5 Live Sound “Gotchas”

Isn’t it great when everything goes right when you’re doing live sound? At least, that’s what I’ve heard. If that’s ever happened to you, you’re in a very select minority. The rest of the world runs into various glitches, and here are some common ones.

1. Revenge of the Subs

Isn’t it odd that those expensive, high quality, powered monitor speakers from a respected manufacturer don’t have any bass? That might mean it’s time to check whether the system defaults to expecting a subwoofer connection. If so, it’s going to power up with a crossover set somewhere around 100 Hz. And without a subwoofer, those low frequencies will be directed to…well, nothing, and no low bass will be the result. Many modern, powered monitor speakers, like the QSC K8.2, include an LCD or similar display. Watch it as you turn a data knob and push the accompanying switches to find out what happens when a system powers up.

2. Assault of the Batteries

Wireless mics are great—no cables to trip over, performers look cool holding the mic without the encumbrance of a mic stand (Freddie Mercury notwithstanding), you can pass them around to different people on a panel discussion, have one in the audience for questions, and more. However, what’s not great is when their batteries die. If possible, change the batteries before any major usage. But if your eco-friendly sensibilities and wallet have a hard time with that, use rechargeables—with wireless mics, their characteristic pattern of discharge over a few hours, then recharging, is ideal for long life. For battery chargers, Ansmann’s ENERGY-16-PLUS Fig. 1) is versatile: it can handle NiMH or NiCd batteries, charge up to 12 AAA or AA batteries simultaneously, and also charge D, C, and 9V battery types.

Figure 1: Batteries get a charge out of the Ansmann Energy 16 Plus.

It does microprocessor-controlled, “intelligent” charging, protects against overcharging, and tests batteries for charge (as displayed by LEDs). Ansmann also makes batteries, like a 4-pack of AA, 2650 minimum mAh batteries, a similar 4-pack of AAA batteries, and 9V rechargeable types—perfect for those battery-hungry, digital musical instrument effects boxes.

3. Be Adaptable

At a conference, a presenter is using a laptop and needs a stereo 1/8″ plug to fit in headphone jack. Another uses an audio interface, and needs two mono cables. A keyboard player uses the stereo headphone output in order to need only one cable, then splits it at the mixer. Get the picture? You need to be adaptable. Make sure you can accommodate stereo, mono, XLR, RCA phono jacks (they still exist), 1/8″ stereo jacks, and the like. As just one example, Neutrik’s NA3MJ 3-pin XLRM to 1/4” TRS female adapter (Fig. 2) takes care of when you need to plug a male 1/4” TRS plug into a female XLR jack.

Figure 2: With Neutrik’s NAM3J, males and females get along very well.

4. The Volume Drop

Let’s re-visit another possible issue with those wonderful powered monitors that default to expecting a sub: How come the output seems half as loud with this venue’s mixer compared to the last venue? Maybe the volume control was set differently, but maybe the problem is that the powered monitor is wired for a balanced, TRS connection, and someone patched it to the mixer using a TS (mono) cable, like a guitar cord. This won’t blow anything up, and the system will seem to work probably, but it will be half the expected level. The solution is simple: Make sure you have plenty of TRS 1/4″ phone plug cables on hand, as well as some XLR-to-TRS and TRS-to-XLR adapters.

Figure 3: This Rapco cable uses high-end Neutrik plugs.

By the way, when it comes to cables, sometimes longer is better, like Rapco’s NBLC-30 30′ model—especially if it’s a long way from mixer to powered speaker. However, sometimes a shorter cable will not only be long enough, but create a neater setup (and be less likely to get tangled up in other cables). It’s best to have an assortment of longer cables and shorter ones, like the Hosa HSS-010 10′ cable, or the Rapco NBLC-6 6′ cable.

5. You Forgot the Gaffer’s Tape?!?

Seriously? Then you might as well just refund everyone’s ticket price, and cancel the gig. From taping cables down to making sure people don’t trip and initiate an expensive lawsuit, to fixing that mic stand that just won’t seem to hold its position, to a zillion other uses, gaffer’s tape is a truly essential item to have on hand for any kind of live sound performance. Better yet, you can find products like the Rose Brand gaffer’s tape in various colors, from boring black that blends in with the stage, to colors bright enough to make sure no one trips over an errant cable.


Figure 4: Rose Brand’s tape will have you seeing red—or teal, electric blue, yellow, green, white, purple, or any of the other seven available colors.

Leave a Reply