Jump to content

Welcome to TheMalibuCrew!

As a guest, you are welcome to poke around and view the majority of the content that we have to offer, but in order to post, search, contact members, and get full use out of the website you will need to Register for an Account. It's free and it's easy, so don't hesitate to join the TheMalibuCrew Family today!

engine noise in speakers


macdaddy

Recommended Posts

Hey crew...I have engine noise in my speakers, does not seem to increase when rpm or speed increases....just constant noise. Where would you all begin to start tracking it down. The boat has 2 batteries, but I am thinking about adding a dry cell battery and putting the whole system on a toggle switch instead of it being wired to the ignition. Any input would be appreciated. Thanks

Link to comment

mac,

Most noise is from one of two causes.

1)The amplifier gains are set way too high. It's rare to have amplifier gains correctly set above the half way point.

2)There is more than one ground or supply reference. So make sure that all electronics including the source electronics and MP3 supplies get a supply and ground closest to the amplifiers. One point of reference only. This also means that all supplies should be comming off the common/output of the dual battery switch and not battery-direct.

There can be other culprits but first check the voltage level, verify that the noise is identical on all sourced (FM, CD, MP3, etc.), and check the above items.

David

Link to comment

I have the same issue but I'm about to get all of my stereo redone now that all of my wetsounds stuff came in. I'll let you know what they say the problem was if you haven't figured yours out by then.

Edited by Armyguy
Link to comment

Plenty of things that could cause this... but I would check your amp levels and also your input wires running from your amp to your head unit. Sometimes those will pick up interference if they are wired next to or on top of other wires that could pick up engine interference.

Link to comment
  • 3 weeks later...

Seeing as Dave @ earmark gets the approval from everyone :-) hopefully he reads this and steers me in the right direction.

My boat is currently having a refurb , she's totally gutted , no seats , dash board , have total access to wiring .

I have a 2008 VLX , factory JBL black box unit (3.0 I think) installed . 4 x Polk Audio DB651 running off the factory wiring . 4 x Rockford Fosgate P1562s (soon to be replaced with Polk's) mounted on the tower running off 1 x Rockford Fosgate P400-4 amp . 1 x Rockford Fosgate P400-4 amp powering 1 x Rockford Fosgate P2 sub & Sony Xplod 1500w sub (bridged) .

Head unit is factory wired . Amps are wired directly to battery (positive & negative with inline fuse , two set of power cables) , remote to black box , plugged into RCA jacks on black box . Amps are placed on bulk head underneath JBL black box . Battery is located in rear LHS locker above drain pump for ballast tank .

I followed the wiring instructions in the Rockford manual .

Questions:

# Should I have the Amps powered this way ? should I run a single positive & negative from the battery up to a power block then take power for each amp off that block ?

# Should I run negative this way ? Should I run negative around front of boat and back to factory negative block under throttle panel ? Again a singular negative back to negative block then splitting off to amps ?

# Out of the two subs , which is the better one ? I'm thinking of removing one ? I had one in the observers locker (p2) , the Sony was behind the kick board drivers side , or should I keep both and cut Sony into front of kick board ?

# Last few times we've been out , I have noticed a slight speaker/interference noise coming from tower speakers ? Any ideas on this one as its never done it before ?

Whilst everything is out I'm removing any electrical connector and soldering and shrink wrapping . All the extra speaker wiring that is not connected I'm cutting off connectors & shrink wrapping to try avoid corrosion/interference .

From memory the subs are set to let the low/base freq through & and towers to all pass . I'm not a tech head with this stuff (freq ranges etc) so I set it the old fashioned way , turn up volume of head unit with amps turned down , find the distortion range then back it off till it stops , then bring in the amps one by one .

Rob

Link to comment

I forgot to add. On the port side of the walk through I removed the netted parcel box to allow the sub to breath so to speak , the sub's also aimed at the port side hull . Good or bad idea ?

The sub in the kick board , was located in a slim fit box aimed forward reason for question to remove or modify etc , the box was cheap pre made one , not really designed for marine application .

Rob

Link to comment
  • 4 weeks later...

Hey crew...I have engine noise in my speakers, does not seem to increase when rpm or speed increases....just constant noise. Where would you all begin to start tracking it down. The boat has 2 batteries, but I am thinking about adding a dry cell battery and putting the whole system on a toggle switch instead of it being wired to the ignition. Any input would be appreciated. Thanks

Macdaddy, did you ever figure out what the engine noise was caused by? I have the same thing happening to me. It only happens when the boat is on. Sometimes I can play around with the amplifier's ground connection and the noise will stop but it always seems to come back.

Link to comment
  • 2 weeks later...

This could very easily be the alternator in the boat as well. It also could be a ground loop. Easier copied then trying to explain myself.

