So, this whole tome I’ve been doing it wrong. I’ve been using the charts as what my amp produced, not what my speakers are rated for. That being said, since I have 4 hertz hcx wired in parallel, my resistance on the circuit is 2 ohm even though the speakers are 4 ohm. So, do I use 2 ohm as my starting point on the chart, or 4 ohm?

 

You will use the the 2 ohm column on the chart because your amp will be seeing a 2 ohm load from the speakers wired in parallel.