Is it advised to turn up the volume knob on the sub woofer itself or to boost the sub woofer signal from the reciever.Which is advisable and what is the difference ?? My onkyo has a boost till 10 db i keep it on 5 as of now and my sub volume is at 12 o clock position, sometimes when i want more bass should i turn the sub volume knob up or boost the signal from the reciever??