Author Topic: Car audio phoolery? (Subwoofer power wiring)  (Read 1218 times)

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Offline dmwahl

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Car audio phoolery? (Subwoofer power wiring)
« on: May 17, 2019, 05:16:32 pm »
I've been looking at adding a relatively modest subwoofer to my car (Pioneer TS-WX1010A, manual available at https://images-na.ssl-images-amazon.com/images/I/C1KBTXalyUS.pdf). The manual states 13A max current consumption and has a 20A fuse. I was originally going to tie in to the trailer aux power wiring harness as it's a 30A fuse (14awg wire) and never once been used in 180k miles of driving. At the point I'd be connecting the sub wiring, it's maybe 15' (5m) or so from the battery, so even assuming 3m \$\Omega\$/ft I only would lose ~0.5V at the full 13A supply current.

It seems all the recommendations are to run 8awg wire straight to the battery for the supply and chassis for ground. This strikes me as excessive. Sure 8awg will minimize cable losses, but 15' of 14awg seems perfectly adequate for the job. Am I missing something? Or is this just an excuse to sell heavy wire and installation services.
 

Offline German_EE

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Re: Car audio phoolery? (Subwoofer power wiring)
« Reply #1 on: May 17, 2019, 05:51:21 pm »
The problem is peak current and it's why people don't (or shouldn't) wire up speakers with the thin 'bell wire. If your audio system needs to produce a sudden pulse of power then it will need a low impedance power supply, this may not be provided by the standard car wiring loom. I see the same problem when wiring up ham radio transmitters where a 100W transceiver connected to a car loom may even cause a fire.

Play safe, chunky wiring direct to the battery with a separate fuse.
Should you find yourself in a chronically leaking boat, energy devoted to changing vessels is likely to be more productive than energy devoted to patching leaks.

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Offline SparkyFX

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Re: Car audio phoolery? (Subwoofer power wiring)
« Reply #2 on: May 17, 2019, 06:09:00 pm »
It seems all the recommendations are to run 8awg wire straight to the battery for the supply and chassis for ground. This strikes me as excessive. Sure 8awg will minimize cable losses, but 15' of 14awg seems perfectly adequate for the job. Am I missing something? Or is this just an excuse to sell heavy wire and installation services.
The ground studs in a car are usually not ideal, being welded studs in steel, painted over, partially oxidized over the years of use.

In the worst case you get a voltage potential between ground connections across the vehicle, having an impact on the signal quality for other things or even an uninteded reverse polarity on inputs, depending on the current spike drawn by the amplifier.

Thats where the recommendation to wire separately comes from.
Regarding the wire size: it might be audiophoolery.
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Online Benta

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Re: Car audio phoolery? (Subwoofer power wiring)
« Reply #3 on: May 17, 2019, 06:59:51 pm »
Very impressive over-unity power technology from Pioneer!

"Power source:... DC 14.4 V [...]"
"Max. current consumption:... 13 A"

14.4 x 13 = 187.2 W

"Nominal power:... 350 W"
"Maximum music power:... 1300 W"

 :bullshit:   :palm:   :--   :-DD

« Last Edit: May 17, 2019, 07:01:39 pm by Benta »
 

Offline stj

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Re: Car audio phoolery? (Subwoofer power wiring)
« Reply #4 on: May 17, 2019, 07:32:10 pm »
probably nintendo numbers,
but keep in mind a good bass thump may be 10 times your supply and be relying on dumping the capacitors in the amp.

i used to do high power car stuff, you would be surprised how fast you can get into trouble.
that said, i'd be tempted to open the unit and see what the actual speaker says - i'v yet to see a real high powered speaker in a comercial product.

we used to use 12" FANE stage speakers.  >:D
 

Offline DDunfield

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Re: Car audio phoolery? (Subwoofer power wiring)
« Reply #5 on: May 17, 2019, 10:10:16 pm »
Play safe, chunky wiring direct to the battery with a separate fuse.

Better yet, TWO fuses! - Unless you are absolutely certain that no ground on the device connects to ground on the car other than through the wire to the battery.

