A few questions for the experts

[Slayer16102]

If I have a single 12" P3SD2-12 thats wired in series to 4 ohms do I use 40.00v (4 ohms) or 28.28v (2 ohms) when setting the gain for that sub with a multimeter.
I know this is the old school method of doing it, but I don't trust doing it by ear to get the best performance out of my subwoofer without exceeding my 400w RMS voltage. I like alot of bass and this way I know I'll never go above 400w when I turn up my audio while cruising.

In my previous thread I said I was having voltage drop issues which I am still trying to resolve, so now I have some more questions to try and narrow this down.
I did not realize before that my 12" dvc subwoofer was not actually running in 2 ohms. I now know the shop hooked it up in series which makes its output 4 ohms.
So under that load my kenwood amp (9106d) can only output 500w x1 RMS at 4 ohms.

So now I have a few questions...
When they installed this in my car they used 0 gauge wire for subs which can only maintain 400w of power and a huge 200A monster block fuse to the fuse box.
Could this 0 guage wire size and the 200A fuse they installed be causing a huge power draw on my cars electrical system? My alternator is 110 amps

Does the fact that my amp has 3 (40A) fuses on it make a difference at all in the power draw on my cars electrical system?
Does that fact they hooked it up to the fuse box and not the battery make any difference at all?
I have looked at other mono amps around the 400-500w RMS range and they usually have a single 20-40A fuse.
If this matters please explain how and why it matters. Again my alternator is only 110 amps

According to kenwoods website the current consumption of the K-9106D is 65A. How does this matter on a car with a 110 amp alternator? Is that a figure for a constant power draw upon my cars 110A charging system no matter what the gain is set at?

Is the kenwood 9106D just way to power hungry for a 110 amp charging system thats all stock? I primarily listen to rap, hip hop, rock, and instrumental rap beats.
If you add up the fuse under the hood thats 200A by itself and if you add up the fuses on the amp itself thats 120A in total fuses on the amp alone. Does that matter when it comes to power consumption of my system what sizes all of those fuses are?

If it is just too much for my car to handle, what is a good amp that you would recommend thats not as power hungry for pushing 400w RMS. The charging system is all stock.

Amp settings:
If my subwoofer is rated for 34-250 Hz with a sensitivity of 85db
What should my LPF dial be set at? The LPF dial ranges from 50-200
What should my ISF frequency be set at? The ISF dial goes from 20 to 50
The subwoofer is installed in a sealed box.

Flattening the system before setting everything:
If I reset my 6800BS back to factory defaults before testing
it sets my EQ to powerful, my fader to 0, my balance to 0, all of my speaker levels to 0,
my crossovers to off, my loudness to off, my bass boost to off, and my SLA to 0.

Should I set the EQ to flat and my subwoofer level to 10 before I set the gain on the amp or should I leave the subwoofer level at 0 [-24-10] at 0 until the gain is set for the targeted voltage I want.
Is it okay to set my front and rear speaker levels back to 5 or should I leave it at 0 while I set the subwoofer gain with a multimeter.

I'm just trying to do this right to resolve the car voltage drop issue, so sorry for all of the crazy questions. I am still very new to this...
Someone told me that I should set up all of my stuff how I like it first "IE" eq, speaker levels, crossovers, loudness, bass boost, sla then set the amp gain while others have said set everything completely flat before doing it. Which is the correct method when setting gain using a multimeter.

Click to read more...

 

[dragon.breath 10+ year member]

Wait. The shop connected 0 gauge wire to the fuse box?!?! Maybe you should post a couple of pictures so we can figure out what is going on.

 

[Slayer16102]

I will post some pictures here for you in a minute. You'll see how they have it wired, maybe thats the issue.
I will also show you a video of my in dash DIC with all of the numbers jumping around on my battery voltage no matter what the gain is set at. The DIC measures my battery voltage constantly. As to why they put a 200A fuse on a 400w setup I'll never know, but as you'll clearly see they did.






I'm not sure why they went to the fuse box, but they certainly did for the main power wire. As I said they used a 0 gauge power wire for a 400w system and a massive 200A fuse for it too.



Even the ground is 0 gauge.

If you look to the left of that you'll also see the 3 40A fuses I was talking about on the amp itself.
The kenwood 9106-D has 120A worth of fuses on it alone.

