New Stereo going together. 4-ohm or 2-ohm?

**kurtis500** · 08-28-2010, 09:01 AM

I'm starting to piece together an all new stereo for my cruiser. Looking at speakers last night there were 2 ohm and 4 ohm speakers. Can someone explain the difference in how these sound and if this is a good idea? I read in another thread that amps ran at 2-ohms get too hot. The speakers i am looking at are infinity kappa's.

Sorry for the elementary questions, I just need someone to briefly explain it.

My plan was to go with a 5ch amp and 4 speakers with one sub in my 21ft cruiser.

If anyone has done a similar set-up a brief description and where you bought the stuff at would help.

**camusmuse** · 08-29-2010, 06:27 PM

Which speakers were 2 ohm....the highs, or the sub?

What brand/model amp are you looking at getting?

I have always preferred a separate amp for the subs. The powersupply for the sub amp will get strained(pushing that big speaker) and cause distortion, that could get passed on to the highs that have to share that PS. A separate four channel for the highs...with its own PS will have relatively little strain and keep things nice and crisp on the upper end.

2ohm speakers will push most amps to their limits and IMO that is not preferred. Some will even argue that the lower the resistance(ohms) the less the sound quality....but thats one of those arguments that can go on and on and on.....

As for where to buy....I'm sure someone more current on the audio scene can help more. I collect and use mostly vintage(1990's) amps, that IMO are better than just about anything made now(except for the REALLY high end stuff that you probably dont want to put in a boat anyway)......

Hope that helps.....feel free to keep the questions coming....I'm new to boats but not audio....so I figure the more I can help here, the more help I'll get down the road....a "pay it forward" kinda deal....

Nathan

**kurtis500** · 08-30-2010, 08:05 AM

Thanks Nathan.

I am looking at CEA-2006 rated amps only. I feel that I can get just about any brand with that rating and know I at least have an amp built to a standard. The speakers I was looking at were Infinity Kappa's but i am open to anything 2 or 4ohm. I am thinking about the rockford m282 8"speakers. Maybe 4 of the rockford m282's and one sub...?? The speakers are rated at 200 watts with 100 watts RMS. Do these sound good or is it overkill in a 21ft cruiser?

**back2k5** · 08-30-2010, 08:11 AM

Originally Posted by camusmuse

Which speakers were 2 ohm....the highs, or the sub?

What brand/model amp are you looking at getting?

I have always preferred a separate amp for the subs. The powersupply for the sub amp will get strained(pushing that big speaker) and cause distortion, that could get passed on to the highs that have to share that PS. A separate four channel for the highs...with its own PS will have relatively little strain and keep things nice and crisp on the upper end.

2ohm speakers will push most amps to their limits and IMO that is not preferred. Some will even argue that the lower the resistance(ohms) the less the sound quality....but thats one of those arguments that can go on and on and on.....

As for where to buy....I'm sure someone more current on the audio scene can help more. I collect and use mostly vintage(1990's) amps, that IMO are better than just about anything made now(except for the REALLY high end stuff that you probably dont want to put in a boat anyway)......

Hope that helps.....feel free to keep the questions coming....I'm new to boats but not audio....so I figure the more I can help here, the more help I'll get down the road....a "pay it forward" kinda deal....

Nathan

I've also had better luck running my Subs with their own amp

**Havasu Hangin** · 08-30-2010, 03:41 PM

It really depends on your amp(s). The resistance of the speaker simply holds the amp back from melting itself (like a rev limiter). Higher resistance will make the amp run cooler, but you will give up some power (ohm's law).

Two 2-ohm speakers in series is a 4-ohm load, but two 4-ohm speakers in parallel is a 2 ohm load, so the installation combinations are endless.

Some sub amps (class d) will run pretty cool at a 2 ohm mono load, while others (class ab) will meltdown without alot of cooling built in to the installation.

**SPL2K** · 08-30-2010, 07:59 PM

Originally Posted by Havasu Hangin'

Two 2-ohm speakers in parallel is a 4-ohm load, but two 4-ohm speakers in series is a 2 ohm load, so the installation combinations are endless.

Thats incorrect. Two 2 ohm speakers in parallel would be a 1 ohm load and two 4 ohm speakers in series would be an 8 ohm load.

