Hello everyone. I installed speakers a while back in my 07 G35 Sedan w/o Bose system. Component Infinity Kappas in the front and kappas in the back. I know these should be good speakers, and I know there is a break-in period for speakers before they really sound great. The problem I think I might have is that the OEM speakers turned out to be 4 ohms while the new speaks are 8 ohms. I used to play in a band so I know the basics of impedance matching with guitar amps and pa systems. I seem to keep getting clipping on these speakers and the lower frequencies don't want to come through sometimes. My question is: will an amp help me match impedance between the head unit and the speakers or do I need a new head unit? I'm not aware of any kits or exact fit aftermarket head units being available so I'd like not to switch it out. If its possible for an amp to change the input imp from 4 to 8 on the output that would be awesome in my case. Any answers?

 

impendance is not something that is linked to the amp, it's linked to the speakers.... an amp is an amp is an amp and sees the impedance supplied to it from the speakers. If you have a pair of 8 ohm speakers then that's what the amp will see and nothing can change that.

i would heavily consider sucking it up and replacing the speakers with a proper set of 4 ohm speakers. the amp is probably not a high wattage amp, hence the 4 ohm stockers to help get some extra power, so using 8 ohms on it will see even less. The Infinitis will 1) require more rms wattage to perform properly than the stockers and even more-so 2) they're seeing half the power of the stockers due to double the impedance, so they're most definitely heavily underpowered.

Get some nice 4 ohm speakers that have a fairly mid/low min. rms rating and they should work better.

 

Are those speakers actually 8 ohms?

 

no, I made a mistake and mis-remembered what they were. I looked it up and they are 2 ohms. So I was planning on getting a JL Audio Slash 300/4v2 amp which outputs 75w at a minimum of 2 ohms. So if the amp outputs down to 2 ohms and the head unit outputs at 4 ohms, the head unit's impedance would be cancelled out or overridden right?

 

I am not sure what the stock head unit is on a non-Bose system, on the Bose it is 2 ohms for most years (maybe all). The way you describe it is a little bit incorrect but I think I know what you mean. Basically if you have a stock head unit without audio output like RCA or balanced outputs you generally end up using something like a LOC (line output converter). That is you will be hooking up to the speaker outputs of the stock head unit.

At this point to the amp you will be connecting too (assuming it doesn't have its own LOC built in (some do) could care less about the head unit since it is isolated from it by the LOC. Its inputs only care about the LOC. The only thing you are doing now is matching the output of the amp to its load, the speakers. Most amps are somewhat tolerant in the upward direction, many are not so tolerant in the downward. That is you can connect an 8 ohm speaker to a 4 ohm output and get away with it most of the time. However going to a 2 ohm speaker on the same 4 ohm output may kill the amp.. Should be an easy install.

 

i'm not familiar at all with the stock components but..... if there's an amp, then it should be getting a preamp signal from the head unit, or the head unit has the amp internally.

so, are the stock speakers 4 ohms, has that been confirmed or are they 8 ohms?

If your running 2 ohms speakers (not 8) and it's designed for 4 ohms, then your probably killing the amp by making it work hard, heat up which can cause it to act erratically, cut out or just not perform well.

either way, you need to have speakers installed that match what the amp has been designed to run at. either that or get another amp and just use the stock head unit for a signal. for what you'd have to pay replacing speakers, you can probably pick an amp up and have even better sound. don't forget sub(s)... components aren't designed to perform in the sub bass frequencies so, you might consider a simple 5 channel, 4 for the standard speakers, then one add'l to run a sub.

check out the jl hd900/5. http://mobile.jlaudio.com/products_amps.php?amp_id=537 will run 4 channels, 75w at 2 ohms and then a mono sub channel at 500w... that's a pretty killer system amp and it's really not too big at all. i have a 4 channel 125w per channel amp that's much bigger.