This car has been constantly having voltage drops, but only when the amps power wire is connected with that massive 200A fuse. Without the amp power wire connected the car will run at 14.28v constantly. The harder I drive the car the faster the voltage drops when I come to a stop. The longer I drive the car the lower the voltage goes. Sitting idle the voltage drops too, but its much more slowly I have uploaded a video to show this. The video 8 minutes long so please watch and be patient to see the effects of the amp power wire connected. You can clearly see the voltage slowly dropping in it. How can a 110 amp alternator be incapable of running 400w with nothingelse installed on the electrical system, but this. Without this wire connected the charging system will run 14.28v constantly.



On the amp itself here is my configuration for the subwoofer.



The subwoofer is a rockford forgate P|3 (P3SD2-12) capable of 400w RMS
The sub is wired for a 4 ohm load since its a DVC shallow mount sub.
28.28v is just barely before 0.5 on input sensitivity when configuring for a 2 ohm load with a multimeter for 400w.

Since I am fixing to head to work right now I will post a video of what it actually does tonight to better show you the voltage drops and how the car re-acts to the audio system over a 40 minute drive. Remember my DIC is constantly measuring my charging system voltage and displaying it in real time so it will give you alot more details with an actual video.

 

[ThxOne Premium Member]

I don't know that a class D running 500w at 4 ohms is going to even make the lights flicker considering it's not going to be close to 500w when listening to music 98% of the time. Is there a second amp for mids and highs? How are the ground wires? Are the battery terminals tight? Corrosion free?

 

[Slayer16102]

Okay so to better understand what all I am saying that is going on with this car when it has the amp connected I have recorded some videos and uploaded them. Hopefully someone can tell me why this is happening or how to fix it. Remember that without the amp connected the car pulls 14.28v constantly.

This first one here is with the amp gain all the way down running idle and watching the DIC voltage display


This next one is checking the voltage at night before driving home from work.


This one here is how the voltage reads with the car being driven in stop and go traffic home from work with the amp connected with only 400 watts (28.28v). Sorry its a long video, but I wanted to show you what happens with the amp connected. The voltage goes up as I drive, but as soon as I slow down or let off the gas the voltage drops. Forgive the shakiness my car is cammed and heavily modified so it shakes like crazy. The longer I sit in a drive thru or in a spot idle the more the voltage will drop overtime.


Is that voltage fluctuation normal in a corvette or should I have the car checked by an electrical expert to find out what is going on. There is no way 400w should be making the car start at 10.9v with rough idles.

 

[ThxOne Premium Member]

C6 Corvette huh? Anyone gonna say run a ground to the battery or should I? The frame on the C6 is Aluminum. Run a ground to the battery from the amp. See if this helps. Or run a ground to a distribution block near the amp and ground the amp to the block... either way, run a ground to the battery.

 

[Graves]

I can't think of any reason they connected to the fuse box and not the battery?
The wiring is overkill but its more fun that way.
For the amps required to produce 400 watts, ~28 amps.. i would think you should have plenty of amps left even on a 110 and that leads me to think the alternator isn't producing all 110 amps maybe? You will get a voltage drop when the system is drawing more amps that the alternator can produce and they do go bad.

So first I would have my connection to the battery NOT the fuse box (especially since you have 0 gauge ran and it will be very easy to do). Second, either your alternator is producing 110 amps and you need more production or 110 would be enough but you are not getting it.

 

[1aespinoza 10+ year member]

There is no way 400w should be making the car start at 10.9v with rough idles.

I agree with ThxOne. Ask your installer to do what is called a Big3 install. It should solve your issues. Since you said the car is heavily modified, I assume bigger injectors and coils, so this also draws more from your electrical plus an amp. This may be more than the oem grounding wire was designed to handle. As for power cable, it is connected to the terminal stud. It is no biggie since the amp uses a maximum of 40 amps at full tilt for very brief moments.

 

[Graves]

I agree with ThxOne. Ask your installer to do what is called a Big3 install. It should solve your issues. Since you said the car is heavily modified, I assume bigger injectors and coils, so this also draws more from your electrical plus an amp. This may be more than the oem grounding wire was designed to handle. As for power cable, it is connected to the terminal stud. It is no biggie since the amp uses a maximum of 40 amps at full tilt for very brief moments.

OP, it doesn't matter that the amp only draws 40 amps full tilt for very brief moments. The 200 amp fuse is to protect the wiring. If there is a short, what will give out first the 200 amp fuse or the wiring to your fuse box terminal? Because it looks to me like the wiring to the fuse box terminal is less than 0 gauge. If the wiring to the fuse box stud is fused or capable of handling 200 amps you are fine. If it is not, then it isn't a matter of opinion, it is done incorrectly.

If it is incorrect drop down to a 100 amp fuse or connect it strait to the battery if you care about your car.


