setting gain with ddm subwoofer setting h/u

[plugger 10+ year member]

so how do you tell how many watts your putting out? what kind of amp meter do i get? what do you have the amp gain set at to test this? and what do you turn the HU volume to?

 

[Atimm693 10+ year member]

so how do you tell how many watts your putting out? what kind of amp meter do i get? what do you have the amp gain set at to test this? and what do you turn the HU volume to?

Any kind of AC clamp meter will do. Here is the Harbor Freight model.

Digital Clamp-On Multimeter

You will have to set your multimeter to AC volts and connect it in parallel with your sub leads. Set the clamp meter to AC current and attach it however the manual says to. It probably just clamps around the wires, no "hard" connections anywhere. It picks up the magnetic field around the wire.

With those connected, set your gain at zero. Play your HU as loud as you will ever have it.

Watts will be calculated with the two readings. Multiply the current in amps (clamp meter) times the voltage (multimeter) and that number is the power in watts. Turn up the gain until you get the desired power output.

 

[OmegaBunny 10+ year member]

In theory you can use a dmm to set output. i.e. acv x aca = watts. What people arent stating is that by doing this and using the manafacturers rating you are most definately putting it in full clip.
Just do it old skool. Set hu volume to 3/4 and slowly bring gain up on amp. Set lowpass to 80ish and ssf 5hz below your box tuning. I never and I repeat never run my sub output above half. Hell most of the time I barely touch it i.e. +1 or 2. Let the amp do the work.

This is good advice if the person knows what they are looking for but unfortunately many won't know the difference between a clipped signal and a clean one. When starting out its hard to differentiate between what clean bass sounds like and just bass, especially in a car environment where you can have rattles from the trunk, doors, etc. Someone may try this and not differentiate between bottoming out and trunk rattles and have not idea something is wrong until the VC burns up or suspension gives out.

 

[thorshammer1 10+ year member]

Long Long Long before the internet, forums etc... installers around the world used and employed the method I suggested. They werent concerened about getting every watt out of thier amps and no shop worried about clamp numbers. Hundreds of thousands of installs all done this way with no problems lol

My pt with using the ddm method is that it is not guaranteed to provide a clean signal.

There comes a pt in the gain in which it just doesnt get any louder. Guaranteed once you step beyond that it is clipping. You dont need a scope to know this. With all settings at 0 its easier to hear when that is. I dont know about yall but I pay alot of attention to my sub. I know what it sounds like if I jump gap(rattle pole), means turn it down lol I'f I'm seeing the peak of my surround, turn it down, if over the course of a song I smell something remotely like coil, turn it down lol

I'm a huge supporter of knowledge is power. Sometimes we just over think things.