BlackS4tt (Josh)

when buying a 12" subwoofer, do i want 4ohm or 2ohm? whats the difference? thank you

edelweiB

It mostly depends on the capabilities of your subwoofer amplifier and the type of sound that you are looking for.

Generally the lower the ohms the more watts are produced by an amplifier, conversely sound quality (SQ) and amplifier stability decreases. An amplifier driving a speaker with lower ohms tends to overheat or and clip prematurely.

A 12inch subwoofer with a 4ohm SVC (single voice coil) will present a 4ohm resistance to your amplifier. This load is more stable, although the wattage that your sub will see will be less.

2 ohm subwoofers are also used when installing multiple subs, if you have two 12inch subs with 2ohm voice coils wired in series they will present a 4ohm load to the amplifier.

In order to drive an amplifier at lower ohms you need to pick up a class D amplifier, these typically have internal fans and more efficient heat sinks so that they can disapate heat. These amlifiers create a higher Sound Pressure Level (SPL) however their Sound Quality (SQ) is not as good.

I am currently powering a 4ohm SVC 12inch subwoofer with a 600 watts @ 4ohms amplifier. I never overheat and my SQ is superb. (I am using an Alumapro Alchemy 12RX and a McIntosh MCC302 amplifier).

TwentyValveB5+S4

good AB class amps will work, though you are probably better off with a class-D just to be safe. I agree with most everything else edelweiB says

bbaudi382

sound quality at 2 ohms is the same as 4 ohms, especially true in sub frequencies in car audio.

an amplifier running at a lower load, when set up properly will not overheat or clip.

you can use 2 ohm or 4 ohm subwoofers to run multiple subs...either is fine, you just have to focus on matching your final load with your amplifier capability.

class D amps are not more efficient because of heat sinks or cooling fans to disappate heat, but because the class D amps run more EFFICIENTLY than class AB. this means if you draw 80amps of power with class D you might get 600 watts, while drawing 80amps of power with class AB might only yield 400 watts. this means you'll have to draw more power with class AB just to match the power of class D, increasing noise, heat, and stress on your electrical system.

again, at these frequencies, you won't be able to tell the difference in noise. the noise in the speaker and the volume of the sub will completely drown out the minimal amount of noise that creates.

sound quality between 2 ohm and 4 ohm subs are exactly the same, so it output. with a lower resistance though, it is easier and cheaper to get that power to the sub. you just have to make sure you match your amp to the final resistance of the system.

HIS4

My sub amp is Class AB is rated for 1500W at 1 ohm and draws 120A at rated output. My other amp for mids and highs is Class AB and rated for 150W x 4 channels. It also draws 120A max. You could probably get a Class D sub amp to put out 1500W and only draw 80A. Class D amps will have slightly higher distortion but you won't be able to tell the difference at lower frequencies. My advice, if you're not going for a full blown SQ system, get the Class D. If your amp is rated for 2 ohms mono, then get a 2 ohm single voicecoil and dual 4 ohm voicecoil sub or whatever makes a final load of 2 ohms.

TwentyValveB5+S4

weren't you anti-D before?

bbaudi382

i try to post when people are spreading false information, especially since theres so much in the car audio realm. the false information is usually perpetuated by low quality "professional" shops that use these rumors to sell unknowing people things they dont need.

the fact is...people say class AB is better than class D because of sound quality, or class D is better than class AB because it will "hit harder" in the previous post...they are just misinformed.

neither amp is better for subwoofer duty, they are the same, at least in terms of sound. if anything, class D is better but only because it will be cheaper and draw less amps from your electrical system...not because it sounds better.

Merkin

single 2 or dual 4

Tgr_Clw

Those are nice.