Tech Bench: Sound Good Live
By Ed Friedland
Tue, 18 Feb 2014
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Over the last few years, Tech Bench has looked at amps, preamps, pickups, hardware, electronics, and many other links in the chain of devices that ends with your bass going boom. Yes, it’s still “all in the hands,” but understanding the technology helps you determine what you need (and want), and implement your gear with more effective results. The bad news is: Even with the right gear and a great set of hands, you can still go to a gig and get crappy tone.

Every performance space presents a new sonic challenge, and no one faces this challenge more severely than the bass player. Bass frequencies are tricky to work with, the waveforms are big, they generate a lot of energy in an environment, and they’re often unregulated—you have the musical equivalent of a runaway bulldozer destroying all in its path. Sometimes the problem is a bad room, a hollow stage, the PA, or the “guy running sound,” but it could also be your fault—amp placement, EQ settings, volume, even your choice of instrument can potentially wreak havoc if not effectively interfaced with the environment. Once you start playing in public, knowing how to match your output to the performance situation is as important as knowing how to play.

For this next series of articles, we’ll examine some of the sonic challenges and ever-changing circumstances of gig life. Sometimes we have to “play the room” with just our amp, while other times, our rig is simply a stage monitor while the house PA does the heavy lifting. In some instances, you may not have a rig at all—you’ll plug directly into the system and will hear yourself through onstage or in-ear monitors. Your success starts with recognizing the specifics of the circumstance and working toward the goal of blending with the band onstage, and in the room.

First, let’s examine the culprit: bass wavelengths. High frequencies have short wavelengths, while bass frequencies have long ones. This explains why you can stand next to a cranked-up 900-watt amp pushing an 8x10 cab and still “not hear yourself.” The frequency of your open E string is 41.2Hz, and the wavelength at that frequency is a whopping 27 feet. So while you’re feeling nothing but a stiff breeze as you pummel out “Paranoid,” a guy 30 feet away just lost sphincter control. Bass frequencies tend to “mask” or bury other frequency ranges, so if the low end gets unruly, it takes over. While low end is our raison d’être, we must balance our desire to crank it with the musical needs of the moment. We’ll examine specific situations in the coming months, but for now, here are some general ideas to keep in mind.

Volume or Low End—Take Your Pick

In a perfect bass-world, you could play as loud as you want with tons of low end, and it would be great. I’m sorry to say, this is rarely if ever the case. Boosting volume and low end can overdrive your preamp, strain your power amp, tax your speakers, and sound like crap. Have you ever wondered if you could blow a 600-watt-rated cab with a 200-watt amp? Sure you can—crank the volume with lots of lows and mids, and kiss your cab goodbye. Boosting EQ adds gain. Take that into account when adjusting your sound.

Cut the Subs

Everyone loves their low end, but the corpulent sub-low frequency range is fraught with problems. If your goal is to flush a besieged despotic Latin- American dictator from his safe haven, pumping the subs will eventually drive him out—but if your goal is to hear what you play, they can work against you. First of all, most bass rigs are not able to reproduce this range; you are simply wasting power resources and creating a thick mess that interacts negatively in the room (especially if “sound guy” has subwoofers to play with). A variable highpass filter (HPF) comes in very handy, as it lets you tune the low-frequency rolloff point to what works best. Rolling off the sub-low range can actually make your sound seem fuller and more clear as the amp and speakers work more efficiently. Many small combo amps have a fixed HPF built in, while other amps include a variable HPF to help take out the offending sublows. Many outboard preamps designed for piezo pickups have this feature as well.

Mids Are Your Friend

Many players don’t understand how mids can help or hurt tone, but they’re quick to adopt the “smiley face” EQ curve that de-emphasizes mids, because they’ve read about it online. While over-emphasizing the lows can create one set of problems, scraping away too much from the midrange can cause a lack of attack and presence. The specific midrange frequencies you’ll want to work with depends on your setup and the room (among other things)— but in general, if you want more punch, instead of cranking the lows, first see what you can accomplish with low-mids. The 120Hz–250Hz range has impact and minimizes the “spill over” into the sub-range. The wavelength at 220Hz is about five feet, which means you will feel it, not the guy 30 feet away. Dialing in high mids can add clarity and presence to a dark tone without making it seem trebly. For example, sometimes I add a small peak at 1.2kHz to my passive P-Bass to bring out fingerstyle attack and detail, but on a particular J-Bass, I bring out a little 600Hz for the same purpose; the different pickup configuration changes which frequency accomplishes the same goal. But don’t take this too literally. Even two basses of the same exact make and model can require totally different treatment.

Avoid Coupling

No, you can still meet that special someone at the gig. “Coupling” refers to the relationship between your speaker cabinet and whatever it’s resting on. Whether it’s the floor or an elevated stage, when your cab sits on it, the vibrations are directly transferred into that surface and can exacerbate low-frequency issues in the room. Put your cab on milk crates, a chair, or something like the G.R.A.M.M.A. Isolation Riser from Auralex. You will hear yourself better and cause less mayhem. However, there are circumstances where you can use cab/floor coupling to your advantage, such as when you have to “cover the room” without PA assistance and your amp is too small.

Even these simple ideas can have a profound effect on your live sound, but never assume that what works in one room will work in another—pay attention to what you hear first, and then work toward what you want to hear. When you start thinking “big picture,” the answers to your sound problems are often obvious.

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