Facing the challenges of a PA head on.
Most of my gigs involve going from a bass to
an amp to the audience’s ears—PA support
is rarely part of the equation. But as soon as
there’s a need to get bass into the house system,
things begin to feel precarious and the
challenges are many. Some potential problems
are within your control, but for others, you
have to hope for good luck. Let’s take a look at
some of those possible problems and what you
can do to avoid them.
Keeping the Level Level
Sound level needs to be considered in two ways: stage level and DI level. Stage level requires a tenuous balance between being heard onstage and not being heard in the house. Send the bass to the board through a direct box (or the pre-EQ setting on an amp’s internal DI), then tweak the amp for a clear onstage sound, rolling off some bass while boosting those mids that pop right out of the mix.
In other words, pushing the low end doesn’t help you hear a bass better onstage. Instead, bump up the mids on the edge of a note. Avoid that smiley-face EQ that scoops out mids while emphasizing lows and highs—it might sound fine at home, but it’s guaranteed to get lost once everybody starts to play.
Regarding the level to the soundboard, the DI built into an amp often sends a hot signal— sometimes too hot. When that happens, the bass sounds distorted in the house and the attack of your notes crunches, maybe even getting to the point of a full-out distortion. One way to manage your direct signal is to turn down your amp’s DI level. Another is to carry a DI pad adapter that knocks down the signal by 10, 20, or even 30 dB. Another good route is to use an external DI box, since these don’t usually add any gain to a bass signal.
Getting a Buzz On (and Off!)
The stage is full of opportunities for hum and buzz. Light dimmers and single-coil pickups don’t mix well, but dimmers are tough to avoid. Ditto for power coming from a generator. One source of buzzing that can be controlled is the ground loop. You have a good chance of ground loop buzzing if you use your amp’s DI, but most amp DIs and DI boxes have a ground lift switch. If you hear a buzzing when the amp powers up, flip the ground lift switch to see if the buzz goes away.
Some of my amps don’t have a ground lift option, though, so I carry a ground lift adapter that can be plugged into the cable going to the PA board. A sure-fire fix is to use an external box instead of the internal DI—these all have a ground lift switch.
To DI or Not to DI
That is the question. Whether ’tis nobler to stick with a DI or to mic the bass cab presents a bassist with a sea of troubles. Using a mic adds yet more “water” to the “sea.” As soon as a mic becomes part of the equation, the tone and volume coming from the cab make a sound person’s job more challenging. It’s no longer possible to thin out the onstage tone for clarity. Even the type of mic and where it’s placed on the speaker make a sonic difference.
My preference is to use an amp’s direct out and then make sure that the sound tech gets a good signal that’s not too hot and doesn’t buzz or hum. A second choice would be a good, active DI box that I’ve brought along and know. The third choice is to use the house DI box—many of these are cheap, passive devices that send a crummy sound to the house and a worse tone to my amp. An active DI, in contrast, buffers the signal to retain the sound I’m after, especially with a passive bass.
Enter the Sound Tech
Beyond your choice of direct out options, the sound tech you’re working with can make all the difference. If the tech suggests using a house DI box, consider that suggestion. You can always ask to use something you’ve brought along, but be sure your signal level is right for the soundboard and that there’s no buzzing from a ground loop.
EQ is the other challenge. For some reason, many sound techs like to show off that their PA system has big subwoofers and powerful amps—that’s my theory anyhow. The result is a muddy bottom, with the bass buried beneath a kick drum strong enough to restart a failed heart. If you can, have somebody go out front during the soundcheck and make sure that the bass is not overpowering on the low end (and make gentle suggestions to the tech about changing the house mix EQ).
In all, when you need to go into the house sound system, the risks abound for producing a less-than-perfect tone. Keep these ideas in mind and you’ll have a better chance for success.
Dan Berkowitz is a professor by day and a bassist when the sun goes down. He plays in blues, jazz, pit, and classical settings. You can reach him at firstname.lastname@example.org