Installing a Marine Sound System
WANT TO INSTALL OR UPGRADE A MARINE STEREO? THIS IS HOW THE PROS DO IT
Two years ago, John Salafia installed a two-speaker sound system on his new 22- f oot Panga, but when one of the speakers regularly gave him problems, he decided to replace and upgrade the whole package. He switched brands and because he wanted two additional speakers in the bow of the boat, he selected Clarion’s new NMEA 2000-certified CMM-30 marine source unit to drive four Clarion CMSP771RGB-SWG speakers.
The CMM-30 is an IP66-rated weatherproof marine source unit with a 3-inch full-color LCD display. It’s SiriusXM-ready, has a digital AM/ FM tuner with built-in NOAA weather radio, Bluetooth audio streaming, a USB 2.0 input for playback from a USB storage device, an analog auxiliary input, an onboard amplifier capable of powering speakers to two main zones, eight channels of preamp outputs and subwoofer functionality. NMEA 2000 certified, it has multifunction display control functionality and is compatible with MFDs from Garmin, Lowrance and Simrad. The CMSP-771RGB-SWG speakers are 7.7inch coaxial marine speakers with built-in RGB illumination. John had also hoped to install a subwoofer, but the Panga didn’t have a spot to accommodate it.
Ordinarily John works on his own boat, but because his job and family were keeping him busy, he turned to his neighbor Mike Garretson. Mike happens to be the owner of Sea and Land Yacht Works in Wakefield, Rhode Island, which specializes in the design, installation, and troubleshooting of marine electronics projects. Sea and Land Yacht Works installs everything from multifunction displays and radars to engine monitoring systems and thermal cameras. The company’s technicians hold certifications in ABYC and NMEA, so everything they do is installed to code. Mike and one of his technicians, Drew Tedeschi, installed the system and shared some tricks of the trade with Soundings.
Mike explained that the first step was to identify the speaker locations and to verify the clearance behind the speakers. Drew put painter’s tape over the area to protect the gelcoat, placed the template over the tape, marked up the tape, and cut the holes for the speakers with an air saw. Mike
says you can also use a jigsaw, but he recommends you use either a metal-cutting blade, or a diamond grit blade, as a standard wood blade will burn up very quickly.
Drew had also pre- marked the mounting holes on the tape. Mike warns that when you’re drilling those holes it’s really important to size the holes correctly. “When you put a stainless screw in a hole that’s too small, you’re going to snap the head off,” he says. To prevent that from happening, they drill holes that are halfway between the shank size and the outer edge of the thread. That way the shanks are smaller than the hole and the screws still get a good bite on the fiberglass. Mike also mentioned it’s important to use a countersink bit to start the hole first to prevent the gelcoat from chipping.
John had planned to run the speaker wires down the sides of the boat, but Mike didn’t want to do that because they wouldn’t be able to secure the wires every 18 inches, an ABYC standard. “They would be hanging and be prone to chafe,” Mike says. Instead, using the hatch boxes, they installed a piece of PVC tubing as a conduit below the deck to prevent anything from damaging the wires. To secure the pipe they used Weld Mount adhesive mounts and an MMA (Methyl Methacrylate) two-part adhesive that glues to pretty much anything. They zip tied the pipe to the Weld Mounts, so it would still be removable in the future.
With the conduit in place, they were able to run all their wires from the amp and head unit in the console to the speakers in the bow. One thing
Mike really liked about the Clarion speakers is that they use Deutsch connectors. “They’re one of the best waterproof connectors available,” he says. Mike says that usually a speaker has just a tail or a spade connector, which isn’t that reliable. The Deutsch connector would make it possible to remove the Clarion speaker if it ever had to be pulled out. “I was impressed by that,” Mike says. The tails from the Deutsch connectors were butt connected to the wiring and then heat-shrinked for corrosion protection.
They mounted the amplifier on a PVC board, which allowed them to lay out all the wire runs and used MMA adhesive to mount the board to the inside of the console. That prevented them f rom having to drill and screw the board into the console. Mike says they used PVC board because it’s easier to work with than Starboard, which has to be pre-drilled. Because the LEDs on the speakers required a 4-wire connection and because Mike is not a big fan of butt connecting so many wires, they also put in an 8-gang terminal block to secure all the wires in parallel on the PVC board and then made tin connections.
The new Clarion head unit and the two new Clarion console speakers fit into the holes left by the old head units and speakers on the console, although Drew used a flapper wheel on a grinder to clean up the old speaker holes for the Clarions.
Because none of the breakers on the console could accommodate the Clarion equipment alone, they connected it to the electronics switch that also powers the Simrad MFD on the Panga. Because the Clarion has a NMEA 2000 network for communications they also plugged that in allowing the stereo to be run on the MFD.
For the safety of the boat, you have to make sure everything is properly fused. The fuses are there for current protection. Without it the wires can short out, get hot and catch fire. A screw going through a wire, or a pinch can also short things out, which is why you use fuses. They put a fuse connection coming off the battery switch, the whip off the Clarion head already had its own fuse— which they used—and the LED circuit had its own fuse integrated into the harness.
After everything was wired and properly fused, tuning the amplifier was next. The Clarion CMM-30 leaves the gain settings to the amplifier, so Drew set the volume on the head unit to 75 percent of the maximum volume and then adjusted the gain on the amplifier. Once the gain was set to zero, he played some music on the unit and then slowly turned the
gain up until he could hear distortion from each set of speakers. Drew warned that you should not go past that point with the gain. “A lot of people think the gain controls how much output you get from the amplifier but that’s not true,” he says. On the Clarion there were three gains; one for the subwoofer, one for the front speakers and one for the back speakers. Since no subwoofer was installed, only two gains were set. Drew explained that some amplifiers have a highpass filter and usually for a subwoofer there’s a low-pass filter. “You want to find the range of the speakers,” he says. “You set the high pass to the maximum frequency of the speakers. You don’t want to go past that. The gain just sets what the voltage from the head unit to the amplifier is, so it knows not to overdo it. For longevity, I never recommend going past 80 percent on the volume.”
John had hoped to add a subwoofer to the package but there was no room for it. Despite that, he’s thrilled. “The bass is pretty darn good without the subwoofer.” He’s also really happy with the installation and feels it was done better than if he had done it himself. ”It looks and sounds really good,” John said, “and it has better clarity than the old system.