corsasport.co.uk
 

Corsa Sport » Message Board » Help Zone, Modification and ICE Advice » Difference between 4 Ohm and 2 Ohm???? » Post Reply

Post Reply
Who Can Post? All users can post new topics and all users can reply.
Icon:
Formatting Mode:
Normal
Advanced
Help

Insert Bold text Insert Italicized text Insert Underlined text Insert Centered text Insert a Hyperlink Insert Email Hyperlink Insert an Image Insert Code Formatted text Insert Quoted text
Message:
HTML is Off
Smilies are On
BB Code is On
[img] Code is On
Post Options: Disable smileys?
Turn BBCode off?
Receive email notification of new replies?

Chappie

posted on 13th Mar 03 at 14:26

Just a slight error in the maths of the last post. The "series" maths is correct, but the parallel is slightly wrong. If you were driving 4 ohm speakers, to get a final impedance of 1 ohm you would need 4 drivers wired in parallel. You only half the figure when two impedances match.

Two 4 ohm loudspeakers in parallel = 2 ohms. These can then be assumed to be one loudspeaker. Adding a third would be like adding a 4 0hm speaker to a 2 ohm speaker which comes out to about 1.35 ohms.

A 4 ohm speaker is harder to drive than, say a 15 ohm speaker because for a given amp output voltage they draw twice as much current. The 15 ohm speaker is an easier load, but its higher impedance (which is just AC resistance) means that less current is drawn from the amp and so the power (volts x amps) driving the speaker will be correspondingly less. So an amp may not be able to deliver its full rated power into this higher impedance.

Never connect speakers so that the resulant total impedance is less than the stated stable impedance output. If you do, the amp can go into thermal runaway and will melt itself if it has no internal thermal protection.

How this helps


jrsteeve

posted on 11th Mar 03 at 18:44

cheers for all ur help guys


ultim8DTM5

posted on 11th Mar 03 at 02:34

Read up on Ohm's law. Its all about resistance and electrical current.
It applies to anything regarding impedance, voltage and amperage.
Reality is that any resistor you join end to end with another, totals the resistance, and joining the resistors side by side, halves the resistance.
This isnt correct according to ohms law, but for all intents and purposes, this rule of thumb works for us car stereo nuts. (im trying to keep it simple here)
This is relevant as speakers, are basically resistors.
So, if you have 3 4 ohm speakers all joined together, pos to neg from speaker to speaker, the electricity has to pass through all three speakers on a single cable, so it sees 4 + 4 + 4 ohms for a total of 12 ohms. This is known as "series" connection as each resistor is after one another.
If all three speakers where joined to the amp using individual cables each to the amp, so that there are 3 sets of cables, the amp sees less resistance because it can travel through all 3 speakers at the same time rather than one after the other. This is known as parrallel conection as the resistors are "side by side"
so, the amp in this case sees 1 ohm. 4 ohms halved twice, 4 = 2= 1 ohm.

Got it?

So, a speaker with 2 4 ohm voice coils, or two resistors can be joined to a amp two ways. if its joined in series, the amp sees 8 ohms, one voice coil after another. or, you can join the coils up parrallel, both to the amp and get 2 ohms.

The same thing applies to amps as well, it is all about resistance of impedences. The lower the resistance, the less regulated the power supply going to the speaker, the more power it gets.


TOMAS

posted on 10th Mar 03 at 23:28

Their is no difference in a subs performance weather it has 2ohms/4ohms etc. Ohms is kinda like how hard the sub will 'suck' power out the amp. Some amps cant be 'sucked' hard, others can but often at the cost of sound quality but often its an unnoticable difference. You must really choose an amp and sub that are well matched 4 the best results.


jipp

posted on 10th Mar 03 at 14:11

2 ohm.
the lower the ohm's the higher the power(wattage) that can be discharged from the amp. the higher the ohm then the less the amp has to 'work' but you get less power from the sub.


Dannys SXI

posted on 10th Mar 03 at 11:06

so what is beta. a 4 Ohms sub or a 2 Ohms sub?

do you count the 2 Ohms as low or high independence?


jipp

posted on 10th Mar 03 at 09:45

the higher the impedance the less 'work' the amp has too do.
the lower the impedence then the harder it is for the amp to put power through the subs.


SteveW

posted on 10th Mar 03 at 09:32

Will ask my ICE guy. Will post up later on tonight.

Steve.


Richie

posted on 10th Mar 03 at 03:50

A sub that is usually set to 2 ohms is usually more powerful, designed for a 2 ohm/1ohm stable amp. Shouldnt notice a difference in sound quality.


jrsteeve

posted on 9th Mar 03 at 21:01

Does anyone know what the difference will be between a 12" sub that is set to 2 Ohms and one set to 4 Ohms?

Sound quality etc?

cheers