You're at a theme park. The smell of funnel cakes has your mouth watering. Hundreds of happy people are walking in all directions around you. As you turn the corner, suddenly you brush up against the fronds of a giant jungle fern. The sounds of drums seem to come from off in the distance, and exotic birds of all kinds chirp and squawk from the trees. You look up, hoping to spot the vibrant plumage of a macaw, but instead see the corner of a carefully camouflaged speaker. Next to you, another speaker camouflaged as a rock provides the sound of a rushing river.
You chuckle to yourself as you've figured out the secret, and marvel at the time and effort put into making the environment so immersive. And then suddenly it strikes you -- this expensive electronic equipment stays outside all day, every day. What keeps it from shorting out when it rains? For that matter, these speakers are out in the blistering heat in summer and the freezing cold of winter. Why do they still work so well, despite their exposure to the elements?
Two interesting cultural shifts have given us much better options for enjoying music outdoors. One is evolution in consumer electronics toward portable devices, as evidenced by the increase of popular devices on the market such as smartphones, tablets and MP3 players. Second is the rising popularity of a consumer category called outdoor living. Sunrooms, cupolas, decks, gardens, patios and poolside cabanas have become a more common part of home life. Audio equipment has followed suit to meet these consumer demands.
Speakers and sound systems are now manufactured to be outdoors 24/7, thanks to advanced materials technology. But underneath the weatherproofing, the speakers themselves aren't much different from the type you have in your living room. In fact, they operate on the very same principles. A speaker's job is to take electrical signals and turn them into the mechanical energy that creates a disturbance in the air that we can hear.
Weatherproof Speaker Basics
If you've read How Speakers Work, then you know that speakers are relatively simple devices. In general, a speaker's three core elements are the drivers, crossovers and the cabinet.
- Drivers: The drivers convert electrical energy into vibrations, producing different sound pitches. A diaphragm -- the external cone-shaped part of the speaker -- moves back and forth to help with this process. Larger drivers that reproduce lows are called woofers, small drivers that reproduce highs are called tweeters. Drivers which produce frequencies in between are midrange.
- Crossovers: These electrical filters split up the audio signal and divide up the sound pitches via the drivers. For example, "two-way" speakers consist of a woofer and tweeter, and "three-way" speakers have the three separate drivers in one speaker cabinet: a woofer, tweeter and mid-range.
- Cabinet: As the name implies, cabinets are the structures which houses the internal components of a speaker. The speaker cabinets (or enclosures, as they are often called) act to manage the sound waves, affecting how sound is produced.
Let's get something cleared up: Although the two terms are frequently confused, weatherproof and waterproof mean two different things. Weatherproof speakers are made specifically to stand up to outside elements, but are considered water resistant, not waterproof. If weatherproof speakers are exposed to humidity, steam, rain or sprinklers they should be fine. Keeping them sheltered will help them last longer, though.
Due to the need to withstand exposure to water, rain, sun, snow and other extreme conditions, weatherproof speakers are manufactured with special parts and materials. They're also subjected to rigorous testing that replicates Mother Nature.
But weatherproof speakers aren't meant to be submerged in water. If you need to install speakers in your pool or hot tub, you should invest in waterproof speakers instead.
What Makes Speakers Weatherproof
Weatherproof speakers aren't much different from indoor speakers. The main difference is the type of material used for the inner and outer components:
- Indoor speakers have steel frames and grilles are susceptible to rusting, corroding and dissolving. Manufacturers of weatherproof equipment use stainless steel, aluminum or brass.
- Unlike weatherproof speakers, which use mylar diaphragms, indoor speakers have paper diaphragms in the drivers, which are sensitive to humidity.
- Weatherproof speakers need tough casings to protect their sensitive internal components from the elements. A polypropylene finish, resistant to rough handling and inclement weather, protects weatherproof speaker cabinets. The cabinetry can also be sealed with a watertight Teflon finish.
Once manufacturers have assembled their products, they typically undergo a battery of tests designed to make sure they'll hold up to the rigors of outdoor use. The speakers go through ultraviolet light tests, salt-spray tests and extreme temperature tests. Many companies evaluate eachcomponent of a speaker to ensure that it meets or exceeds expectations.
As you probably know, changes in temperature cause materials to expand and contract. Manufacturers of waterproof speakers check their products' dimensional stability to make sure that temperature and humidity changes don't cause damage. How do they do it? Testers measure the speaker components to see if exposure to heat and cold causes warping and damage. They'll also look for signs of weakness or gaps in the gasket -- a ring around the outside of a speaker that surrounds its frame.
Accelerated life tests stress a product to replicate the effects of aging and extreme temperature changes. They help manufacturers improve product reliability. And acoustic stress tests attempt to duplicate what a speaker might sound like after 10 years of use.
Installing Weatherproof Speakers
Traditionally, weatherproof speakers have been installed using wired connections. These speakers are often mounted under rooftop lines, in patio corners and under the deck. Speakers wired underground can have an omnidirectional design, so listeners don't have to be sitting in a particular sweet spot to enjoy the music.
