subwoofer impendance... which is better 2 or 4 ohms?

[Alex]

Hey all,

Finalizing the choice of my amp + subwoofer for my car setup...

these are my amp specs: (sorry theyre in portuguese but im sure it'll be easy to figure out!)

Número de Canais: 4
-Potência PMPO: 1800W
-Potência RMS 13.8V:
Stereo 4 Ohms - 4 x 80W
Stereo 2 Ohms - 4 x 120W
Bridge 4 Ohms - 2 x 240W
-Consumo: 0,6 a 56A
-Tensão de Alimentação: 13,8V
-Resposta de Freqüência: 15Hz a 50KHz
-Relação Sinal-Ruído: > 90 dB
-Sensibilidade de Entrada: 0,2 a 6V
-Distorção Harmônica Total: < 0,2%
-Impedância de Entrada: 50 K Ohms
-Impedância de Saída Stereo: 2 Ohms
-Impedância de Saída Bridge: 4 Ohms
-Fator Damping (amortecimento): > 400
-Lo Pass: 40 a 700Hz
-Hi Pass: 70 a 700Hz


so basically, should i get a 2ohm or 4ohm subwoofer? the price is the same!!

thanks!!!!

Alex

 

[So]

Two things you should know.

1. Audio components work best when impedance matched. If your amp is 4 ohm, go with 4 ohms, it'll work better than w/ 2 ohms.

2. P = IV (Power = Current * Voltage). Since real world devices are essentially voltage sources, lower impedance will generally deliver more power.

Remember, you get optimal power with matched impedance. If you have a 4 ohm amp, you'll get worse performance w/ a 2 ohm sub.

<-- EE, not audiophile.

Edit: So, since it looks like you have 2 ohm output, go for the 2 ohm sub and connect it to the 2 ohm out.

 

[SithSolo1]

You have to get a 4ohm sub(or two since when it is bridge it is out putting two audio signals on this model), a 2 ohm will more than likely fry it. Is the sub the only thing going on the amp?

Edit: to tell you the truth you'd be better off saving a little more and getting either a dedicaded mono amp or a 2channel stereo amp that bridges to a mono signal.

 

[So]

Originally posted by: SithSolo1
You have to get a 4ohm sub(or two since when it is bridge it is out putting two audio signals on this model), a 2 ohm will more than likely fry it. Is the sub the only thing going on the amp?

If he has a two ohm out...why would it fry it?

 

[pinion9]

120 watts RMS? I would say, don't buy the amp!

 

[SithSolo1]

Originally posted by: So

Originally posted by: SithSolo1
You have to get a 4ohm sub(or two since when it is bridge it is out putting two audio signals on this model), a 2 ohm will more than likely fry it. Is the sub the only thing going on the amp?

If he has a two ohm out...why would it fry it?

I was assuming he was putting the sub on the bridged connection. Most people try to avoid using 4 ch amps for subs.


EDIT: Also are these single or dual voice coil subs?

 

[CombatChuk]

Originally posted by: So

Originally posted by: SithSolo1
You have to get a 4ohm sub(or two since when it is bridge it is out putting two audio signals on this model), a 2 ohm will more than likely fry it. Is the sub the only thing going on the amp?

If he has a two ohm out...why would it fry it?

If the output is 2 ohms and the sub is 4 then it won't blow it, it'll have less power going to it. If it is was reversed then the current draw from the from the sub would be more than the output can handle which and fry the amp

 

[skimple]

Originally posted by: SithSolo1
[I was assuming he was putting the sub on the bridged connection. Most people try to avoid using 4 ch amps for subs.

Right. It depends on how you hook it up. If you are going to run stereo, you can use either, but if you bridge, you can only run 4 ohm.

Personally I would stick with the 4 ohms. If you have to get a new amp, or want to sell the subwoofer, I think the 4 ohm is going to give you more choices.

