The Home Stereo Hi-fi

This is the stereotypical setup we usually mix for: I tend to imagine a listener and/or significant other sitting on a sofa looking at a fireplace or window with loudspeakers on either side. I assume they are listening fairly carefully, they are seated on the median plane (more or less) and that the quality of reproduction is pretty good: say, 60 Hz. to 15 KHz. +/- 5 dB with 50 dB signal-to-noise ratio.

Such setups are extremely variable, of course, so that on the low end we have cheap rack systems that don’t even approach the above specs and on the high end we have audiophile systems that reproduce from DC to UV. The central commonality, to me, is that they all have a viable median plane with the loudspeakers pointing at a so-called sweet spot along it, and at least reasonable signal-to-noise ratios.

When we mix, it is these setups that our studio mixdown monitoring configuration usually is supposed to represent.

The Mono Radio/TV

This is the forgotten bottom end of the audio playback food chain. There are simply zillions of table radios and TVs out there, sitting in bedrooms, kitchens, garages, RVs, dens, boats, bathrooms, patios, hallways, basements, fire escapes, front porches, and other spots where humans hang out and listen to music, with or without accompanying video.

Such situations have marginal audio quality: 250 Hz. to 8 KHz. +/- 5 dB and limited power output (except through the adoption of massive distortion) so that usually sound levels will be between 60 and 80 dB SPL at 4 feet. There is no stereo and therefore no median plane. On-axis listening is mostly irrelevant, so the frequency response will often be even worse, and the surrounding noise floors (showers, lawn mowers, dishwashers, furnaces, street noise, etc.,) reduce the signal to noise ratio to something like 10-15 dB.

While the temptation is to simply throw up our hands in disgust and say, “I can’t mix for those conditions; this is really stupid!” it is important to remember that a great deal of music is listened to under these circumstances (including much MTV!!!!), so it may be really important to you to mix recordings that have impact even under these really marginal conditions.

Headphones

Headphones are just about the exact opposite of the mono table radio. They are also everywhere. Some of them isolate the listener from the outside world, some of them don’t. Because they are so close to the eardrum, limited power can generate quite high sound pressure levels with minimal distortion. 100 dB SPL is pretty easy. Bandwidth is very good, because of the small transducer (for high frequencies) and the coupling to the eardrum (low frequencies). Further, you get stereo with a vengeance, because the middle of your brain is by definition the median plane. If the phones provide 15 dB of isolation, you can expect something like 60-70 dB signal-to-noise ratio. Actually, stereo on headphones is a little different than stereo through loudspeakers. The phantom image behaves a little differently and there is significant variability between various listeners’ perception of stereo while wearing headphones.

Three big problems emerge. First, low frequency response can be highly variable with headphones and so the effect of the equal-loudness contours (low-frequency balance changes) are very pronounced. Second, reverberant detail is greatly magnified, so that what seems appropriate with loudspeakers seems crassly overdone on headphones, and vice versa. The third big problem is simply the dynamic range. If you mix for the dynamic range of a table radio and/or car, your actual program material is going to have a dynamic range of about 6 dB. Over headphones, that feels like you are being beat around the head with a blunt two-by-four. If you mix with dynamics for headphones, your table-radio and drivetime listeners are going to miss big low-level chunks of your recording.

Cars

Ah, yes. L’automobile. Drivetime. Backseats. Top-down life in the fast lane. Running her up in third through some fast sweepers, the big V-8 bellowing its sweet machine song. Sitting at traffic lights, snail-trailing in the middle lane. Music, America, the great post-war cultural tradition of Highways, Wheels and Road Music. We got a lotta ‘motional baggage here.

For some whacked out reason, it works, although physically speaking it really shouldn’t. Your basic modern car sound system has four small speakers (two in the front doors, two on the real deck panel) driven by low-power amplifiers. It can crank out just about 90 dBA SPL if you throw in copious amounts of distortion to help it along. The noise floor of the car at speed, with the windows closed, is typically around 65-70 dBA SPL. You are off-axis to all the speakers, you can’t possible get near the median plane (unless you have bench seats in an old Cadillac Eldorado or Ford Fairlane - but then you don’t have stereo sound), and the whole situation is just about hopeless. Signal-to-noise is usually around 10 dB, frequency response is 100 Hz. to 5 KHz. +/- 10 dB.

