Mixing consoles and loudspeakers tend to dominate the discussion when it comes to church sound gear.
However, it is extremely important to consider the smaller components that can make a huge impact on the sound quality before the signal even reaches the mixing console.
Microphones and direct boxes are very common input sources, but there may also be a variety of other sources connected to the church sound system. Each type of device has its own special considerations worth learning about to ensure that the best quality signal is sent to the mixer.
Microphones can be wired or wireless. It is important to use the right microphone in the right place and for the right purpose. A poor choice in microphone or improper placement can result in bad sound quality that cannot be fixed in the mix.
For example, use a dynamic microphone for handheld close-up vocal use, but don’t expect to get great sound quality when placing the same mic at a long distance from the source. Use a more sensitive condenser mic for most microphone placements exceeding 6-12”.
Experiment with mic placement to ensure that the best sound is being captured from the vocal or instrument being miked.
>>Tech Tip: Use headphones during soundcheck and have an assistant move the microphone around an instrument until the “sweet spot” is found.
There are several instruments that can benefit from the use of a direct box instead of using a microphone to capture the sound.
A direct box, or DI for “direct input,” takes an instrument input and converts it to a microphone output.
Instrument cables should be 20’ or less in order to minimize interference on the cable. Using a direct box allows an instrument signal to be sent longer distances, like between the stage and the mixing console. This is an important step in maintaining signal quality.
Passive (unpowered) direct boxes are easy to use and have a basic audio transformer that converts the instrument signal to a microphone level signal (this is an unbalanced to balanced conversion). Active (powered) direct boxes can provide a boost in the signal level and improve the audio quality for certain instruments like the acoustic or bass guitar. Just be sure to use phantom power or batteries to provide power to active DIs.
Stereo direct boxes are available for sources with left and right outputs like keyboards and some electric guitar effects processors.
>>Tech Tip: Always use a quality direct box to send instrument (unbalanced) audio signals from the stage to the mixing console. It may be ok to directly connect an instrument to the console if the total cable length is less than 20′.
Computers & MP3 Players
It is easy to connect a computer or MP3 player to the church sound system with the right equipment.
The biggest thing to know about this type of input is that both the left and right signals need to be sent to the sound system, even if the sound system is operated in “mono” mode (e.g. not using discrete left and right loudspeaker channels).
While there may be long 3.5mm stereo cables and other adapters available to connect an audio player to the sound system, it is best to use a direct box that can properly convert the signal and maintain the best sound quality.
Some direct boxes can combine the left and right channels to a single mono output so that the sound system receives both channels at the same level. Like instruments, it is important to use a direct box for any unbalanced audio input using a cable longer than 20’.
>>Tech Tip: Use a converter like the Radial Stage Bug or Whirlwind podDI for stereo-mono conversion. Use a true stereo direct box like the Rolls DB24 or Whirlwind PCDI for discrete left and right channels.
Wireless & Digital Inputs
Besides using wireless microphones, there are a few other ways to transmit digital audio from a device to the mixing console.
The most important consideration with any sort of wireless transmission and digital conversion is delay (also known as latency). Audio signal delay can be a big deal for mixing live sound, especially when using Bluetooth wireless transmitters and receivers.
Standard consumer quality Bluetooth transmitter/receiver units are often limited in range and have too much latency to be truly effective for live sound reinforcement.
Another big issue is audio quality. Cheaper Bluetooth devices can use a lower standard for converting and transmitting the audio signal, resulting in limited bandwidth and low-quality sound. (Consider trying the Radial BT-PRO or Switchcraft 318BT AudioStix.)
WiFi audio transmission can be a useful method when using the right devices. Connection reliability and distance limitations can also apply to this type of wireless transmission. And it is important to carefully manage the wireless network for other traffic that may interfere with wireless audio transmission.
Sending and receiving audio via USB can be a great way to capture clean digital audio if the mixing console supports the digital input. Many digital consoles have a built-in USB port for use with computers and USB drives that can play digital audio files.
>>Tech Tip: It is important to thoroughly test any wireless or digital audio device before using it in a live situation. Make sure the signal quality is good and that there is minimal delay when sending/receiving audio.
Garbage In, Garbage Out
Ultimately, the goal is to capture great sounding audio so that it can be properly mixed and reinforced.
Even with some advanced EQ tricks and processing options, there is very little that can be done to truly fix bad sound quality if an audio source doesn’t sound good going into the microphone, direct box, or mixing console.
Using the right gear for the right application will go a long way in helping you get great sound.