Speaker wire low voltage question

I’m working to install a sound ordnance b-8 using the high level inputs. I tapped the front two channels off the back of the factory headunit. The sub isn’t powering on so I got the voltmeter and it’s only reading 6-7 Volts at the sub and only 6-7 volts directly off the back of the factory head unit. Any thoughts to get a higher voltage so the sub powers on?

 

Need more info. Generally the aftermarket subs i have used have a 12v trigger to turn the power on/off. This is in addition to the signal wires.

 

My understanding was by using the high power inputs the sub would automatically turn on with the head unit. I could be mistaken though.

 

I'm going to try this now, thanks for the help. I believe my understanding of high level inputs was not correct.

 

The voltage you’re getting is normal from the back of the head unit

the manual for that sub doesn’t list an input voltage range so it’s hard to know for sure. Most powered subs like that would work with 6-7v. Double check your switch to make sure it’s set to auto. Super easy to overlook

 

I just want to make sure I'm understanding your setup. You use the speaker input to turn the unit on and provide the signal, but you also have the +12 and ground connected, correct? It's not a single line hookup, you need at least 6 wires going to the sub (front left +, front left -, front right +, front right -, power, ground). Also, there's a switch on the unit to select between high level input power on and remote +12 power on. Make sure the switch is in the right spot.

 

Thanks for all the help everyone! The way I had it set up was 12v+ from battery, ground to chassis, and speaker input wires I tapped from the back of the head unit (left front and right front signal). With the sub switched to auto it wouldn’t turn on so I ended up running a remote trigger wire and the sub functions as intended. I’m thinking the sub may have an issue with the auto on feature.

 

Not surprising. Lots of entry level subs and amps seem to have issues with it