I am a little bit frustrated tonight with a static/crackle/pop issue I am having with my front tweeters. I have gone through quite a bit of diagnosis tonight, and I think I have a bum amp, but I wanted to pass it by some of the other audiophile on here that I respect to see if anyone has any ideas that might help me out.


First, Here is my Setup;

Clarion DXZ655MP HU
RF 300.2 Amp
CDT CL-61 Front Speakers
CDT CL-6EX Rear Speakers

For a year I had the Stock HU in Place with a David Navone Line output Converter feeding the RF Amp 2ch Amp. I had the Front R and Rear R Speakers run in Parallel on One Channel (Making 2 Ohms) and the Front L and Rear L on the other channel. I had no crackle or pop issues at volume. I did this primarily to just have a few tunes on something a tad better than stock with some equipment I had laying around.

I installed the Clarion HU recently and for a week ran with it still connected to the line output converter with NO issues at all.

I disconnected the LOC and installed a Set of RCA cables directly from the HU to the amp. I also Removed the Rear speakers from the Amp, Leaving only the front two speakers (Not at a 4 ohm load) on the 2 channel amp. (With the rears now disconnected)

Now at high volume, I have a crackle/pop noise in the tweeters every time there is a dynamic sequence of music with a lot of bass/treble. Every “peak” pops the tweeters.

I have adjusted the Gains down to a minimal level (well matched) and still have the issue.

To try and do a little problem solving, I replaced the CDT Tweeters with a set of MB Quart Premium 1” tweeter I had laying around. Still had the same issue. I tried a set of MBQ Reference Tweeters.. Same issue.

So I replaced the CDT Satnet Crossover with an MB Quart Musicomp that Is known to work well at high volume. Same problem.

Even attenuating the tweeters down 3db on either crossover (CDT or Quart) netted the same crackle or pop.

To Further Test, I disconnected the source unit and connected an IPod. At the highest volumes I received some crackle/pop, albeit a bit less than before. I turned on the “Bass Boost” on the Ipod and Had the same level of Crackle/Pop as the HU put out.

Any Ideas on what is causing this? The amp possibly having a static issue at 4ohms instead of 2?


Thanks!!

 

That is a tough one! Hang in there.

Remove the line converter, and all stock amp connections from your legacy HU harness and run new amp wires.

If that's ok, the high-power fault suggests an amp ground loop or power crosstalk issue.

)Did you run battery power not within 1" of either speaker or unshielded wires?
)Is your chassis ground lead short? ~6"

Good luck! Please post what fixes it.

 

hmm...so you confirm its the tweeter that is doing this?

meaning, if you say, connected just a midbass directly to the amp BEFORE the crossover, will there be a crackle? becuase if its the HU or hte amp sending the crackle to the sepakers, then doing this should still cause an audible crackle in just the midrange...

now, if its JUST the tweeter that is doing it, and swithcing the crossver ddidnt change it...try this:

can you find a way to completely high pass the signal coming out of hte amp, saying high passing it very high, so NO lower signal goes to the crossover or any part of the speaker system, if this still causes the crackle, then you know that its not too low of a frequncy that is popping hte tweeter...

in most cases, tweets popping is them being overpowered or being powered by too low of a freq...have you also check the wiring betweent he crossover and the tweeter? a torn wire that is being slightly grounded can cause issues too

b

 

The LOC is completly out of the system.

Checking the Power and Ground, My Ground is less than 12" in Length and well secured. I can re-check them though, Good Idea there.

Power Wire is run on a different side of the car and Only comes close to the RCAs in one spot about 6 inches from the amp, The RCAs "Cross" the Power Wire in a perpendicular fashion to avoid picking up interferance. I can Temporarily Move them to try and see if that aleviates some of the problem. Another Good Idea.

 

The noise is there with the engine running and not?

If the noise is there with the engine running this could be spark plug popping. You didn't say it was engine related so I'm guessing not.

If it occurs with the engine off have a look at the voltage on your dash guage. I found that when the meter was up above 12.5 Volts my system sounded fine but dropped pretty rapidly below and I too started to hear large amounts of distortion. Starting the engine and charging the battery gave me another 20-30 minutes of listening time before the noise started.