When two or more devices are connected to a common ground through different paths, ground path noise, or a ground loop can occur. Thus, a system grounded at two different points, with a potential difference between the two grounds can cause unwanted noise voltage in the circuit paths. Currents flow through these multiple paths and develop voltages which can cause damage, noise or 50Hz/60Hz hum in audio or video equipment. The ground loop can be eliminated in one of two ways:

  • Remove one of the ground paths, thus converting the system to a single point ground.
  • Isolate one of the ground paths with an isolation transformer, common mode choke, optical coupler, balanced circuitry, or frequency selective grounding.

Sometimes its easier to fix the problem then identify the cause. A cheap way to many times get rid of that is to install a Ground Loop Isolator.

Its a simple inline solution that can take away the noise. Here is a simple one http://www.amazon.com/PAC-SNI-1-SNI1-Noise-Isolator/dp/B000K50HJE

This post has lots of great info http://www.themalibucrew.com/forums/index.php?/topic/37203-ground-loops-and-proper-wiring-home-run-hum-hiss-pop/

Edited by bkdlays
Link to comment
  • 10 years later...
Tgreene2098

I know this is an old thread but I bought @macdaddy's 247 LSV I am tracking down the buzz in the speakers as well. I think I have it traced to the throttle body which sounds crazy, but the buzzing only happens when you turn the ignition on (like when the fuel pump is priming) and when the motor is running. My theory is when you turn the ignition on the fly by wire throttle cracks the throttle body to get the requested air. I have a feeling there is a bad ground in the throttle body.  What I need to know is which of the 5 or 6 wires is the ground so I can ground it somewhere better and eliminate that as the source of the interference or fix my problem. 

The amps were older, so I replaced the in boat and tower speaker amps with two brand new wet sounds amps, tried jumping the RCAs with a brand new set. Moved power and ground direct to the house battery, tried different grounding points on the motor. I am fairly certain its the throttle body at this point causing the interference. 

I am hoping someone can provide a schematic of the throttle body on the 8.1 vortec motor. Any help is appreciated!

Link to comment
  • 2 weeks later...
On 7/20/2022 at 9:13 PM, Tgreene2098 said:

I know this is an old thread but I bought @macdaddy's 247 LSV I am tracking down the buzz in the speakers as well. I think I have it traced to the throttle body which sounds crazy, but the buzzing only happens when you turn the ignition on (like when the fuel pump is priming) and when the motor is running. My theory is when you turn the ignition on the fly by wire throttle cracks the throttle body to get the requested air. I have a feeling there is a bad ground in the throttle body.  What I need to know is which of the 5 or 6 wires is the ground so I can ground it somewhere better and eliminate that as the source of the interference or fix my problem. 

The amps were older, so I replaced the in boat and tower speaker amps with two brand new wet sounds amps, tried jumping the RCAs with a brand new set. Moved power and ground direct to the house battery, tried different grounding points on the motor. I am fairly certain its the throttle body at this point causing the interference. 

I am hoping someone can provide a schematic of the throttle body on the 8.1 vortec motor. Any help is appreciated!

even though new amps are remote power and ground is the HU snd switch that turns everything on remote power and ground as well??

Link to comment
On 7/20/2022 at 9:13 PM, Tgreene2098 said:

I know this is an old thread but I bought @macdaddy's 247 LSV I am tracking down the buzz in the speakers as well. I think I have it traced to the throttle body which sounds crazy, but the buzzing only happens when you turn the ignition on (like when the fuel pump is priming) and when the motor is running. My theory is when you turn the ignition on the fly by wire throttle cracks the throttle body to get the requested air. I have a feeling there is a bad ground in the throttle body.  What I need to know is which of the 5 or 6 wires is the ground so I can ground it somewhere better and eliminate that as the source of the interference or fix my problem. 

The amps were older, so I replaced the in boat and tower speaker amps with two brand new wet sounds amps, tried jumping the RCAs with a brand new set. Moved power and ground direct to the house battery, tried different grounding points on the motor. I am fairly certain its the throttle body at this point causing the interference. 

I am hoping someone can provide a schematic of the throttle body on the 8.1 vortec motor. Any help is appreciated!

I would be surprised if the stepper motor in the throttle body is causing it.  The fuel pump is much more likely to cause EMI, in my opinion. 

Please post a short video of the noise as you turn the key on.

Link to comment
Tgreene2098
On 8/2/2022 at 12:18 PM, granddaddy55 said:

even though new amps are remote power and ground is the HU snd switch that turns everything on remote power and ground as well??

I have eliminated the switch and just use the power button on the head unit now. Are you asking if the HU is powered and grounded directly to the battery? I'm a little confused by the question. 

 

On 8/2/2022 at 2:53 PM, justgary said:

I would be surprised if the stepper motor in the throttle body is causing it.  The fuel pump is much more likely to cause EMI, in my opinion. 

Please post a short video of the noise as you turn the key on.

I actually ran a ground off the fuel pump to the battery and to the motor and no difference. 

 

I tried running the power and ground from the head unit direct to the battery as well and it made no difference. Other than the throttle body I am kind of at a loss for ideas at this point. I am going to try and get the part number off the throttle body this weekend and look up schematics for it. Please offer any other ideas you can think of!

