With all our getting (of gear), we need to get understanding (of how to use it). This paraphrase of Proverbs 4:7 may not pass muster in seminary, but it is true in tech world. One important aspect of understanding audio is to grasp the importance of aligning acoustic signals in an enclosed space. It is important to note all frequencies travel at the same speed and there is no such thing as time delay, since time cannot be delayed, only signals can. When multiple sound sources generate in near time from various locations within the room, the sonic result can be displeasing to the ear. Here are some ways to clean it up:
Evaluate the sources and locations of sound generators used during the service of worship. The obvious ones are the main speakers and wedges monitors, but also consider the instrument amplifiers, any acoustic sources, such as drums and piano and ancillary speakers, both within and outside the sanctuary. Note the level and frequency make-up of each source and realize they all combine in differing degrees at every location in the room. Each of these devices creates a unique timbre, and does so from a unique location. Unfortunately, each listener is also in a unique location, so correcting arrivals for one seat creates issues in other seats.
2. Remove or Reduce
Remove or reduce as many secondary sources as possible. The popular trend away from floor monitors and to IEMs (In-Ear Monitors) is largely due to the detrimental backwash wedges create, and their elimination is a great start toward cohesive sound. Remoting guitar amps is another common way to take sound generation off the stage. Aside from commercial solutions, there are a number of worthy DIY designs available online. Finally, consider adding stage isolation gobos. These acoustic panels are easily home built and can dramatically reduce the time smear of piano mics picking up cymbals and other signals out of sync with their origin point.
3. Delay speakers
Get the delay speakers in step with the mains. Under and over balcony, along with front fill and side fill speakers, are often not delayed correctly to the main speaker system. The result is a cacophony of sound with no cohesion. A properly set delay speaker cannot be heard locally when the mains are on. Only when the mains are off should the delay be heard as a separate source. With DSP LMS (Loudspeaker Management Systems) available now for little money, it is a worthwhile investment to make. Setting the delay involves laying in output delay to the ancillary speaker in an amount equal to its converted distance to the primary cluster plus a few milliseconds added to reduce precedence of the first heard wavefront (the Haas Effect). Each zone of delays will need its own setting. Usually, the extreme highs and lows are rolled off and the level is kept below the threshold of perceptibility.
4. Consider Delaying the Entire Audio System
Consider delaying the entire audio system to the loudest noise on the stage. In a contemporary praise band setting, the sound system can be “aligned” to the snare drum if the acoustic signature of the snare impedes on the PA. A simple step is to measure the distance from the main speaker back to the snare drum and add that amount of delay to all the speaker outputs. For instance, if the snare is eleven feet behind the cluster, add 9mS delay to the LMS outputs. Sound travels just over a foot per millisecond (1130 fps) so the math is straightforward. This trick will often “tuck-in” the mains and delays to the stage energy for a tighter sound in the auditorium.
5. Make the Subs Part of the Solution
Make the subs part of the solution. There are several methods for pulling subs and mains together in a constructive fashion, but one simple path is to delay the subs back to the mains, either with tone and polarity or by measuring the distance differential. If the subs are on the floor, they will likely be physically in front of the mains, so delaying their arrival to the audience to coincide with the mains makes sense. If the subs are flown, they are in the same plane and should not need delay.
Creating a coherent arrival for all the sound sources in a room can make a world of difference in the performance of the sound system. Now that you have an idea of what to do, start dialing in some signal delay.