stilov

So I am learning this car stereo stuff...

I am trying to understand a principle here so let me give a hypothetical and tell me if I am understanding.

I have a pair of 2 ohm speakers and I have an amp that is capable of 4ohm 50w per channel or 2ohm 75 watts per channel.

I am starting to understand wiring in parallel and series, but I don't think that applies here.

I can just wire the speakers to the amp right, since the amp is capable of running at 2ohm?

If I think about it correctly...you have trouble when the amp cant run at that ohm...then you have to rewire speakers to fit the amps capability right?

wc11

Yup. Since your amp is 2 ohm stable, just plug'n'play.

veleno

Technically if you plug the speakers into the wire terminals of your amp, your amp will be in 4 ohm mode (not unless there's a switch to toggle between 2 or 4 ohm). In this case, your 2 ohm speakers will not be running at 2 ohm (hence less output/performance).

If you wire your speakers according to the owners manual of the amp for 2 ohm mode, you'll be running your speakers at their correct ohm range and you'll probably be more happy with the output and dynamic of the speakers.

And you are correct in that if you run an amp at a certain ohm rating that it's not stable at then your amp with begin to run very hot, work much harder, and will go into thermal shutdown if ran at high volumes for any given period of time. You can also fry some internal caps as well as the circuit board.

Kevinmacd

I doubt you have to do anything other than hook the speakers direct to the terminals of the amp. You already stated the outputs are capable of driving 2 ohms so there should be nothing to worry. I doubt you will ever see a switch, since the amp states 2 ohm capable means the output devices are capable of handling the current required. The lower the impedance the higher the current.
If there is a switch then it is not a pure 2 ohm capable amp, because the switch will throw in a circuit to increase the output impedance negating the 20hm speaker impedance.
You are correct, wiring in parallel or series based on description of the amp capabilities is not necessary since if you wire in series, your 2- 2 ohm speakers will now be 4 ohms and if you wire in parallel your 2 2 ohm speakers will be seen as 1 ohm.

So just connect as normal.

LT Texan

I do believe the amp will deliver 50 watts into a 4 ohm load or 75 watts into a 2 ohm load.

Obviously, the speaker is the load.

Cyberpunky

I will take a guess and suggest you are talking subs ?
If your amp is 2 ohm stereo stable then it is only 4 ohm mono stable, so how subs are wired up is important. If you wired up a 2 ohm sub, bridged on a 4 ohm stable amp, you will fry the amp.
If you have full range speakers that are 2 ohm, then wiring in stereo won't be a problem.
What are you specifically trying to wire up and to what amp. More info is needed to answer your question properly
peace
Cyberpunky

stilov

Actually, no to the subs... I mean I will do subs also but from the dedicated sub channel.

I was actually thinking of speakers originally. I guess I am just trying to see what all options I have as far as making a decent system.

Cyberpunky

Not many companies make 2 ohm full range stereo speakers. I think soundstream did some but thats about it. Not really ideal as low impedance(2 ohm) will effect damping factor of amp and although not as important with subs, it is not ideal for full range typically. Just get the best sounding 4 ohm speakers that you can afford and that fit your car.

stilov

Its mostly to run the bose stuff that is in there for now, and then replace speakers as I go.

Cyberpunky

Bose stuff will fry most amps, as very low impedance (1 ohm from memory) and as impedance is nominal(averaged) it actually changes at various freqs, so amp can see a load well below the nominal rating when music is played. I would avoid using bose speakers with the amp or chances are you will be amp shopping again V soon

wc11

The days of a switch to select speaker impedance are long gone.

LT Texan

Still get to switch impedance settings on some tube amps!


Most modern amps are built to handle high current, low impedance loads.

Kevinmacd

Bose speakers are 2 ohm not 1 ohm. As I posted earlier your amp is 2 ohm capable just hook it up

Cyberpunky

Kevin the imp of some Bose speakers can be as low as 1/2 ohm, so unless you know for a fact these particular speakers are 2 ohm, then you could be the cause of his amp frying by suggesting to just hook it up. Even if they are 2 ohm you could still have issues, as imp may dip below 2 ohm as imp is freq dependent, and so will vary with freq played and you are on the edge of amps stability threshold. You could hook them up and have no issues and better quality amps will have more ability to cope with a dip in imp, but it is a risk if you don't know for sure what you are dealing with
peace
Cyberpunky

Kevinmacd

I know for a fact that Bose speakers in Porsches are 2ohms. I doubt Bose ever produced a speaker that 1/2 ohm of nominal impedance, why because under certain frequencies the impedance would drop to a dead short. If an amp is rated at 2 ohm nominal impedance it by design can handle the swings in the impedance under frequency!