If the strap between the battery (-) and the car frame becomes corroded or otherwise fails to make a good connection and your device offers a path between battery (-) and ground, your device will now be the ground path to the starter....

Dave

 
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Online Zero999

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Re: Car audio phoolery? (Subwoofer power wiring)
« Reply #6 on: May 17, 2019, 11:01:25 pm »
Running a thick cable directly to the battery is generally good practice. Many people swear by large 1F decoupling capacitors, but these are only needed st very high power levels, if the battery is bad or the wiring not thick enough.

Manufactures often lie about the power output of their amplifiers. The only way to know the truth is by measuring the power consumption.
 

Offline Cyberdragon

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Re: Car audio phoolery? (Subwoofer power wiring)
« Reply #7 on: May 18, 2019, 05:49:04 am »
Running a thick cable directly to the battery is generally good practice. Many people swear by large 1F decoupling capacitors, but these are only needed st very high power levels, if the battery is bad or the wiring not thick enough.

Manufactures often lie about the power output of their amplifiers. The only way to know the truth is by measuring the power consumption.

1F? Pffft. That's tiny these days. At the car audio section of stores I've seen 5F caps the size of family sized soup cans with digital readout circuits on top.

« Last Edit: May 18, 2019, 05:51:28 am by Cyberdragon »
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Offline tooki

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Re: Car audio phoolery? (Subwoofer power wiring)
« Reply #8 on: May 18, 2019, 07:31:26 am »
Very impressive over-unity power technology from Pioneer!

"Power source:... DC 14.4 V [...]"
"Max. current consumption:... 13 A"

14.4 x 13 = 187.2 W

"Nominal power:... 350 W"
"Maximum music power:... 1300 W"

 :bullshit:   :palm:   :--   :-DD
https://de.wikipedia.org/wiki/Musikleistung
https://en.wikipedia.org/wiki/Audio_power#PMPO
 

Offline Brumby

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Re: Car audio phoolery? (Subwoofer power wiring)
« Reply #9 on: May 18, 2019, 07:41:04 am »
Whatever you do, don't be too casual about the chassis connection.

My son put a sub into his car and did everything right regarding the power supply - but the sub played up terribly.  I had a quick check of his power wiring and then did one measurement - the voltage from the vehicle's chassis and the negative terminal of the sub's amp.  It measured 7V, when it should have been zero.  Simply establishing a proper chassis connection fixed the problem magnificently.
 

Offline stj

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Re: Car audio phoolery? (Subwoofer power wiring)
« Reply #10 on: May 18, 2019, 08:52:33 am »
while we are giving advice,
dont run it without the engine.
 

Offline Electro Detective

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Re: Car audio phoolery? (Subwoofer power wiring)
« Reply #11 on: May 18, 2019, 10:03:04 am »

if you wanna kick serious doof doff boff doom doooom ass, playing autotuned kiddie chunes  :palm:  vs insane asylum come gangsta noise  :palm:, shaking the car boot off its hinges, 

or someone with spare cash that truly appreciates good tight defined bass to enhance or do justice to real music  :-+ 


then the wiring connections MUST be 100%, before blaming or blowing unnecessary cash on  anaconda diameter cables  :horse:

Biggest cables from battery to amp,
realistic sized cables going to the speakers.

This is when two clampmeters come in real handy to quickly lay BS to rest,
one for battery to amp (DC mode)
the other to measure the AC current to the speakers

@multimeter hoarders FYI: a third meter to check the battery voltage is a goer too,
and a fouth to...  :-[

You won't get the best 'accuracy' but the ballpark numbers will be good enough to save you a bundle on overpriced, overgirthed caraudiophoolery cables

Double fuses as suggested above sound like an awesome semi idiot-proof idea in case shtf aka DIYdumbassery   :phew:

FWIW: if you listen to real music at moderate levels, and the speakers aren't flapping about and crackling on louder peaks, then the system is fine as is,
but check those connections anyway regularly.
Crusty and or shaky connections won't do you or your battery/charge system any favors.

