Dance club sound system installation
Crutchfield designs a very loud and highly reliable system for a popular college-town nightclub
In the 1950's, I'd take the family television's vacuum tubes down to Willow Grove Radio and TV Repair, check them with the giant tester machine, buy new replacement tubes, and reassemble the repaired television, so my mom and dad could enjoy their precious, respectively, Dean Martin and Red Skelton shows. In the 1960's, I studied radio and electronics at the Franklin Institute in Philadelphia. After college, in the early 70's, I joined a rock 'n roll band as the soundman, learning how to operate the electronics that make music sound good. Then, I worked in a music store in Austin manufacturing, installing, repairing, and operating sound systems and components for recording studios, nightclubs, and touring bands. I moved back to Charlottesville permanently in 1984 and opened a little demo recording studio. I also attempted to put to practical use the creative writing degree I had picked up along the way. In 2006, I finally came to my senses and got this job at Crutchfield where they actually pay me to ramble on, rant, and explain the things I love about music, electronics, and getting good sound.
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Trinity Irish Pub, a busy nightspot near the University of Virginia, presents DJ music and dancing four nights a week. The club wants to entertain its patrons with hard-hitting music that will keep them coming back night after night.
Unfortunately, most of the speakers in their old system blew out after being played too loud for too long. The club needed better speakers and more power.
Dallas, with the amplifiers, speaker management device, and power conditioner
Dallas, one of Crutchfield's Pro Audio Specialists, worked with James, one of the house DJs, to come up with a system that would fit the size of the venue, put out enough sound so everyone in the crowd could feel the beat, and stay within the club's budget.
System design goal number 1: must be loud
Both James and Dallas like the way JBL speakers sound, so they started there. Dallas knew that to attain proper coverage in the room, the speakers would have to hang close to the ceiling, pointing downward, and handle about twice the power than the old speakers could.
System design goal 2: must be bullet-proof
"I wanted to make sure they had a perfectly matched system with PA management features," Dallas said. "Using the dbx DriveRack makes it a perfect system that can easily be setup and recalibrated as needed. Guest DJs simply plug in their rig and the system is set up so they can’t damage anything." And because restaurants and clubs usually have very inconsistent and noisy AC power, Dallas made sure the system included a power line conditioner and surge protector.
Here's the list of gear they decided to get:
JBL PRX412M 12" PA speakers (4): One of these speakers at each corner of the 20' x 30' dance floor provides full coverage.
JBL PRX418S 18" subwoofer: This 18" subwoofer really digs down low and puts out a terrific thump.
Crown XTI 4002 power amplifier: Powers the 12" PA speakers (2 speakers per channel, 600 watts per speaker).
Crown XTI 2002 power amplifier: Provides 1,600 watts of power to the subwoofer.
dbx DriveRack PA+ speaker management system: Limiter circuit protects the speakers. Auto EQ tunes the sound to suit the room.
Furman M-8Lx power conditioner: Protects the system from AC power spikes and eliminates noise that may radiate from the club's wiring.
It's no coincidence that the speakers, subwoofer, and amplifiers all have the same power ratings; JBL, Crown, and dbx are all part of Harman International, so their gear works well together.
XLR plugs for guest DJ rigs.
Tailoring the sound to the room
The dbx DriveRack PA+ includes a real-time analyzer (RTA) which, when you connect your calibration microphone, illustrates the sonic spectrum that results from the PA speakers' interaction with the room. This helps fine-tune a system to sound great, with no boominess, or shrillness, or unintelligibility to the sound anywhere in the room.
The DriveRack generates the calibration signal and uses dual 28-band equalizers to automatically shape the tone so all the frequencies sound right. Dallas set up a calibration mic in the center of the room, to make the measurements at an average listening position. He then chose the "DJ setup" preset for the target EQ curve, and the DriveRack's Auto EQ Wizard did the rest. Normally, one would then engage the automatic feedback suppressor at the end of the process, but the DJs at the Trinity Pub don't use microphones, so that feature wasn't used.
DJs John and Brian rocking out in the daylight
We rocked the joint
We visited the dance hall during the day, when it was empty and not packed with people as it usually is on dance nights. But DJs John and Brian cranked up the music for us anyway and it was crystal clear and plenty loud. The subwoofer provided a thick, driving beat that had most of us nodding along. If the daytime chaos created when the music played is any indication, every night must be a regular riot. An extra benefit of the careful speaker placement is that the sound stays focused and concentrated on the dance floor alone, and does not blast the other bar areas, where people want to talk.
Experienced professional installers mounted the four 35-pound speakers securely.
The Trinity Irish Pub has become the place for the college crowd to dance on Thursday to Sunday nights. It's so popular that they often have to turn people away at the door. "The system plays loud and clear and people can't get enough of it," DJ John said. "The new speakers sound awesome and really help make each dance night a blast." Check out the Trinity Irish Pub's system yourself — they're at 1505 University Avenue, Charlottesville, Virginia.
You want one too?
If you need help designing a sound system for your business, school, or church, call 1-800-555-9369 and talk to a Pro Audio Specialist at Crutchfield.
The Trinity Pub dance floor at night