centre speaker.A good, identical centre speaker will give you a far more solidstereo image, as well as a more focussed centre image, greaterclarity etc. Meanwhile if you’re mostly mixing dialogue to thecentre speaker then it takes on great importance in monitoringdialogue EQ. You’ll also find with mismatched front monitors thatleft/right panning will lack smoothness. In short, don’t settle foranything less than three identical front monitors.

Significantly, when it comes down to budgetary decisions, experi-ence would suggest you’ll get better results using your cash to buyfive identical cheaper speakers than trying to mix and matchexpensive speakers with cheaper ones.

Speaker PlacementHave a look at the accompanying diagram on the next page. Thekey here is that all five speakers are placed so they are equidistantfrom your listening position. Which makes sense… in a stereostudio you don’t monitor with one speaker two metres away and theother four metres away, same applies to 5.1.

Front Speakers – As mentioned, aim to have all three frontspeakers identical, just like you would with a stereo setup. All thefront speakers should be equidistant from your central listeningpoint. If you’re placing your monitors on the meterbridge of yourconsole you immediately encounter a problem. The centre speakerwill be closer to you than the left/right speakers. A quick fix here isto leave the left/right monitors where they are and place the centrespeaker on a stand at the required distance back. If you can’t dothis then plan B is to time delay the centre speaker.

As well as being equidistant, the three front monitors’ acoustic

1. Speakers: the minimum requirement for mixing surround is fivefull frequency ranged speakers and a sub. It’s nice to have a set ofdedicated nearfields as well. You can use these to check your stereo compatibledownmixes for reference.2. An eight-bus mixing console.3. A Multitrack machine or DAW.4. A way to simultaneously monitor the signals you’re sending to your final 5.1destination as you mix.5. Encoders and decoders.6. An MDM for distributing discrete mixes, as well as the encoded version on tracks seven and eight.7. A timecode DAT for distribution of encoded data.8. A CD burner for distribution of encoded data

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centres need to beon the same horizon-tal plane – this willnormally mean liningup the tweeter toyour ear level.Sounds obvious,but often with5.1 a centrallypositionedvideo monitormakes this a bitdifficult. If youare in thisposition try layingthe centre speakeron its side, with thetweeter centrallylocated. Althoughmake sure it’s mag-netically shielded oryou’ll end up with abig green splodge atthe top of yourscreen.

Surround Speakers – For ‘critical’ 5.1 listening the ITU has issued a guideline whichplaces the surround speakers 110 degrees each from the centre speaker [see diagram].In reality, you can probably be a little more flexible. Engineers’ preferences range fromplacing the surrounds directly to the side all the way to directly to the rear. The finalchoice will come down to a bit of experimentation and the room’s acoustics. Regard-less of the angle, ensure that the front and surround speakers areequidistant from yourlistening position. [See the ‘Opinion on Surround Speaker Placement’ box for more.]

Low Frequency Effects (subwoofer) – Originally, having a dedicated low frequencychannel was the film community’s way to stop those big Death Star rumbles inter-modulating with higher frequencies in the same channel. But the good news is thatyou can make this separation of the low frequencies work for you in music mixing.

First up, you don’t necessarily need a separate sub if that’s what you prefer. Ifyour other full range monitors satisfy your bass requirements, then there’s nothingto compel you to add the ‘.1’ in 5.1. But if you do opt for an independent basssource it does give you more flexibility as far as placement and level matching. Theaim is to place the sub so that it blends seamless with the upper frequencies.Placing the sub near a wall or in a corner will reinforce the bass significantly – youcan use this phenomenon to your advantage, but there’s no substitute for experi-mentation with the placement.

5.1-channel audio typically consists of five discrete,full range main channels (Left, Centre, Right, LeftSurround, and Right Surround) plus an optionalband-limited Low Frequency Effects (LFE) channelfor added bass (the ‘.1’). 5.1 allows preciseplacement of sound at any location and precise pansin any lateral direction. Dolby Digital and DTS arethe only 5.1 discrete digital formats currentlyavailable to the consumer.Other surround formats:Two speakers with psychoacoustic phase, (eg. SRS3D).

Four discrete,(Quadraphonic).Three front speakers with phase-encoded mono rearand combined sub (Dolby ProLogic, and othermatrixed stereo analogue formats, known as LCRSor 4-2-4 format).‘Circle Surround’ (matrixed five-speaker surround).SDDS (Sony 7.1 system comprising five discretespeakers along the front, two surround and onesub).