Best car audio using cheap generic components I hit on first time up: flexible welding cables from battery to amp/s
and a diced up 15 amp caravan style extension cord from the amp to the speakers

Worked great till the battery went flat, parked at the beach engine off  ::) watching the waves roll in... whilst waiting for someone to rock up for a boost start 

 

Online Zero999

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Re: Car audio phoolery? (Subwoofer power wiring)
« Reply #12 on: May 18, 2019, 02:51:58 pm »
Running a thick cable directly to the battery is generally good practice. Many people swear by large 1F decoupling capacitors, but these are only needed st very high power levels, if the battery is bad or the wiring not thick enough.

Manufactures often lie about the power output of their amplifiers. The only way to know the truth is by measuring the power consumption.

1F? Pffft. That's tiny these days. At the car audio section of stores I've seen 5F caps the size of family sized soup cans with digital readout circuits on top.
I question whether those are genuine. It wouldn't surprise me if it's fake.
 

Offline dmwahl

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Re: Car audio phoolery? (Subwoofer power wiring)
« Reply #13 on: May 20, 2019, 02:47:03 pm »
if you wanna kick serious doof doff boff doom doooom ass, playing autotuned kiddie chunes  :palm:  vs insane asylum come gangsta noise  :palm:, shaking the car boot off its hinges, 

or someone with spare cash that truly appreciates good tight defined bass to enhance or do justice to real music  :-+ 
Thanks for all the replies, I'm only in that first category when my wife walks out to see what I'm doing, and then only to get that eye roll going. Mostly just want some decent quality bass to complement the mid range and tweeters already in there. Not interested in shaking the rust off. Fortunately I have an actual ground bolt at the rear to tie into, not just pulling out some random bolt from a seat or whatever. My interest is largely in minimizing how much of the interior I have to pry off to run the wires without making things sound worse.

So I'll start with using the existing wiring since it's there and easy, moving towards 0 gauge ultra pure directional litz wire if I'm not happy with it or if my music tastes change to the kiddie autotune stuff ED seems to be a fan of.
 

Offline Electro Detective

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Re: Car audio phoolery? (Subwoofer power wiring)
« Reply #14 on: May 22, 2019, 10:31:31 am »
If you want real deal current carrying power from the battery to the amps,

NOTHING can beat thickish welding cable,
not even the best audiophool copper anancondas can squeeze every DC amp out of copper that well  > end of story   :popcorn:


Please ignore the 'NOTHING' part if the copper anancondas are merely eye candy enhanced Audiophool badged welding cables,  ???

in which case buying affordable welding cables means you won't have to mortgage the property again  :phew:

and if things get a bit warm from under the hood to the amps, a dual protective sheath welding cable won't care, nor drop volts/current,

and a good chance your descendents will be re-using the stuff in the far future to wire up their thug pumpin pimped up airborne chariots on the cheap   :clap:

 
« Last Edit: May 22, 2019, 10:04:13 pm by Electro Detective »
 

Offline dmwahl

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Re: Car audio phoolery? (Subwoofer power wiring)
« Reply #15 on: May 24, 2019, 01:58:23 pm »
I read some comparison between fancy speaker wires and a bent up coat hanger, nobody could tell the difference. Maybe I'll just raid the closet for some of those (fused and wrapped in duct tape for insulation of course, I'm not stupid).
 
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Offline Electro Detective

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Re: Car audio phoolery? (Subwoofer power wiring)
« Reply #16 on: May 31, 2019, 10:32:35 am »

If you sandpaper the coat hanger ends, and add random mild bends along their length,

you will achieve better clarity, stereo definition, depth,
'air' without any negative turbulence,
minimum parallel wave interference,
6.6.db road noise reduction on a jammed freeway,
and enough Audiophool money saved to finance a new car,
and book a ticket on the space shuttle in whatever decade the forever speculating vendors finally get their shyte together   

Best of all, on board pets won't try to chew into them a second time,
especially during loud real music passages,
or humpy boot rattling thug rap yo yo mofo repetitive kiddie noize,
30 years past it's 'Use By And Discard Responsibly Date'  :palm:

 
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