Link to comment

Throttle body wiring is covered in the MEFI-5 manual, which you can download as a PDF.

EMI doesn't just travel in ground loops.  The positive power line is just as likely to radiate noise as the return (ground) line.  A brushed motor (such as the fuel pump) is a broadband emitter that requires extra shielding to contain.  The flame shielding is probably sufficient, but perhaps that one pump has an issue.  Perhaps something else is doing it.

Again, please post a short audio or video clip of the noise so we can help diagnose the issue.

Link to comment
18 hours ago, Tgreene2098 said:
On 8/2/2022 at 11:18 AM, granddaddy55 said:

 

I have eliminated the switch and just use the power button on the head unit now. Are you asking if the HU is powered and grounded directly to the battery? I'm a little confused by the question. 

yes,  i did a completely ( alternate HU source snd Bt rocker switch source, EQ, amps, rgb conttoller)  remote power snd ground system including the acc switch that turns on the whole system, the rgb controller snd its switch,  at first i hadn't done that and my noise was significant,  made all the difference .  i also had significant rgb noise that was eliminated by moving the controller 2.5 or more feet away from rca’s snd their sources, we even installed some home audio filters not even powered up just pass throughs for the source outputs before EQ

i totally eliminated all dash ground buss or power connections,  my system could drain the battery if acc switch left on

even the independent USB power station i installed was the same, couldnt use  the sony HU PLUG because phone would get confused blue toothed to the RS while receiving power snd communicating with the HU so i was forced to install an alternate in the coffin 

Edited by granddaddy55
Link to comment
Tgreene2098
19 hours ago, justgary said:

Throttle body wiring is covered in the MEFI-5 manual, which you can download as a PDF.

EMI doesn't just travel in ground loops.  The positive power line is just as likely to radiate noise as the return (ground) line.  A brushed motor (such as the fuel pump) is a broadband emitter that requires extra shielding to contain.  The flame shielding is probably sufficient, but perhaps that one pump has an issue.  Perhaps something else is doing it.

Again, please post a short audio or video clip of the noise so we can help diagnose the issue.

Our weather here in Pittsburgh this weekend isn't so great but I will try and get a video this weekend. I appreciate the help!

 

7 hours ago, granddaddy55 said:

yes,  i did a completely ( alternate HU source snd Bt rocker switch source, EQ, amps, rgb conttoller)  remote power snd ground system including the acc switch that turns on the whole system, the rgb controller snd its switch,  at first i hadn't done that and my noise was significant,  made all the difference .  i also had significant rgb noise that was eliminated by moving the controller 2.5 or more feet away from rca’s snd their sources, we even installed some home audio filters not even powered up just pass throughs for the source outputs before EQ

i totally eliminated all dash ground buss or power connections,  my system could drain the battery if acc switch left on

even the independent USB power station i installed was the same, couldnt use  the sony HU PLUG because phone would get confused blue toothed to the RS while receiving power snd communicating with the HU so i was forced to install an alternate in the coffin 

I do not have an RGB controller that i know of. the LEDs in my boat are just green rings and cant be changed. I have also eliminated all any rocker switches. the source unit just turns on with the power button on the radio wired direct to the battery now. the ground is wired direct to the same battery as well.

Link to comment
4 hours ago, Tgreene2098 said:

the LEDs in my boat are just green rings and cant be changed.

When do those turn on?  The LED controller will no doubt use PWM even if they are only one color.

Link to comment

If it's EMI, it should do it with the stereo isolated from the boat, right?  I.e. disconnect house battery from the rest of the system, turn stereo on (running only on house battery power) then start boat... is sound still present?

Dumb Q no. 2... have you tried an alternative source than your headunit?  Like a headphone to RCA cable straight from a phone into the amps?  It sounds like you've replaced RCAs and amps and the sound is still present.  I'd sure want to make sure it's not a bad HU/black box too.

Link to comment
Tgreene2098
On 8/5/2022 at 8:48 AM, justgary said:

When do those turn on?  The LED controller will no doubt use PWM even if they are only one color.

Only when I have the rocker switch turned on, which is only really at night. The sound is constantly on once the boat is running and the radio is on. If the motor is off and the radio is on= no whine noise. if the boat is on and the radio is off= no whine noise. I didn't make it down there this weekend but I will get a video on Wednesday when I'm there.

On 8/5/2022 at 9:01 AM, shawndoggy said:

If it's EMI, it should do it with the stereo isolated from the boat, right?  I.e. disconnect house battery from the rest of the system, turn stereo on (running only on house battery power) then start boat... is sound still present?

Dumb Q no. 2... have you tried an alternative source than your headunit?  Like a headphone to RCA cable straight from a phone into the amps?  It sounds like you've replaced RCAs and amps and the sound is still present.  I'd sure want to make sure it's not a bad HU/black box too.

The boat had an older Sony radio in it when I bought it which was also making the same noise. replaced the old sony with the wet sounds MC-2 and its still making the noise. 

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...