All Bass is Covered, Part 2

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A dictatorial approach to bass management in surround music mixing.

By Richard Elen

Last time, we began to take a new look at music surround monitoring by considering the role of bass in a 5.1 system. In the second and final part of this series, we consider how to listen to it successfully.

Part II: Getting Music Surround Monitoring Right
What do you use to monitor surround music in your control room? In many cases, you will probably have five quite decent loudspeakers. Even most nearfield monitors are large enough for the majority of home theater receivers to consider them “large,” i.e., capable of handling bass. When you were monitoring on two of those speakers in stereo, did you need a subwoofer? No. Do you need one now? If so, how should it be connected? Yes, a lot of home theater systems have a sub, but they have a sub driven by bass management, and this is the important difference. And in bass management lies most of the answers to these questions.

Do you have bass management in your studio? Probably not. Do you need bass management? Almost certainly. Thus, rule #3:

If you have a subwoofer, and/or you use the LFE, you need bass management.
Here’s the one situation where you may not need bass management in the studio: if (a) you have five full-range speakers (or something that most people would consider full-range — it might be nearfields in your case, but be sure you know how much bass they actually give you in case the average listener at home can hear the low end better than you can); (b) you have no subwoofer; and (c) you are not putting any information in the LFE.

This, obviously, is an extension of what you’ve been doing for decades in stereo. You know the speakers and what they sound like. You don’t need a sub to hear the bass (you never used one before now) and you are not putting anything in the LFE (Rule #1 from last time), so routing any additional bass from there to the existing speakers isn’t an issue. You are mixing and monitoring in 5.0. This is probably the simplest way of successfully monitoring your surround mix.

Add a subwoofer and you immediately need bass management. Otherwise, if you connect it directly to the LFE, as too many people, I have found, do — you will be fooling yourself.

Your DAW will let you put signals into the LFE, because if you’re mixing film sound, you need to be able to do that. In film sound, you may have asteroids to contend with. And dinosaurs. Of course, it will sound impressive if you route some bass guitar down there, but what will happen at home?

What will happen is that the listener may well get too much bass — even more than that little push you intended. If they have a sub, they’ll probably turn it down. The setting on the receiver (or on the back of a powered sub itself) turns the sub down, not just the LFE, so now they have ruined the balance at the bass end of your mix, because in turning down that errant bass guitar’s bottom end, they have also turned down what may be the only thing in their system that’s putting out any bottom end at all.

If they have five full-range speakers, on the other hand, they will simply curse and hunt around their receiver to see if they can find the tone controls. If they find them and turn the bass down, they will have done the same thing: ruined your bass balance. Because you did it wrong.

Meanwhile, reviewers, who all have properly configured bass management, are complaining about how the bass end of some instruments doesn’t integrate with the rest of the mix, and there is too much bass being generated from all kinds of things. This will hurt sales, which is the last thing you want at the moment.

Can you do any worse than this? Yes, you can. You can start messing with the lowpass to your sub (the one that’s still connected to the LFE with no bass management) so that it doesn’t crossover at, say, 80–120 Hz like Dolby suggests, or like the people have at home (because Dolby designed their system at some level) but at some other frequency. You can probably imagine the trouble this will cause with the listener at home hearing holes or bumps in the frequency response — something entirely unlike what you intended.

If you feel you need a sub — either to compensate for lack of bass in small speakers or because you want to emulate the typical home system more closely — or you need the benefits of bass management, there are several systems available today that include it, such as those from Audient, Blue Sky, M&K, and Martinsound, for example. There are also powered subs, for example, from Genelec, that take the full-range signal from all your feeds and handle bass management for you. Steinberg’s Nuendo Surround Edition includes bass management plug-ins.

So now you have your bass-managed monitoring system, matching the situation at home, where listeners also have bass management. What happens if, as will now inevitably be the case, you want to push the bass just a bit in the chorus to give it a bit more oomph? Well, that’s easy. You just push the bass (or split it and use two faders, or whatever). You aren’t sending anything to the LFE. One or more of the five main channels carries the extra bit of bass, which is fine — there’s plenty of room.

At home, let’s say, the listener playing back your mix has some reasonable speakers with a sub. The extra bass emerges from one or more of the main channels and is fed to the sub, where it gives the extra “kick” you intended. Which, of course, is the whole idea: people hear what you wanted them to hear — what you heard.

You can take all this one step further and hook up a replay system to play back the disc itself on your monitors just to check that it still sounds the way you intended, and control all this with a suitable surround controller, which can also handle various decoders and systems.

And we could leave it there, except for one thing. What about all those people at home (of whom, of course, there are many) who do not have their systems set up properly? We know that many people put their stereo speakers in silly places — one channel up on the bookcase and the other behind the couch — so how many million even worse combinations might they have used to ruin the effect of your carefully monitored surround mix?

People who care about music will generally set up their systems, using the manual or on-screen instructions, and will generally get it reasonably right. (There, of course, will be some who simply don’t manage it because it’s too complicated for them — but this is an issue for the consumer audio manufacturers). Record companies also can, and do help (especially the smaller ones) by including audio setup tracks on the disc, or information in the liner notes.

There is nothing we can do about the guy who has his speakers in funny places, and his sub turned way up so that the effects on the latest action movie jiggle his guts more. I suggest that the people who don’t care, won’t care what you do; while the people who do care, care a lot. Make records for the latter, and let the former look after themselves. They will anyway. They may even think you meant it that way.
Whatever you do, don’t make a guess at how to fix it for the people who don’t care and thereby damage the effect for the people who do. The people who care are the main people who buy your surround music mixes.

Richard Elen is director of creative and technical services at Apogee Electronics Corporation in Santa Monica, CA. The views expressed in this article are those of the author and do not represent those of his employers.

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