I was by no means was I disagreeing with ThxOne, by all means why not have an immediate ground to the car and a wire to ground for shits and giggles (although aluminum is a better conductor than steel so Im not sure I understand what point he was making there)? It is great advice to make sure everything is tight and corrosion free, especially when experiencing issues.

From what you are describing, lower RPM's more voltage drop, increased RPM increased voltage, big voltage drops when only running a 400 watt amp tells me you need more amps and that makes me wonder if your alternator is still preforming to specification.

I think you are spot on about having the electrical system checked, i'd make sure that includes a "alternator amperage output test". Easy to do with a clamp on ammeter.

Good luck!

 

[sicone22]

a shop installed that? You literally have the correct battery terminals to install the wire why the....... just don't go back there. Tell your friends and their mothers, just do not bring your car back unless they are giving you money back and they never touch a car again.

What is the other wire that runs off the fuse block and goes to a round fuse holder? that style fuse holder is crap, shouldn't be just hanging out vertical either at that as water gets in there it will sit and corrode the connectors faster as there is no heat shrink even.

Yes ground needs to be confirmed good on that vehicle. the power wire needs to be moved to the battery and can be robbing power from the relay/fuse center especially if the ground is incorrect that will be drawing a serious load and that is the cars source of power, the ECU will not be happy with this.

to the ground being 0ga- yes ground needs to be the same or more that of the power, it is a circuit.

Why is there water on your amp? Keep it dry please!

that 200a fuse is not indicative of what your amplifier can or can not pull, that is for the wire incase there is a short. the fuses in the amp are for the amp. It is not more resistance to have bigger wire and higher fuse rating, it would be less if anything but it is equivalent of having the correct sized, so you have headway so youre good there.

the connections at the amp is astonishing a shop would think it is in the least "ok" and the power coming from the vehicles power distribution box is mind boggling.

 

[Slayer16102]

The water on the amp was because it was raining when I shot the pics. Don't worry the amp is normally dry all of the time. When I lifted the trunk lid to take the shots it let some water drip off the lid.

 

[Slayer16102]

a shop installed that? You literally have the correct battery terminals to install the wire why the....... just don't go back there. Tell your friends and their mothers, just do not bring your car back unless they are giving you money back and they never touch a car again.

What is the other wire that runs off the fuse block and goes to a round fuse holder? that style fuse holder is crap, shouldn't be just hanging out vertical either at that as water gets in there it will sit and corrode the connectors faster as there is no heat shrink even.

Yes ground needs to be confirmed good on that vehicle. the power wire needs to be moved to the battery and can be robbing power from the relay/fuse center especially if the ground is incorrect that will be drawing a serious load and that is the cars source of power, the ECU will not be happy with this.

to the ground being 0ga- yes ground needs to be the same or more that of the power, it is a circuit.

Why is there water on your amp? Keep it dry please!

that 200a fuse is not indicative of what your amplifier can or can not pull, that is for the wire incase there is a short. the fuses in the amp are for the amp. It is not more resistance to have bigger wire and higher fuse rating, it would be less if anything but it is equivalent of having the correct sized, so you have headway so youre good there.

the connections at the amp is astonishing a shop would think it is in the least "ok" and the power coming from the vehicles power distribution box is mind boggling.

Yes, a shop actually did the install. Thats what they thought was what an install was supposed to look like. The amp isn't mounted either if you notice.

That is the old power wire for my old setup, they never removed it. They just disabled the line by removing the fuse.

The ground I will definately have checked.

I will definately move the power wire to the battery when I get home from work tonight.

 

[sicone22]

Yes, a shop actually did the install. Thats what they thought was what an install was supposed to look like. The amp isn't mounted either if you notice.

That is the old power wire for my old setup, they never removed it. They just disabled the line by removing the fuse.

The ground I will definately have checked.

I will definately move the power wire to the battery when I get home from work tonight.

Where are you located? I should open a shop there lol. Surprisingly they removed the fuse even.

Do you have a multi meter? Check grounds yourself?

I am willing to bet the ground is the problem with the alternator. That mixed with the fact the alternator is too small to begin with. If the ground is not connected to the alternator it will pull its power and not be able to dump it causing a serious load. Why amplifiers (some) don't have a ground fault protection or is even able to power on is beside me. I highly recommend getting a higher output alternator if it is only 110a that comes in that car. Don't have to go all out, a 220 or around there will be just fine, hell 170-180 is a certain improvement. You could possibly get away with a little AGM powersports battery added but I would upgrade the alt as if you ever end up modifying more there is a point where you'll need to anyway especially in the higher rpms