Can You Use A Powered Loudspeaker As A Bass Guitar Amp?

Working with accomplished Bass Guitarist Andrea Bensmiller and The Live2Play Network we substituted a QSC K12 Powered Loudspeaker for her bass guitar amplifier at a Las Vegas club gig. It was a pretty gutsy move for Andrea, not knowing whether her instrument would have the sound and punch she was used to, or if the speaker would even hold up under such a grueling test. If it does work, it'll give musicians one more way to adapt their gear to the size of venue where they are playing. In Andrea's words, "I end up hauling an enormous cabinet just for me onstage, which is stupid, because the house guys take a line out and I can't hear what's onstage anyway. I use a small amp for this gig usually-but it's SO NOISY once I get it up to compete with the guitars. My big rig for large rooms is an ampeg 4x12 cabinet (125 lbs) AND a racked head (another 40). And it's only 800 watts. ! Like I said...STUPID."

In the not distant past, plugging a bass guitar into a powered loudspeaker usually resulted in a toasted speaker. However, with all the gains made with loudspeaker construction, Digital Signal Processing (DSP) and amplifier design, that's all changed. But to what extent? Bass guitar amplifiers are purpose-built for bass guitars, whereas powered loudspeakers are designed to be used Front Of House or as stage monitors. So, we wanted to find out if an off-the-shelf powered loudspeaker could actually stand up to the torture of being used as a bass guitar amp for one night in a Las Vegas club. One company, QSC Audio based in Costa Mesa, CA was up for the challenge and loaned us one of their K12 models for this test.

I've personally used the K12 (as well as the larger KW152-see links list below) on a variety of DJ and sound jobs. Thus far, they've never let me down. The built-in mixer is especially handy for those occasions when all that's needed is a place to plug in a mic or instrument. The trapezoidal shape allows for easy adaptation to stage monitoring. QSC's K12, with a 12" cone transducer and 1.75" diaphragm compression driver, is largest 2-way powered loudspeaker in the K Series. The maximum SPL is 131dB and coverage is 75° axisymmetrical. all of the K and KW Series speakers use a 1000 W continuous (2000 W peak) Class D amp (500 W LF, 500 W HF). A built in 2-channel mixer offers balanced and unbalanced connection points for male and female XLRs, 1/4" and RCA plugs. Constructed of impact resistant ABS, the K12 weighs just 41 pounds.

So, with all that out of the way, Andrea loaded up her gear and headed out to The Boulder Dam Brewing Company to perform with the Justin Mather Band. Used to hauling around a bass amp that weighs close to 80 pounds, she found the K12, at about half the weight, quite refreshing. As bass amps tend to be non-directional, most player find that for a gig of this type, the best place to put the amp is right behind them, so they can hear what they are playing. Being that the K12 needed to be stand-mounted, the only place it would fit was off to the far side of the stage away from Andrea. Here's a short video shot at gig.

The morning after the gig, we caught up with Andrea to get her impressions while they were still fresh in her mind. "It was an interesting change not having an amp on stage but to be using a speaker with a completely different profile-The K12 sprays with a 75° angle, whereas I'm used to having the amp right behind me. It had a really, really nice round, beefy bass tone and, more importantly, even at higher gain it was super clean—Justin really liked that there was no noise.

There was only one thing I didn't like about it-without any processing between my bass and the speaker, it lacked a bit of high end attack, so when I wanted to get some 'punch,' like when I was soloing, that wasn't there, and when slapping and popping that high end wasn't quite there. So, if I did this again I would either put a compressor or an EQ in between my bass guitar and the loudspeaker-that would have solved the problem completely. Using a powered loudspeaker is really a very interesting idea for musicians-I was really happy with it, it's a cool, cool tool."

The band is the Voodoo Cowboys playing at Roxie's in Sam's Town Casino, Las Vegas, NV. Matt-never having used it before-plugged his guitar, pedals and a Tech 21 pre-amp into a QSC K12 powered loudspeaker and used it as his only amp for the gig.