My subwoofer makes a "Doof" when it is powered up.

[Walt]

Whenever i turn my key on, then when i start the engine and the cd player comes back on, or when i just turn the head unit on, my sub kicks a really loud and solid "doof". It scares the hell out of you if you arent expecting it. But all i was wondering was that my mates doesnt do it, and he had his profesionally installed, where as i did a back-yard mechanics job on mine, still using the proper wiring kit and all. Just wondering what is causing this, cause im guessing it cant be good for my sound gear.

[fullmetaljacket]

are you running a capasitor?

[MUDRATGQ]

Gday mate some amps do it others dont just check your earthing on your amp make sure you have good grounding sometimes cheap RCA leads can cause this to my amp dose it it's just a small power surge dont worry this wont harm your system

[Crusa]

Heres a thought, check the POLARITY on the Sub! Obviously the power is being fed to the amp via the REMOTE wire, usually kicks in 1-2 seconds after power up.. could be that the polarity is around the wrong way +- .. and its causing the sub to thump backwards rather than forwards ( speaker sinking in rather than pumping out) .. just try switching the polarity... if it works great, if it doesnt , ill shut up, ha ha .. also trying this wont hurt the sub, but over time , a sinking sub will.. hope this helps mate

[Walt]

are you running a capasitor?

Nah its only a small system, only a 10 inch, cant rememver what wattage im running it at, about 350 i think, but as in capacitor are you talking about the "Blow a hole in your hand" 1 farad kind?

[fullmetaljacket]

Nah its only a small system, only a 10 inch, cant rememver what wattage im running it at, about 350 i think, but as in capacitor are you talking about the "Blow a hole in your hand" 1 farad kind?

thats the one.....funny you say that, I had a sub with a hand print on the center........now there's a hole.......maybe thats why my hearing is shit

[taresk]

Does it have a kill switch that would allow you to turn it on after the head unit goes on? If not, might be worth putting one in to avoid that initial surge to the sub.

[hillbilly123]

These things go Doof Doof usually dont they. Perhaps u are turning it off when its only gone Doof and its the one left over coming in when u turn it. on:D :drink: :)

[crewser]

These things go Doof Doof usually dont they. Perhaps u are turning it off when its only gone Doof and its the one left over coming in when u turn it. on:D :drink: :)Bwaaaahahahaha. That must be it, the left over doof. hahhaha

[Patrolling Paddy]

Man that sux, I just wrote a long winded really cool answer and my signin died and I lost the lot. This version will have to do.

My old stereo started 'doofing' on startup and powering up the stereo after 7 years of abuse and a couple of not so successful water crossings. It stopped the 'doof' when the stereo finaly died. I now have a new stereo and no 'doof'.
How old is your stereo setup? Has it ever been serviced or cleaned? What sort of abuse does it get? Did you buy it new or has someone else abused it first? Have you tried turning the volume right down before shutting it off? (didn't work on mine)
Write it off as character for now untill it either goes away or dies a miserable death.
OR you could leave it running a little longer to let it get out the other doof before you shut it off, LOL

Cheers

PP

[Walt]

the head unit is 6 mnths old, its an alpine, my old unit was an alpine too. the amp/sub is probably 12 mnths old and its always done it. from word go. It cops some abuse (what is this "screwing the amp down" buiso?) the amp just kind of floats from here, to there, maybe over here, behind the seat, nahs its not that bad, is normally held down by things packed around it. But if i turn the volume down or the sub off before turning off, the next time i power it up its doesnt make the noise.

[Walt]

so actually while im on this topic if anyone has any great idea on how to fix an amp to the cab of a 75 without screwing holes in the steel i would like to know.

[Patrolling Paddy]

so actually while im on this topic if anyone has any great idea on how to fix an amp to the cab of a 75 without screwing holes in the steel i would like to know.


I had mounting issues with mine in my GQ ute and it was originally fixed to the carpet not into the floor and this worked really well till the cab got a little wet and it drowned x2 amps.
My solution was a custom roof console running from front to back, it uses all the std mounting holes from other acc. now the amp is mounted securely and stays dry (if it gets wet I'm in BIG trouble).

[wado]

The pop or doof you hear is a power surge when the amp is turned on making its way onto the audio line. Make sure your earth lead is very short and at least as thick as the power cable. If this doesn't fix it then it is due to the amplifiers poor internal filtering abilities. An expensive amplifier should not pop on start up unless it is faulty. A super cheap auto amplifier will almost always pop due to poor design.

[safari wagon]

yeah gotta check that wirring. as they have said above, its the current getting to the sub before the head unit does. doesn't do any real damage. are you getting the same noise when head unit is down low or up high. ive installed a few stereos. my latest was 2 2500 watt amps running 2 1500 watt 15' subs. that made a very big pop (sorry guys, new stereo, no left over doof) had one of the wires earthed wrong. 2 fifteens make alot of noise in a tin garage.

[Bazza_rips]

I'd say the amp is probably on it's way out. buggered amps can make a loud popping sound when they turn on. would probably sound like a doof through a sub.

[Walt]

Thanks guys for the help, but no need to worry anymore, cause it looks like Bazza rips was right on the money. Was driving home today and it looks like my amp went ka-fooey.