Subwoofer pop when stereo turns off

[SavageTusk]

I have an issue that you small electronics guys may have a solution for.  When I turn off my car stereo, there is a delay for the screen to shut down. Once the stereo turns off there is a loud thud from the subwoofers connected to an amp.  I have reduced the remote turn on wire from 12v to 5v via (2) 1k ohm resistors and still does it.  My thinking is that there it a voltage spike when the radio turns off causing the problem. What would I use to catch this or how would I "filter" this spike? 

[Mopar1973Man]

Just like me shutting down my exhaust brake I get the crack from the discharge of the solenoid magnetic field just like an ignition coil. You'll need a proper filter diode like in quality relay have that reduce the discharge spike across the diode.

[SavageTusk]

3 minutes ago, Mopar1973Man said:

Just like me shutting down my exhaust brake I get the crack from the discharge of the solenoid magnetic field just like an ignition coil. You'll need a proper filter diode like in quality relay have that reduce the discharge spike across the diode.

 

A relay makes sense  Any specifics on what you used? Or just any relay will do? 

Edited October 6, 2018 by SavageTusk

[Mopar1973Man]

Talk to @IBMobile he knows the relay to use.

[2000Ram2500]

It also couldnt hurt to check your connections. I've installed dozens of stereos in several different cars. Several for me personally I put a stereo in everything i own but also for friends and family. Start with the basics. Ever used the zipties that come with a stereo install kit? They are the WORST. You cant even pull them tight they just break. Well the wire they provide is of the same quality. Obviously not all kits but you know which ones im referring to.

 

I had an old e30 BMW. 91 318i. No ac. Nothing extra electrical aside from foglights and a coil on plug conversion. I had a hard time tracking down a static noise which then turned into a crackle upon shut down. I looked at grounds, connections, even looked to see if one of my wires was shorting on the body or anything and no luck. I actually had to completely replace the rca cables that i had run from the head unit under the carpet along the tunnel and under the backseat because they were cheap rca's and the insulation they used wasnt enough to shield the wire from its own interference. That was a nightmare to say the least.

[Mopar1973Man]

Ground connection should be short as possible and kept away from the positive power lead. There is also no need to run ground all the way back to the battery. 

[SavageTusk]

Thanks for the tips, yes the ebay stereo wires are super thin and cheap.  Of course you know the instructions that come with these are lacking to say the least.  I got to thinking about it and the auto antenna / amplifier blue wire as it's mentioned in the manual is really just for auto antenna.  There is a delay in turning it off.  I ran my amplifier remote wire to the switched red wire and my turn off pop is gone.  This is because it turns the amp off with the key and then the stereo turns off.  At first I thought I may need a delayed relay to eliminate start up pop but so far so good.  No thumps.  Thanks fellas. 

Edited October 8, 2018 by SavageTusk

[2000Ram2500]

1 hour ago, Mopar1973Man said:

Ground connection should be short as possible and kept away from the positive power lead. There is also no need to run ground all the way back to the battery. 

 This is a good point as well. Always the shortest ground possible with these. My amp gets grounded to the nearest bolt and usually a seat bolt. Stereo gets grounded to the nearest piece of metal in the dash I have used a few self tapping screws before but the amp needs a good solid bolt holding it down.

 

Thats interesting about the antenna ive never had an auto antenna before and the one car that did it was broken anyways.

[SavageTusk]

That's what I do too.  4 gauge right to the seat bolt.  I'll do that with the stereo, ground to a nearby bolt in addition to the harness, just for good measure.  I have some extra 4 gauge so. I'll do the big 3 with it.  First time with an ebay head unit.. I don't think I'd recommend it but for $50, I'm not complaing...too much. I figure I'll let the eq/dsp do most of the work later on. So far today no start or stop pops so. I think I'm in good shape. 

[KATOOM]

6 hours ago, SavageTusk said:

 

I like the looks of that deck...  What brand and size?  It may be an illusion but it looks bigger than a 1 din but smaller than a 1.5.

[SavageTusk]

2 hours ago, KATOOM said:

 

I like the looks of that deck...  What brand and size?  It may be an illusion but it looks bigger than a 1 din but smaller than a 1.5.

Here's the link.  It is a 1 din but has a 4.1" screen. Nice for the backup camera.  Operationally, it's OK but there's a lot I'd change for ease of use.

 

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F263819416493