Figuring out the subs

by Dan Willis

Back in college at Penn State, we had a band called Wits End. If you’ve ever been to central PA before, you know that it’s pretty rural and not the best indie music scene around. With strict as hell liquor laws and having to be 21 in order to get a gig at the bars (as the baby of the band I was only 18) we had to suck it up and do 3 hour sets of covers at the frats, and then work in our originals here and there, which usually was the time everyone went to get another beer…don’t get me started. Anyway, we wanted to be self-sufficient rather than give away half our take to some guy from the local music store with all the live sound gear. So we threw all our money back into the band and got speakers, mics, a mixer, and all the right stuff to blow out your ear drums. The only problem was that the learning curve sucked and we ran into a ridiculous amount of problems, but none was more annoying than trying to get the subwoofers to work right. They would always clip and even though they were biggest and heaviest speakers we had, we could never turn them up very much. I mean, we wanted full body vibrators at just the right time. You know what it’s like looking at gigantic speaker cabs and not being able to rev those babies up? Well, we never figured it out and then the band broke up after we all graduated and moved away.

The Fix

What a crappy story that would have been if that was the end. Well, flash forward to a couple years later and I’m letting one of my friends borrow our old main speakers for a DJ-ing gig. Once the mains were setup and active, we realized that not all of the low end was coming out of the subwoofers when we hooked them up…same old problem. Now I’m not a technical guy, but my friend the DJ has been building speaker cabinets for close to a decade, so he explained to me that the speakers were out of phase. This essentially means the positive and negatives are switched compared to the other speakers, so that when the main speaker cone pushes out, the subwoofers were pulling in and vice versa. And then the weird thing was, almost that same day the old guitarist from the band emails me and says that he randomly found an article talking about the Peavy Kosmos (the piece of gear we used to split the mix to mains and subs). He said how if the “Quake” knob is turned up, most subs will clip because this knob is actually an EQ knob for a very low frequency that most speakers can’t handle.

So in the end, after putting the subs back in phase by switching the positive and negative wires on the cable insert and turning down the quake knob all the way to fix the other problem, those suckers just about kicked me in the nuts.