 

In all of my tests I did not detect any Midbass crackle, only Tweeter crackle, I have not tried only the Midbass, I will have to give that a try.


The most I could Hi pass on the equipment in place was 200hz, At that level, I stil had the crackle.


I did check the wiring, no frays or cuts on either side. The Power issue is something to consider, the RMS of the Amp at 4ohm is 75w. Power Handle for the Component set is 90W RMS, so I am right in the Ballpark for matched set.. I Thought it was an over-gain issue at first, but Adjusting the gain down to a level that It will not crackle leaves a system that will not play over90 db at full volume on my DB Meter...

Any volume on the HU over 75% causes the Crackle.. I am wondering if I have a bad PS in the amp that is causing a spike for the high frequencies only? I may have to pick up another amp and do some testing...


I hate spending money anymore though... All I wanted with the Z was some clean sound.. No wonderfull imaging or Top end SQ... What a week...

 

A couple things to look at:
Check the speaker wire connections at both ends making sure there are no stray wire fibers touching metal(grounding out) on the amp chassis,car,etc or touching the opposite terminal.

Check gains on the amp. If you've got them set too high you will get distortion(clipping) at high volume...it will manifest first in the tweets with a pop and crackle. With your loc...you likely needed a good bit more gain than with the clarion so you need to reset your gains properly for the increased line voltage from the clarion.

A simple down and dirty way to set amp gains:
Start by turning the amp gains all the way down. Next with a good sound quality cd turn up your deck to about 3/4 volume(above this and many decks start clipping the signal). Now slowly start turning up the amp gains...when you hear funky crap(distortion,pop,etc ) back the gain off a tad. This will get you in the ballpark.

 

ahh simultainous(sp?) posts.

It should be "cleaner" with low level(rca) signals. Usualy systems with loc's are the ones with problems. Yours is just the opposite.

Did the loc you had do anything special with the speaker grounds? Such as floating them or combining them?

Any chance of a screw or sharp object nicking the rca wire when re-assembling the interior causing it to ground?

EDIT:
THe z's stock elec. system should be able to handle one 300.2 no problem. Unless your alt or battery is going bad. You should have at least 8ga. wire power wire going to the amp.

 

does either of your crossover network have a tweeter protection device, in other words, a little light bulb that lights up when the power going to the tweeter is getting to be too much?

the fact that you get:

1. no midbass crackle
2. only does it at high volumes
3. only does it at the tweet

suggests to me that the tweet is being overpowered...

try one more thing, put the woofer on the tweet wires coming out of hte crossover, see if it makes any crackles, if it doesnt, then its the TWEETER itself crackling, if it does, then its hte signal chain before the speaker that is generating it...

b

 

Update:


The problem goes away completely with the new amp (Clarion 450) and is much cleaner than the Rockford. I can increase the volume considerably louder without any crackling or distortion on the system now, so it looks like an amp issue.

Thinking back, The LOC had adjustable output voltage, Now I am not quite sure what I had it set to since it is not marked on the LOC but I do know I could have easily been putting 4+ volts to the amp. The new Clarion has only 2v outputs. Could that have possibly caused the problem, even with correct gain settings on the old RF amp?

 

Sounds like you were driving your amplifier into clipping but that's not the sound you were describing, or at least the way I'd describe clipping.

 

sounds like the 300.2 is having some problems, and maybe even passing some dc current causing the tweeters to pop. you can check it with a multimeter on the output of the amp. you shouldn't have dc voltage. if you do you've got a problem.

 

I Think I will just shelve the RF and Keep the Clarion in Place Full Time, it sounds so much better.

 

+1
I had an old Phoenix Gold amp "dc" on me once. With an extremely loud pop, that shook the whole car, it blew the speaker wire terminals off the connectors on my JL subs when it did. Didn't hurt my subs thankfully. Basically what happens when an amp starts passing dc instead of ac current the amp is trying to push the speaker in one direction only. You can replicate this by connecting a small 9volt battery to a speaker. Depending on how you wire the +/-(polarity) it will either push the speaker cone all the way out or pull it all the way in and hold it there.

Now a tweeter would be very sensitive to this even if the amp is just starting to "dc". The tweets would react to noticeably it first so yah...I'd shelf that amp or have it looked at for repair.