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just wonderin, thin i need to upgrade, im runnin 4 gauge main from the battery..

My 8 guage is fine for my 2 amps and active crossover.
--- Kicker impulse 352xi -- 35x2/100x1 RMS
--- Carver m2040i -- 40x2/80x1 RMS
--- 4 way active xover with dashmount bass control

I've got 10 gauge running to my RF 100z2. This summer if I get a job I'm either gonna run 4 or 2 gauge to a dist. block then 4 gauge to sub amp and 8 gauge to speaker amp.

I've got 6 guage wire running to my amp. Its a cheap Legacy 300 Watt Amp. Powering an older Infinity 12 in a sealed box. Gonna put that speaker in a bandpass box this summer. It hits pretty good for what it is but that bandpass will help it out a lot with the low powered amp. Had a Kicker Solobaric a few years back powered by a Phosgate 200ix Amp. Had just one of those Solo 12's. That thing shook my poor truck apart and sounded damn good.

Just noticed, you didnt even tell us what kinda amps your running Reg.
Silly firebird owner

I read somewhere that 4 guage is biggest you'll need, since the battery can't supply more current than can be utilized by anything fatter. If you need more juice, then it's time for another/bigger battery and power caps.

viperoni my stereop specs should be etched in bronze here already Im running 2 mtx thunder 280's each bridged to a pair o 12" Cerwin Vega AI 12's, and i have a thunder 240 waiting to get into the fray. simply AWESOME underrated amps!

You should be fine with the 4 guage for the 3 amps in that case

Originally posted by bitSLAP
I read somewhere that 4 guage is biggest you'll need, since the battery can't supply more current than can be utilized by anything fatter. If you need more juice, then it's time for another/bigger battery and power caps.

The amount of power pulled from the battery and/or alternator depends on your fuse rating. If your fuse rating exceeds the alternator output you will get dimming problems which is what a cap helps to cut down. Now the battery is used if the alternator can't put out enough juice. In many professional car stereo installs you will see 0/1 gauge power wire being used and multiple alternators being used. 4 Gauge max fuse rating is 150A or 200A. 150A should be the max anybody needs for a daily driver and no competing. To maximize the amount of current flow and minimize the chance of burning the wire up, especially with a long distance, it's better to step up a gauge. In my case it's around 20 ft. from my battery to where my distribution block will be. I will have around 1800W total in my system. 4 gauge will work but I'm gonna use 2 gauge to be sure.

Please don't use a bandpass box. If you ask most people that compete or that are really into car audio they will say that bandpass boxes make a crappy sub sound better. It produces boomy bass and usually they have the plexiglass on the front which you have to rescrew in every now and then. If you want it louder go ported. For more quality go sealed. The reason you aren't getting the best bass Predator is because it is a Legacy amp. Most likely it is overrated. So it says it's producing 300W when it probably is only producing around 200W. Instead of going to a bandpass get a better quality amp. What is the RMS and ohm of that Infinity sub?

Subs in bandpass boxes will easily go louder than in sealed or vented, with increased power handling, but with lower SQ.
SQ vehicles almost never have bandpass boxes.

I'm not exactly sure what you're trying to say, Busby.

As you stated, 4 guage is rated at 200 amps. You can't pull anymore power than 130 amps (assuming 20 amps for the rest of the car) continueus or aprox 200 amps peak (with a hard bass beat, battery acts as a buffer) in this case anyway. I agree that if you add another battery or alternator, then you'll need fatter wire.

If your fuse rating exceeds the alternator output you will get dimming problems which is what a cap helps to cut down

How does a fuse determine the maximum current your battery/alternator can supply? The fuse is just another peace of wire, which btw will burn long before that 4 guage wire will.

A cap acts as a faster buffer than a battery, because a battery has limited power on demand. Again, the wire only needs to carry as much current as the battery/alternator can supply, even if your system wants to draw 300 amps.

I'm no expert in car audio, but common sense tells me 4 guage is all you need for a standard alternator and battery.

Originally posted by bitSLAP
How does a fuse determine the maximum current your battery/alternator can supply?

