Audiophiles can’t go anywhere without high-performance sound — not even, it seems, under water. For the hi-fi enthusiast with cash to spare, piping music into a swimming pool is a no-brainer.

Built-in underwater speakers are another example of how resorts are influencing the residential pool. Just as waterslides, grottos, lazy rivers and tanning ledges have become staples of the ultimate luxury pool, so too have sound systems. Having experienced immersive audio at Disney and Hard Rock properties, vacationers, understandably, want to recreate the experience in their own backyards.

The good news: Wiring a pool for sound is pretty straightforward. (Know how to install a pool light? You’re qualified.)

The bad news: It’s expensive.

Underwater speakers can fetch upwards of $1,500 each, and larger pools will require at least two. Plus, your clients will need an amplifier and mixer, and they’ll likely want to integrate underwater speakers into the overall outdoor sound system for uninterrupted tunes in and out of the pool. It’s not a small investment.

But for some consumers, cost is of no consequence, which is why audio equipment manufacturers say they’re making inroads into the residential arena.

“For a lot of these high-end pools, $20,000 is nothing when they’ll spend $60,000 on a ramp or walkway or fake tree,” says Edward Harper, owner of Oceanears in North Canton, Ohio.

Others see an uptick in sales to the backyard market. The lesson: Never underestimate the desire to keep up with the Joneses.

“Dealers have realized that when underwater speakers are in a pool, that pool becomes the envy of the neighborhood,” says Bill Phillips, president of Littleton, Colo.-based Clark Synthesis.

Here’s your guide to creating soundsational pools.

Sound science

As a conduit for sound, air isn’t ideal. Soundwaves travel more easily through material such as wood and steel. That’s why you’re able to hear the chugging of an oncoming locomotive when pressing your ear to a railroad track.

The same principle applies underwater, where molecules are denser, allowing sound to travel approximately four times faster than through air.

In fact, water is such a great conductor of sound that researchers are currently exploring its therapeutic applications —the theory being that, because the body is composed primarily of water, then perhaps a submerged body would be more sensitive to certain frequencies.

Fringe medicine aside, one thing is clear: “It’s just crazy how good the sound is underwater,” enthuses Marshall Foote, partner at Colorado Pool + Spa Scapes in Glenwood. Every year, about three of the firm’s projects involve audio systems.

Underwater speakers provide a sensation unfamiliar to many. Tunes heard below the deck can even cause confusion among the uninformed as they try to identify the source.

“If they don’t know underwater speakers are there, it kind of plays with their mind. They think they’re hearing the music that’s above the water,” says Frank Giuffre, owner of Coastal Audio Video in Sarasota, Fla. (He’s also the AV wiz who frequently appears on Animal Planet’s “Insane Pools.”)

Of course, that would be impossible. A swimmer would not be able to hear open-air speakers from the bottom of a pool — not well, anyway. The water/air interface is too difficult for soundwaves to penetrate. The only way to deliver audio with optimal clarity is to install speakers directly in the water.

Fortunately, you don’t have to waterproof a 7.1 THX system to bump beats in the deep end. Built-in underwater speakers mount pretty well flush with the wall using the same niche housing that you’d use to install a light.

Despite their slim profile, they pack a punch. That’s by design.

Unlike its land-based counterpart, this type of speaker doesn’t need to accomplish the big displacements needed to push sound waves through the air. In other words, there isn’t the rhythmic undulating seen on conventional audio equipment.

That’s because underwater units use transducers to deliver sound through vibrations. In effect, transducers convert the surface they’re attached to into a speaker. Think about how sound vibrates off a cello. It’s the same idea. In the case of a pool, they’re sending musical vibrations throughout the vessel. You can even hear the music from the deck as it reverberates through the foundation. This, however, isn’t the best way to enjoy a playlist while relaxing poolside — outdoor speakers are still recommended for that.

An ear for design

Underwater, you will not find sound produced in stereo. That’s because the waves travel so fast in water that the human mind can’t process if they’re coming from a left or right channel. This makes swimming pools strictly a mono environment.

But that doesn’t always mean one speaker will do the job.

To deliver adequate sound, one supplier suggests one speaker per 20-foot-by-20-foot area of pool. For lap pools or those with long and narrow segments, install one for every 20 linear feet.

This is important to know ahead of time, because contractors must determine where the speakers will go before shooting or pouring the pool or spa shell.

For more complicated projects, such as freeform pools, installers may want to supply a layout to the audio manufacturer to determine optimal speaker placement.

When it comes to retrofits, some contractors avoid adding speakers, because it can’t really be done without chiseling out a niche or swapping out the pool light for a speaker, which is possible since they are installed in standard lighting niches.

Generally speaking, speakers are affixed 18 to 30 inches below the tile line. In cold climes, installers should insure that they’re below the freeze line. You may even advise your client to unmount them before the pool freezes through.

Here’s another tip, and this one is crucial: Do not install the speakers directly opposite of each other. This could cause the soundwaves to cancel out. So, stagger them.

Installers advise keeping speakers a good distance from waterfalls and swim jets and other features that could interfere with sound quality. For large pools with these amenities, the client may have to spring for multiple speakers.

“Three is my go-to number, because you can cover a great amount of area if you do have water features,” Giuffre says.

But why stop there?

Some clients opt to have as many speakers as they do lights.

“They tend to want them equidistant from the lights,” says Foote, the Colorado builder.

Yeah, but is it safe?

With the pool industry on edge about recent electrocutions involving pool lights, some might question whether the addition of audio wattage is wise.

Manufacturers stress that all bonding and grounding requirements for pool and spa lights also apply to speakers. In addition, speakers are installed with an isolation transformer, and the amplifier should have a ground fault circuit interrupter — all of which make audio in the water perfectly safe, experts say.

As an added precaution, the National Electrical Code now requires that speakers include a stainless steel grill and mandates that they be installed in a stainless steel niche to contain any stray voltage.

This is in contrast to several years ago, when speakers were installed open-faced inside a plastic niche.

At least one manufacturer believes this is a bit of an overreach as a swimmer has never been killed by a speaker. That grill doesn’t do the sound quality any favors, either.

“I hate to say it, but it does have an influence,” Hooper says.

Professional installation

As mentioned earlier, the process for installing a speaker is basically the same as it is for a light.

After affixing the niche and running the conduit, the pool contractor’s involvement in the audio portion of the project should be complete. AV specialists take it from there.

Audio professionals should be relied upon to handle the tuning and wiring intricacies, such as tying the underwater speakers to the whole house audio system.

This set-up commonly includes integrating the landscape speakers and underground subwoofers and adjusting the levels accordingly. For example, there should be separate volume settings for patio speakers and pool speakers. (You want music under water to be pleasing, not ear-splitting.)

The result should be superior sound whether grilling or swimming.

“It’s seamless,” Giuffre says. “You go in and out of the water and hear the same tone — it’s amazing!”