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Confused about OHMs

 

Barry
Unregistered guest
I guess this question covers more than just amps -- I am trying to fully understand the ohms situation in the system I am about to install and am completely confused.

Here's the stats for my "Kicker KX 600.4" 4-channel amp:

RMS Power in Watts, all channels Driven:
@ 13.8V, 4 ohms Stereo, 0.085% THD 75 x 4
@ 13.8, 2 ohms Stereo, 0.2% THD 150 x 4
@ 13.8, 4 ohms Mono, 0.4% THD 300 x 2

So does this mean that if I have a set of components that say they operate at 4 ohms and one 10" dvc 4 ohm sub, that I will be sending 75 w to each of the components in stereo and 300w bridged mono to the sub?

I would truely appreciate any help understanding this.
 

Silver Member
Username: Carguy

Post Number: 247
Registered: Nov-04
Ok Barry, the above spec means that if you use the amp in 4 channel mode, you'll get 75W x 4, if you use the amp at 2 ohms mode, meaning your speakers are 2 ohms, it'll put out 150w x 4. Now if you decided to use the amp to power subs in mono mode, then at 4ohms, it'll give you 300w x 2. Therefore if had 2 subs that were 4 ohms, then you hook them up to each channel. Basically you're combining each pair of channels into one, that is why it says 300w x 2.
You can only be used either as a stereo 4 channel or mono for the subs, not both at the same time.
 

Silver Member
Username: Chevy_for_life

Post Number: 213
Registered: Sep-04
The mono will be only 1 channel and probably be less stabe then what the 3 channel would be..
 

Bronze Member
Username: Thrust

Post Number: 59
Registered: Nov-04
Hook up you seperates to 2 channels, one to each (that is if they can handle 75w rms), then hook up the other two channels to each voice coil of the sub.
 

Bronze Member
Username: Thrust

Post Number: 60
Registered: Nov-04
or you could buy another dvc sub and run the sub channels at 2 ohms
 

Sucubus
Unregistered guest
"You can only be used either as a stereo 4 channel or mono for the subs, not both at the same time. "

That amp is tri-way capable.
It has 2 seperate crossovers for front and rear.
You can run your sub off channels 3 and 4 bridged
for 300w @ 4ohms
However...You have a 4 ohm DVC sub...which is incapable of presenting a 4 ohm load.
So...get a 4 ohm SVC, or a 2 ohm DVC.
Unless you take Isaac's advice from another post and run it at 2 ohms bridged, which I wouldnt do.

You can run your comps from channels 1 and 2
respectively at 75w @ 4ohms with no problems.
 

Barry
Unregistered guest
Isaac, I'm not trying to argue by any means, and maybe I didn't post enough info about the amp, but I'm still confussed:

"You can only be used either as a stereo 4 channel or mono for the subs, not both at the same time."

. . . but my manual shows 3 different configurations:

1) Stereo 4-channel operation -- diagram shows 4 speakers conected to the amp.

2) Briged Operation (Mono) -- shows 2 subs conected to the amp

3) Stereo and Bridged -- shows 2 speakers and 1 sub conected to the amp and the description reads: KX amplifiers are capable of operating into a minimum independence of 2 ohms stereo and 4 ohms bridged operation.

Though it doesn't come out and say so anywhere in the manual, everything seems to make it appear as though there are two seperate 2-channel amplifiers in one box--there's two of everything on the amp and it's all labeled amp 1 or amp 2.
 

Sucubus
Unregistered guest
Dude...Read my post again.
 

Barry
Unregistered guest
Sucubus, thanks.

Your post wasn't there when I started writing my last one.
 

Silver Member
Username: Carguy

Post Number: 248
Registered: Nov-04
Opps sorry, I didn't know your amp was tri mode capable, my fault.
If that's the case, does your amp mention anything about a filter? You might have to get a coil for the subs and a non polarized capacitor for the speakers. Personally I woudn't use any amp in a tri-mode. I'd get a 2nd amp.
 

