# easy question... 2ohm or 4ohm ?



## Robb (Dec 5, 2008)

Just seeing what the difference is between running a set of 2ohm component speakers vs 4ohm. The amp is good for 2 or 4 ohm.
The amp plays 50x2 @ 4ohm or 90x2 @ 2ohm.
Is it better to buy a set of 2ohm or 4ohm components speakers ?
What will sound better ?


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## dbiegel (Oct 15, 2006)

http://www.diymobileaudio.com/forum/diyma-tutorials/31-real-deal-8-ohm-drivers.html


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## Robb (Dec 5, 2008)

dbiegel said:


> http://www.diymobileaudio.com/forum/diyma-tutorials/31-real-deal-8-ohm-drivers.html


I dont really care about efficiency, I care about which sounds better.


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## brownmoses (Jul 23, 2008)

honestly, there are going to be a good amount of people who tell you about both sides of the fence. as far as i stand, im starting to opt for higher impedences contributing to sq. im learning, but have experienced both sides of the fence. this is my personal preference however. i would advise to you to try and figure a soultion that is capable of both, or check with friends from both sides of the force.....


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## Robb (Dec 5, 2008)

AFAIK, lower impedances have higher THD and lower Damping factor..
Is this true ? Cam this in turn can cause poorer SQ ?


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## Candisa (Sep 15, 2007)

The speaker that sounds best to your ears is the speaker that sounds best, period.

The fact that an amp puts out more 'wattzzzzz' on a lower impedance doesn't matter at all, it doesn't mean it will be louder, it will only use more current and make the amp work harder.

An example of a test I did recently. Since a couple months, I have a 1992 Volvo 940 with 4 stock (still fine) speakers and a cheap Sony headunit the previous owner put it because he wanted a cd-player.
I disconnected a stock speaker and connected a Peerless HDS Exclusive 5.75" speaker to the original wiring on the passenger side, just laying around on the passenger seat, since the Peerless is to deep to get in the original place without customizing.
Despite the fact the left front stock speaker was boxed and 4 ohm, the 8 ohm Peerless free-air sounded much louder and the headunit didn't lose control that fast on the right side.

If a higher impedance speaker does the job as well as the lower impedance speaker, no doubt I'll go for the higher impedance speaker.

I see only 1 reason why an amp should be low impedance stable: the ability to connect multiple speakers to it. 

greetings,
Isabelle


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## t3sn4f2 (Jan 3, 2007)

Robb said:


> Just seeing what the difference is between running a set of 2ohm component speakers vs 4ohm. The amp is good for 2 or 4 ohm.
> The amp plays 50x2 @ 4ohm or 90x2 @ 2ohm.
> Is it better to buy a set of 2ohm or 4ohm components speakers ?
> What will sound better ?


Chances are that in practice the 4 ohm setup will sound better, but that depends greatly on the amp used.


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## bobduch (Jul 22, 2005)

Ray at TIPS would tell you 4 ohm hands down. He really hates low impedences. I mean with a passion. And given his expertise and the fact that he has been around so long and is so highly regarded, well, that is enough for me.


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## squeak9798 (Apr 20, 2005)

Robb said:


> AFAIK, lower impedances have higher THD and lower Damping factor..
> Is this true ? Cam this in turn can cause poorer SQ ?


Neither of which will be an audible change, so no it doesn't matter.


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## bass_lover1 (Dec 10, 2005)

Robb said:


> I dont really care about efficiency, I care about which sounds better.


Well seeing as you're going to be the only one to figure out what sounds better to you, there is no solid answer to that question.

I've gone from 4 ohm door speakers to 8ohm, and back to 4 ohm, and honestly I couldn't notice a difference between them to say without a doubt that using 4 ohm drivers is better. Really what you should be thinking about is what do I want the driver to do, what frequency range do I want it to play. 

Power is so cheap these days, that worrying about something so trivial as impedance, really isn't worth the time.


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## cravenmh (Jan 14, 2009)

Ray at Tips may have done enough testing to come to this logical conclussion. I can only go by the textbook.
Electrolytic power supply capacitors have a maximum ripple current rating. As the load impedance goes down by half, the current demand goes up by 4 . This will drain the power supply caps quicker and having a limited ripple current, they should work better by retaining proper rail voltage into the higher load. Possible dynamic compression during bass transients ?


