My stereo upgrade summary

[ATX Cobalt]

First, thanks to everyone that offered their help and opinions on our recent stereo rebuild. Especially, Islander208 and Big Block Power! I’ve learning so much about marine electronics doing this myself and gained a greater understanding of the electrical systems on our boat. This forum and Youtube are amazing resources if you are considering doing a similar project on your boat.
My goal with this rebuild was to install a new upgraded system in our boat (2007 200) without breaking the bank. Initially I was going down the JL Audio path, but once I started adding up all the component cost I couldn’t justify spending that much on this boat. We are planning to upgrade to a later model Cobalt in the next few years. In addition, we usually park our boat in a cove and listen to music at a moderate level. However, this system sounds great in my opinion and any component can be easily replaced for under $150. The equipment was approximately $900 (purchased on Amazon), and I spent another $350 on wire, connectors, amp installation kit, power blocks, tools, etc.

System Specs:

• Sony DSXM55BT Head Unit
• 2 - Rockville RXM-S30 Amps RMS 4 X 200 Watts @ 4 Ohms CEA 4 X 90 Watts @ 4 Ohms
• 6 - Kicker 6.5” KM65 LED Speakers Max RMS 195 Watts
• 1 - Kicker 10” 45KMF104 LED Sub Max RMS 350 Watts
• 1 - Kicker 41KMLC LED Controller

Wiring:

I ran all new 4 AWG marine grade power and ground leads to the battery switch (power) and port side battery (ground). In addition, I installed the fuse supplied with my amp kit to the right of the battery switch for easy access. I used two 2way power distribution blocks to split the power and ground leads for each amp. New Anchor Marine 14 AWG wire to all the speakers (highly recommended product). You will see a common theme on this forum to abandon the factory wiring and install new for any upgraded system on your boat.
Running the LED wiring for the speakers was very time consuming, but the visual results was well worth the time invested. I’m using the matching Kicker controller, but it seems like a lower quality unit to me. If it fails down the road I may swap it out for a different one. I used the factory plug for the docking lights to get my power and use the helm switch to power on/off the LED lights. If your boat doesn’t have factory docking lights this is an easy place to grab power. My plug was located in the anchor box just to the left. I have Islander208 to thank for this great tip! I mounted the actual control unit in the open area above the helm side cup holder niche.

Head Unit:

I actually replaced my head unit last year when I purchased the boat because the original head unit was dead. After I installed it I quickly realized the original Sony speakers were toast, which lead me to this project. I would not recommend the DSXM55BT unit because it is much shallower than the original unit (no CD). Therefore, it will not reach the factory rear support bar and has to be rigged to stabilize the unit. We purchased it for the Bluetooth connectivity and that works great, but it doesn’t completely match up with the factory installed remote either. Probably going to replace it eventually with a Fusion head unit and install their wireless remotes at the helm and swim platform.
Amps:
I’ve been very pleased with the Rockville amps and the power they deliver. They were easy to install and tuning the gains, LPF, & HPF wasn’t an issue. I’ve included a link of a dyno ran on the 2 channel version of my amps and another explaining how to calculate setting your gains with a volt meter. There were several other videos that were helpful in explaining how to set the LPF and HPF levels. I set my 6.5” speakers at 80Hz HPF and my sub at 100Hz LPF, which seems to be the right mix for my layout. Understand these are approximations, unless you purchase some expensive equipment (SMD Distortion Detector) you can’t set these precisely. If anyone in the Austin, Texas area has said equipment I would love to borrow it!

https://www.youtube.com/watch?v=2Hs6clPmqc0 Rockville amp dyno on 2 channel RXM amp, mine are the 4 channel version.

https://www.youtube.com/watch?v=gg2gl-fz2Qc How to adjust your gain controls with a volt meter

My 6.5” speakers calculation = 195W X 4 Ohms = 780 Sq. Root = 27.9 Volts at amp output

My 10” sub calculation = 350W X 4 Ohms = 1,400 Sq. Root = 37.4 Volts at amp output

Special Note: You need to play a 0db 50-60Hz test tone (free on Kicker website) through your amp when tuning them to the correct voltage. Put the test tone on repeat to keep your hands free during the tuning process. Ensure your speakers are disconnected as well!

Using stainless steel hardware, I mounted three 12.25”L X 2”W X .5”D pieces of PVC sheeting material for my amp bases. Then I cut two holes through the carpet and plywood under each amp to run the wire underneath for a nice clean look.

My head unit only has 4 RCA outs (2 Stereo & 2 Sub). I ran the stereo RCAs out and attached 2way splitters on each end connecting them to the four channels on the first amp. Then, I ran a set of RCA cables from the output on the first amp to channels 1 and 2 on the second amp to bridge them together. I ran an addition set of RCA cables from the sub outlet of the head unit to channels 3 and 4 of my second amp. Try to keep your RCA cables away from you power leads to avoid any interference. I bridged channels 3 and 4 on the second amp for my 10” sub, and used the other 6 channels for my six 6.5” speakers. I split the remote wire coming from the head unit and connected each to an amp to power them on/off with the radio/key. Reminder – turn your key to the left when listening to your stereo while the engine is off. Turning it to the right can accumulate hours on your boat without the engine running.

