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Discussion Starter · #181 ·
May bad I just read that you've tried it already.
I think I'll just record a 4k video and post it on YouTube. I feel I'm wasting everyone's time posting here. It's hard to explain everything in writing and lots of stuff will become clear and easy to see with the video.
The only limitation is sound will probably not translate perfectly.
 

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Embarrassed to say I don't know the difference between active/passive. They're part of the speakers/tweeters Infijity Reference 6530CX.
They're mounted at the bottom of the doors, so I wouldn't anticipate any interference there 🤷‍♂️
this is mounted in your doors? is there anything next to it that might cause interference? window motors, control boards, wiring?

Rectangle Audio equipment Circuit component Font Electronic component
 

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I don’t disagree that it could be a ground issue...I just don't know how to find it
All I'm saying is my amp ground in the trunk is solid. Battery ground is solid. All grounds have 0 resistance between them.
Picture attached is the ground wire for engine block/chassis. While it's not my picture, it's the same on my car. I removed the cables and cleaned all surfaces with wire brush / sandpaper. Obviously cleaned wire terminals and made sure resistance is 0 between two points.
View attachment 338831
That looks fine, I really don’t know, would have to be there to troubleshoot.
 

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Discussion Starter · #184 ·
this is mounted in your doors? is there anything next to it that might cause interference? window motors, control boards, wiring?

View attachment 338836
Yes, I just used stick-on thin foam on the bottom of these little boxes and spray-glued them to the bottom of the doors inside, where they're low enough that the window won't touch them when rolled down.

Of course the doors have window motors/regulators, but they're not on, so they shouldn't interfere...
 

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Sorry not going to read the entire thread....

Did you ever have the alternaotor checked for a bad diode resulting in AC ripple voltage ??

Did you ever swap to another amplifier to make sure it is not a failing component within the amp??

Did you ever replace the HU or swap the music source to make sure it isnt the HU??
 

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Sorry not going to read the entire thread....

Did you ever have the alternaotor checked for a bad diode resulting in AC ripple voltage ??

Did you ever swap to another amplifier to make sure it is not a failing component within the amp??

Did you ever replace the HU or swap the music source to make sure it isnt the HU??
#3 when he uses a phone to rca connector there is no noise at all.
 

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Discussion Starter · #188 ·
PROGRESS

"I remember when a few months ago I used my phone as a source of music by connecting 3.5mm jack to my phone and Y splitter to 2 rca ports on the amp, music was without interference. "

This really says a lot right here. In your first post you mention that you ruled out the headunit yet when you eliminate it from the stack there is no more whine? If you can play music from a phone via an adapter into the amplifier with no interference then all your problems are in the HU.

I know some people have actually grounded the rca's to the casing of the head unit via a wiring wound around the outer shell on the rear of the headunit. I know a lot of the adapters for headunits are plastic now so the casing isn't attaching via metal to the car chassis anymore due to that plastic. They do make ground loop filters just for the head unit itself but you mentioned an attempt at that. I take it you don't have any headunits just sitting around as your latest statement tells me that either the HU is defective or the grounding there is not good.
I know I said I tried it, which I did. But I need to revisit this.
Basically when I started this thread, I knew nothing about audio. So I was just mindlessly trying what people suggested without understanding what I was doing.
After trying for so long and no success, I came back to the only thing that has worked before. 3.5mm Y rca adapters.
The reason I didn't put so much faith in it before, is because when I plugged 2 rcas from HU to amp, it played way better than if I plug all 4.
Another factor is that I had whine with rcas plugged just into the amp, and not connected to the head unit.
And the third factor was that it's a second headunit.

And that's why I wanted to try phone jack to 4 rca adapter, but I don't know if it's possible and if such adapters exist...

So today I tried using just the old 3.5mm to 2 rca adapter and had no whine. I mean at least something works, so I decided to really concentrate on this stage.

I found 3.5mm to 4 rca adapter on Amazon. It's some no name brand with no reviews, so no clue if it's any good, but at least something to try.

I then tried connecting just 2 rcas to headunit and amp. The music kinda played muffled and not full frequency. The whine was pretty bad as well. I already tried grounding rcas to HU body and didn't feel like that would work but for some reason I felt like trying it.
So I tried connecting rca ports on headubit to the body of the headunit.
The whine completely disappeared!
I attached the wire to HU and as soon as I barely touched any of the 6 rca ports of the headunit with the other end of the wire, the whine was gone.

Now, unfortunately, this does not fix all my problems...
When I connected all 4 channels instead of 2, the whine kinda creeped back, although a lot less loud.
I tried moving rca cables around and connecting them to different ports on the headunit one by one, two, three, four.
And it's kinda weird. Some speakers/tweeters sounded great, some muffled, some had a bit of static, some a bit of whine. So it's like out of 4 doors, each played differently.
This is kinda weird behavior and it really make me feel like the headunit is the problem. Or a major contributor.

