high Frequency sound coming from... the headunit? - Honda Prelude Forum

DeadFish · 06-17-2009, 04:17 PM

No not musical sound... more like an annoying high tone... it is not coming from the speakers... and I dont get it.

It's a Clarion DXZ775USB.

The sound only happens when my lights.. or my jdm fogs are on... the rest of the time I get no noise... dead silent. The sound does not go up in volume with the speed of the car.. it just stays at a constant high frequency tone.

The only thing that I can think of is with the ground... I just used a twisted end cap to cap the grounds together.

Do you think it will make any difference if I change the ground to the car itself? I just assumed that with this end cap... that at the... other end... somewhere.. its actually already grounded to the car as a base.

The other thing that might be effecting this is... the bolts that hold it on to the side bars or rails inside the kit.. are screwed in with pointy ends.. is it maybe some how creating a sound via this? That doesnt make sense either.. but I will mention it for you sound gurus in here.

My JDM fogs are grounded up front. like way up front before the engine bay.

Thanks in advance.

indylude18 · 06-17-2009, 09:13 PM

That headunit has the ability to turn off the internal amp. Turn it off, and listen for the squealing sound. Obviously while doing this there will be no sound coming from your speakers. If it still makes the sound, your probably going to have to live with it or replace your head unit. If it stops, find a better ground.

Does the tone get higher in pitch with higher engine speeds? Does the headunit make the noise while using all the different inputs(cd, radio, usb) or just one?

DeadFish · 06-18-2009, 02:05 PM

^ Thanks for the reply...

Yes there is a setting for turning the internal amp off... I will try that tonight. But I already think it has been set to OFF.

Since I am using a 4 channel amp for front/back.. and a separate amp for my sub. - both are grounded together at the same contact point..in trunk... but not at the same one as the headunit... obviously.

So I will be testing it with sound....

which yea.. I should mention.. that when I hit MUTE... the high frequency sound is still right there... when my lights are on. When they are off.. its dead silent.. with the mute... or lowering the volume down. No noise.

Regarding driving with this system:

There is no difference in sound with engine noise.. its just one constant sound.. no change.

and there is no difference in sound of the noise what I am using: USP,ipod input, sattelite, tuner, cd.

I turn on my headlights.. or just my JDM fogs... and the sound appears.
FYI: for the headunit.. the dimmer works like normal... it dims when lights go on.

Any ideas?

indylude18 · 06-18-2009, 08:40 PM

You are 100% sure the sound is not coming from the speakers? Grounding 2 amps to the same spot on top of each other usually causes the speakers to squeal. Did you run your power and RCA's on opposite sides of the car?

The problem may be related to that dimmer switch somehow, since it is the only direct link between the lights and the stereo. I didn't hook my HU up to the dimmer, so I don't know if that is doing it or not but mine doesn't squeal.

Here is a rundown of what I would do:
1) Remove the faceplate, start the car and turn on the headlights. If the sound still happens, the problem isn't coming for the radio since it doesn't power up with no face plate. Time to look elsewhere.
2) Check every ground you can get your hands on. Make sure you have good bare metal on metal contacts. I would recommend separating those two amp grounds even though it won't fix the HU squeal, it could prevent the speakers from squealing.
3) If it still makes noise, pull the HU and unhook the dimmer control wire. Start it up and try again.

Report back with your findings.

DeadFish · 06-18-2009, 11:32 PM

Thanks, I will try that and let you know how it works out.

DeadFish · 06-20-2009, 12:51 AM

4uck me the sound is coming from the tweeters only... I know that I have those wired through the honda wire harness.. then out... I think I need to play around with those and my speakers in my kickpanels up front. My previous clarion had no problem playing both.

I think if I detatch from wire harness and plug those into clarion and let the headunit play those...

its going to work.. wont know till sunday.
It was so bad on this date tonight.. I turned the stereo off.

indylude18 · 06-20-2009, 06:22 AM

Quote:

I would recommend separating those two amp grounds even though it won't fix the HU squeal, it could prevent the speakers from squealing.

90% chance that will fix your problem. It is either the amp ground, cheap crossover, cheap RCA's, or a RCA that is run too close to the power cable.

Also I assume you have a crossover on the front components, which means if you run the tweets from the HU, you will have to run the front woofers from the HU as well. Underpowered woofers sound crappy.

DeadFish · 06-22-2009, 06:07 PM

Instead I did this... I removed the speaker wires from the amp going to the front speakers... where the high sound was coming from... I attached them to the internal ( 55 watt each).. amp from the head unit. Tried the speakers with the headlights on etc... No annoying sound heard anywhere.
Woohoo! I dont drive around all day with the music cranked to the fullest anyway except for some occasions... set the High pass to 125 Mhz and up for the front... same for the rears.. and 80Mhz and below for the sub. So yea I am happy... after playing around with the fader and the balance to confirm everything was working. Oh and switched the gauge to Internal Amp ON, ofcourse. Its kinda cool.. to be able to shut off the fronts completely from the HU.. and just hear the 6x9 and sub if I want to. Doubt I will.. but yea.

High Sound Annoyance... Eliminated. With a loss of an additional 25 watts to the front (75x4 amp)... but so what dont care. Rather have dead silence.. then a f'n mosquito sound.