jimy

2007 Base Coupe. Arc Audio 4 channel behind the drivers seat, Focal Components in the door and a single 10" sub and OEM HU. The plan is to run the door speakers and the sub only. I got all the engine whine out by separating wires. But, I have like a light hiss coming from the door speakers. Does not go with the RPMs. And, it is still there when the radio is off. Is there anything I can try to get that out?

markcz

With the car on or in accessory mode, but the radio off, does turning down the gain adjustment for the front channels make the hiss change volume or go away?

jimy

That's it! I turn down gain, hiss goes down and away. With radio on and off. So, I turned the gain to 30% and we ok. But, is that what I have to settle for? When I had it at 60%, it sounded great. Is there something I can do to get the gain up and hiss go away? Never had a hiss in a system with the radio off. I figured if the radio was off, the system should be killed and nothing should be heard.

markcz

Part of the problem is the way the OEM radio keeps the amp turned on even when the radio itself is off.

Do a quick DIY 'tune' on your amp and see where it ends up...

Download test tones HERE

Turn down all amp gains to 0

Play the 50Hz tone and set radio volume at about 75%

Turn up sub gain until you hear distortion, then back off a touch. Note the level and turn it back down to 0

Play the 1kHz tone at 75% volume and turn up front gain until distortion, then back off a touch.

Turn radio volume down and turn it off.

Adjust sub gain back to level noted during test.

Play several songs that you're very familiar with, listen to balance between sub and fronts. Since both are set at maximum distortion-free level, if not balanced turn down the one that is overpowering the other (fronts vs. sub).

This would be the ideal level for your amp gains. If you still have the hiss, then turn down both gains evenly to a point where you can live with it. If you're lucky the max level won't have much hiss.