I'm getting very low volume from my speakers, even though the volume is turned very high- level 39 as well as crackling.

I just bought a Plymouth Breeze '99 with a DEH-P940MP head unit and 6x9 Planet Audio Model No. P693 speakers in the back. (Unsure in the front). The head unit offers 50W x 4. The Planet Audio rear speakers are 75W. So, if the front speakers are 50W (guessing) then my speakers require a total of 250W and my head unit is offering 200W.

The previous owner removed his amps and left the wires exposed, where they previously connected to the amps. I've re-connected the speakers direct to the head unit.

I think these speakers are underpowered and thus I am having the low volume and the crackling.

Is this correct? I don't have any money for an amp- at all. I know this is what you'll recommend but I really don't have any cash and no car audio friends.

This deck offers a 3-way network mode as well as a Standard mode. The 3-way mode offers the ability to create different sets of amps and speakers for low mid and high ranges.
I'm worried that the system is set for this advanced config (because he had two amps- one for sub and one for speakers). From what I've read in the manual, you can change the mode by a physical switch on the SIDE of the headunit (thus I have to uninstall it).

1. Is there anyway I can direct all power to the rear speakers? (Just combine the wires together) and thus send more power to them? IE: 50W times 2 wires = 100 W per speaker?

2. I've looked through EVERY menu on the stereo to check if there were any customizations to change, to verify if there are custom settings (IE; send only highs to the rear, etc.) I've also reset the processor on the head unit.

Thank you for reading. Any suggestions on what I can do other than buy an amp?