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Lessons Learned from an Outdoor Pool Area Audio Calibration

Our client eventually wanted more. He wanted to “blanket” the pool area with sound in addition to being able to crank it up even more.

We have a great client in south Texas who loves music and good audio reproduction. He has numerous audio zones throughout his living compound, but really takes pride in showing off his outdoor pool audio system. Although our client enjoys listening to tunes while swimming in the pool, which he does often, his real kick is taking guests out on the pool cover at night to “play concerts” controlled from his iPhone. The interesting thing is that the pool cover is rated for 150 lbs. per square foot, so he can have several people out there at once laying on it like a gigantic waterbed and listening to audiophile-level music under the stars. Of course, swimming around in the pool when the cover is open sounds awesome, too.

First, A Little History
I will start by providing some insight into how the system came about and why our client wants to keep taking it to the next level. He had his pool area with the associated pool house built about 10 years ago. There were two in-ceiling Sonance 6-inch speakers installed in the pool house driven by an Integra receiver. The audio for the pool house patio consisted of two outdoor Sonance Mariner speakers and a separate amplifier. Additionally, the outdoor pool area audio incorporated eight Sonance 8-inch 70-volt Mariner speakers mounted to fence posts and driven by a Crown CDi 1000 70-volt amplifier.

Our client’s content mostly came from three Sonos Zone Players (now called CONNECTs) — one for the pool house, one for the pool house patio, with the third for the outside pool area — with inputs for the TV and a CD player. This gave him a wide variety of music selections while being able to control each audio zone from his iPhone. The sound was impressive.

This worked well for several years, but our client eventually wanted more. He wanted to “blanket” the pool area with sound in addition to being able to crank it up even more. After all, the neighbors were over two miles away!

There are many options to consider between price, performance, audio quality, weather conditions, reusability of equipment, and the impact to the landscape when migrating to a new platform. We ended up bringing in our demo Sonance Landscape Series (SLS) kit and temporarily setting it up around the pool area just to get a feel for how it might sound. While it was quite an improvement, the single 10-inch Sub and four 4-inch Satellite speakers (SATs) from the demo kit were nowhere near enough.

Fortunately, we work with a great pair of Dana Innovations (Sonance) reps from the San Antonio and Dallas areas that were willing to drive down and help us out. They each brought their SLS demo kits so we could evaluate what it would take to fill the pool area with great audio in addition to figuring out where we needed to place the speakers.

For those who do not know, the SLS product line uses Crown CDi Series 70-volt amplifiers. That means we had the ability to add speakers or move them around at will by connecting them to a set of 70-volt lines we strung around the perimeter of the pool. This was an advantage because it gave us a lot of flexibility in trying several configurations while not having to worry about how we would run a bunch of individual speaker wires back to a pile of amps. It made wire lengths less of an issue, too. It really allowed us to think out of the box, which is important when experimenting and optimizing the outdoor listening experience.

Another interesting design criterion came into effect as we were determining the best configuration. Getting the sound to fill the space is not a matter of just installing several big speakers and turning up the volume. The appropriate approach is to distribute the sound through a larger number of smaller speakers spread evenly over a larger area. Making it louder is not just turning up the volume. The way to increase the overall sound pressure level (SPL) is to add more speakers and keep the amplifier’s volume at the same level. Since the speakers connect via 70 volts, we could keep adding speakers until the sum of the fixed speaker wattages approaches the total output wattage of the amplifier (minus some headroom).

Installing the SATs low to the ground as one normally would (on their ground stakes) worked out well, but the soundfield still did not “envelope” the area as much as we would have liked. We came up with a way to mount some of them up higher on the fence posts. Adding this “height layer” (similar to what Auro 3D is offering now) made all the difference in the world. We doubled up speakers for some of the areas to supplement the speakers at ground (pool) level with the additional height layer. It really filled the sound out, and the difference impressed my Sonance buddies, too.

Our client absolutely loved the sound. In fact, he had us add some additional speakers to fill out the space even more! This initial configuration ended up using 22 6-inch SATs (mounted high and low), two 10-inch Subs in the middle for some punch, and four 12-inch Subs at the ends to bring out the low end. A year or so later, we upped the ante once again and added 12 of the just-released Sonance High Power 8-inch SATs and two of the new 15-inch Subs to up the SPL even more.

The pool area from above.

The pool speakers as seen from the Hot Tub Deck.

There are quite a few nice sweet spots in the pool with a “front row” listening area just south of the pool itself.

The south end “Front Row” speaker lineup.

