THE GREAT OUTDOORS
Aug 1, 1998 12:00 PM, Mark Halvorsen
Ah yes, the familiar sights and sounds of summer. Tofu dogs decomposing onthe barbecue, cheery and gay squeals of young siblings engaged in lethalaquatic horseplay, oil slicks of SPF-400 sun/mosquito screen, and themuffled roar of an overdriven, indoor-bound hi-fi system inadequatelyfilling the acoustic needs of the neighborhood just so you can hear itpoolside. Perhaps you restore high-frequency fidelity and keep theair-conditioning mostly inside the house when you poke a bookshelf speakerout a partially closed bedroom window. At best, it is still only acompromise.
There are more permanent solutions to outdoor decadence. Hi-tech gadgetsbeyond pilotless ignition (for the grill and the spa heater) abound for thebackyard swimmer. In addition to the solar-powered algae busters andenzyme-based body waste disintegrators, a myriad of entertainment- andcommunications-related products are ready to stimulate our senses with thesafety, reliability and ease of use that one demands on summer holiday.Familiar indoor devices that play music, control its volume, select itssource or even illuminate its listening area at night almost all haveoutdoor counterparts from established manufacturers that were founded inenthusiasm for bringing the party outdoors.
As with any installation, the client's needs and desires, often profoundlydissimilar, will dictate the style, design, budget and irrational behaviorthat goes into bringing an idea to fruition. The single greatest benefit ofa distributed sound system in any application is low level, intelligiblecoverage throughout the place-anyplace. Although typical homeowners don'teven notice a well designed distributed system when they're at the airportor miniature golf course, they can certainly grasp the idea of keeping thevolume low, yet clearly heard around the house and yard. Given that, ourjob as system designer is to deliver the goods. Find out where they lounge,where they grill, where they want to hear audio. Find out what they enjoylooking at in the backyard. If its loudspeaker boxes and strings of wire,you're in luck. If it's rocks, fountains, or nothing conspicuous, you'restill in luck.
Architectural design of the home and of the landscaping contributeenormously to the selection and placement of loudspeakers. When loudspeakerlocations are determined, the question becomes one of running cable.In-wall applications see anything from $.15/ft, 18 gauge lamp zip chord tothe most esoteric, oxygen free, thick and twisted cable offerings. Newconstruction is always easiest, drilling holes through exposed two-by-fourstuds and pulling wire for all you're worth. Retrofitting after the factcalls for an experienced installer's bag of tricks, which inevitablyincludes the utilitarian flexible drill bit. Usually about four feet (1.2m) long, these handy devices are also sometimes referred to as bellhanger's bits, and when used carefully, can make short work of running wirethrough a finished wall. These bits almost always include a tinypre-drilled hole in their tip for the purpose of attaching a twine orstring while accessible in the in-wall loudspeaker cavity, then pulling thebit and the string back down to the junction where drilling commenced. Atthat point, the final loudspeaker wire is attached to the string and pulledback up to the cavity where it can be plugged in (sometimes months later)to the installed loudspeaker. It's a push-me, pull-you, pull-me-backoperation that doesn't have to take any longer than 10 minutes. Just besure and invest in the special application bit-bending tool that helpsprevent damaging wall paper or custom mixed paint around the edges of yourjunction box.
Sending an audio signal to outdoor loudspeakers doesn't have to be any morecomplicated. Snaking wire inside a wall up to an eve-mounted boxloudspeaker is certainly tidiest, if not easiest. To prevent wire chafing,wrap a few turns of tape around the wire jacket portion that may come intocontact with the edge of the hole you've poked through the wall. Seal thatwhole hole when you're done, too. No sense letting the varmints in. If,however, your speaker is out in the yard or across some other open space,you'll probably need a shovel. As opposed to most code requirements forunderground transmission of line voltage (110/220 VAC), which usually callsfor wire in conduit to be buried 18 inches (457 mm) underground orunprotected romex at 24 inches (610 mm) subterraneous, loudspeakers andlow-voltage lighting typically use wire that falls under UL categorycontrol number PITY (there must be a pun for pitiful sound contractors) for"medium voltage cable." This stuff can usually lay on top of the ground,although aesthetics and safety would have a conscientious installer bury itat least a few inches underground. Parameters for wire vary wildly,depending on the level of audio performance expected, resistance toenvironmental factors like temperature and humidity, and the number ofconductors required (two for a loudspeaker, four for a stereo pair and morefor loudspeakers with illumination features.) There also exists armoredgopher-resistant cable with steel reinforced jacketing but no guarantee offlat frequency response.
"Beware of an induced 60 Hz hum," warned Bruce Busacca of Secure inBakersfield, CA. "With sound and lighting features scattered over the hugebackyards around here, the homeowner's temptation is to have the lowvoltage wire pulled through the same conduit or laid in the same ditch asthe electrical service for the pool equipment or a fountain. Try not to runthese wires parallel, or even near each other. Why risk the vulnerability?"
With regard to underground junction splicing, Busacca added, "Unbroken runsare obviously the best. But if you have to splice underground, then youhave to splice underground. I've had the most success with a two-part gelpack that surrounds my splices with an epoxy like resin that is veryappropriate for direct burial." A variety of splicing materials can beused, from brush-on coatings and adhesive sealant patches toheat-shrinkable adhesive sealed butt splices and recommended tapecombinations ("do the rubber stuff first, then the black plastic stuff.")
