It’s important to note that these levels are high enough to trigger the human auditory system’s natural protection mechanism. Threshold shift occurs when the ear is desensitized due to exposure to loud sounds, and no one is experiencing this more than the musicians on stage.
If one musician “cranks it” a bit due to threshold shift, the others have to compensate to keep the same balance.
Since they can’t turn the first musician down, they can only turn themselves up – and the “arms race” is on. The drummer doesn’t have a level control, so they simply play harder to keep up. This sets a new base line level on stage and the balancing act starts all over.
If the instrument levels increase, floor monitors must be turned up to maintain balance, hence the common “we need more monitor” pleas from the musicians.
If the monitor levels are increased, the house level must go up to maintain the balance, so the already uncomfortable audience gets a little more uncomfortable.
If the house system is held at the same level, the monitor spill dominates and the overall sound is mushy.
So it’s a no-win situation. It’s either going to be too loud or it’s going to sound bad, and all because the stage level is too high.
None of this is news to anyone who has operated a sound system. I merely put some numbers to it for clarification and to point to the obvious and only solution. The bottom line is that the levels from the stage often force the levels produced by the mains to exceed the comfort limits of the audience.
And since we can’t redesign the human hearing system, the only solution is to start with the desired level of the house system and work backwards.
More Logical Order
First, let’s start with the maximum level that we can operate the house system at: 95 dBA-Slow. After all, there are probably hundreds of audience members and only a few musicians.
To maintain the desired S/N ratio, let’s set the level of the monitors at -10 dB relative to the house system. This means that the monitor “spill” should not exceed 85 dBA-Slow in the audience. To be generous to the band, we’ll compromise and allow the level on stage to be 85 dBA-Slow and rely on the distance between the stage and the audience to provide the needed attenuation.
You’ll remember that the on-stage level estimated earlier was 105 dBA, so the stage level is 20 dB over the 85 dBA that is acceptable. Something’s gotta give! The electronic instruments have volume controls so we can just turn them down.
But what about the drummer? He or she will have to “back off,” something that is not as easy as it sounds.
Other solutions include using brushes instead of sticks (most drummers won’t like this suggestion) or using electronic drums (they might not like this either).
There are other band-aids (pun intended) such as plexiglass panels or even a drum cage. And assuming that we can get the drummer’s level under control, there are still the floor wedges, instrument amplifiers, etc. It’s easy to see why in-ear monitors and electronic drums are growing in popularity!
While the actual numbers will vary due the many variables involved, we can conclude that unless a system operator keeps the stage level under control, the house sound is either going to be too loud or it’s going to be dominated by the monitor spill.
The arms race between mains and monitors is responsible for degrading the sound reproduction in many, many venues of all types. Do we please the audience or the musicians?
Both, preferably.
More Church Sound articles by Pat Brown on PSW:
Vital Impact That Acoustics Can Have On Sound At Your Church
How To Illuminate The Audience With Beautiful, Consistent Audio Coverage
Proper Loudspeaker Placement: How To Avoid Lobes and Nulls
Ten Reasons Why Church Sound Systems Cost More
What Makes A Quality Loudspeaker?