You want to run your mids and highs amp at 4 ohms per channel in a boat. The amp will run cooler and more efficient.

**Chris1530** · 08-30-2010, 11:07 PM

Well like they Said the choices are Endless..

Multipal 2 ohm speakers can be used, They offer 2, 4, 8 ohm speakers, alot of ppl use 2 ohm speakers due to the fact that amps make more power at 2 ohms which means you can buy a smller less expencive amp and run 2 ohms, vs a larger amp more money, to run the same wattage in 4 ohms. and while 4 ohms is the most effiiecnt in car audio, 2 ohms in STEREO is not unefficent. its when you start bridging amps into 2 ohm loads that the really start producing heat.

You can use 4 ohm speakers with, less channels say 2 speakers per channel if wired in parrel. ( Say a 2 channel 200 watt per channel RMS amp rated at 2x200@ 2ohms ) you could effectivly run 4 speakers the 4 ohm speakers wired in parrel will make a 2 ohm load for the amp.(the rockfords you listed are 100 watts Rms rated) from the 2 channel amp at 100 watts per speaker. this would eliminate Fade from front to Rear.. or left to right.
So id say do you want it to fade ? left to right , fron to back ? if so you need 4 channels for 4 speakers 1 amp..
you could get an amp like: 4X50@ 4 ohms, 4X100@ 2 ohms
Sub and sub amp seperate. its more efficent.

Also when conectting more than one speaker to a channel it splits the power between the 2.. or 3 or however many speakers you ran off the channel.
And 2ohms STEREO on a amp isnt that hard on the amp, it will cause more heat than if it 4 ohm. but with a good amp it shouldnt be excessive..

Remember only look at the RMS rating peak means nothing, RMS is constant power or power handling.

Are you going to Run all Marine stuff ?
myself i like the name brands, rockford, Kicker, pioneer, kenwood, alpine, JL audio, MTX,
Id try to keep it all the Same, or at least same speakers, diff amp.
Myself in car world, ive Had good luck with rockford, Kicker, pioneer, kenwood, alpine, cewin vega , audiobahn.

And as far as ohms and heat think about how long you plan to run it, and how loud..
my car, has kenwood speakers, kenwood deck, Autobahn amp, cerwin vega sub. And my amp is a high current model, supposed to push around 2400 rms. right now im running it @1 ohm, it has dual fans and i can run it about 80% volume,(palying rap) for about an hour before it shuts down from the heat. straight Metal ive never had it shut down.
.
So amps with fans is another thing to think about, but im not sure if they have any "marine" amps with fans.
oh also id use a Mono sub amp, and not a 2 channel amp bridged..

had to quit sorry got caried away..lol..

**Havasu Hangin** · 08-31-2010, 01:32 AM

Originally Posted by SPL2K

Thats incorrect. Two 2 ohm speakers in parallel would be a 1 ohm load and two 4 ohm speakers in series would be an 8 ohm load.

Sorry, had it backwards! lol

**kurtis500** · 08-31-2010, 10:43 PM

Great information guys.

I plan to go with all name brand stuff. For the amp I am not really particular on name brand as much as I am CEA-2006 rating. My assumption is that this is the standard and to get a cea2006 their amp has to really perform. The deck will be rockford probably or a CMD5 or 6. The speakers I just want to be powerful. I was thinking about tower speakers but no one I'm with really cares to listen to music wakeboarding and the hopped up BBC is kinda noisy anyways. Actually that brings up a question. Are tower speakers good inside the boat as well? Or are installed speakers much better?

I've gone the route of cheap electronics years ago. I didn't care much about the stereo system and ended up buying cheap...Pyle and Boss.. Total garbage. The stock stereo in my mother in laws 99 cavalier outperformed those junk systems. I would never install those brands in anything I own again. The speakers alone were the worst ever.

**1978sprint** · 10-06-2010, 03:54 PM

I did not read all the replies. I run my amps on 2-ohms as long as it is a quality amp. If you buy 4-ohm speakers and run them parallel you can run twice as many speakers.

i am also a fan of having a separate amp for the sub. Most amps can handle 2-ohms. Now one ohm is a different story!

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New Stereo going together. 4-ohm or 2-ohm?

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