mikekay

Here's the setup:

Kenwood KFC-6983PS
Nominal Impedance 4 Ω
Rated Input Power (RMS) 110 W
Frequency Response 66Hz - 22kHz

Dual XPA 4100 Amplifier
RMS Power at 4 Ohms: 50 W x 4
RMS Power at 4 Ohms: 150W x 2
RMS Power at 2 Ohms: 75 W x 4

KFC-1693PS
70W Rated Input Power
4 Ohm Impedance
80Hz - 22kHz Frequency Response

Alpine CDA-105 Head Unit
3 Outputs
18W RMS x 4


I've determined that my AMP is a peice of and want to get a new one. I have a pop that happens randomly at one consitant volume, and its driving me insane. I did all the noise testing mute plugs-- eliminated the deck as cause for noise. Elminated Speakers because I switched the bridge and the popping started comming through the fronts but some noise was still relevant in the back but not nearly as much. The other thing is that after testing everything I rehooked everything back up and now my bass and volume are insanely low, and very high in treble. Im going to get an amp from a friend and just and drive 1 speaker at a time just to see for sure that its the amp. I've tried insulators, ground points etc. Also one last thing that I would like to add is that the sound appears fuzzy even at low volumes the bass is somewhat grainy, not distorted just grainy.

Also if buying a new amp is the solution what would be the best amp for my setup. Is it bad that I have different wattage for my fronts vs backs? would I need two seperate amps?? Plus one for sub??

PLEASE ANY ADVICE WOULD BE VERY APPRICIATED, Im good with electronics, multimeters, grounds, wiring but this one has got me stumped.

Thanks in advance,
Mike K

MR2NR

iTrader: (66)

I would say that you have definitely found your issue. There is no set in stone rule as far as providing power to your speakers, you can have different power speakers front to rear. Come up with a budget on a new amp and I will materialize a deal on a new amp for you.

mikekay

would underpowering my speakers.. Putting in 50W instead of 100W make it fuzzy?

I would like to spend around $150 on a new amp. I know its cheap, but I dont have alot of money for electronics which is why im so upset at the fact that my amp is and now WALMART wont take it back, and the vendor wants me to send it back... not worth it.

So upto 200$/4channel but something to push the backs at full power... while the front are close to max. is it possible?

would I need 2 seperate amps for that?

MR2NR

iTrader: (66)

You can underpower a speaker all day long and it will not make it fuzzy. If a speaker is fuzzy, it is either blown or seeing all sorts of distortion that is will faithfully reproduce. How old is the amp? Walmart has a great return policy, go back to them again.

Ignore trying to get an amp to power the backs at full while the front is at close to max, there are very few "staggered" amps like this in the industry today. Get as large an amp as you can afford and set the gains properly. I would recommend that you step up your investment some to get a solid amp, get out of the bargain basement type of amplifiers.

mikekay

Yea ok,

Thats what I thought it just wont have the same 'loudness' value.

So with my amp right now if I have a 50W powering the back I could gain them and get the same

So I called wally-mart I cant get a exchange im over 30 days... so Im just gonna go in buy another one and return my 2 month defective one for money back, and theyll take care of the shipping to supplier for me that way =D

My friend said that I could bridge my speakers across the backs, plug the fronts into the deck and that would be okay.

Do you think running 150W in my rear kenwoods would be too much? 40W more? long as I watched the volume **** I should be okay right? They have a 420W peak

MR2NR

iTrader: (66)

Run the amp in 4 channel mode as it was designed to. You will lose more than you will gain if you run it how you are thinking you want to.

mikekay

Yea okay I thought so.

Another question is If I am running 50W x 4 and I set the Gain up to 2V lets say?

What am I actually changing, I understand Gain isn't a volume setting what is it actually changing in the amp? could I max out my speaker and get the same thump I would have gotten from running 110W by setting the gain using 50W? or close to at least?

MR2NR

iTrader: (66)

The difference in power levels from 50w to 100w is only 3db, a difference that you can perceive as louder and not a large amount louder. Set the gain PROPERLY, not just to 2volts unless the decks outputs is 2v. The front speakers are the important ones, the rear ones are larger and will sound louder with the same amount of power due to more than likely being more efficient and having a larger surface area. Turn the rear gain down some if you have to. Front speakers is where it is at.

RomanticMoments

Think of a car's steering wheel. Assume you have two cars that are identical, but one takes 2.5 turns to get lock to lock, the other 1.5. Also assume niether car's tires turn any further than the other's. Naturally, the latter car has more sensitive steering. Say you have two identical decks, two identical amps, but set their gains to different sensitivities. One will reach it's limit before the other (aka lock to lock). The difference between a car's steering and an amp is that once the wheel hits lock, that's it. An amp will try and go beyond it's limits to continue amplifying it's input power, but once it does this it creates "dirty" power. It will start to "clip" which sounds to you like distortion

mikekay

thanks for all your help so far you are helping me get somewhere for sure!

Also from the specs of my radio the gain pre outs are 2V, what does this mean for my setup.