So I ordered more rca cables just to rule them out one more time
Amazon Basics 2-Male to 2-Male RCA Audio Stereo Subwoofer Cable - 8 Feet Amazon Basics 2-Male to 2-Male RCA Audio Stereo Subwoofer Cable - 8 Feet : Amazon.ca: Electronics

These seem to be bulletproof cables!

Also ordered a brand new headunit
Alpine UTE-73BT Mech-less Digital Media Receiver with Bluetooth® Wireless Technology Alpine UTE-73BT Mech-less Digital Media Receiver with Bluetooth® Wireless Technology : Amazon.ca: Electronics

I feel like it's really weird that the more rcas I connect to the headunit, the worse it's playing, and doesn't play equal in all doors.
With how much $ and time I've spent so far, I feel trying out another headunit would be worth a try!
 

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And the third factor was that it's a second headunit.
Are you saying that you have TWO head units connected at the same time or that you are already using a different HU and the same whine problem persists??

I then tried connecting just 2 rcas to headunit and amp. The music kinda played muffled and not full frequency. The whine was pretty bad as well. I already tried grounding rcas to HU body and didn't feel like that would work but for some reason I felt like trying it.
So I tried connecting rca ports on headubit to the body of the headunit.
The whine completely disappeared!
I attached the wire to HU and as soon as I barely touched any of the 6 rca ports of the headunit with the other end of the wire, the whine was gone.
it is very difficult to understand the specifics of what you are doing here!!!

Are you plugging in your phone speaker jack to the HU aux input?
Or are you plugging it into the amplifier inputs?
Or BOTH ??

THAT SAID ... if grounding the HU body eliminates the whine, then your HU is not installed and grounded properly.
Your problem might be THAT simple !!!

Go back and double check your HU install and grounding points...also be sure to ground the HU to the same poin that the amplifiers are grounded to

I feel like it's really weird that the more rcas I connect to the headunit, the worse it's playing, and doesn't play equal in all doors.
The more you split the Y cable from your phone source the less power goes to each RCA thus the sound from each speaker is more muffled and uneven.

ALSO, if you are simply plugging in the speaker phone jack into the either the HU or the amp and then moving it around, then the crossovers in the HU or the amps would definitely affect the sound quality coming out of each speaker.
 

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Discussion Starter · #192 ·
I'm sorry if my post was confusing.
I didn't connect both headunits at the same time.
I had Kenwood KDC-X302 as my first headunit while I had this whine problem.
It died, so I bought Kenwood KDC-X304 and have the same whine. I bought Kenwood KDC-X304 second hand. Maybe it was bad, that's why the person was selling it?

I was trying to say, when I used my phone as audio source, there's no whine.
Basically this adapter.
AmazonBasics 3.5mm to 2-Male RCA Adapter Audio Stereo Cable - 4 Feet AmazonBasics 3.5mm to 2-Male RCA Adapter Audio Stereo Cable - 4 Feet : Amazon.ca: Electronics


I'm not connecting my phone to AUX on the headunit. Just connecting my phone to amplifier via this adapter.

Grounding headunit body to headunit RCA ports (this is where rca cables running from amp are plugged) helps with the whine but doesn't totally eliminate it.

If I only use two channels I think the whine is gone. But if I use 4 channels, the whine is there. And I don't know why it's happening.
So if I have 2 rca cables running from the amp to HU, I'm able to get rid of the whine. If I plug another rca cable into the headunit, the whine starts creeping back.
This has been the issue from the beginning, that on two channels it's been ok, but not on four. So I'm wondering if headunit is the problem or if it's still related to grounding/power issues?

That's why the test where I connected my phone to amplifier and played music from my phone is inconclusive. Because I can only power 2 channels from my phone. I cannot power 4 channels so far.

Tomorrow I'm getting a new alpine headunit and also rca splitter for 4 channels, like I mentioned in a previous post.
So if I can use my phone as an audio source for all 4 channels of the amplifier, then it'd be interesting to see if there's any whine.
Then I can also test new rca cables and new headunit.
 

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So, the conclusion so far is that HEad unit obviously has some problem, probably with micro fuse. If you still have noise issues and everything else is correctly installed, then try to lower your gains since that might also be a problem and causing noise.
IF speakers are not equaly loud L/R or F/R, then check your head unit settings like balance and fader.
If Alpine HU does have 4 stereo RCA outputs,connect them all to the amp.
Also, check how amp inputs are configured....

at least we have some progress
 
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Discussion Starter · #194 ·
Knowing how treacherous this system has been, I'm not drawing any conclusions yet:)
But today will reveal a lot.
I set my headunit to flat balance everywhere in settings and the set it to 75% of top loudness and then start turning gains up slowly from 0.
Both headunits have 6 rca preamps, as I need 4 for the speaker amp and 2 more for sunbwoofer amp.
Kenwood hu has 5v preouts and alpine hu has 2v preouts. I heard 5v is better, but I'm not sure it really mattets at my level. I set my up to 100mv-2v sensitivity on the amp. I read that's the right setting even if headunit preamp output is higher.
Bass boost is at its lowest.
Only question I wonder, if I need to set up high pass filters for my speakers/tweeters.

