NVTHIS

Ok, I just got through hooking up a set of components and 12" subwoofer to a Hifonics ZX4400 amp. This sounded awesome while the cars switch was turned to the accessory position, but after about a mile of me driving the car, the protection light came on, and the amp cut out. I have a Farenheit ck12d dual 4 ohm subwoofer on channels 1&2 ( Bridged ). The components are on channels 3 & 4. I'm thinking the wiring configuration on the sub is what caused the protection light to come on and therefore cut the power to the amp. The sub is wired as follows: Positive to positive and then to positive lead on terminal and negative to negative and then to negative lead on terminal. This would produce a 4 ohm load, but after you bridge it it will produce a 2 ohm correct? I came back home and turned the car off and cranked it back up and the sub produced a loud pop. I then disconected the sub and the components work fine while the car is running. Is there any other way to wire this to accept this sub along with components? The amp is capable of 4 & 2 ohms stereo per channel, or 4 ohms mono bridged operation. I also get a little bit of engine noise/ whine. I have the power wire routed on the passenger side and the ground wire going to the seat frame mount on the drivers side. The RCA cables are also ran along the drivers side. Should I reroute the ground to the passenger side seat frame mount, or could it be another problem. BTW, my headunit is a Kenwood MPC(?) 828. Any help would be greatly appreciated. I know this amp is not big enough for this sub, but I'm just trying to get by right now.

Thanks
-Jason

scott_fx

you are correct with the 2 ohm load and that is what is causing your amp to cut out. you can try to run each voice coil of the sub to a seperate channel on the amp. this will be in the safe zone

NVTHIS

Ok, cool! Easy enough,lol. What do you suggest concerning the engine noise/ whine?

-Jason

fej

Engine noise is generally associated with either poor RCA quality, poor RCA routing (rca's running over/very near wires carrying power) or possibly poor grounds (loops etc). I would look at the RCA's first as they carry your signal and are generally the culprit to engine noise.

I don't know the exact specs to that amp but generally speaking for 4 channel amps they are designed to play "stereo" on channels 1/2 and bass on channels 3/4. Most 4 channel amps have much different crossover settings on channels 1/2 vs channels 3/4. Often times there are subsonic filters and bass boosts set up for channels 3/4 as well. No idea if you are using the crossovers on the amp at all or if this applies to this particular amp.

Reread your post and you should route rca's and power wire on opposite sides of the car if possible. I ran my power and rca's on the same side (passenger) but routed the RCA's taped up along the passenger side of the console and around the amp (mounted underneath passenger seat) to the connections and ran the power wire inside the carpet line edge and to a small fused connection and then to the amp. Closest the rca's come to power wire is at the amp about 6" apart and thus far I do not have any noise.



Fej

DPG

i ran my rca's along the tunnel on the pass side and my power cable along the door sill on the pass side. I think this is far enough.

Halfway

Is it worth it to spend some extra $$$$ on some high quality RCA's (MONSTER) to prevent this?

Thanks guys.

pentavolvo

personally I find that high quality RCAs make a very minimal difference, if you have good grounds that will take care of your noise 99% of the time

fej

I would not run out and spend $100 on rca's but I also would not throw some radio shack plastic ended $4.99 set in either. The rca's I got from knuconceptz were solid, well insulated nice screw on connectors that fit snug without modification. They were like $20 for 2 meters which was all that I needed

Fej

NVTHIS

Alright guys, I ran both 4ohm voice coils of the sub to the positive and negative terminals on the amp on channel 3 & 4. Right now I have two sets of components in my vette. I have a set in the doors ( Which are not hooked to the amp at present ) and I have a set built into a partition that I built. The headunit has outputs for front, rear, sub. and aux in. I am running a good set of rca's from the RCa's in the back of the headunit labeled rear out. These rca's go to channel 1 & 2. The rca's for the sub come from the headunit and go to channel 3 & 4. Right now I have front components playing, rear coaxials playing, rear amplified components and a 12" subwoofer. Iam telling all of this because something doesn't sound right with this scenario,lol. Anyways, after I switched the sub wiring around to channel 3 & 4 and rewired the sub to the correct ohm reading and wired up the rear components to channels 1 & 2, the sound from the radio came from the rear coaxials and the sub and the front components. This was set on 4 channel mode on the amp. Well I switch it to 2 channel mode and everything seems to work fine. My rear amplified components come on along with everything else. I also received engine noise while in 4 channel mode, but do not receive it in the 2 channel mode. My intentions of this amp was to be used to run both the front and rear components and just let the headunit run the rear coaxials. Then I would buy another mono amp for the sub. Right now, I am wiring it this way until I get more time to tap into the front set of components,lol and buy another amp. What I am getting at is that isn't this amp supposed to be in 4 channel mode instead of 2 channel mode. The 1/2 channel x-over is set at high and the 3/4 channel x-over is set at LP/BP. Also, where do I set the Hi pass, Low pass, Bass EQ and level at. On the high pass it ranges from 10 hz-1.2k, on the low pass it ranges from 30 hz-150 hz, on the bass eq it ranges from 0db-18db and the level ranges from 6v-0.2v. Sorry for the extremely long post, but trying to make sure everything is done correctly as this is my firsttime wiring up a amp,lol. Thanks for the help guys!