Barry
Unregistered guest
Thanks for your guys' help, but now that I realize my stuff won't work, I have new questions:

"or you could buy another dvc sub and run the sub channels at 2 ohms"
-- would this be possible? Is it ok to run subs in stereo?

or, Is there any way to wire up (2) 8" DVC 4 ohm subs and pull a total mono load of 4 ohms to the bridged amp?

Sorry if I'm getting further off the deep end here, it sucks when you realize you were sold components that won't work together because you were naive and the sales guy was an idiot. I'm just trying to figure out my options here. (System was bought 3 years ago and never put in--for reasons that are irrelevant, so I can't really take the sub back now.)

Isaac--I don't see anything about a filter. You lost me on the coil and the capacitator. And while hindsight is 20-20, it's not finacially feasible for me to get new amps.
 

Barry
Unregistered guest
So I found this on Basic Car Audio Electronics http://www.bcae1.com/.

"This is the wiring diagram for woofers with dual 4 ohm voice coils. This will give you a 4 ohm load. The voice coils of each individual speakers are wired in series. This gives each speaker an 8 ohm impedance. Wiring them in parallel will present the amp with a 4 ohm load."

If I'm reading this correctly, it suggests that I could indeed get two 8" DVC 4ohm subs and end up with a 4 ohm mono load. The particular 8's I'm looking at are rated up to 200 watts RMS each. So I would be sending a total of 300 to the set of them. Am I missing something here? Because this sounds good to me.

Thoughts?
 

Help2
Unregistered guest
That will work for sure :-)
Series/Parallel wiring for 2 4 ohm DVCs is
4 ohms.
Just watch the gains when underpowering to avoid clipping.
 

Gold Member
Username: Glasswolf

NorthWest, Michigan USA

Post Number: 5834
Registered: Dec-03
for more info on underpowering and clipping, se the "too little power" section of bcae1
 

Barry
Unregistered guest
Thanks everyone for your help. I think I've got this thing figured out save for one last question: In using the two 8's, I'll have the option of wiring them up together to present a 4 ohm bridged Mono Load to the amp (300 watts RMS) or wiring them to individualy present 2 ohm stereo loads to the amp (150 watts each). Would one method be preferable over the other for any reason, or is it 6 to one--halh a dozen to the other?
 

Gold Member
Username: Glasswolf

NorthWest, Michigan USA

Post Number: 5853
Registered: Dec-03
same end result. it's up to you if you want to bridge or go stereo.
you don't gain anything either way over the alternative.
the only really good use for a bridged amp is with a single 4 ohm sub. when you get to two subs, you can go stereo and get the same outcome.
I use two subs and two bridged amps in my car, but each sub is dual 2 ohm coils and the amps just happen to be stereo and support bridged mode.
worked out well.
 

Barry
Unregistered guest
Well, thanks again everyone. You've helped tremendously. I can finally get to working on this thing.
 

coreymeroney
Unregistered guest
i have (2) audiobahn aw1208t dvc subs and i have wired them at 1 ohm they are 1500 watts rms each 3000 watts rms total... i want 1 mono amp but if i have the subs wired ay 1 ohm will the amp need to be 1500 watts rms or 3000 watts rms???
 

Silver Member
Username: Carguy

Post Number: 269
Registered: Nov-04
Hey Coreymeroney, if the subs are 1500W rms each, then you need one 1500W rms mono amp to drive them.
 

coreymeroney
Unregistered guest
isaac,
so it won't split the power between the two subs?
thanks
 

New member
Username: Lordoftabs

Post Number: 4
Registered: Oct-04
there's less resitance at 1 ohm, so you will not need 3000w. I would go with a 2000w 1ohm monoblock.
 

Silver Member
Username: Carguy

Post Number: 272
Registered: Nov-04
No Coreymeroney, the subs can only handle 1500W each, meaning they may add to 3000W total, but individually, they can only handle 1500W. You can use 2 amps rated 1500W to drive each speaker or you can use 1 amp rated 1500W to drive both. Personally I'd use one 1500W class D amp.
 

coreymeroney
Unregistered guest
thanks for your help!!! i will get (1) 1500 watt rms class d amp
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