The boat features 11 Polk speakers. The boat originally had 4 speakers, so some means was needed to mount the additional speakers - hopefully where they made sense.
Two speakers were needed in the front area of the salon, but there was nowhere they could be suitably mounted. So I came up with this idea of speaker balls. The articulated RAM 199H arms allow the speakers to be pointed in almost any area I desire. I used a pair of Polk DB525 (5.25" dia) speakers here.
A detailed project page for the speaker balls can be found here:
In the rear berth, I used a pair of Polk DB400 (4" dia) speakers. I did commit somewhat of a Cardinal Sin of speakerbuilding as I built square speaker cubes. To minimize internal reflections, the ideal speaker's dimensions will follow the Golden Ratio of 0.6:1:1.6. This means the first dimension would be 0.6 of the second, and the third dimension would be 1.6 the size of the second. In contrast, the cubes I built have a ratio of 1:1:1 where all dimensions are equal.
On the other hand, in the aft cabin, the audio is used more for background than anything else, and the speakers ended up sounding fine. I used the same RAM mounts as I did for the speaker balls for mounting to the boat.
For the subwoofer, I used a single Polk DB104 (10" dia) heavy duty subwoofer. This speaker is a single voice coil version as the subwoofer uses a dedicated amplifier, and the bridging of the L+R channels is done in the amp. The photo here does not show the sofa, but in actual practice, a sofa sits in front of the subwoofer, which keeps it out of sight.
The subwoofer is mounted on a removeable access panel, as some of the boat's mechanical systems are located behind the wall.
A detailed project page for the subwoofer can be found here:
A pair of Polk DB650 (6.5" dia) speakers are located in each rear corner of the salon. This is one of the original locations of the speakers in the boat, and I upgraded the speakers to Polks to keep everything similar.
On the rear deck, another pair of Polk DB650s have replaced the stock factory speaker locations. I used to have a pair of so called "Marine grade" speakers located here, but they didn't even last one season to the weather - and this is in Michigan weather. I replaced the speakers with Polks, and after 2 seasons, they are still in good shape.
Lastly, a pair of Polk DB650s are mounted in spun aluminum canisters and mounted to the radar arch. Unfortunately, the clearance of the aluminum cans was such that I had to either point them down at an angle, or mount them to the top of the arch. Since my purpose of the speakers were for the helm, pointing the cans down was the proper angle. Even though the enclosure is up, there is little diminished audio from the speakers.
I have included a Cobra MR-F300-BT Bluetooth handset to the system. The Cobra handset can be attached to the helm, and pairs with my cell phone. If I desire, I can redirect the handset's audio to the arch speakers for extra volume. Since there can be a lot of ambient noise at the helm, the additional speakers provide for better conversation. Kind of like a speaker phone on steroids!
At the helm, to the right of the pilot's seat, I placed the remote for the radar arch amplifier. There are two controls here; a switch that selects either the Cobra BlueTooth mic or the stereo system to the arch speakers, and a control knob to control the audio volume of the amp.
The PolyPlanar ME-50 Amplifier is located at the helm. The amp is attached to a starboard panel for east mounting. In addition to the amp, the little black canister is a RCA remote relay which switches the audio signal between the Stereo system and the Cobra Bluetooth Mic.
David Navone Engineering N-806 Electronic Switch
The little "black box" is a potted assembly of steering diodes to allow the on-off switch shown above to not only control the N-806, but to also turn the amplifier on as well.
| Function | Arch Amp Switch | Cobra BT Switch | BT Speaker Switch |
| Arch speakers: Stereo | |||
| Cobra Bluetooth On | |||
| Arch speakers: Bluetooth |
Arch Amplifier Wiring Schematic
Lastly, a Shakespeare Galaxy SRA-40 Sirius Marine antenna is atop the radar arch. This is the white mushroom looking antenna to the left of the radome. Please note that the radome is located above the SRA-40 antenna, which is the proper method of mounting to minimize interference from the high power radar signal.
Stereo RCA Connection Schematic
