Stereo Information (Wiring, Upgrades, etc...)

[Emilbadal]

So I just tested my amp only and seems like that I have both amp noise and source noise as well. So tomorrow I’m going to attempt to ground my amp with the shortest distance of Ground wire possible to see if my amp has a high “noise floor” or it just has a weak ground.

So this is how To test the amp noise:
1- Turn off the car and make sure your amp is turned off as well.
2-disconnect the RCAs at the amp side
3- use a short RCA cable to connect the amplifier inputs to each other. For exmple if you have a 4 channel amp. Connect the front channel input to the rear channel inputs. According to my research some amp designs introduce noise if there is no connection is made to their input RCAs. And by connecting the input channels to each other basically you’re making sure the amp does’nt receive any sort of signal whatsoever.
4- turn on your car and see if the white noise is still present. If it is then your amp is creating that noise. In my case the noise was lower but still present. i played with the gains and the noise was increasing as I increased the gain.


If you do the test and the noise goes away, congratulations you don’t have to worry about your amplifier ground or amplifier design. Your next test should be at the headunit.

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[SpeedRacerXT]

Update: I used Forscan to turn off the fake engine noise this evening and it was totally successful. It also got rid of the loud hum I was experiencing. Thank you Relak for pointing me in the right direction. One step closer.

Yep, use Forscan and turn off the built in EQ too, especially if you replaced the cheap factory speakers.

 

[Emilbadal]

UPDATE: I just shortened the ground cable to my amp to 3" of 4 AWG wire. Unfortunately still have the hissing noise. I checked the AB data in ACM and strangely the 727-01-01 and 727-01-02 lines were changed from when I did the Sync3 conversion. I edited the lines back to get the line level outputs and flatten the EQ. However that didn't have any effect on the hissing sound but the sound got a little bit cleaner and more balanced.

 

[5.0_SD]

Where did you ground? I put mine on a 0/1 to where the tire inflation kit bolts to up to a ground distro block to two amps and a dsp, no hiss whatsoever.

 

[Emilbadal]

I mounted my amp under the rear shelf, I sanded the paint 2.5 inches away and used a self-tapping screw to connect it to the body. It might be the amp or it might be my Pro sound tweeters and midranges with really high sensitivity.(tweeters are 115db sensitivity).
My active sparetire subwoofer is grounded exactly to that ground point that you mentioned.

 

[5.0_SD]

And I assume you metered to ensure no resistance in your ground? (I know I asked that weirdly, tired). It sure as heck sounds like your ground should be good. And I assume no power wires near signal wires unless you have shielded cable. I wonder if could be coming from the HU?

 

[cheezhed]

So what brand 3.5" speakers are people upgrading to? Looking around I see options are limited.

 

[5.0_SD]

I can tell you that the Hybrid Audio Unity U3 fit perfect for me.

 

[cheezhed]

And the sound?

 

[5.0_SD]

Outstanding. I am really enjoying the Hybrid Audio speakers I put in(the one's I have aren't even their top of the line)...see my sig for other components. If you don't do active crossover they have have passive ones already for them IIRC. If you haven't been to the diymobileaudio forum, do so, tons and tons of great info and knowledgeable people. I'm going to have a guy on there remotely tune my dsp. I have it tuned myself and it sounds great, but since I don't know all the tiny intricacy's of the helix dsp, I bought a microphone to plug into the laptop to really fine tune it...I'll eventually get to it, but for now, I'm extremely happy with my setup.

 

[cheezhed]

Thanks!

 

[cheezhed]

Just finished wiring my GT 401A non shaker and installing amps and dsp. Speakers are Milles on order. I used the iDatalink HRN-AR-FO3 Harness which makes nearly everything plug and play. No cutting of factory harness but there is soldering your speaker wires from iDatalink harness to DSP, then from amp speaker outs to iDatalink harness again. Equipment is:

• iDatalink HRN-AR-FO3 Harness
  
• Polk Audio D4000.4
• Kicker CXA1200.1
• AudioControl DM-608
• SoloBaric L7S 10"

With the rears and center not connected or needed, the sound after some rudimentary tuning with the stock factory fronts is in a word, amazing. The amps and DSP make all the difference here. I'm seriously debating cancelling the Mille order it sounds that good.

 

[Cobra Jet]

I mounted my amp under the rear shelf, I sanded the paint 2.5 inches away and used a self-tapping screw to connect it to the body. It might be the amp or it might be my Pro sound tweeters and midranges with really high sensitivity.(tweeters are 115db sensitivity).
My active sparetire subwoofer is grounded exactly to that ground point that you mentioned.

I haven’t read all of your responses here but did see you’re having noise issues.

If you ran new RCA’s or any other cables - do you have all other cables separate from the power cables?

Sometimes folks make the mistake of having the power cables and all other cables zip tied or taped to each other when running those cables front or back and when hiding the cabling under interior panels or carpets.

The hissing or noise is sometimes attributed to the sound cables (RCA’s) picking up engine noise being so close to the power cables - which is actually generated from the alternator.

Just a thought if you either didn’t know or haven’t tried that diagnosis yet.

 

[Emilbadal]

I haven’t read all of your responses here but did see you’re having noise issues.

If you ran new RCA’s or any other cables - do you have all other cables separate from the power cables?

Sometimes folks make the mistake of having the power cables and all other cables zip tied or taped to each other when running those cables front or back and when hiding the cabling under interior panels or carpets.

The hissing or noise is sometimes attributed to the sound cables (RCA’s) picking up engine noise being so close to the power cables - which is actually generated from the alternator.

Just a thought if you either didn’t know or haven’t tried that diagnosis yet.

Well, I ran the power cable and remote wire from the passenger side, and the RCAs are routed through the driver side. The noise that I’m getting is not buzzing sound of alternator, it’s just constant high frequency and high pitched hissing noise.The only place that I suspect that the RCAs would pickup any noise from would be the fuel pump regulator under the rear driver seat. But still as far as I remember RcAs are roughly 6” away from that thing.

 

[Emilbadal]

So this afternoon I ran ground test and amplifier input isolation test. So basically for the ground test, I referenced the factory ground point underneath the plastic cover and then tested the amplifier ground connection.So this reading is off of the factory ground point:

And these two photos are from the amplifier’s ground plug:


As you can see, you can’t get any better than this. Btw I used the battery negative terminal as the ground reference point. So the ground issue is out of question.

For the second test, amp input isolation, basically I bought 4 RCA plugs and soldered the internal positive and negative posts together.(WARNING: these plugs only should be used on INPUT RCAs ONLY). These plugs basically zero any type of possible amp’s input noise. At this point I turned on the ignition and there’s still a faint and soft hissing sound coming off the tweeters.(This is called Amplifier noise floor). I turned on the engine and I noticed that the annoying high pitched noise is not present. So that tells me that the the high pitched noise is coming through the RCAs.

In my previous post, I mentioned my suspicion of the fuel pump regulator which you can see in this photo.

The bundle of the RCAs pass roughly 3 to 4 inches away from it, and that’s my primary suspect. I didn’t have the tools that I needed to either relocate or the mu tape to wrap around the RCA bundle to isolate them. I will report more once I relocate or isolate the RCAs in search of the infamous noise.

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