Channel 1 is for the front speakers and tweeters+crossover, channel 2 is for rear speakers and tweeters + crossovers

I included a picture of the rear of my amp

Sub and amp for sub are disconnected for now. Trying to figure out the speakers first.

Still waiting on those transformers, they're taking forever.
 

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I suggest to you that you weight tunning options on HU and AMP, and decide where you will make x-over settings (Head unit or amp) to avoid confusion set settings on only HU or only on AMP .

You can definitely set hi-pass for front system - let say arround 70-80Hz for starters. CH 1/2 front, ch 3/4 rear... Bass boost is only option on channels 3/4.
 

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Discussion Starter · #196 ·
With how often my headunit gets disconnected right now to work on things, I should stick with making settings only on the amp.
Right now my settings are set to FULL (attached picture was a screenshot from a product page).
How do you set frequency to 70-80 Hz when the dial has such a wide range, 50-500 Hz, with no indicators in between??

Bass boots is probably just useless on this amp for me. I figure it assumes you're running 2 channels for speakers, and 2 rear channels for sub, which could then get boosted. But since I have a separate amp for a sub, I won't have to worry about it.
 

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Discussion Starter · #197 ·
Test #1 - phone to amp adapter- success

Used 3.5mm phone jack to drive all 4 rca cables going to the amp. No whine.
Maybe I should just use an extension for this cable and listen to music this way?! How good is Galaxy S21 phone compared to a headunit?

Test #2 - rf chokes - fail
Used those clip on choke filters on power lines to amp, HU etc., did absolutely nothing.

Test #3 - new headunit - fail
Powered up new headunit.
Whine is still there. Tested resistance between amp ground and HU ground - 0.
If headunit is on, resistance goes up to 50ohmn. Probably normal.

Now the main thing. I say main because this hasn't changed after changing amps and headunits.

If I connect 2 rcas between amp and HU, it seems to play fine, I can set the gain pretty high, no whine. There's some faint sound coming from the tweeters, like a bird flapping its wings, but it's pretty mild.
Now if I connect 3 or all 4 rcas, this is where I'm getting the whine again.
Only if I set gains to 0 on the amp, does the whine disappear with the car idling.
But if I put my ear next to the speakers/tweeters, I can hear it again!

I don't understand why there's no whine with 2 channels, but whine come back at 3 or 4 channels?

Also I'm not sure if it matters, my channel 1&2 seem to be giving sound on the left side speakers, front and back. While channels 3&4 drive the right front and left doors.
I thought channel 1&2 was for front doors, and channel 3&4 for rear doors. Does this make any difference?

Last
I ordered new rca cables, and the picture lead me to believe there would be 2 cables x 2 rcas. I only got one cable, which only runs 2 channels. I'm going to order another cable to exclude the possibility of bad rca cables or interference.
 

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Also I'm not sure if it matters, my channel 1&2 seem to be giving sound on the left side speakers, front and back. While channels 3&4 drive the right front and left doors.
I thought channel 1&2 was for front doors, and channel 3&4 for rear doors. Does this make any difference?
Sounds like you need to check your wiring. You can use a battery like a 9 volt to test speaker wires from the trunk. Disconnect all the wires from the amp and test. Did you say the noise went away when you tested with the head unit in the trunk? Where did you get power from? Did you draw power from the trunk or extend power wires from the dash? If it worked powering the head unit from the trunk maybe try running a power wire to the dash.
 

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Discussion Starter · #199 ·
Could you elaborate on how to test the speakers with a 9 volt battery? Like energizer?
Liquid Rectangle Fluid Material property Font


When I previously tested in the trunk with no noise, I don't remember if I used 2 or 4 channels. I also used twisted pair rca cables running overtop of the carpet, and I discarded those cables, as they were old and cheap. I also learned that my system needs insulated rcas, not twisted pairs. I know for sure I previously grounded the headunit on the amplifier ground, and for power I used ignition switch wires. Right now I'm using a wire I ran off the battery's positive terminal. I also tried to power again with ignition wires, but that didn't help.
Tomorrow I'll have new rca cables on hands to test them. I feel maybe there's some interference for some reason.
I should also be getting those Jensen transformers this week, so will finally give them a go!
 

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Yes like the one pictured. Disconnect all your speaker wires. Touch the positive wire to one terminal and tap the other wire to the negative post. The speaker it’s attached to will make a popping sound. Use that to verify all your wires are connected correctly. You can also test polarity if you can see the speaker moving.
 
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