Noise with Acceleration in Newly Installed Alpine Head Unit (1 Viewer)

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chroad

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Put a new Alpine in the LX the other day, and now I've got some interference-type noise in the system. It increases as you accelerate, decreases as you slow down, and seems to increase and decrease as the volume is turned up or down. I can't tell if it goes away completely when the volume is at zero, but it's close. Also, when the LX is shut off, the whole system makes a loud pop. While not normal, I think its made worse by the front speakers being busted up pretty well.

This unit has three preouts and I'm using two of them with the factory amp.

Any idea about what's going on? Has anyone else experience this? Did I get something crossed, or is it just that something is laying up against something to cause some interference?
 
Maybe get rid of the factory amp. I don't htink you have something crossed. It is either a problem with the amp or some wires may need some type of shielding or maybe thicker wires. Just thoughts as I have seen this problem back in the day with older stereo systems. Not an expert.
 
Disconnect factory amp by the glove box.

Next ground the head unit body directly as well as the ground wire.
 
Loose it permanently now that you have a non OEM/Toyota head unit.

Check search for easy instructions.
 
chroad said:
Lose the factory amp permanently, or just disconnect to troubleshoot?
Click to expand...

Disconnect it to troubleshoot, but I think you will find that it is the cause for your problem, so you will likely be removing it permanently.

The problem could be that the new head unit is sending the factory amp a signal that is much higher voltage than the signal it received from the factory head unit. The factory amp was not built to handle the higher viltage signal, and that is why the engine noise comes through. Plus, the higher voltage signal to the low-output factory amp usually results with very poor sound quality anyways.

Ditch the stock amp all together and run the speakers from the Alpine directly, or run an aftermarket amp and you will like what you hear.

Hope this helps.:)
 
Sounds like a classic GROUND LOOP problem.

Ground your head unit DIRECTLY TO CHASIS/BODY... (do not use stock ground wires)
Use a good guage wire.
DO NOT run ALL ground to same point, or tie all grounds together to same ground lead! (I would not even use provided stock ground lead)

If this does not solve your problem try a DIRECT +Positive line from the battery to head unit. (you can run an external line for testing)
Use a good guage wire.

This will almost allways correct a ground loop problem..
On another note: Some newer head units have a way to lower the voltage of the pre-amp outputs... you can try to lower that through the menu sysytem if you have it!

DO you have any other sound hardware? (ie:amp, crossover, preamp... etc...)?

AS Bryson308 mentioned, your NEW head unit probably has more power then the STOCK amp.
If you decide to bypass amp, you will need to use you headunits Hi-power output wires and use the other radio harness (not the amp harness)
If your new head unit does NOT have any HI-POWER outputs, THEN you will need a NEW AMP.
 
Last edited:
Sounds like maybe you have speaker wires grounded.

Sent from my DROID BIONIC using IH8MUD
 
Sounds like we're honing in on a ground issue. I'd believe that. Now to track it down.

While we're on the subject, anyone have any idea of what the specs are on the LX factory amp? I've googled around a little but haven't turned up anything.
 
Yep, I'm still using the factory speakers. But they are basically trash. I'd buy some new ones but I'd rather spend that money on other things for the LX right now... springs, shocks, baseline needs, etc. The Alpine HU was more or less a present, but speakers weren't in that box. :doh:

However, my plan for speakers had been some inexpensive Pioneer replacements... maybe something purchased at Wal-mart. Something with a shallow mounting depth that I can retain the stock grills. My LX is not my daily driver, so I just want the stereo to sound decent. That said, even if I use something low-end, am I going to need the additional wattage over the factory amp?

That Power Pack looks pretty cool though, I must say.
 
I’m having this same engine noise interference issue with my newly installed Sony XAV-ax1000. The HU is wired up to the factory amp. I had it professionally installed (I know a guy).

Can I keep the wiring linked to the factory amp and somehow adjust the ground wires to get rid of this engine noise?
 
Yeah, ground loop.
As another said, the Alpine prob has more power than the factory amp anyway. But only if you use the line-outs most likely.
Yes the factory speakers (or even new replacements of same size) are classic vintage tin. If audio is a major priority for you, then treat it as such. Use the pre-amp outs from the HU to a real amp. Then new wiring to the new, *larger* speakers you have already installed(right?).
Screwing around with any of the factory stuff is sufficient for low volume AM talk radio. (which is fine if that's your thing)
 
I should’ve mentioned I have aftermarket Infinity 6.5” speakers in the front. Nothing in the back, for now, butI plan to remedy that.

For right now I would like to get rid of the “whirring” noise when I accelerate and decelerate. I listen to music/ podcasts 50/50

So it sounds like better wiring to the speakers, and a proper aftermarket amp are my pathways towards clear, unobstructed audio.
 
I have a similar issue with a Sony XAV-AX5000 I installed about 2 years ago.
My model 80 had no factory amp, and I put in new Pioneer speakers (low quality if like to replace).

I have a kenwood compact amp I'm yet to install under the dash.
I've already run heavier power wire ready for the amp.
Sounds like a better grounding solution is the way to go.
 
@mudgudgeon so the heavier wires did not fix your problem? It’s ongoing?
 
Dirt Ferguson said:
I should’ve mentioned I have aftermarket Infinity 6.5” speakers in the front. Nothing in the back, for now, butI plan to remedy that.
Click to expand...
Good start at the front. Do you stand with your back to the stage at a concert? No audio should come from behind you, except omni-dirctional bass (sub). Add some good tweats and a dash center to the front stage and call it good. (sorry, old-school IASCA bubbling up lol) It's a few speakers less expensive tho.

Dirt Ferguson said:
For right now I would like to get rid of the “whirring” noise when I accelerate and decelerate. I listen to music/ podcasts 50/50
Click to expand...
LC's (80 series at least) are negative-switched, or so I understand. Curious if that makes this noise more difficult to resolve. Also curious to what other Toyotas this may apply. I've successfully performed the steps outlined above in several other Toyotas (couple Supras and a Celica) and never had the loop issue.
Dirt Ferguson said:
So it sounds like better wiring to the speakers, and a proper aftermarket amp are my pathways towards clear, unobstructed audio.
Click to expand...
Def the way forward for many reasons, not just the noise. Someone also mentioned not grounding the devices to the same *point of ground*. I truly forget, but that is either correct or the opposite is correct (been 20yrs).
No matter. Easy enough to t-shoot either way.

Usually these issues boil down to mismatched circuit load (ohms), and stem from using line-outs (total shade-tree approach) either from the HU or to the amp, trying to use factory components in an aftermarket setup, or trying to use factory wiring to connect aftermarket components. If you can work around (or eliminate) these pitfalls the result is generally a success every time.
 
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