Acoustic Expertise: Club Sound
Jul 27, 2011 12:25 PM, By Bob McCarthy
Audio principles for nightclubs and bars.
If the system is poorly designed, poorly maintained, or just got completely reconfigured by last night’s mixer, it will be much more difficult to prevent a nightly round of build-a-band workshop. A well-designed and calibrated system should have no need for nightly adjustment of crossover points, amplifier gain trims, and most of all, limiter thresholds. Adjustment of any of these parameters will open a Pandora’s box of bad outcomes for the sound system.
The seating in a club environment will range from the edge of the stage to the back wall. The ceilings are generally lower than concert hall venues and therefore the speaker positions are often quite close to the front-line listeners. This informs the design of the main speaker system and also the peripheral systems. The main systems in small venues should be made the most compact arrays and not comprised of super-narrow components. Small spaces simply will run out of room before long arrays or extremely narrow devices can fully combine to create a uniform shape. The reality in small venues is that it will almost certainly be louder in front than at the rear. The direct sound from the musicians and the stage monitors make it very loud in front without any help from the PA. This is why front-fills are minimally required in these applications, and if used, should be fed by a matrix output that contains only the channels that are not already too loud off the stage. As we move further back into the venue, the PA becomes the dominant sound source (hopefully) and a balanced mix can now be spread over the room.
One of the casualties of club settings is sound image. In the near area, the image may be very realistic for the drums and guitars because the direct sound is what you’re hearing. But once we move out into the room, the sound image is destined to move out to the stacks. This not Broadway. We are not trying to fool anybody into thinking they are hearing unamplified sound. Spoiler alert: The lead singer is holding a mic up to her lips; I guess we are hearing the PA. In a club environment, things are so small that we don’t have to worry about the sound being out of sync to what we see. Therefore, the only type of image distortion we are concerned with is placement, and that concern is far down below making sure we have enough power and coverage.
One of the unusual aspects of club sound is determining where we don’t want coverage. This contrasts to a concert hall environment where we want to uniformly cover all of the listening area enclosed by walls and doors. Entry and service areas such as the bar are isolated from the listening space to keep noise in, and to keep noise out. In a club setting, the bar area and entry area are often in the same room as the entertainment. These are areas where patrons need to communicate with bartenders and other patrons. This is also the area where pickup lines are tried out. It’s hard enough to deliver these lines once so it’s a bummer when your well-crafted intro line is met with, “Huh? What?” Therefore, careful consideration should be taken to aim the speakers so that these areas are on the outside edge of the coverage pattern.
In a disco environment, for example, uniformity of level over the space would be a bad idea. Make it hot, hot, hot on the dance floor and then cool it down in the peripheral areas. This will allow the patrons to move in and out of the sound energy field and allow for in-depth meaningful conversation between the gyrations. Since the music never stops, it is important to provide the opportunity for a sonic downtime without forcing people out of the club. The LF range will still be present everywhere so people will still feel the music, but bringing down the mids and highs reduces ear fatigue and clears the vocal range for communication.
Which brings us finally to the background music side of things. There are a couple of cardinal rules about background music (BGM). Number one is don’t make it FGM (foreground music). Keep the level down so that it does not stop the conversation. Rule number two is don’t make it flat. Let the low end be the dominant range so that it sounds like speakers from far away. Why? This gives us the essence of the music and fills the gaps but does not compete with the conversation. Next: don’t use an audience level sensor that causes the BGM level to rise up as the patrons make more noise. It is bad enough that we are trying to talk over the noise of everyone else without adding an ever-rising tide of BGM to the mix. Sensor systems in clubs (and restaurants) should work in reverse, ducking out when the joint is jumping. The final rule is so important that it seems that no ever violates it, but I just felt like it had to be said: If there are music videos playing on TV screens, always play a different song through the speakers so the video people look even sillier than they would with their own song.
Hopefully these considerations will be of some use to you in your designs for nightclubs and bars. Bottoms up!
Bob McCarthy is president of Alignment and Design. McCarthy specializes in the design and tuning of sound reinforcement systems and conducts trainings around the world. He is the author of the book Sound Systems: Design and Optimization.
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