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## mikey7182 (Jan 16, 2008)

Assuming the same drivers with the same efficiency, you're talking about a ~2db gain at max output with the 2 ohm drivers vs. the 4 ohm. This will come at the cost of your amp working quite a bit harder to earn a minimal increase in output. If you're not worried about output, I'd run the 4 ohm drivers, or even a more efficient 8 ohm. You say you're not worried about efficiency, but you have to take that into consideration. How much harder are you driving your amp at 2 ohms than at 4 or 8? Sure, the manufacturer may say it's putting out more power, but at what cost? Are those costs audible? It's easy for all the techies here to say yay or nay, but without doing a comparison and hearing the difference (or the absence of one), it's hard to say. Personally, I run higher efficiency, higher impedance drivers with amps rated above the power I want to use, because it allows me to keep my gains down and keeps the stress on my amps to a minimum. Does this translate into "more SQ?" Who knows. Like has been said, power is cheap these days. If you're considering 2 ohm drivers because you want to extract every ounce of output from your amp, my suggestion would be to sell your amp, buy a more powerful one, and run 4 or 8 ohm drivers.


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## cravenmh (Jan 14, 2009)

I agree with Mikey. Heat is current squared, times resistance. Quadruple the heat with a 2 ohm load and you WILL shorten the life of transistors(thermal expansion) and electrolytic capacitors greatly. The high magnetic field around a higher current conductor will add some back ground noise to your low level preamp section, if not properly shielded. Physics 101


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## t3sn4f2 (Jan 3, 2007)

If your amp is a quality amp and you know how to set gains and be responsible with your volume knob then the whole impedance things is much less important. 

I don't think there are many here that would not connect a 4 ohm sub to a bridged channel pair but no one wants to use a less current hungry component set or midbass on those channels pair unbridged at 2 ohms?


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## mikey7182 (Jan 16, 2008)

t3sn4f2 said:


> If your amp is a quality amp and you know how to set gains and be responsible with your volume knob then the whole impedance things is much less important.
> 
> I don't think there are many here that would not connect a 4 ohm sub to a bridged channel pair but no one wants to use a less current hungry component set or midbass on those channels pair unbridged at 2 ohms?


Correct me if I'm wrong, but I would think that audible distortion is a lot more evident in the upper frequency ranges. Assuming impedance reduction increases audible distortion, of course.


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## kyheng (Jan 31, 2007)

If really into SQ, I will use 4ohm amps to power 8ohms drivers. You will able to feel that the sound is rounder at 8ohm.
Consider Ohm's law where efficiency are at 100%(never happen in real world), you will need a [email protected] amp to power a [email protected] driver.


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## MiniVanMan (Jun 28, 2005)

Robb said:


> The amp plays 50x2 @ 4ohm or 90x2 @ 2ohm.


So, you have an amp that only has a 20% loss when dropping the load in half? DAMN!! I want that amp. 

I can almost guarantee that if that amp actually puts out 90 watts @ 2 ohms that it's actually putting out much more than 50 watts @ 4 ohms (60-70). 

That makes more sense by the numbers.

As far as what sounds better? More power sounds better. You need power to cover the dynamic range in music. In a car you need more power to drown out environmental noise. Generally if a person says one amp sound better than another and they're both rated at the same output, then the one or the other is lying, or both. In other words, they're not really putting out the same power. The one that sounds better is putting out more. Considerably more if it's audible. 

Get a more powerful amp if you're that concerned.


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## t3sn4f2 (Jan 3, 2007)

mikey7182 said:


> Correct me if I'm wrong, but I would think that audible distortion is a lot more evident in the upper frequency ranges. Assuming impedance reduction increases audible distortion, of course.


True there is that part which is not an issue with the sub running the amp that way. Although with care the distortion when running mids that way can still be avoided.


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## mikey7182 (Jan 16, 2008)

MiniVanMan said:


> So, you have an amp that only has a 20% loss when dropping the load in half? DAMN!! I want that amp.
> 
> I can almost guarantee that if that amp actually puts out 90 watts @ 2 ohms that it's actually putting out much more than 50 watts @ 4 ohms (60-70).
> 
> ...


\thread


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## t3sn4f2 (Jan 3, 2007)

MiniVanMan said:


> So, you have an amp that only has a 20% loss when dropping the load in half? DAMN!! I want that amp.
> *
> I can almost guarantee that if that amp actually puts out 90 watts @ 2 ohms that it's actually putting out much more than 50 watts @ 4 ohms (60-70). *
> 
> ...


Especially in car audio where they typically rate power output from 20Hz to 20KHz into 4 ohms and only at 1KHz into 2 ohms. Which can be as much as 25% inflated into 2 ohms then.


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## rain27 (Jan 15, 2009)

Focal speakers come in 2 ohm, so I assume this would mean sq is not diminished?? The argument being that Focal makes solid speakers...


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