Understanding Ohms (audio)
 

I am confused as to whether or not i should purchase a subwoofer with a 4 ohm impedance or a 2 ohm impedance. I understand the basic concept of wattage in relation to ohms, however which will deliver the best sound quality/spl? Also, if i am understanding this correctly a dual coil sub can be wired in parallel/series? fill me in on your audio knowledge!

It depends on what amp you are using and how many speakers you are pushing with that amp. If the amp is 2 ohm stable you can produce more power with 2 2ohm dual voice coil speakers wired in series to each other and then parallel (bridged) to the amp. That would produce a 2 ohm load. If the amp is not 2 ohm stable, then 2 4ohm dual voice coil speakers wired series and then parallel to the amp would produce a safe 4ohm load and will prevent destroying your amp.

As far as sound quality is concerned, I don't think sound quality suffers either way as long as the speaker/amp/head unit is matched up properly. SPL is stronger the lower the ohm load the amp sees due to the increase in power (enclsure design is just as important for SPL/SQL). An amp rated with a max of 700w might be at 2ohms but would realistically only see 350w at a 4ohm load. Most multiple channel amps are not 2ohm stable(bridged). Phoenix has some amps that are stable to as low as .5ohm though.

Check out the Crutchfield website for some good information as well as carstereo.com and caraudio.com.

What amp are you wanting to use?

i was looking at pairing a clarion pxw1251/52 sub with a clarion dpx1800 amp. However, the 1251 is a dual 2ohm where as the 1252 is a dual 4 ohm. I want to pair it with the amp only if I can run it at 2 ohms but i didn't know if the amp could handle that. here are the links for both:


Sub- http://www.onlinecarstereo.com/CarAu...roductID=17464

Amp-
http://www.onlinecarstereo.com/CarAu...roductID=17289

Maybe I am incorrect however. Don't you wire the dual coil sub in series so that it equals 4 ohms? or can you wire it so that it is just 2? im slightly confused on that matter. Thanks for the info so far!!

You want a 2ohm load in order for that amp to make 800w. In order to do that you need a dual 4ohm voice coil sub wired in parallel. If you wire it in series, the amp would see 8ohms(4ohm+4ohm). If you went with a dual 2ohm voice coil, and wire it in series the amp would see a 4ohm load giving your sub 450w. If you went with the 2ohm and wired it in parallel the amp would see a 1ohm load and probably fry itself. So yes, you can wire it in series so it would see a 4ohm load but only if you use a 2ohm dvc sub. Get the 4ohm sub and wire it in parallel and get ready to jam! I'm running an Alpine Type R 10 4ohm dvc wired parallel with an Alpine mono amp and it's more bass then I could ever need! I chose Alpine for the sound quality.

Crutchfield has a pretty good def here
http://www.crutchfield.com/ISEO-rgbt...fers_dual.html

Go to www.Caraudio.com to the forum section and post their, they are very helpful. Youll get imput real fast.

Why are you going with clarion? Is it cause the subs seems massive? You do know that those subs are 500watts rms right.

Heres how it goes if your only buying one subwoofer, and assuming you buy a monoblock amplifier.

dual 2 ohms voice coil subwoofer= 1 ohm stable amplifier. wired in parallel



dual 4 ohms voice coil subwoofer= 2 ohm stable amplifier. Wired in parallel

Danger Caution Watch Out
 

This kind of "ohms" is different than the kind you just add up like in a battery circuit. They are to be considered as "units of compatibility" as in "coupling" circuits together. input or output. If you put a 8 ohm speaker, for instance, on a 4 ohm audio output there will be a mis-match resulting in reflected audio power back to the amplifier where it translates to heat and eventual damage.

No matter the equipment be sure to match the values of "impedance" for best performance. And, yes there are devices which can match up otherwise uncompatible equipment but they reduce effeciency a bit. Stay away from them if you want a good boomer.

In your question above you need to see what the output impedance of the amplifier is then buy a woofer of the same value for proper operation. Any other value will result in the reflected power scenario as I described above.

None of you guys make any sense... Yes you have to find an amp that's 2 ohm (or lower) in stability. As for now, think of the amp as an obsolete part of the equation because its however you wire your speakers that brings the ohm load to the amp. Not the speakers, before you wire them, being compatible with the amp... that's just ridiculous. Now. I personally go with dual 4 ohm subs with a mono block (single channel amp) and wire them down to a 1 ohm load. I would recommend googling any subwoofer wiring diagram on the net. its all up to you on how u want it to sound. the less ohms the harder ur stereo will hit. But the less sound quality. (home stereos being 8ohms) The quality isn't really anything you can tell in a vehicle, it being such a small area and all. Your next choice,... Enclosures. Ported (vented) or sealed. They both have differant frequency responses. I like sealed. Ported sounds almost to sloppy to me. Good luck to you, and the other obvious group of non stereo gurus.:eek3:

Hey, you guys are really helping me out here, but what does "rms" mean? I went into a stereo shop and they were talking rms and ohms and crap I have no idea about.