MasterMix - audio mastering

Working in Surround...Set-up & Mixing Tips

It is likely a challenge for the engineer who has spent their studio life translating a musical performance (or series of musical performances) into a stereo perspective for presentation. Studios and playback systems have been stereo-capable for decades, and surround's only correlation is much more recently in theaters and live venues. We offer these thoughts to aid the mixing engineer, producer, and artist in defining a 'starting point' so that they can move more quickly into the task of 'making music in surround'.

Monitoring

First, it is crucial to consider the monitoring environment that you are working in. The typical facility does not have a properly designed control room for surround monitoring. Many $$ may have been spent to make this area 'stereo-accurate', however adding more speaker locations was not likely planned for, and the acoustic requirements change drastically when this happens. To make the best in a temporary situation, you should use 5 (or 6) speakers of identical (or nearly identical) characteristics. This can most easily be accomplished by using components of the same manufacturer. It is ideal that they be the same size, however it may work to use larger versions for the Left Front and Right Front, as these will likely carry much of the 'weight' of the music (more on this later).

The generally accepted speaker placement in the room is for all main speakers to be equidistant from the primary listening location. You can do this by fixing the listening position, then creating a 'circle' with this point as the center. Each speaker would be placed along this circle facing the center. Doing so minimizes image shift due to sound arrival times at the listening position. You an increase the 'sweet spot' somewhat by overlapping the Front and Rear foci a bit (see diagram). In addition, it is best if the room and speaker placement is 'symmetrical'. Try not to have large objects (like walls, racks, etc.) nearer to some speakers than others, especially if this will skew the Front Stereo, or Rear Stereo perspective (also see diagram). The angle between front speakers is typically 60 degrees, with the rears @ 110 - 150, depending on your preference. The NARAS P&E Wing has made some recommendations regarding this setup, which you can find here.

Each main speaker should be have its acoustical output calibrated to some typical level (say 80 dB SPL) using a known pink noise source and a reasonable quality SPL or meter. This should be done using C weighting, slow response, with an omni mic at the listening location. The proper setting would have each speaker providing the same amount of energy into the space as measured at this location. I recommend using a band-passed pink noise source (500 - 2kHz) so that room modes do not affect this measurement (all small spaces have significant room modes due to their dimensions). When calibrating the LFE, the pink noise source will need to be changed to band-limited 20-120Hz at the same level. The SPL should be adjusted to be the same setting used for the main speakers, and this speaker is best placed off-center in the forward part of the room, as near as possible to two room boundaries (like the floor and a wall).

It is also desirable to have all speakers angled at no more than 7 degrees downward. Try to keep them level with the mix postion 'ears' if possible.

Once all of this is laid out, carefully mark speaker locations, to make resets and verification easier. Often surround mixing is done over a period of time, and your setup may have to redone several times.

Mixing

Now for the mixing 'concept'. No matter what you intend to do, or who may be listening to it, there are several rules or practices that have been developed.

Rely on the Left and Right Front speakers to provide the musical 'foundation'. There should be enough information here to tell the musical story, particularly in the bass and vocal region. You may supplement this by adding foundation to the other speakers too.

The Center Front should be used to support the Front Stereo perspective. It is particularly effective at 'nailing down' the primary vocal or lead instrument location. Engineers often put some of the drum kit here (snare and kick, mostly) and a bit of the bass as well. Remember that not all home playback systems will have a properly placed center speaker, and your musical presentation should not rely on this element to be understood.

Surround speakers are where the fun begins! Be creative, but don't overdo the 'pan-around' effects. Most mixers will use these speaker locations to enhance depth and separation. A mix for a 'live video' would seem distracting if too much energy or instrumentation was from behind the listener, whereas one without video might not. Listen to your mix with the Front Left and Right turned off to scrutinize what is going on there, as well as with select combinations of Front and Rear speakers.

Last but certainly not least, what about the LFE? Well, as implied by the abbreviation, this is an 'effects' channel. Therefore, use it this way! In many media presentations (DVD-Video, specifically), it will be band-limited to 120Hz, and an individuals 'subwoofer' and receiver settings may affect how it will be reproduced anyway. So...use with discretion is a good guide. If you need special enhancement in a particular part of a song that 'extra bass' will add, use the LFE. If you want to have signal present throughout the song, add some of the bass instrumentation (including kick if you like). Check to make sure that the LFE signal is not 'missed' if is it missing when played back.

As you begin the mixing process, move around the room to determine if anything 'weird' happens (phasiness), as listeners do not always sit in the center of their listening space. The listener should feel immersed in the performance, but not uncomfortable. This is a very subjective definition, and you will have to judge this for yourself. Certain music styles may allow for more 'aggressive' presentations than others.

Mastering Prep

Naturally, we want to help you with preparing your master 'tape' so that it is in a form that makes it easier to work with. Check out our 'Formats' section to see what delivery methods are best for you.