To get a real feel for this, imagine, some time when you are mixing, that your console is installed across the dashboard of a Chevy Caprice, you are in the driver’s seat, your producer is riding shotgun (hmm, there’s an image for you), you are on the New Jersey Turnpike at 4:45 PM headed south through Newark accompanied by several thousand trucks, buses, cars, vans, motorcycles and low-flying airplanes ‘n helicopters, and it’s raining heavily. Now, contemplete your mix. How about a little extra reverb on the harmony vocals and maybe make the bass a little less tubby. What vocals? What bass?

The automobile presents all of the table radio problems, with stereo thrown in to make it a little more challenging. What is working for you is that you’ve got bored, captive listeners who are just sitting there and whose minds are ripe for the great musical turn-on – drivetime is fantasy time, and if your mix can work while the semis whiz by, you’ve done good for everybody. Consider 3 dB dynamic range, bandwidth from 150 Hz. to 4 K and phasey stereo effects. Forget the stereo image because nobody can possibly hear it anyway.

The Boom-box and Stereo TV

The boombox, as you well know, is a small, portable playback system with left and right speakers up to about 18 inches apart. The speakers are usually of mediocre quality, there often is ersatz EQ, bass and stereo enhancement, and the whole production is generally pretty cheesy. The little dears will put out about 85 dB SPL @ 4’ on a good day, with bandwidth from 200 Hz. to 8 KHz., plus or minus a lot. Signal to noise ratio can be quite good, because you can stick ‘em right in your face! Harmonic distortion is a standard artifact included with all models.

Stereo TV is the same thing with a big video monitor stuck on to the top of the boombox. It isn’t nearly so portable, and usually you sit across the room from it so the dynamic range is about the same as a mono table radio/TV.

The stereo we get from these things is different, but it is fairly interesting. With speakers stuck so close together, you’d expect there to be little stereo spaciousness at all. However, there is a clear “stereophonic” effect that gives a kind of depth and solidity to the audio, plus sometimes a sense of spaciousness. When you listen “in-yer-face,” the stereo becomes a little more normal.

The Boom-van

The boom-van is a recent arrival in the consumer listening systems sweepstakes. Without dwelling on the sociology of it, it seems to me to be related to the evolution of low-frequency sound in rap music. This is definitely worthy of study. Briefly stated, a boom-van is any vehicle rigged out with a high-power sound system and particularly a subwoofer. Because of the compliance of the outer shell of the vehicle, there is a fair amount of low-frequency decay (which is why we hear the characteristic “doommmmfff doommmmfff doommmmfff da-doommmmfff” of boom-vans as they drive by). Because considerable care has been taken with the installation of the HF speakers, frequency response is going to be fairly broad (some might say hyped), with plenty of bottom end (to 40 Hz. in a full-sized van). The multiple speakers (eight?) make for spacey, phasey stereo, and due to the higher power, the levels probably reach 120 dB SPL casual, but not without a little distortion. The signal-to-noise ratio improves from 10 to 30 dB.

What I’ve noticed since I’ve started studying rap ‘n boom-vans is that the kick-bass aesthetic of rap and hip-hop music is dramatically different from the rock kick-bass (an article is in progress on this) and it seems particularly well-suited for the boom-van – low-frequency pillows of sound that pulsate, rather than the hard-edged attack of the Quincy Jones kick drum. As I said above, I suspect there is a relationship here. Stay tuned.

The Home Theatre

The home theatre has a 5.1 set-up that will range in quality between mediocre and superb, and will include a decent L/R stereo pair of speakers, a center speaker, surround speakers that may be of lesser quality, and a subwoofer. At their best, such systems are stunningly good, while at their worst they are slightly better than mediocre home stereo systems. My experience has been (writing from 2005) that they are a LOT of fun!