I did not say that bitslap. I simply said that if your fuse is rated at 100A and your alternator only produces 60A then it will drain power from the battery, which takes power away from your other electrical devices, which causes the most noticeable effect of the dimming of the lights.

Your statement that 4 gauge was the largest wire needed is by far not clear enough. What if he wants to do major competing? He'll need bigger than 4 gauge.

Originally posted by Viperoni
Subs in bandpass boxes will easily go louder than in sealed or vented,

Then why do all the SPL pros use vented/ported boxes? Bandpass boxes make a shitty speaker sound good. They do not increase the power handling. You can get the same amount of power handling out of a sealed or vented/ported boxes as with a bandpass.

lol busby I don't think you know what you're talking about.

a 100 amp fuse is just a piece of wire that will mealt if current passes through that exceeds the rating. How does having a higher rating than will pass through the wire take "power away from your other electrical devices"?

What if he wants to do major competing?

Sorry, but it would be beneficial for you to read my whole post.

I agree that if you add another battery or alternator, then you'll need fatter wire.

Also,

Viperoni is right I believe. Properly designed bandpass boxes have higher power handling, because the open airflow allows for better thermal dissapation from the voice coil, which is the main reason why subs blow. The problem with them is that normally they are at the mercy of the drivers natural frequency response without the aid of dampening (sealed) or augmenting (tuned port), and thus they sound bad.

SPL competitors use ported boxes mainly because they provide the most sound for the least amount of air volume. Bandpass boxes usually need to be big, and require a lot of air around them to breath properly.

Again, I talk the talk, but I'm not a pro by any means.

Bitslap, I hate to argue, and luckily I dont have to argue with you.
Lemme *try* to explain this more clearly.

You have a battery that holds, say 750amps.

You have a alternator that puts out say 75 amps.

Supposed you have a stereo system that eats up 50 amps at MAX SPL.

With the engine running, theres no way the stereo would eat up all the batteries power, unless the engine is off (and alternator NOT producing power). It's simply not possible. The alternator recharges the battery faster than the stereo can suck away the power.

Now to the wire.

It's just a piece of thick wire that takes the power from the BATTERY and bring it to the amp(s).
If you have a fuse between the battery and distribution block, all it does is protect the battery from a accidental short circuit if the wire were to get chaved and touch the car frame/body/chassis/etc.

SO

Assuming the above scenario, if you have a 30 amp fuse; IT WILL BLOW.
if you have a 40 amp fuse, it will blow as well.
However if you have a 60amp fuse you will not blow it.

Plain and simple.
Your stereo takes up 50amps max and thats it.
Fuse rating has no effect.
You could put a 150-300amp fuse and it would make absolutely no difference.

Why? Because it's over the 50amp maximum current draw of your amps.

Viperoni is right I believe. Properly designed bandpass boxes have higher power handling, because the open airflow allows for better thermal dissapation from the voice coil, which is the main reason why subs blow. The problem with them is that normally they are at the mercy of the drivers natural frequency response without the aid of dampening (sealed) or augmenting (tuned port), and thus they sound bad.

Actually, bandpass boxes can be designed to have the vent on the front or back side of the speaker; front is usually a bit more beneficial (more surface area)
And another fact is that bandpass boxes exhibit TREMENDOUS control over the driver; thats why you see so many guys overpowering subs in bandpass boxes and the voice coil rips apart from the cone, stuff like that. The sub may not be moving much inside the box although it's giving you good SPL, but it's under tremendous amounts of stress.
The selaed and ported sections of the box both work together to control the subs movement.

What makes bandpass boxes sound bad is that they only play in a certain range, and the fact that you're only getting sound from a small port.


The reason why SPL vehicles don't use bandpass boxes is like bitslap said; too big space requirements.
But if tuned to maximum SPL, I could easily get a 10inch to play into the 140's in a small car.
Why? I just tune it to have a super big peak at a tiny range of frequencies.

Ahhh, the life of a speaker engineer

*cracks knuckles*

Another reason for lower guage wire (thicker) is to have less voltage drop over the cable run.

IE; 8 guage wire may experience a 2v drop, while a 2 guage wire might only a experience a .3v drop.

It's all proportional to how much current your amps need.

More current draw + longer run = bigger guage needed