What does the "ohms" mean?

Question

some subs are like for example 300 watts rms at 2 ohms

and the same exact brand and size sub might be 300 watts rms at 4 ohms. what does this even mean? i have a system but i've never paid attention to this and does it matter when trying to match an amp to your sub? would you want like a amp with 2 ohms to be put on a sub with 2 ohms or what?

Answer 1

The Ohm rating is the resistance offered by the Sub. You want to keep this in mind when considering what amp you use, or if you already have an amp, keep this in mind when considering the sub. Most amplifiers are stable at 2 Ohms, and all are stable at 4. However, most amps are able to put out (roughly) double the power at 2 ohms, because there is "half" the resistance. If you're going single sub, I recommend going with a 2 Ohm sub (or if it's dual voice coils, 4 ohms). If you're going with two, I'd go with the 4 ohm (or if it's dual voice coil, 2ohms). The reason for this is because of how you wire them.

(There are 1 ohm stable amps out there, but they're typically only found in higher end amps). Here is an example of how to wire to get the most out of it:

1 sub single voice coil:

    It'll be however many ohms it says

1 sub Dual Voice Coil or two subs with single voice coils:

    If you plug both positives into the positive of your amp, and both negatives into the one negative of the amp, you'll end up with half of the ohm rating that each has (so if you hook up two 4 Ohm subs like this, you'll present a 2 Ohm load to the amp).

    If you hook up the Negative from sub one to the negative of the amp, the positive of sub one to the negative of sub two,

and the positive of sub two to the amplifier, you present half of the rated load to the amplifier (if you do this with two 4 ohm subs, the amp will see an 8 ohm load).

Here is an example: I have a Rockford Fosgate P3D412 hooked up to a Rockford 300.1. The certificate the amp comes with said mine tested at 434watts @ 2 Ohms which is a decent match for the 500w RMS of my sub (though a higher rated amp than sub is typically desired). I have both positives hooked to my amp's + and both negatives to my amp's - (in bridged mode). My amp then sees 2Ohms and is able to put out that 434 watts, versus the 217ish it tested at with 4Ohms.

Answer 2

the ohms mean how much power the component the object will have to use itself

this matter lots because the amp and sub should always match as far as ohms go

the lower the ohms the more power will be taken from your amp 1 will take the most out of your amp and 8 will take the least

this kind of matters because the more your amp has to work the more its life will be shortened and it'll heat up more when worked more causing the life of it to be shortened also

2 or 4 ohms are good because they are well balances

1 ohm is too low and 8ohms isn't using enough of the available power

there you go

Answer 3

OHM is the measure of it RESIST voltage (or current).

Basically you can put speakers with higher ohm (than rated or recommended) but that will create less watt (or sound level).

But you CANNOT put speakers with lower ohm (than rated or recommended) as that will create MORE watt (or sound level) - but eventually will burn out the amp and / or speakers.

Good Luck...

Answer 4

its the impedance or resistance running through the wire. It is very important they match. Many sub amps can running at a different impedance, but it wont usually come up unless you are bridging channels on the amp, or running more than one speaker per channel or have dual voice coils

Answer 5

This will tell you everything

Impedance

The total opposition to the flow of alternating current in an electrical circuit at a given frequency. Impedance is measured in Ohms. Although car audio manufacturers label the impedance of most car speakers and subs at 4-ohms, the impedance of a speaker is actually not a constant. It's actual impedance changes with frequency and can vary greatly. Therefore, though 4-ohms is the standard impedance in car audio, this standard is more of an average impedance for speakers and amplifiers when driven within the part of the audio spectrum for which they are designed.

Ohm

The unit of measurement for impedance or resistance. It tells you how much a device will resist the flow of current. If you take two signals of exactly the same strength and send one to a 4-ohm speaker and the other to an 8-ohm speaker, twice as much current will flow through the 4-ohm speaker. In other words, the 8-ohm speaker will require twice as much power (wattage) to play at the same volume

Resistance

The opposition to the flow of electrical current. Resistance is measured in Ohms.

RMS Power at 2 ohms

This spec tells you how much more power your amp delivers when presented with a 2-ohm stereo load. You can achieve a 2-ohm load by using parallel wiring or by using 2-ohm speakers.

Theoretically, amp output should exactly double as the impedance drops from the usual 4 ohms to 2 ohms. However, amp makers use different degrees of regulation on power supplies, which can restrict the actual increase in output.

Less regulated power supplies come closer to doubling their output into 2-ohm loads. An amp with little regulation can achieve higher wattage into lower impedances. An amp with stiffer regulation maintains rated output from your amp as other electrical accessories demand voltage from the battery.

here is a link to show you how different sub setups (DVC or SVC, - 2, 4, and 8ohms, and number of subs) will give you different impedances (ohms) at the amp http://www.the12volt.com/caraudio/woofer...

the lower the final impeadnce at the amp the lower your sound quality, and most amps are not stable at 1ohm and lower-   so i like to go with 2ohm (final impedance) setups