What is 5.1?

The ITU guideline places the surround speakers 110º fromthe centre speaker and the left/right speakers 30º from cen-tre. All speakers are equidistant from the listening position.

30º

110º

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The ConsoleThe demands that 5.1 place on your console are very different to traditional stereomixing. Regardless of whether you have a million dollar SSL or a $1000 Behringerconsole you may need to think about how your console is going to cope. The fun-damental requirement of a 5.1-channel mixing console is a minimum of sixdiscrete output buses (for Left, Centre, Right, Left Surround, Right Surround andLFE) per input/output channel. Thus any eight-bus console would be adequate,analogue or digital. Currently more and more of the console manufacturers areoffering surround mixing capabilities as standard in their new boards. Reasonablypriced digital consoles such as Yamaha’s 02R or 03D, Mackie’s D8B, Sony’s DMX-R100, Tascam’s TMD-8000 and 4000 etc., are designed for use with surroundsound. There are also VST/TDM plug-ins available for surround sound mixingfrom your computer. [See Software Solutions box.]

One thing about cheaper desks, which isn’t often addressed, is the timing errorsthey can impose with their signal processing. If, for instance, your left/right signalspass through the console relatively untouched but the centre channel has someheavy EQing applied, theremay well be a signal delay tothat centre channel. Thesetiming errors are an issue withstereo recording but becomeeven more of a concern inmultichannel audio.

MonitoringMonitoring in a 5.1 setup isperhaps a bit trickier than youmight at first think. This isbecause most consoles don’tprovide separate multichannelmonitoring paths.

You’ll probably be using yourconsole’s bus outputs to feedyour mastering multitracker(e.g. a DA88, ADAT and the like), so to be able to adjust your control room monitoringlevels without messing with the constant level going to that recorder here’s what you’llneed to do. Take the outputs from the DA88 or ADAT and run them back into sparechannels on your console and then use the auxiliary sends of the mixer to feed youramps and speakers [see preceding diagram]. Of course there isn’t one pot which

Michael Gissing: If you are trying to assess therelative width of your mix to go into a cinema orhome cinema environment, I think 110 degrees istoo wide to place your speakers. If you’re panning asound to match the relative position on a videomonitor, wide speaker placement (too far from theside of the video monitor) will give a false audioimage. My experience suggests that (becausespeaker placements in the home vary enormously) itis better to think of the speaker positions as beingrelative to the size of the video monitor you areworking with. If you’re working with a big video pro-jection then, sure, let the speaker angle be 110degrees or even more. But, typically, smaller videomonitors will be used in small studios, so narrowthe speaker width accordingly.DTS’s Lorr Kramer: For music mixing and with thecentre channel in use, the front panorama can bewidened without causing a ‘hole in the middle’.Thus, some mixers like to move the left and right outpast the 30 degree standard, to 45 degrees. The

surrounds, similarly, can be employed in a widerspread (up to 135 degrees) as some mixers feel the110 degrees does not afford sufficient rear phantomimaging. I’d say, 135 degrees is probably anoptimum for phantom imaging at some penalty ofenvelopment, and this width should not really beexceeded.NB: Australian Television has embraced Dolby’s AC-3 for HDTV and Standard Definition digitalbroadcast, so for those intending to aim theirrecordings towards commercial advertising andtelevision work, the ITU’s standpoint is probably thesafest option.

Opinion on Surround Speaker Placement

A basic monitoringconfiguration.

50

There are a number of software platforms which alreadyprovide surround panning as part of their packages.Emagic’s Logic Audio Platinum 4.5/6 (PC or MAC). Theflagship of Emagic’s Midi+Audio software, has a variety offeatures and applications.Soundscape’s Mixtreme (v1.1) software and card with twoTDIF interfaces as standard plus optional I/O boxes.Steinberg’s Nuendo for PC (currently) and Mac (coming).Nuendo is Steinberg’s professional package aimed at thepost production market. Unlike Cubase its focus is moretowards video applications rather than sequencing.Nuendo is unique in the fact it has a reconfigurablesurround panner to cater for all potential speaker quanti-ties and positioning. It also inclues a matrix encoderwhich is compatible with LCRS applications (DolbyProLogic, for example).Minnetonka Mx51 – native or with their proprietary V8Labs card (PC only). This software package is a limitedbut very easy to use DAW orientated to audio editing andpanning (bussing) for the 5.1 and stereo formats.The last two programs can employ a game-style joystickfor surround panning, and all of the above can utilisecontrol surfaces (Midi controllers like Peavey 1600 andothers, or a few digital consoles, if you have one) forautomating mixes.Surround panner plug-ins also offer an alternative. Kindof Loud Technologies make a surround panner plug-incalled Smart Pan Pro which works with an interlinkedplug-in for LFE management for the Digidesign ProToolsTDM format called Woofie. They also make Real Verb 5.1.