Speakers:

To be honest I never went out to an audio store and listened to marine speakers for this project. There has been great debate on this site and there are various opinions out there. I choose the kicker speakers for the positive reviews on Amazon/Youtube, the LED grill option, and the price point. The 6.5” speakers fit in all the factory openings, but I did have to drill new screw holes to mount them. The sub was a different story, I had to cut a new hole for it and that will get your blood moving. I basically followed Big Block Power’s example and located my sub in front of the port side seat. I taped off the area I was cutting out, marked the opening (Kicker has a great template BTW), and used a Dremel tool to cut the opening. I broke off two cutting bits and completed the opening with a third. They get hot! Lucky me, the sub fit nice and snug the first time I placed it in the opening. Beginner’s luck I guess! My sub required 5” of depth clearance and I only had 3” before I hit the wall. I had to increase the size of the factory cut out and put some blocking in between the plywood and carpet on front of the board to get the needed 5”. The factory cut out is located more to the right on my boat and I wanted the sub centered. This entire process was actually much easier than I expected it to be.

Advice:

Be patient, creative, ask questions, do your homework, buy good wire, allow yourself twice the time, and stay hydrated with plenty of adult beverages! Rock On \m/

Almost forgot the most important thing, I don’t recommend doing your install during August in Texas! Talk about blood, sweat, and tears… no joke

[ATX Cobalt]

More pics

[AsLan7]

Nice write up ATX!....and even nicer attention to detail in your build.

[jhnmdahl]

Nice writeup - shows you don't have to spend thousands to get a nice upgrade in sound.

Note the procedure for setting gains will indicate the maximum gain that each channel should be set, but doesn't do anything to ensure the subs aren't way louder than the main speakers or vice-versa (e.g., your subs may be 86 dB at 1W/1M or however else specified, while the main speakers are 93dB at 1W - a pretty stark difference). In a nutshell, you can turn the louder channel down from the settings found using the above procedure to balance the sound, such as by using an SPL meter or doing it by ear to taste.

[ATX Cobalt]

I did turn my sub down a little yesterday, I was surprised how much bass I'm getting from the 6.5" speakers. I used the calculation method because my amps have a stronger output than my speakers handle. I didn't want to over power and damage them.

[ATX Cobalt]

Nice write up ATX!....and even nicer attention to detail in your build.

I appreciate it! It was well worth the effort/time.

[Big Block Power]

Looks very nice. Congrats. Yea I bought the meter for adjustments. I sent it to Nauti for a very large fee and he said his volt reading settings were pretty close. I made him pay for shipping it back. The price was priceless!! Yes I made it in person

[jhnmdahl]

I did turn my sub down a little yesterday, I was surprised how much bass I'm getting from the 6.5" speakers. I used the calculation method because my amps have a stronger output than my speakers handle. I didn't want to over power and damage them.

I think calculating and marking maximum safe power for the speakers is a good idea, even if you also have some sort of distortion meter or an oscilloscope (look for the peaks of a sine wave to start flattening and back off a bit). In a nutshell, maximum power for the drivers and distortion are two different maximums, and it's best to select the lower of the two for each channel. Then, turn down whichever channels you need to from there to balance sound between channels/drivers.

John

[ATX Cobalt]

Looks very nice. Congrats. Yea I bought the meter for adjustments. I sent it to Nauti for a very large fee and he said his volt reading settings were pretty close. I made him pay for shipping it back. The price was priceless!! Yes I made it in person

Thanks for all your help! Cutting the hole out for the sub wasn't nearly as bad as I thought it would be.

[Driller]

Great write up and a great job ATX

[Big Block Power]

Looks very nice. Congrats. Yea I bought the meter for adjustments. I sent it to Nauti for a very large fee and he said his volt reading settings were pretty close. I made him pay for shipping it back. The price was priceless!! Yes I made it in person

Thanks for all your help! Cutting the hole out for the sub wasn't nearly as bad as I thought it would be.

Did you have foam sandwiched between gel and glass on the other side?

[ATX Cobalt]

Looks very nice. Congrats. Yea I bought the meter for adjustments. I sent it to Nauti for a very large fee and he said his volt reading settings were pretty close. I made him pay for shipping it back. The price was priceless!! Yes I made it in person

Thanks for all your help! Cutting the hole out for the sub wasn't nearly as bad as I thought it would be.

Did you have foam sandwiched between gel and glass on the other side?

No, mine was maybe 3/8” thick gel and glass. I’ll take a pic of the piece I cut out next time I’m out. I saw a good tip on YouTube saying to keep your strap to use as a test piece when sizing up drill bits to different screw sizes. I drilled multiple holes in it throughout my project for the various screws I was using. Good tip.

[Big Block Power]

I wish mine was 1 piece. The saw blade kept hitting the back piece and bending. Really made it a pain in the arse. Plus my screws had to be long enough to go through both pieces. The frt gel was pretty thin. Wet sounds also had a nice template. They also have a rubber gasket. Plus I had to mage a slot at the bottom for the led wire and I didn't want to go to far down that the grille wouldn't cover it. Slow and steady.

[ATX Cobalt]

Kicker luckily has a niche built in the speaker for the LED lights and a gasket as well. I thought I was going to be face a ton of dust when I cut the opening, but didn’t on my side. When I went to the inside to inspect the cut I had a two inch pile of dust under the cut line! Should have taken a pic. Dremel tool must force the dust to the inside.

[ATX Cobalt]

Tool I recommend