Driving the Speakers

For the SLS system, one normally installs a single Crown CDi amp that is capable of delivering the required wattage based upon the number and types of speakers. The Crown amps from Sonance have custom Digital Signal Processor (DSP) EQ settings pre-configured for the types of SATs and Subs installed, although we had to use a single setting for the combination of the 10-inch and 12-inch Subs from a single amp. Additionally, each speaker has custom-built audio-quality transformers optimized for the characteristics of their drivers in addition to having the crossover roll offs built into the speaker itself. That way, we can have a single-pair 70-volt line drive all speakers for each channel whether they are SATs or Subs. However, because we wanted tighter level and EQ control on the bass, we opted to incorporate separate amplifiers for the subs. I will talk about why this turned out to be an advantage later.

The primary source material is stereo from a Sonos CONNECT through an Arcam DAC. We have all the inputs to the SAT amps and Sub amps for each channel wired together, which makes sense for this configuration and for ease of use from a Sonos perspective.

Areas That I Felt Could Use Improvement
First, let me just say that the sound around the pool truly was awesome and everyone got into it. I love the warmth and “airiness” of the Sonance speakers. If desired, the system could deliver mid to upper 90 dB levels (C weighted) while still maintaining audiophile-level quality. It sounded better than most indoor listening areas.

However, while the low-end pumped away as far as an unobtrusive outdoor audio system goes (buried Subs), it seemed “peaked” in certain ranges in addition to needing some more kick to it. If we cranked up the levels for the subwoofers (remember we used separate amps and 70-volt lines for driving the Subs), it occasionally would start to “honk” in a certain range (an example is the drum piece at the beginning of the live version of “Hotel California” from Hell Freezes Over). Our client likes his bass, but we had to keep it constrained to preserve the accuracy of the music. Additionally, the high end started rolling off somewhere around 6K, and we wanted a little more “sizzle to cymbals.” We wanted to optimize the balance and tonal quality between the higher powered 8-inch SATs and the smoother 6-inch SATs if possible, too.

We always like to push the envelope, so we were curious if we could make the outdoor audio system deliver even more if calibrated. We are huge fans of the Datasat RS20i audio processor (see sidebar at the end of this post for more details), and we already have one installed at this location for the living room, so that is the product we opted to use for seeing how far we could take what we already had in place.

While we are certified Dirac Live calibrators, we decided to solicit help from an industry expert on the RS20i, Mike Skrzat from Datasat Digital Entertainment. They are the ones who make the RS20i. Mike, like us, had never calibrated an outdoor pool audio system before, so we were not sure what we would encounter.

The Calibration
My plan was to see how well we could overcome the perceived deficiencies in the current setup by calibrating and optimizing the configuration. The goal was to develop a plan for “the next phase” of tuning that we then could present to the client. Unfortunately, we were on a limited time schedule and needed to “put everything back” when finished. We opted to not rewire the source feeds and then have to put everything back again after this test, which would have been ideal.

Mike Skrzat, from Datasat Digital Entertainment, placing the Dirac calibration microphone on the pool cover.

We took six different readings, most of them at the “sweet spots” where people laid on the cover most of the time.

 The calibration computer on the outdoor kitchen counter with the mic in the background.

The following graphs are from the output of the Dirac Live software. They show the main curve before and the target curve after the Dirac optimization. You can see how erratic the “before sound” actually was. We probably could have boosted the target dip at 10K a little, and we did not try to modify the target curve to flatten it because we wanted to spend our time listening to the results rather than tweaking it to perfection. We also just copied the same target curve to all output channels. Note that there was no separation of the LFE channels, either.

Screen capture from the Dirac Live calibration software.
We then spent a little time using the RS20i’s VNC interface on an iPad to adjust the actual levels for each output channel while listening to a variety of sources.

Mike remotely adjusting the Datasat RS20i’s audio parameters using an iPad.

The results were noticeably better. The high end was much cleaner with a wider response and the low end was a lot smoother. Doing the calibration really cleaned up the bass and extended the range, which is what we expected. The important thing is that the results of this exercise eliminated the issues we were trying to overcome, especially the “honking” in the low end.

Lessons Learned

 In-Ground boxes for connectivity (shown at the South end with 6-inch SATs and buried 12” SUBs) gave us a lot of flexibility for additional speakers and wiring configurations.

 The west fence line speakers hidden by plants and shrubbery.

