Popping and noise coming from front speakers

[Sephious 10+ year member]

To start things off, my system specs:

Speakers: CDT Audio CL-61A-25 Pro

Headunit: Stock Mazda 3 w/ LOC

Amp: Hifonics Zeus ZXI6010

Wiring: Alpine KWP-600K

I got everything installed today by a guy who has done hundreds of installs and is a fantastic installer. I caught him just before he went on vacation (so unfortunately can't troubleshoot the issues with him until he's back on Tuesday). I then took it home and tuned the amp to 22V for 121 watts to the speakers at volume 25 on the deck. Volume 25 is fairly flat when it comes to stock head units, which is why I chose it as the max.

Now onto the problems I'm having:

Number 1: ***SOLVED***

Alternator noise. When the car is on the alternator makes noise through the speakers. When you rev the engine the noise changes and gets faster.

What I've done to troubleshoot so far: Disconnected the RCA's with the car still running. The noise stops. So it's not a power wiring or speaker wiring issue. I'm thinking it's possibly a ground loop and grounding the deck to the same place the amp is will fix it. Any thoughts?

EDIT: I've tried a ground loop isolator and that did not solve the problem. Could it still be the fact that the stock deck is grounded to a different (or possibly crappy) point?

Number 2: ***SOLVED***

Popping noise at louder volumes. I can't pin down an exact level where the popping noise happens as it only happens with certain frequencies, mainly hard midbass hits. If I had to guess it starts happening around 50 watts 0dB 1000Hz tone, unknown actual wattage listening to a song.

I don't even know where to begin diagnosing this one.

Please help, so when the guy gets back from his vacation he can fix this!

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[GetLikeMe 10+ year member]

IVe herd the popping noise with those CDT mids is kinda common. turn your hpf up a bit maybe and ive known some people say it goes away after some break in time..

 

[Sephious 10+ year member]

IVe herd the popping noise with those CDT mids is kinda common. turn your hpf up a bit maybe and ive known some people say it goes away after some break in time..

Yep, you are exactly right, I didn't have the HPF up high enough. My HPF goes from 10 at 7 o'clock to 150 at 5 o'clock and I have it around 3:15. I'm thinking with the way they go, that's probably right around 100 or a bit higher. I'm guessing after they burn-in and loosen up I'll be able to lower it some. Also, is there a way to have a closer estimate than eyeballing it when it comes to high pass filters?

At any rate, one down, one to go!

Anyone have any ideas on the alternator noise issue?

Also: Do you think the Hifonics will do its rated 150RMS per speaker without clipping? They're not quite as loud as I'd like them so I'd like to eek out everything I possibly can.

 

[Sephious 10+ year member]

Bump! Tried a ground loop isolator and that did not solve my first problem. Please help me out!

 

[Sephious 10+ year member]

Come on guys, I know there's at least someone out there who might have a possible solution or at least be able to confirm that it might just be a crappy ground. Let me know what you think!

 

[okiedokie 10+ year member]

Where dio you have your ground grounded to?

Have you tried to move your amp ground to see if that will solve the problem?

I didn't understand where you have your amp gains at!

if your gains are set to high you can get alternator noise as well.

On your deck you have your highpass filter set at 3:15?

Your head unit might also be picking up a ground noise.

Have you deaden your doors yet?

 

[Sephious 10+ year member]

Where dio you have your ground grounded to?Have you tried to move your amp ground to see if that will solve the problem?

I didn't understand where you have your amp gains at!

if your gains are set to high you can get alternator noise as well.

On your deck you have your highpass filter set at 3:15?

Your head unit might also be picking up a ground noise.

Have you deaden your doors yet?

My amp gains are set at about 120 watts via DMM. I haven't tried to move the amp ground or the deck ground yet. The deck ground is still the stock deck ground. I'm going to try hooking up something directly to my amp and see if there's still noise. I did try a ground loop isolator and that did not solve the problem (or lessen it, even). The noise does not vary with deck volume. No matter the deck's volume, the noise stays at the same volume.

On my amp I have my highpass filter set to 3:15, which is roughly 110Hz or so.

Yeah the doors are deadened.

 

[jtomsic 5,000+ posts]

sounds like your ground on your amp is bad to me..check that and move it and see if it helps.

 

[Sephious 10+ year member]

sounds like your ground on your amp is bad to me..check that and move it and see if it helps.

Hooked up my MP3 player directly to my amp and had no alternator noise or any other kind of noise, so it shouldn't be the amp ground. I'm thinking it's either gotta be the RCA cables taking in noise or a bad head unit ground due to the troubleshooting I've done.

 

[Sephious 10+ year member]

Alright, so if anyone cares the noise was caused by a combination of the LOC and the crappy stock head unit ground. The head unit was grounded to where the amp is, and the majority of the noise went away. The remaining noise was lessened by a better LOC. Now it is inaudible unless the deck is off, so I'm happy. Even when the deck is off the engine revving up makes more noise than the sound coming from the speakers anyway.

As a bonus, the better LOC seems to have improved sound quality, especially on the lows and low mids. Now if I put a drink in my door cup holder while cranked, the drink jumps around like a Mexican jumping bean.