amp for car sub placement

For livingroom sound better than in a theatre.
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himhimself
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Location: Vancouver BC & Bloomington IN

amp for car sub placement

#1 Post by himhimself »

What are the pros and cons for where to mount a sub amp in a vehicle. Better to keep the power to amp short and longer speaker cable run from amp to the sub, or the other way around? I see stupid heavy gauge amp power cables out there - if I can easily power my whole PA rack through a 100' 10ga cord, who needs 4ga pipes to run 12v power a few feet? I don't get it... This will be for powering a truck tuba in the back of my ford excursion.
thanks
2xT30 (20", 3012LF)
2xT30 (21", 3012LF)
4xOtop J-array (Beta12, melded/straight piezos)
Truck Tuba (MCM)
Next up: 2xJack12 or family of table tubas

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Bill Fitzmaurice
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Re: amp for car sub placement

#2 Post by Bill Fitzmaurice »

Amp power cables are large to handle high current. The current is high because the voltage source is low. 1000 watts at 110v is 9 amperes, 1000 watts at 12v is 80 amperes. This being the case put the amp close to the power, to minimize the required power cable gauge.

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Seth
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Re: amp for car sub placement

#3 Post by Seth »

Image

In the past, I've pretty much only used 8ga or 4ga, depending on whether the total system power was over or under 1000w. Never done anything over 1500 or so.
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

caddylackn
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Re: amp for car sub placement

#4 Post by caddylackn »

Big power cables generate significant magnetic field interference. Keep the big power cables well away from sensitive electronics and all EFI computer stuff. Run the big fuse or large breaker for the power cable right by the battery. If the power wire ever shorts from being cut from sheet metal where it goes through the body, it can start arc welding itself to the car body and start a fire and never even trip the fuse if the fuse is located all the way down by the amp.

For a truck tuba you will only need 100-200 watts of power to the driver to make your ears hurt. A 10 gauge wire would be enough for 20' length or less.
16.5" AT w/ Infinity 860w
TLAHs w/ 9 mids & 16 tweets
17" THTLP w/ Dayton RSS315HF-4
16" TAT w/ Infinity 1060w
18" TT w/ Dayton DCS-205-4
5.5" TrT w/ DCS-205-4
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33" THT w/ Dayton Titantic 1200
DR200s

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Bill Fitzmaurice
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Re: amp for car sub placement

#5 Post by Bill Fitzmaurice »

caddylackn wrote: Fri Oct 02, 2020 2:00 pm Big power cables generate significant magnetic field interference.
Not with DC. There is a field, but since it's not an alternating field it won't create potentially noise inducing EMI. Even with AC EMI is easily avoided with balanced transmission over twisted pairs. That's what make it possible to combine a signal cable and AC cable in the same jacket for powered speakers.

ketoet
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Re: amp for car sub placement

#6 Post by ketoet »

if you run the power cable next to the signal cable you will hear the alternator sign as the revs go up.
the low pass for the sub should filter it out though.
building BFM speakers isn't a hobby , it's an addiction

1 x THT
1 x autotuba
2 x dr250 melded

2 x wedgehorn 10
2 x tlah

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