System	Bandwidth	Min/Max Levels	Dynamic Range	Stereo Quality
Home Stereo	40 – 15000 Hz.	50 – 100 dB SPL	50 dB	Good to excellent
Mono Table Radio/TV	250 – 8000 Hz.	65 – 80 dB SPL	15 dB	Nonexistent
Headphones/ Walkman	20 – 17000 Hz.	40 – 110 dB SPL	70 dB	Excellent
Automobile	60 – 8000 Hz.	70 – 90 dB SPL	20 dB?	Poor
Boombox/ Stereo TV	150 – 8000 Hz.	60 – 95 dB SPL	30 dB?	Fair
BoomVan	30 – 15000 Hz.	70 – 120 dB SPL	50 dB?	Poor/Good
Home Theatre	20 – 15000 Hz.	50 – 105 dB SPL	55 dB	Excellent (surround)

Table 1. Various end-user systems and their basic ranges and attributes.

Mixing For All of The Above

Obviously, there is no single way to mix for this range of systems. There is no right and wrong, no approved method. Further, there is no single “sounds best” type of answer. The systems are, in many respects, mutually incompatible.

The good news is that, odd as it seems, “good” mixes seem to sound good everywhere; it’s the mediocre ones that don’t travel so well. So, if you can manage to pull off a “good” mix, you may be back in the sweepstakes. But first:

Targeting Your Mix

You have some decisions to make abut who your fans are. No sense mixing for audiophiles when you are doing a compilation of house hits. Forget the boom-van when you are doing an acoustic jazz CD. Don’t worry about the mono table radio when you are recording a Beethoven String Quartet. You are going to take lumps somewhere. Take ‘em where they don’t matter much.

Resolving Incompatibilities

To me, there are three big incompatibility areas: mono-stereo, dynamic range, and stereo image/spacey stereo.

Whatever stereo techniques you are using, make sure that they don’t destroy the mix in mono. I did a piece on this last winter if you want to check out what I think “mono-compatible” means. The only exception to this is when you are utterly indifferent to whether or not your work is going to be commercially broadcast.

Dynamic range is a curious one. There are two parts to it. First, there is the range in level between the loudness of the signal and the loudness of the noise floor. You’d like this to be huge in your recording, so that the noise floor in the playback environment always masks the noise floor in your recording. The second part is the range in loudness of the signal itself: the range between the softest signal (not noise or ambience) versus the loudest signal. In acoustic music, this range tends to be pretty substantial (40-50 dB, maybe). For drivetime, think 6 dB. For conventional pop recordings, 6-10 dB is a nice range. For more experimental, alternative or unplugged stuff, think of 15-20 dB. If the loudest program peak just tickles +3 VU on your standard “VU” meters, then when the meters are barely moving your signal is 20 dB down.

Stereo has a couple of attributes: there are both the sense of localization and the sense of space, also called “envelopment.” Localization requires careful control of the stereo soundfield, listening on the median plane, and lots of attention to sonic detailing. Spaceyness may be as simple as a very wet stereo reverb wash. Coincident mics yield comparatively less spaceyness (not necessarily a bad thing), while spaced mics yield comparatively more. If there is lots of time-difference stuff in your direct sounds, you will have mono-compatibility problems. If only your ambience (say 6-10 dB below the direct sound in level) has lots of time differences, the mix will sound spacey while remaining mono compatible.

Testing, Testing. Check, One, Two . . .

As you can imagine, there is no substitute for listening to your work. You’ve got to take your mixes out into the field to try them out. Ride around in your car. Hell, ride around in your boom-van! Listen over headphones, listen in a living room. Listen over a mono table radio or it’s equivalent, the Auratone. Listen, listen, listen. Make notes. Then go back into the control room and try to adjust the mix to take care of the problems you noticed. Then out into the field you go again, to test once more. As you get good at this, you should need less and less time to refine your mixes – you will come to intuitively know what works and what doesn’t in each environment, and also have a pretty good sense of how much it will matter in any given musical case.

Happy clients!