2Sub 2Amp setup help

 

New member
Username: Albgk

Post Number: 1
Registered: Apr-10
So I recently got a sub and amp setup and I only got one sub/amp... and i was wondering how to make a second identical setup... to run with it...
i have the sony xs-l124P5B
12 in
1300W peak
380W rated

and the Rockford fosgate prime R150-2
50 watts X 2 @4 ohm

150 @ 4 ohm w/ all channels combined

now I had this setup professionally installed (because I didnt want to run the cables and drill the firewall)... so I want to add this second setup without having to do to much (besides spliting some cables) and without having to pay to have it professionally installed

I want this to work as efficiently as possible (duh!)

-albgk

ps if you guys have a better idea please post

(better=cheaper.... normally)
 

Silver Member
Username: Skdooley

Roanoke, VA Usa

Post Number: 458
Registered: Oct-09
To run an additional amp you could get a distribution block for your positive and negative wires. You would run the ones you have now into the blocks, then from each one you could run out 2 wires, 2 positives and 2 negatives. Get the same enclosure (most cost efficient instead of getting a custom built one for both subs) and run a remote wire from the one amp over to the other. Set the gains correctly and evenly on both amps to match up. Done deal.
 

Platinum Member
Username: Glasswolf

Columbia, SC USA

Post Number: 12759
Registered: Dec-03
better bet is to get a second 4 ohm (or dual 2 ohm coil) sub, and swap amplifiers. go to a mono (one channel) amp rated for 600-800 watts RMS @ 2 ohms.

This means you only need to installthe second sub with enclosure (or go to a single 2-sub box) and swap amps, then set the gain, crossover etc on the new amp and go.
 

New member
Username: Albgk

Post Number: 2
Registered: Apr-10
GlassWolf, I just recently got the amp so it would be a waste to get a better one for 200+ when i could the same amp for 100 but thanks


Shawn I like your idea but, my amp kit has an 8 guage power cord and most dist. blocks are 2 or 4 guage in and 4 or 8 guage out, so unless you guys know an 8guage in and out id have to run a new powercord, which id rather not do....
actually could i take a 4 guage in and 8 guage out and just tighten it really tight?

also will 8 guage be sufficient to supply power to two of those amps i had in the first post?
 

Silver Member
Username: Gcs8

Atlanta, Ga

Post Number: 348
Registered: Sep-09
http://sqelectronics.com/power_management_distr.html the PDB104S

http://www.the12volt.com/info/recwirsz.asp

It should take anything you want from 8ga to 1/0. I have a couple of them. Used 8ga in it out to an amp so it does work. Now 8ga wire can take up to 100 amps put you want to fuse it at about 60-80 amps. So as long as you don't exceed that, but it sounds like you are using around 20 - 40 amps for both amps maybe.... 300 / 14.4 = 20.83 amps but if they are slightly under rated they may draw more, or may be fused for more which is why I say up to 40 amps from what the spec's you listed are.
 

Platinum Member
Username: Glasswolf

Columbia, SC USA

Post Number: 12765
Registered: Dec-03
8ga is not sufficient for two of those amps.
4ga is.

4ga off the battery to a fused dist block, then 8ga to each amp, with the 8ga kept as short as aesthetically possible.

Look I get that you have an idea in your mind of what you wnt, and you don't want to spend any more than you have to in order to get there, but the fact is, you need larger power wire for that much current, over that distance, and you're going to end up spending about the same to buy another (not that great) $100 amp as you would to sell the one you have now, and buy a single, larger amp (which still needs at elast 4ga wire to run it)
 

Platinum Member
Username: Glasswolf

Columbia, SC USA

Post Number: 12766
Registered: Dec-03
by the way, the amount of current that wire can handle is based on two factors. length of run (ground and positive combined) and the wire gauge. 8awg can handle 100A, yes, for a maximum run of 4 feet. Most in-car battery to amplifier runs with ground are in the 12-16 foot length range. Those lengths require a minimum of 4AWG wire.

Also, your current calculations need to factor in amplifier efficiency.
alternator output above idle is 13.8 typically
high output alternators above idle are usually 14.4VDC
if the system is for competition that requires the car be turned off, figure 12.6VDC
a class AB amp is 60% efficient, whereas a class T or D is 80%.

if you are using all class D amps, divide your combined total RMS wattage by 12-14.4 volts (whatever you like) then multiply the result by 1.2
use a multiplier of 1.4 for a class AB amp (multichannel full range amps)
 

Silver Member
Username: Skdooley

Roanoke, VA Usa

Post Number: 459
Registered: Oct-09
Yep, you'd be better off running 4 guage wire through the car, if not maybe even 1/0 guage if you go through the trouble of running new wire. I wouldn't run those 2 amps off a single run of 8 guage.
 

Platinum Member
Username: Nd4spd18

Philadelphia, PA

Post Number: 11028
Registered: Jul-06
If you didn't buy the stuff yet, don't. Sony is crap, the bottom of the barrell, you can easily get something better.
 

New member
Username: Albgk

Post Number: 4
Registered: Apr-10
Thanks all of you guys....

GlassWolf you will have to forgive me... im a complete newb to this stuff so what I think is good probably isnt... so thank you very much for your help

and the whole new power wire problem isnt really the price its more of the running it through the car....

one question

is 1/0 guage the best guage?
 

Silver Member
Username: Gcs8

Atlanta, Ga

Post Number: 351
Registered: Sep-09
4/0 but you wont need it
 

Silver Member
Username: Skdooley

Roanoke, VA Usa

Post Number: 462
Registered: Oct-09
1/0 is the largest you would need up until you're pulling some serious power. Running wire through cars normally isn't so bad. It can be tricky with some but if you look hard enough you will find a way to run it.
 

Platinum Member
Username: Glasswolf

Columbia, SC USA

Post Number: 12770
Registered: Dec-03
don't go larger tahn 1/0 seriously. When you do, it starts getting very hard to find things like distribution blocks and ring terminals to accept that large of a gauge, and it gets very very expensive, as in by magnitudes as you get over the 1/0 gauge, typically.

I know my suggestions aren't what you wanted really, but with 20 years of experience in the field, as a hobby and professionally, and as a competitor, I am simply trying to not only give you better results in the short run, but save you some money and make you happier in the long run, even if it means savinga bit more now, or working a little harder to get those results.

MS has a point though. I'd suggest avoiding Sony. I've heard they've gotten better lately, but I've had years and years of bad experiences with their car products and I'm hesitant to change my mind about them very quickly. Look at better options for about the same price. If you have a budget in mind, present it here and we can all give you some ideas for products.

1/0 gauge will be a bit harder to run, although through the firewall, you a wire hanger to route the wire path through a grommet, or tape a string to the end of your 8AWG when you remove it, then tape that string to the larger new wire and use it to pull the new wire back through the same path. That will save you some time.
For the ground spot, sand the paint away to get a good bare metal connection between your ring terminal and the chassis. This makes for a better electrical connection, although while 4AWG is fine for a chassis ground, I do suggest that if you ever use large enough amplifiers to NEED 1/0 gauge (not just running it for future what ifs) that you run a 1/0 gauge ground directly to your battery, too.
chassis spot welds are only on par with 4AWG wire, and drawing any more current through the chassis than that on a modern car isn't going to provide the power you need cleanly.
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