Gr0dy

I just bought 2 kenwood kfc-w2509 10 inch woofers and a kenwood kac-7251 amp. i don't know much about car audio at all so i have a question.

The specs for the woofers can be found here: http://www.crutchfield.com/S-12McaRA...13W2509&tp=111

Specs for amp here: http://www.gopcplus.com/pcplus/produ...roductID=91005

my question is, is it better to run 150 watts RMS x 2 at 4 ohms or 230 watts RMS x 2 at 2 ohms ? Im not sure what bridging is , but it says 460 watts RMS x 1 bridged output at 4 ohms, if that means i can run both the woofers at 230 rms at 4 ohms would that be the better way to run them? Thanks in advance

lurkin' eg

okay, basically you have two options. with both subs being 4 ohms, you can either go to 8 ohms (you dont want) or 2 ohms together. now there is a third option and thats basically running each sub to each channel (ie: one sub to one channel and the other sub to the other channel). doing it this way will allow 150 rms to each sub. the only problem with this is that it is a stereo signal so its possible to get voices, vocals coming out of the subs. but with proper tweeking you can have just bass. moving on, now you can "bridge" the amp, basically combinding both channels together (it should say bridged on the amp). doing this will allow you to get 460 watts rms from the amp in a mono signal which is what you want for bass. the only problem is that its at a 4 ohm load meaning you can only run 1 sub because like i said before, the subs can only be wired up at 8 ohms or 2 ohms if together. you can technically run the subs at 2 ohms (combinding the subs coils in parallel) and get 460 rms or more out of the whole system, but the problem is that the amp is not stable at 460 watts rms at 2 ohms if bridged. it only says 460 rms at 4 ohms, you follow? so if you do try to run the subs in parrallel while the amp is bridged you can chance blowing you amp (as long as you dont turn it up too much). my advice (sorry if its taking too long) is to just run each sub to each channel. the benefit of this is that you wont blow the subs if you turn up the amp all the way, plus its an easier install. you will get a total of 300 watts rms for the whole system (150 rms per sub). and if you dont want to have voices and other sound coming from the subs becasue its in a stero signal, use the low pass filter to only allow just bass to pass through. if you have some more questions, just post it or pm me. hope that helps

Fabrik8

Being mono or stereo has nothing to do with whether "voices come out". This only has to do with whether both left and right channels are separate (stereo obviously) or have been combined into a single channel (mono).

I think what you mean to say is that coming from a head unit, outputs that are stereo are usually full bandwidth, meaning they output the entire frequency range of the music, whereas mono outputs are often already low-pass filtered so they only output frequencies meant for a sub.

This just means that you have to know what type of outputs the head unit has, which determines whether or not you will need to use a low pass filter for your sub amp.

p-stone

Nice, I even learned something.

lurkin' eg

yeah you got it man. i guess i was just using it as an example of how stereo would sound vs mono. but Fabrik8 is correct, it also depends on the outputs of the deck you have. some decks have preouts for subs (mono) which would then solve this issue. if you have a factory deck you will need to purchase a LOC (line out converter).

98formulaLS1

all the post above, if combined, provide the right info for you.

Let me just sum it up for you real quick in one post.

1. Wire each sub to it's own channel. This will be the 150wRMS @ 4Ohm x 2 setup.
2. Make sure that you turn ON the LPF (Low Pass Filter). If you DON'T, then you will destroy the woofers because the the full range of audible frequencies will be sent to the woofer.