Applying acoustic environments in athree dimensional space is quitedifferent to stereo applications as youcan well imagine. Sold separately is aplug-in named Tweetie (cute, don’t youthink?) which assists you in the calibra-tion of your surround monitoring con-ditions and ‘downmixes’ your 5.1 mix toa preview stereo track for reference ofnon surround sound playback.Then there’s Dolby’s Surround Tools,encoders and panners. These plug-insare available for ProTools TDM andSoundscape’s Mixtreme packages. Theencoder plug-ins are for LCRS (DolbyProLogic) only.There are also a couple of softwareencoders for AC-3. At present, asidefrom Astarte’s APAC (for Mac), the onlyother software digital encoders are available for the PCplatform. The reason for this, as far as I am able toascertain, is software developers are waiting for therelease of the OSX (Apple’s latest OS) as OS9x is believedto be an interim release.Sonic Foundry’s ‘Soft Encode’ (usable only for musicencoding). It’s hard to believe, but after repeated emails toSonic Foundry it appears this software only provides oneframe rate (30fps) while encoding. This of course is finefor the Americans, but as Australia uses 25fps, this wouldseem quite useless for any video application.

Minnetonka AC-3 Dolby Digital(encodes to an AC-3 file for DVDauthoring, or a Dolby Digital .WAV filewhich can be transferred across aS/PDIF connection). Minnetonka alsomake a DTS version as well. Obviouslythis works better with their Mx51product, as these software packages canbe directly linked to each other internal-ly.As well as the digital formats there is ofcourse the psychoacoustic encodingplug-ins that can work with all the PC orMac-based DAWs and sequencers.These plug-ins include: Waves S1

stereo imager, Free D 3D imager and GRM Tools Shuffler.These are also available in ProTools TDM format as wellas other TDM plug-ins which include the A3d Pro, DUYwide, H-TDM hyper stereo, among others.Bill Rigby.

Surround Software

controls the level of all those auxiliary masters to adjust monitor levels– i.e. there’s no equivalent to a control room level pot. You begin tosee why monitoring can be a hassle.

Most people decide to buy another small digital console for mon-itoring purposes only. That way you can take, for example, theTDIF outputs from the eight-track mastering recorder, run it intosomething like a Tascam TMD1000 or Yamaha 01V, then send thesignals on to the amps, and you can use that console’s master faderto control your room’s monitoring levels.

The FutureLike all emerging technologies there is often more questions thananswers. One thing’s for sure: surround sound looks to be here forthe long haul. Soon we’ll be watching the TV in surround, listeningto our music in surround, playing Pokemon in surround, enjoyingsurround in our cars, enjoying DVDs on our PC/Mac, accessingsurround from our broadband Internet connection, and partying tothe sounds of surround in the clubs. Consequently there will be an

increasing demand for those who can mix in 5.1.Currently setting up a surround sound studio is not a poor man’s

pursuit, but neither is it purely the preserve of the big Hollywooddubbing theatres. The challenges of designing a 5.1 room on abudget are considerable (acoustics, new and changing technologies,room sizes and shapes, etc.) but so are the pay-offs. More and moresound engineers are realising the creative potential of this newworld – mixing in surround really is a whole new pallete to paintfrom. The buzz from spinning your first sound around the room, tocreating the final mix and hearing it back in another location willmake it all worth the effort.

Bill Rigby is the owner/operator of the studio `Suite Surround` andan Audio Director at TCN Channel 9. Contact Bill onsuitesurround@hotmail.com

Michael Gissing of Digital City Studios has years of experienceworking in 5.1 surround. [See Michael Gissing article on remasteringMidnight Oil’s ‘20,000 Watts RSL’ DVD in AudioTechnology Issue 6.]

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