Ohms?

[justafifteen 10+ year member]

Ohms have me a little confused. I know what they are, I've read the "water flowing through a hose" analogy etc. But what I don't get is how do you change the ohms that an amplifier is putting out?

I'm assuming it's all in the wiring... Like the way you run the + and - from the amp to the sub determine whether it puts out 4 ohms or 2 ohms etc. But, how do you get something like .5 ohms? or 2.x ohms?

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[bubbagumper6 5,000+ posts]

The amplifier doesn't "put out" ohms...Ohms is a unit of measurement, and it's the way we measure the impedance or "load" that the amplifier sees. You can change this by (like you said) changing the wiring on how the subs are wired.

Think of it in terms of resistors. If you have a 1 ohm resistor, it would read 1 ohm, but if you take two 1 ohm resistors and put them in series, the circuit would read 2 ohms. If you wired them in parallel, it would read .5 ohm.

http://www.bcae1.com Do some reading

 

[x1le 10+ year member]

you are correct. an amplifier will put out power depending on the ohm load.

The way you calculate resistance, or ohms, is if it's wired in series or parallel.

An easy way to remember it is like this. Series is running + terminal to a - terminal. When wiring in series, the resistance is doubled.

Parallel is running the + of a terminal to the + of another terminal, and - to a -. When wiring in parallel, resistance is divided by 2.

So for instance. If you have 2 subs that are 4 ohm single voice coil, wired in series they would present an 8 ohm load, and parallel and 2 ohm load.

It's all dependent on the subs. A dual voice coil 1 ohm sub can be wired in parallel to present a .5 load. You can also mix series with parallel. So say you have 4 subs that are 4 ohm svc(single voice coil), you can wire 2 pairs in series, so each pair would be 8 ohms, then wire those pairs in parallel to present the original 4 ohm load.

Idk if I'm confusing you, but I feel like I'm rambling ha.

take a look at this site - http://www.bcae1.com/

 

[MmatsDude 10+ year member]

You will be capable of getting certain ohms depending on the subwoofers. For example; you could wire a dual 2 ohms sub to 1 ohm and 4 ohms, and a dual 1 ohm sub to 2 ohms and below 1 ohms, you will get a certain ohm load like mentioned before depending how you wire the subs, now to get .5 ohms you will need to have 2 dual 2 ohm subs to be able to wire it to .5 ohms

here is a diagram

http://www.the12volt.com/caraudio/woofer_configurations.asp?Q=2&I=22

but you will never really be at an exact perfect ohm load due to box rise, etc

 

[justafifteen 10+ year member]

The amplifier doesn't "put out" ohms...Ohms is a unit of measurement, and it's the way we measure the impedance or "load" that the amplifier sees. You can change this by (like you said) changing the wiring on how the subs are wired.
Think of it in terms of resistors. If you have a 1 ohm resistor, it would read 1 ohm, but if you take two 1 ohm resistors and put them in series, the circuit would read 2 ohms. If you wired them in parallel, it would read .5 ohm.

http://www.bcae1.com Do some reading

you are correct. an amplifier will put out power depending on the ohm load.
The way you calculate resistance, or ohms, is if it's wired in series or parallel.

An easy way to remember it is like this. Series is running + terminal to a - terminal. When wiring in series, the resistance is doubled.

Parallel is running the + of a terminal to the + of another terminal, and - to a -. When wiring in parallel, resistance is divided by 2.

So for instance. If you have 2 subs that are 4 ohm single voice coil, wired in series they would present an 8 ohm load, and parallel and 2 ohm load.

It's all dependent on the subs. A dual voice coil 1 ohm sub can be wired in parallel to present a .5 load. You can also mix series with parallel. So say you have 4 subs that are 4 ohm svc(single voice coil), you can wire 2 pairs in series, so each pair would be 8 ohms, then wire those pairs in parallel to present the original 4 ohm load.

Idk if I'm confusing you, but I feel like I'm rambling ha.

take a look at this site - http://www.bcae1.com/

Thanks for all the info. I'll read up on that site. but the "series doubles, parallel halves" explains it to me. Thanks!

 

[MmatsDude 10+ year member]

you are correct. an amplifier will put out power depending on the ohm load.
The way you calculate resistance, or ohms, is if it's wired in series or parallel.

An easy way to remember it is like this. Series is running + terminal to a - terminal. When wiring in series, the resistance is doubled.

Parallel is running the + of a terminal to the + of another terminal, and - to a -. When wiring in parallel, resistance is divided by 2.

So for instance. If you have 2 subs that are 4 ohm single voice coil, wired in series they would present an 8 ohm load, and parallel and 2 ohm load.

It's all dependent on the subs. A dual voice coil 1 ohm sub can be wired in parallel to present a .5 load. You can also mix series with parallel. So say you have 4 subs that are 4 ohm svc(single voice coil), you can wire 2 pairs in series, so each pair would be 8 ohms, then wire those pairs in parallel to present the original 4 ohm load.

Idk if I'm confusing you, but I feel like I'm rambling ha.

take a look at this site - http://www.bcae1.com/

beat me to it:

 

[bubbagumper6 5,000+ posts]

When wiring in parallel, resistance is divided by 2.

That's incorrect

While this stays true if your only talking about two loads of the same value, it's incorrect otherwise.

The correct formula is: 1/R1 + 1/R2 +...+ 1/Rn = 1/Rt

Where R1, R2,...Rn are your resistance values and Rt is your resistance total

 

[x1le 10+ year member]

That's incorrect

how do you figure? unless you're wiring components with different resistances together, ie: 2 and 4

 

[bubbagumper6 5,000+ posts]

how do you figure? unless you're wiring components with different resistances together, ie: 2 and 4

Read my post again, I elaborated.

 

[x1le 10+ year member]

Read my post again, I elaborated.

ahhh, I hear you. that's good to remember. it would seem like the only time what I said can't be used is when there's an odd number being used. i just posted up what has worked for me, personally //content.invisioncic.com/y282845/emoticons/blush.gif.99bc659ee2012b7d826165e26fb5eebe.gif

 

[bubbagumper6 5,000+ posts]

ahhh, I hear you. that's good to remember. it would seem like the only time what I said can't be used is when there's an odd number being used. i just posted up what has worked for me, personally //content.invisioncic.com/y282845/emoticons/blush.gif.99bc659ee2012b7d826165e26fb5eebe.gif

Well what you said does work, but only with a specific set of circumstances. When applied in a broader sense it doesn't work. It's better to understand the math behind it than to just remember what works some of the time.