Wiring and installing weatherproof speakers isn't extremely complex, but some people find the prospect of drilling into the exterior of the house and running cables through floors and ceilings to be a bit intimidating, so they contact local custom installers. Speaker cables can run through walls, attics, crawlspaces or the yard before finally being hooked up to the weatherproof speakers outside. For outdoor and underground wiring, installers use specialized, outdoor-rated cable designed to withstand the elements.
Most people who have a weatherproof speaker system use an indoor home theater or audio sound system to power the setup. By adding an additional zone to their existing setup, homeowners can hook up speakers to an independent volume and source control. If you're building a new house and have been thinking of adding an outdoor sound system, now's the time. An electronic systems contractor (ESC) will work with you and the builder to design a plan for outdoor speaker placement and cabling.
Lastly, you'll need to think about how to arrange your speakers so they'll sound most pleasant to you when you're outside. As with any new home project, you'll need to plan to get the effect you want. Make sure you:
- Position outdoor speakers as you would with your indoor sound system -- point them toward your desired sweet spot.
- Think of speaker placement like you think of lighting, in terms of where you want the light distributed and where you want to concentrate it.
- Keep in mind how trees, bushes or other foliage may impede the sound -- the environment can dramatically affect the speaker range and sound quality.
- Tilt the speakers so they face slightly down if they're mounted near the roofline.
- Experiment with your speakers before you permanently mount them and hook them up to cables.
- Consider where people will gather the most. Put speakers as close as possible to that area.
- Avoid cranking the system volume, which could distort the sound -- and disturb the neighbors.
Once your outdoor soundscape is complete, invite your friends and neighbors over for a party in your backyard, and show off your new weatherproof sound system!
More Great Links
- Babowice, Hope."Kids ask: Why does sound travel faster in water?"Daily Herald (Feb. 14, 2012) http://classifieds.dailyherald.com/story/?id=330044
- Baron, Al. Product Line Manager, Polk Audio. Personal Interview conducted Jan. 28,2010.
- Bedell, Doug. "Music Blossoms in the Back Yard with Creative Speaker Hook-Ups." Knight Ridder/Tribune Business News. The Dallas Morning News. Page 3D. July 17, 2003.
- Carpenter, Jason. "Outdoor Speakers." This Old House Magazine. (Feb. 14, 2012) http://www.thisoldhouse.com/toh/article/0,,1072838,00.html
- Consumer Electronics Association. Speaker Types Buying Guide. (Feb. 14, 2012) http://www.digitaltips.org/audio/speakerTypes.asp
- Dawson, Stephen. "Outdoor Speakers." Connected Home technology. Nov. 10, 2009. (January 27, 2010) http://www.connectedhometechnology.com/article/outdoor-speakers
- Dawson, Stephen. "Wiring for outdoor audio." Connected Home technology. Nov. 10, 2009. (Feb. 14, 2012) http://trade.connectedhometechnology.com/article/wiring-outdoor-audio
- Derene, Glenn. "The Ultimate Outdoor Digital Playground." Popular Mechanics. July 2009. (Feb. 14, 2012) http://www.popularmechanics.com/technology/how_to/4323063.html
- Donegan, Fran J. "The Ultimate Guide to Wiring." Creative Homeowner. 2007
- Encyclopedia Britannica. "Sound." (Feb. 14, 2012) http://www.britannica.com/EBchecked/topic/555255/sound
- Flynn, Michael. "More yards get wired with chic speakers." Citizen-Times.com. June 22, 2007. (Feb. 14, 2012) http://www.harmonyinteriors.com/news/chic-outdoor-speakers.php
- Newcomb, Doug. "Great Sound Outdoors." Sound and Vision Magazine. June 2003 (January 27, 2010) http://www.soundandvisionmag.com/article/great-sound-outdoors
- Ops A La Carte. "Reliability Services - Accelerated Life Testing." (Feb. 14, 2012) http://www.opsalacarte.com/Pages/reliability/reliability_prot_alt.htm
- Orfield, Kevin. "Grow Your Business with Combination Outdoor Lighting Stereo Systems." Lowe's Commercial Services. April 2008. (Feb. 14, 2012) http://www.lowesforpros.com/grow-your-business-with-combination-outdoor-lighting-stereo-systems
- Polk Audio. "Atrium Series." 2012. (Feb. 14, 2012) http://www.polkaudio.com/homeaudio/atrium/
- Puente, Maria. "Home Notes." USA Today. June 3, 2004. (Feb. 14, 2012) http://www.usatoday.com/life/lifestyle/2004-06-03-audio-rocks_x.htm
- Sabin, Rob. "How to build your own speakers: Step-by-step DIY tech." Popular Mechanics. July 22, 2008. (Feb. 14, 2012) http://www.popularmechanics.com/technology/how_to/4274625.html
- National Oceanic and Atmospheric Administration. "Sound travels faster in water than in air." U.S. Department of Commerce. (Feb. 14, 2012) http://oceanservice.noaa.gov/facts/sound.html
- U.S. Department of Energy. "Speed of Sound and Air Conditions." February 2012. (Feb. 14, 2012) http://www.newton.dep.anl.gov/askasci/phy00/phy00591.htm