CliffA
Well-Known Member
- Dec 29, 2009
- 4,712
- Boat Info
- 2001 Sea Ray 340DA
Name: 'Happy Place'
4.5kW West. Generator
Purchased Nov. 2014
Fresh Water Use
- Engines
- Twin Merc. 6.2L (MPI)
640 hp (Total)
Raw Water Cooled
V-Drive Transmissions
a couple weeks ago i added two new 6" x 9" JBL marine speakers in the cockpit of my boat just in front of the rear bench seat....they compliment the two 6" JBL speakers that were already installed in front of the captain's and passenger cockpit seats.....i also installed a Pyle marine 400W four channel amp behind the dash to power the 4 cockpit speakers....i use the stereo head unit to power two speakers in the cabin and two speakers on the transom.....i have wired in a selector switch to be able to select which speakers are active....i can select to play only the cabin speakers, only the cockpit speakers, or only the transom speakers or different combinations of speakers...
everything sounds great when the engine is not running...however when i start the engine i get engine (alternator) noise through the cockpit speakers only....the cabin speakers and transom speakers that are driven by the head unit sound fine...so this tells me i have a problem with the amp driven cockpit speakers.....
here are the details concerning the amp installation:
i used an 8 gauge power wire directly from the battery to the amp.....this is a fairly long run of approximately 20 ft......i used a smaller gauge wire (not sure what gauge) as the ground between the amp and the main ground bar behind the dash...the length of the ground wire is around 2 ft......i used 12 gauge speaker wire from the amp to the 4 cockpit speakers for the speakers + and - connections......i wired the 'remote start' terminal of the amp to a spare 'Accessory' rocker switch on the dash....so i can turn the 4 cockpit speakers on/off with this 'Accessory' switch by turning the power to the amp on/off.....i used triple shielded twisted RCA patch cables between the head unit pre-out terminals and the amp...the length of these patch cables is 3 ft.....i tried adjusting the 'gain' controls on the amp which helped some but did not remove the engine noise.....
i have done a little reserch on possible causes of the engine noise....here are the items that i know of i should check...
- do not route speaker wires too close to any power wires
- may need to increase the gauge of the ground wire to the same gauge (8 gauge) as the power wire and keep the length under 3 ft.
- do not route the RCA patch cables too close to a power wire
if anyone has any other suggestions on things to check they would be appreciated....
cliff
everything sounds great when the engine is not running...however when i start the engine i get engine (alternator) noise through the cockpit speakers only....the cabin speakers and transom speakers that are driven by the head unit sound fine...so this tells me i have a problem with the amp driven cockpit speakers.....
here are the details concerning the amp installation:
i used an 8 gauge power wire directly from the battery to the amp.....this is a fairly long run of approximately 20 ft......i used a smaller gauge wire (not sure what gauge) as the ground between the amp and the main ground bar behind the dash...the length of the ground wire is around 2 ft......i used 12 gauge speaker wire from the amp to the 4 cockpit speakers for the speakers + and - connections......i wired the 'remote start' terminal of the amp to a spare 'Accessory' rocker switch on the dash....so i can turn the 4 cockpit speakers on/off with this 'Accessory' switch by turning the power to the amp on/off.....i used triple shielded twisted RCA patch cables between the head unit pre-out terminals and the amp...the length of these patch cables is 3 ft.....i tried adjusting the 'gain' controls on the amp which helped some but did not remove the engine noise.....
i have done a little reserch on possible causes of the engine noise....here are the items that i know of i should check...
- do not route speaker wires too close to any power wires
- may need to increase the gauge of the ground wire to the same gauge (8 gauge) as the power wire and keep the length under 3 ft.
- do not route the RCA patch cables too close to a power wire
if anyone has any other suggestions on things to check they would be appreciated....
cliff
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