-Jason

scott_fx

i'm not gonna touch the tuning part of your question, i have a feeling fej will jump all over this.

can you try something for me.... put it back to 4 chan mode and switch the rca's at the amp... does the hum go to the other speakers?

NVTHIS

Switch them as in how? the 1&2 to the 3&4 and the 3&4 to the 1&2?

Thanks
-Jason

NVTHIS

Here is the side view of the amp:

scott_fx

correct

fej

I think part of the problem may originate with the RCA's at the deck. I looked up your deck and it appears that there are 4 total RCA outs, one being "rear auxilary" and 3 being what I am guessing is full range 5v outs.

I think part of your problem is that your deck is not sending the proper signal via your choice of rca outs to your amp. I think the problem is that when in 4 channel mode the amp is trying to use both sets of rca's and one of those sets is not sending a full range signal which is causing issues when coupled with the crossovers on the amp (IE the signal that is being sent is below the crossover frequency).

The sub rca's seem to be working fine and should stay on channels 3/4. You can mess around with the 0-18db bass boost features if you want but they tend to add a fair amount of distortion along with the boost. Keep your gains down if you are going to use it IMO.

I would do the following:

Reconnect your "good" set of RCA's to a different set of females on the HU. Start your HP filter for your front stage at around 100hz. Play your bass starting at around 80hz low pass. I am not sure of the rolloff on your amp crossovers but if it is 12db you may have to set the bass at a lower crossover point to keep it tight. Try and tune the system in pairs of speakers. IE midbass first, then connect the tweets and get it set up to a point of "loud as I am going to listen" without distortion. Use about 85% or so of the decks max volume and then SLOWLY bring your gains for your front components up to loud but "clear" (distortion free). Then add your bass and bring it in slowly at the rear gains until you get a nice blend that is not too overpowering. We are in a small car and you do not need a ton of gain to fill that cab with bass The goal is to set it up as loud as you can without distortion and then you will not have to do a lot of messing around with it for various types of music.

If your mids sound good at 100hz try sneaking them down until they start sounding "muddy" or what sounds to you like distortion ... the lower you can cross them generally the better your midbass is (toughest thing to do well in a car IMO).

Be sure to use a fadeable out for your RCA choice as it is likely that you will want some sort of option to fade the rear coaxials for your rear fill since they will be on HU power (and HU power is not very efficient nor clean and tends to get ugly around 70% of max volume)

PM me if you want to give me a call to help bro

Fej

NVTHIS

Ok Scott I switched the rca's around and voila! No engine noise at present do I hear and everything is working as should in the 4 channel mode. I forgot that since I switched the sub to channel 3 & 4 that I needed to switch the rca cables also,lol. I guess this cold medicine I'm on has me thinking in left field,lol. Now I got to get down to the tuning! I appreciate greatly the help that Scott-fx ,Fej and others have provided. Now I need to know if anybody has any suggestions on where to set these levels at on the headunit. Rear volume ( 0-35 ), Subwoofer level (-15-+15 ). I will have to do what you said tomorrow Fej concerning the other adjustments. Just a good ballpark range is what I am looking for.

Thanks
-J

fej

I usually tune with bass at about +5 (subwoofer setting that is) with Alpine's. They work from 0 to +15 though. You could probably start at 0 since + and - 15 is quite a big range. Sometimes you need to pull some bass out for certain tracks and sometimes you just want some serious boom

As for the other question I am thinking that you are referring to 0-35 on the headunit volume for the rears? I would personally disconnect those speakers in the rear for tuning purposes and then when you do connect them start at about +6 faded to the front ( I believe this should work with how you have it wired now) to keep full signal strength to the front components and send a guesstimate of about 60% strength to the rears regardless of volume number. IE at 27-28 volume ( I would tune for max around here .. most headunits start sending a clipped signal at around 85% of max) the rears should be seeing approximately 16 volume which should make for some decent rear fill. (cough hehe) If they are too quiet bring the fader more towards equal. Vice versa if they are still too loud.

Disclaimer I don't generally recommend using the fader to assist in tuning a system .. but in some circumstances when both amps and headunit power is being used it can be beneficial to overall sound.

G'luck
Fej