 

[Riverhound777]

2ohm isn't better than 4ohm or vice vs. You need to choose the correct one for your situation. A 2ohm sub can be wired to 1ohm or 4ohm. A 4ohm sub can be wired to 2ohm or 8 ohm depending on if you wire it in series or parrallel. And if you are working with 2 subs, it is another story. It all depends on your amp. There shoudl be sub wiring diagrams to help you out. Your amp will most likely make different output wattage at different ohms I.E. 400watts at 4ohm, 800watts at 2ohm, 1200watts and 1ohm. but not all amps are stable at 1ohm. You should really be doing research before you buy anything.

Edit: It also depends on if the sub are Single voice coil, or dual voice coil.

 

[So]

Originally posted by: skimple

Originally posted by: SithSolo1
[I was assuming he was putting the sub on the bridged connection. Most people try to avoid using 4 ch amps for subs.

Right. It depends on how you hook it up. If you are going to run stereo, you can use either, but if you bridge, you can only run 4 ohm.

Personally I would stick with the 4 ohms. If you have to get a new amp, or want to sell the subwoofer, I think the 4 ohm is going to give you more choices.

Fair enough, as I said, I'm no audiophile, but if he's going to hook it to the bridged, 4ohm output, he should definitely get the 4ohm sub.

 

[Alex]

its a 2 coil sub

i realize that it's not ideal to have it on a 4-channel amp but i just don't have the money right now to buy a mono amp for my sub... i already have this amp for my speakers and i read that i could hook up a sub with the bridge

i also realize that even with the bridge it'd be 240W RMS and this is a 400W sub but this way my options are open should I choose to get a mono amp in the future and leave this one dedicated to the speakers once again!

 

[Riverhound777]

Originally posted by: So

Originally posted by: skimple

Originally posted by: SithSolo1
[I was assuming he was putting the sub on the bridged connection. Most people try to avoid using 4 ch amps for subs.

Right. It depends on how you hook it up. If you are going to run stereo, you can use either, but if you bridge, you can only run 4 ohm.

Personally I would stick with the 4 ohms. If you have to get a new amp, or want to sell the subwoofer, I think the 4 ohm is going to give you more choices.

Fair enough, as I said, I'm no audiophile, but if he's going to hook it to the bridged, 4ohm output, he should definitely get the 4ohm sub.

No, that might not be correct. If he gets a 4ohm DVC sub and hooks it up, it will run either 2ohm, or 8ohm.
http://www.crutchfieldadvisor.com/learn...rs_wiring.html?subs=1&impedance=DVC4x2

But if he gets a SVC 4ohm sub, than yes that will work.
http://www.crutchfieldadvisor.com/learn...fers_wiring.html?subs=1&impedance=SVC4

 

[Riverhound777]

Originally posted by: franguinho
its a 2 coil sub

i realize that it's not ideal to have it on a 4-channel amp but i just don't have the money right now to buy a mono amp for my sub... i already have this amp for my speakers and i read that i could hook up a sub with the bridge

i also realize that even with the bridge it'd be 240W RMS and this is a 400W sub but this way my options are open should I choose to get a mono amp in the future and leave this one dedicated to the speakers once again!

What sub are you looking at? Is it 400watts RMS or max? Underpowering the sub can damage it.

 

[SithSolo1]

Do you know the brand and model of the sub? Also if you don't mind me asking how much are you paying for it?

If they're dual voice coil then I believe that you would need the 2ohm version to get to 4ohms.

Also you say you have this amp for your speakers, how many speakers do you have connected to it?

 

[Alex]

i have 4 speakers connected to it... 2x 6" and 2x 6-9" speakers
its 400W RMS

the more feedback i hear the more i realize im going to have to buy a seperate mono amp...>!

 

[b0mbrman]

Originally posted by: Riverhound777

Originally posted by: franguinho
its a 2 coil sub

i realize that it's not ideal to have it on a 4-channel amp but i just don't have the money right now to buy a mono amp for my sub... i already have this amp for my speakers and i read that i could hook up a sub with the bridge

i also realize that even with the bridge it'd be 240W RMS and this is a 400W sub but this way my options are open should I choose to get a mono amp in the future and leave this one dedicated to the speakers once again!

What sub are you looking at? Is it 400watts RMS or max? Underpowering the sub can damage it.

No, underpowering the sub will not damage it

The Best Buy rep that fed you that garbage was just trying to sell you a bigger amp