impedance Questions

[Kevex]

I want to pick up 2 Kicker comp vr12(dual 4 ohm). I know that I can run them at 2 or 8 ohm correct? The amp I have is RF 300S (75w X 2 @4ohm, 150w X2 @2ohm, & 300X 1 @ 4ohm) I figured each run at 2ohms will get 150watts. Am I correct? How many watts would they get if they were run in 8 ohm configurations? Would this be enough power for them?(all I got for now) Should I run the 2 or should I get just 1 for now? ($154 for 2 on Ebay) Thanks for any answers.

 

[Robb]

OK................good luck!

Robb

EDIT: Sorry, you fixed your post

 

[WoodysX]

#1 I figured each run at 2ohms will get 150watts. Am I correct?

Yes, if you get the 2 you will be able to run 1 sub to each + - input on your 2 channel amp

#2 How many watts would they get if they were run in 8 ohm configurations?

To get an 8 ohm load you would have to wire both 4 ohm subs in series. Im not shure about 2 dual 4 ohm subs though, maby someone else could help you out on that.

#3 Should I run the 2 or should I get just 1 for now?

If you only get 1 sub you would still be able to get 150watts out of your amp since you can only get the 300x1 if you have a 4 ohm sub woofer.

Also I have heard that RF amps are under rated so you might actually get more power than 150x2, maby even get 200x2??

 

[Rscotts1]

Kevex, I have those same Subs. Yes, you will get either a 2 or 8 ohm load depending on the wiring. Wiring them in Parallel (2 Ohm load) will give you the most power. As mentioned above Rockford amps are underrated. My 500.2 is actually rated at 674 Watts @ 14.37 Volts per the Birthsheet. That is approx 330 Watts per Sub on my system. I would get 2 Subs, unless space/room is a major concern. Good luck. Check out my system below:

 

[Rscotts1]

.....yes, wired in series, dual 4 ohm voice coils will show an 8 ohm load.

 

[Kevex]

Rscotts1-- Actually I did see yours when I was looking in another post --Real nice and clean- I see you have them sealed would they sound louder ported(take up more room also though? My question for the 8 ohm wiring was what would the wattage be going to each sub if 8 ohm configured?

 

[Rscotts1]

Kevex, If I was to wire my Subs to show an 8 Ohm load, I would be putting only approx 85-90 Watts to ea Sub (if my calculations are right....somebody please check this). As you can see....not very much power!! As for ported or sealed........you will get alot of opinions. For myself, I prefer a sealed box which yeilds a better sound quality, gives a very smooth bass response with good low bass extension and takes up less space and is easier to build. The vented/ported box is difficult to build, but gives you more output at certain frequencies. Unloading is another disadvantage in the ported design in which the Sub can go into full excursion which can be harmful to the Sub's integrity. Thanks for checking out my system and good luck.

 

[pband599]

Just for the record, half the resistince, double the power and it goes the other way too, as in double the resistince, half the power. 500w x 1 into 2ohms would be 250w x 1 into 4ohms or 125w x 1 into 8ohms and so on.

As for you setup, I would say run both speakers (voice coils) in parallel then series (the parallel voice coils) them to the amp,

vc--vc vc--vc
\ /
[ amp ]

Wire each VC + to + and - to -, then wire the + on one speaker to the - on the other then wire the other + & - to the + & - on the amp (bridged at 4 ohms, running @ 300+ watts).

Hope the ASCII art helps.

 

[pband599]

Damned ASCII art didn't work, so here goes...

I am an Artiste`

 

[MrExplorer]

My math tells me 32.5 watts per channel at 8 ohms... Dont think the amp would like being that high in inpedence. The amp is rated for 2-4 ohms. So yes running the VC's in parallel would give you 2 ohms and 150 watts per channel. Im not a big fan of dual voice coils. They work fine and give you more options, id just rather have a single VC rated for the impedence for my application. Just my 2 cents...

 

[pband599]

I get 37.5w ( at 8ohms), half of 75w (at 4 ohms)

 

[MrExplorer]

Lol...oops.. that would be correct! I had the correct formula but brain fart on the math...

 

[pband599]

Don't we all sometimes