Car Stereos: Headunit wiring, max output level, woofer box

Question
My headunit (Pioneer DEH-P4050UB) booklet says:

Max power output:
50w x 4
50w x 2/4 Ohm + 70w x 1/2 Ohm (for subwoofer)

Continuous output:
22w x 4 (50Hz to 15000Hz, 5% THD,4 Ohm load, both channels driven)

Load Impedance:
4 Ohm to 8 Ohm x 4
4 Ohm to 8 Ohm x 2+2 Ohm x 1

Pre-out max output level: 4V
Equalizer (3-Band Parametric)

Q1:Can i connect my Rear and Front speaker +ve wires with each other and negative to each other to power only 2 speakers so that they get more power? What will happen to Ohms?

Q2:My headunit says 40/80/100/160 Hz in low but in HPF and subwoofer its says 50/63/80/100/125 Hz so does that mean i wont be able to hit my subwoofer low as 30Hz? Even if my amplifier frequency says 30Hz?

Q3:What does Subwoofer(mono) mean? Mono?

Q4:Is a wider woofer box better or a deeper and what is the difference between woofer magnet inside the box and woofer face?I like low frequency and smooth bass with lot of vibrations rather than hard hitting bass.

Answer
Hi Ismael,

1.  No, you cannot combine the front and rear speaker outputs in this way.  This would result in the deck's internal amplifier shutting down for protection, or in lots of distortion.  You cannot combine any of the speaker leads on this head unit.

2.  When you set the HPF (high pass filter) you're setting the crossover point, below which the deck will begin to roll off the output.  For example, if the HPF is set for 100, then the deck will reproduce all frequencies above 100Hz without modification, but will begin to cut off lower frequencies starting at 100Hz.  The subwoofer filter works the same way, but it's a low pass filter, not a high pass filter.  In other words, if you set the filter for 100Hz, then all frequencies below 100Hz will pass.  Therefore, a 30Hz signal will reach the subwoofer without any reduction; only frequencies above the subwoofer crossover setting will be affected.

3. A "mono" signal combines the left and right audio signals into a single output.  That means if you're using a single subwoofer, it will play all bass notes, regardless of whether they're recorded on the left or right stereo channel.  If you use multiple subwoofers, they will all play the exact same output--there's no "left" or "right" subwoofer the way you have a left and right front speaker.  Subwoofers work best with a mono output.

4.  The volume of the subwoofer box is the only dimension that matters.  Provided the subwoofer can fit into the box, it doesn't matter whether you use a wide, shallow box or a cube-shaped box, as long as the internal volume is the same.

Hope this helps!

Brian