Flat is great for home stereos, headphones and interstate highways, but sometimes not so much for church sound systems.
On more than one occasion, I’ve been called to a church to inspect the facility for the purpose of designing a new sound system. Upon arrival, I discover that the church has perfectly adequate audio components that have been tuned and balanced perfectly inadequately.
It never fails - when I inform the owner that the system is fine and simply needs to be properly tuned, I get the response that the church has just paid somebody several hundred dollars to tune the system with pink noise and a computer, and thus, it is as close to “flat” as possible.
But these clients have been sold a fallacy: flat is always good, and flat is what you want.
Not so fast, and here’s why. About 40 years ago, home stereo systems began to improve exponentially. The ability of loudspeakers to exactly reproduce what was happening in the studio recording became extremely good, and providers of high-end stereo system equipment began bragging that the loudspeakers had nearly perfectly flat response. They were indicating to the potential buyer that the loudspeakers were going to exactly reproduce what the studio engineer had worked so diligently to create in the recording studio.
Without question, a stereo system with a perfectly flat response over the entire audio spectrum is indeed a wonderful thing to experience. So why is “flat” not the end-all and be-all?
As previously mentioned, the recording and mastering engineers go to great lengths to EQ every single track on a project to sonic perfection. These guys are true professionals at producing breathtaking audio, and they don’t want your home loudspeakers messing with their art. Therefore, a perfectly flat loudspeaker response should in theory reproduce a sonically perfect example of the original work.
Because many of us enjoy listening to music in the home (and some pursue sonic perfection with great zeal), it has become widely known that flat is good. Flat is desirable. Flat is what we want.
Let’s get back to our church. The technician we speak to about tuning the room tells us that he will use a computer analysis tool to determine which frequencies in the spectrum are deficient, which ones are too prevalent, and which are just right. He’ll reduce the overly prevalent and increase the deficient, until all frequencies in the audio spectrum are represented at the same decibel level. The system response is now flat. Oh good! This Sunday the sound is going to be awesome!!
But Sunday comes along and the sound is very thick, muffled and somewhat dull. Disappointment city. Why?
Because flat usually only sounds good if you’re playing a recording through it. Recall that the studio engineers went to great lengths to sonically shape the sound.
If your church is fortunate enough to have a quality console with lots of sweepable EQ on each channel and an engineer that really knows how to listen and how to mix, each individual channel can be tweaked to sound fabulous (just like they do in the studio).
On the other hand, if your console is closer to entry level and your Sunday mix engineer is a volunteer who is helpful and willing but perhaps lacks adequate experience, then it’s time to rethink the “flat” idea.
I own and use a spectrum analyzer, but the work doesn’t start there. It ends there.
First I get rid of feedback using the system EQ. Then I get rid of lingering overtones, and then I do some tonal shaping (again, using the system EQ).
How do I do this? By listening first (see my prior article about EQ). When I’ve got the system sounding as good as possible, I then fire up the Real Time Analyzer (RTA) to see what it looks like. I may find a part of the spectrum that is lower than it should be and will tweak it up a bit. Almost always, with very few exceptions, the midrange has to be reduced in relation to the lows and highs because the human ear hears mids more readily, and we need to compensate for that.
Take a listen to a quality recording of a singer you like. Notice how crisp and breathy - yet rich and full - that singer sounds. It doesn’t take a lot of listening to realize that the magical voice you have grown to love has been carefully EQ’d. We have to do the same thing with our sound systems in order to achieve that musical quality, both in speaking and in singing (and of course in all the other sound sources one can find in a church).
Technicians who tune systems by listening sometimes get a bad rap in the the pro audio industry. Computers and analysis programs are wonderful tools that help us in the field to achieve better results. There is, however, no computer that will tell you that if the sound is nasal you should reduce 1 kHz just a bit, or that if the sound is too boomy you should get rid of some level at 100 Hz.
If a technician tells you they tune by ear, ask for some references. You may be very pleasantly surprised. The system will be tuned nowhere near flat, but hopefully it will be crisp and articulate without being piercing, as well as rich, warm and full without being muddy or boomy.
Flat is great for home stereos, headphones and interstate highways. In our church sound systems, sometimes it’s better with some valleys and hills.
Originally published at ProSoundWeb
Jon Baumgartner is a veteran system designer for Sound Solutions in Eastern Iowa, a pro audio engineering/contracting division of West Music Company. Feel free to e-mail him with your questions at firstname.lastname@example.org.