When we get to installing “the next phase” permanently, we definitely will need to separate the audio feeds for the individual amps and speaker types. We then can use the RS20i for managing the crossover points and inserting the appropriate bass management for the Subs. We also will have separate Dirac Live control over the 8-inch and 6-inch SATs, which we really want to do (we prefer the warmth of the 6-inch SATs, but need the SPL of the 8-inch ones). We think we will be able to get several more dB SPL out of both types of SATs and each type of Sub while having less strain on the overall system by doing this. Although not recommended by Sonance (unless you make the effort to go to this much trouble), we also will disable their equalization curves in the Crown amps and use the Datasat for handling the EQs and optimizing the response curves.

As usual in this industry, new products are always coming out. To be fair, the new Sonance 2-750 DSP-based amplifiers also provide a great feature set, which we are considering as well. They may not end up being as versatile as an RS20i, but we still want to check out their new capabilities. They do have bass management in addition to providing a level of calibration using Sonance’s new SonARC room correction software. We should have a lot of control over the DSP settings, too.

In summary, we definitely need to separate out the LFE bass management, the equalization, and the levels for the SATs from the Subs. Ideally we also need to have separate calibration control over the 6-inch and the 8-inch SATs. While the current implementation sounds fantastic, we now know we can squeeze even more out of the current speakers by focusing on the equipment in the rack and improving the final product through calibration. The good news is that we have it wired already for supporting whatever approach ends up being the best.

Why go to all of this trouble? Because our client loves to hear music the way it was recorded, and we now have the technology to deliver that!

Derek Flickinger is an electronics concierge providing consulting and implementation services for consumer electronic integration companies and manufacturers on new technologies, products, and strategies related to standards-based distributed audio, video, communications, and control (DAVCC) systems. He focuses on home and consumer market spaces. He is co-author of the book HDMI Uncensored: Inside HDMI available at Derek’s long-term goal is to be instrumental in the development and deployment of entertainment systems in space stations and space colonies.


More About the Datasat RS20i

For those not familiar with the Datasat RS20i, it has several features that make it a great fit for this application.

• Dirac Live Audio Optimization — The RS20i features Dirac Live technology, which we think is one of the more flexible audio calibration offerings on the market. It is like taking the best room calibration feature in an AV receiver and putting it on steroids. The implementation works quite a bit differently, though. The Dirac graphical calibration software runs on a PC or laptop. The specialized Datasat Dirac Live calibration kit includes a “calibrated” microphone (with a file that matches its characteristics for loading onto the PC) and a high-end preamp that plugs into the USB port on a computer. It lets us capture readings from various locations, optimize the LFE and high pass characteristics, and “draw out” target optimization curves for each channel. The software calculates the matching RS20i-specific DSP parameters used for reaching those curves. We then save those profiles into the RS20i across the network. It lets us name each of those profiles and later associate it with a different routing configuration or source. It does a lot more like impulse response correction and channel delays, but some of these features are not applicable to the pool audio system because we are running multiple speakers off a single output channel as opposed to having an amplifier channel per speaker.

• Great Bass Management — The RS20i supports up to four Low Frequency Effect (LFE) outputs with complete control over each one. It is very flexible when it comes to optimizing the bass, the crossover characteristics, and how they interact with the other speaker channels. It also allows the four LFE channels to run as a mono feed if needed (we just happen to be using four Sub channels into the amps — two for the 10s/12s and two for the 15s).

• Sixteen Output Channels — The RS20i lets us dynamically route any of the various inputs to any or all of the outputs, channel by channel. This means we can take each stereo input and map it to the appropriate outputs for each of the amplifiers with individualized control over the audio characteristics and levels for each output channel. This ultimately allows us to calibrate the 6-inch SATs separately from the 8-inch SATs.

• Twenty Memory Presets — This seems like a superfluous feature at first, but it allows us to perform multiple Dirac Live and other calibrations, save those configurations, and then call each one back up at any time. That means we potentially can have different audio configurations optimized for different types of music, TV, live material, or whatever.

Extensive Equalization – Each output channel has thirty-one bands of third-octave and three user-adjustable bands of parametric equalization. In addition, each channel includes low, high and bandpass filters. While available, we did not take advantage of these for this experiment.

• Remote Configuration, Management, and Control — We wirelessly can configure the RS20i remotely from a tablet, phone, or PC with a VNC client using the same interface as the unit’s built-in LCD screen, which is essential when the RS20i is sitting in a rack inside and we are outside. Additionally, it has a full control command set, which lets us select the various presets mentioned above in addition to manipulating just about every parameter over the network.