After wires have been run underground and across the yard, they've got tocome up for air or termination. Ground-dwelling loudspeakers sit on motherearth and termination requires the care, especially if vulnerable tomoisture and critters. Garden-destined box speakers may take advantage ofapplication specific stakes. Some handy devices have a pointy end and atechnical end. The pointy end is pounded into the ground about a foot and ahalf. The technical end is a multitudinous cluster of holes, slots andbevels that allow for direct fastening of a loudspeaker box with holes onthe top, bottom, back or side. They can be machined with tabs that bend upor down, creating a miniature platform for the box to rest upon and bebolted to. However, if rough and ready more aptly suits you or yourcustomer, a fine piece of one inch (25.4 mm) stock square tubing offersmany of the same long, hard fastenable features, with an additional benefitof providing a safe conduit to run the wire up through. Securing any ofthese stakes in a concrete footing adds a huge degree of theft deterrence.
What about the transducers, the loudspeakers, the woofers and tweeters? Acontemporary home with sharp angles, vast monochrome surfaces, andultra-low maintenance concrete landscaping around the pool might be bestserved with in-wall , weather resistant loudspeakers strategically placedto maximize acoustic phenomena created by the side of the house. Weatherresistant, flush-mounted, in wall loudspeakers ranging from four inch (102mm) two-ways to 12 inch (305 mm) subwoofers are offered from many dozens ofspeaker manufacturers, most all with nominal 8 V impedances. Manymanufacturers of marine application loudspeakers also fight the elementswell and are usually of the 4 V spec more typical of the 12 V, car-ficounterculture underworld. Even with polypropylene or nylon diaphragmcoatings, weather resistant is differentiated from weatherproof so as tokeep us installers from making false promises. Let the client know thatthis is an evolving category with subsequently unperfected technology.
"Even with salt fog, humidity, and temperature testing of Mil Standard XXXas a benchmark, you can never tell if El Nino winds will throw a treebranch through a loudspeaker grille or if floodwaters might turn aground-level installation into an underwater warranty claim" laments LarrySchatz of Xantech/Videolink.
For placement of flush-mount loudspeakers yielding the best outdoor sound,your acoustical gut instinct will probably be right if you've been in thebusiness long enough. Separate low-frequency drivers placed in the boundaryloading corners of walls, planters, the house and pool deck will alwayssatisfy a quench for rich, full bass even at low-book-reading, ray-soakinglevels. Several in-wall eight inch (203 mm) two-ways are available, said toperform quite satisfactorily in excess 85 dB/1 W/1 m without the benefit ofa 3p stucco corner. Near-field monitoring is not limited to the recordingstudio either. Ear level on a horizontal plane can also mean just a fewfeet off the ground when listening from a hot tub.
"I've placed in-wall speakers less than 12 inches (305 mm) above the footerplate just to point the tweeters into the foam," said Bob Buehler of OhHi-fi in Ojai, CA. "Close proximity and directional high frequencies likensthe effect to wearing headphones in a bubble bath."
A designated lounge chair area or poolside picnic table may also be reasonfor installing nearby in-wall loudspeakers at a seated person's ear level,particularly if windows and planters make the aesthetic more pleasing.Being sensitive to the neighbors wouldn't hurt your chances of a Christmasfruitcake either. High frequencies go where you point them, and if you canpoint them into a fence instead of over a fence, the neighbors will alwaysappreciate it.
Surface-mounted box loudspeakers are a little more flexible. Most of themcome with at least the simplest bracket, allowing installation by directlyfastening to walls, trees, posts, beams, railings, rafter tails or anywherethat lends ample safety to a little box overhead. Many companiesmanufacture brackets designed to bolt to the back of just about anyloudspeaker enclosure, thereby offering the advantage of a nearomnidirectional swivel. Alert speaker manufacturers choose box surfacematerials that are easily painted so as to blend in with the decor of thehouse or disappear into the bushes. With some designed as acousticsuspension (sealed box) systems and others bumping a bass-reflex curve,outdoor tolerant, residentially appropriate flush-mount loudspeaker systemsare commonly available.
Novelty loudspeakers are far and away the most fun, if not of suprisinglyhigh fidelity. Models are available in sandstone, granite, coral gray andlava red, and they sometimes come equipped with a lifetime warranted glassfiber reinforced concrete shell. Desert Stereo's Richard Wood is one of agrowing number of installers who likes to mix and match componenttransducers for truly custom system design.
"Because paper disintegrates over time," he said, "we've come to count oncomponent transducer with a metal alloy cone with ceramic coating and acast aluminum chassis. Materials resistant to UV degradation are alsoessential, although most of mine go into overhangs or eves. We really tryto shield the speakers from the elements whenever we can."
An elegant approach to outdoor sound that also incorporate low voltagelighting are the loudspeakers that employ omnidirectional dispersiongeometry with ported enclosures made from DuPont's Corian material thathave been hand milled and hand assembled.
The outdoor home audio system market certainly cycles as the seasons doeach year, and is more prevalent in regions of the country where theweather is good for longer periods of time, but as the sophistication ofthe home automation market expands and more of the market is tapped, thissegment will continue to be an important revenue stream for the installer.