Subwoofer Sounds Muffled

Hello. I hope you can help me. I have 2 Habringer v2212 (active) 600 watt speakers. They sit in my living room. I have them connected to a Yamaha M606x (6 input mixer).. This mixer has the following Inputs: 2x mono [mic/line] & 2x stereo [line]. Outputs are 2x stero out and 1x headphones I also have a Behringer Professional 2000-Watt PA Speaker with Dual 15" Woofers and 1.75" Titanium-Diaphragm Compression Driver (Model VP2520). This is connected (speakon to speakon) to my Behringer EPQ2000 Europower 2000W Lightweight 2-Ch Power Amp. This amp specifications: Output power: 500 watts @ 8 ohms per channel/700 watts @ 4 ohms per channel RMS; 600 watts @ 8 ohms per channel/1,000 watts @ 4 ohms per channel peak R26; Input impedance: 10 k ohms unbalanced, 20 k ohms balanced R26; Frequency response: 20 Hz - 20 kHz, 0/-1 dB R26; S/N Ratio: >100 dBA R26; Dimensions: 3.7" H x 19.0" W x 10.6" D (94 x 483 x 269 mm) R26; Weight: 15.4 lbs. (7.0 kg). The amp set to "crossover", the mode is set to "stereo" & the "limiter" is on.I have a numark Mixtrack Pro plugged tnto the M606x using its rca jacks to the mixers "phones"A young lady at the Guitar Center who seems to be very knowledgable gave me the following set-up:Mixtrack Pro into RCA- 1/4 in line 3/4 of the mixer. I became confused relating to each of the XLR coming from each of the active speakers. I am not sure if I should daisy chain these speakers or connect them individually into the mixer 1& 2 channels. As a result, I connected the speakers into the mixer seperately on each channel of the mixer. Then as the young lady indicated, I am using the "headphones" output to connect to the amp through it's rca jack. I used the 1/4 jack with the rca male end on it.My 2 actiive speakers sound great. My sub sounds muffled. I know something is not connected. What am I missing here? I appreciate any help!!