Wednesday, February 24, 2016

Acoustics, Congregational Singing, and Carpet

The Sanctuary at Ashland's First United Methodist Church (AFUMC) certainly looks like it should be a great place for congregational singing. It is a big room with a high pitched wooden roof. But when I sing in the choir it is hard to hear what else is going on. It all feels a bit dead. When I sit out in the pews it is not an encouraging place to sing. When I play guitar as part of an ensemble, I play through the deadness hoping that the people in the sanctuary can hear a blend of the noise the instrumentalists are making.

The problem is--acoustically speaking--the space doesn't give much back. It is hard to hear yourself and it is harder to hear others.

What's the problem? It really shouldn't be this way.

When the congregation announced it was building a new church back in 1957, it had music on its mind. The Times Gazette reported on July 26 that “the chancel will be wide and open with room for 40 choir members on each side.” The sanctuary (including overflow seating in the narthex) “will comfortably seat 740.”

The current organ is particularly grand. Church historian Sidney Boyd recorded that First Methodist bought the “two manual Kimball” from Chicago in 1915. It was so large it completely obscured the stained glass window at the front of the old sanctuary . In 1949, the church spent $10,000 on a new consul separate from the organ so that the organ could be installed in the new church-- that's the equivalent of $100,000 in 2016! (Sidney Boyd, The Story of the First United Methodist Church, 1963).

Clearly the congregation spent huge sums of money so that the church--congregation, the choir, and the organ--would sound awesome.

But it doesn't.

Somehow the sound in the sanctuary, that should be so resonant, is muted and muffled.

The church has tried a number of solutions. A previous choir director area mic'd the choir and positioned monitors in front and to each side of them. After cluttering the front of the church with black boxes and wires, the problem remained unsolved. If the monitors were loud enough to overcome the deadening acoustic at the front of the church and satisfy the singers, then the congregation enjoyed squealing feedback. As an audio engineer explains: "The acoustical conditions of where a choir is will have a direct impact on the choir. You can’t ignore the acoustical environment of where the choir is because it will determine how they sound to each other and therefore how they will perform." In other words, amplification might help but it won't fix the problem.

When my wife took over the choir, we tried an acoustic solution--we ditched the microphones, and the monitors, and the cables and moved people and instruments around. I wrote about the experiment on this blog. It lowered the volume in the sanctuary and helped the congregation hear themselves sing -- but the sense of deadness and having to "push through" didn't go away.

I am not just being an acoustic snob here; this stuff really matters for the worshipping life of a congregation. I have been poking around the internet for the last couple of days and on an organ builder's website I found an excellent explanation of why acoustics matter in church.
Congregational Singing - Individuals want to join in singing if they feel the company of their fellow worshipers. Individuals will not participate if they feel conspicuous and alone. . .
Choirs - Individuals are more likely to join choirs if the room is acoustically suitable for their work. They won’t sing if they can’t be heard. The choir’s effect is greatest when its music sounds best.
Sermon - It is hard to hear a preacher whose energy is absorbed rather than radiated. It is artificial, and finally discouraging, to hear the voice only through loudspeakers. It feels more natural, and our response to the words is greater, if we can hear the natural voice.
The solution is plain, what you need are "solid walls, floor, and ceiling." What you don't want are "padded pew backs, padded walls, drapes, and carpet."

As you can see from the photograph, at AFUMC we have a massive thick and heavy set of drapes hiding the organ pipes and lots and lots of carpet.

Carpet, it turns out, generates amazing amounts of animosity from audio engineers. No superlative is left un-hurled in their attempts to get congregations to understand what a bad idea carpet is. Here are some of my favorites:
"Putting a choir on a carpeted floor is like pulling out their vocal cords." -- Art Noxon “Church Acoustics - Frequently Asked Questions”, Acoustic Sciences Corporation
"Wall-to-wall carpets kill congregational singing . . . As far as the choir area is concerned, I can think of no justifiable reason to have it be carpeted. If you ever expect music to be sung or played from the choir area, the only reason to carpet it is if your congregation's musicians are so bad that you really don't want to hear them." -- Evan Kreider “How to Deaden Acoustics and Seriously Damage Congregational Singing” American Catholic Press
"To sing in an absorbent room is as frustrating as to look at pictures in a room painted black." -- Ross King Co. "Acoustics for Worship Spaces"
And it is not just choirs that shouldn't be put on carpet:
"When a piano is played over carpet it dulls the sound. Try adding an office chair plastic carpet protector under the piano and you'll hear how it brightens up and starts to actually sound like a real wood instrument." -- “Church Acoustics - Frequently Asked Questions”
One of the ways to gauge the acoustics in a space is to measure its reverberation time. Basically that is how long it takes a sound to die away. Your bathroom with its tile, linoleum and mirrors has a long reverberation time and your living room with drapes, carpet and cushions doesn't. That is why you sing in the shower.

One of the sites I visited had this information: "A pleasing concert hall might have reverberation that lasts from 1.6 to 1.8 seconds or so (with audience in attendance)." It turns out that Cleveland's Severence Hall's reverberation time is 1.7 secs with a full house. Of course a church's acoustic requirements are different than an auditorium:
An auditorium has only one acoustical function, and that is to project music produced on stage so that the audience can hear it clearly. A room used for worship, on the other hand, has two acoustical functions. The first is identical to that for auditoriums: to project the sound produced by the choir, soloists, instruments, and preacher. The second function is to provide an atmosphere which encourages and supports congregational singing. Both acoustical goals must be met if the building is to be successful for worship.
I love being alive in the age of Google -- I found a site that taught me how to measure reverberation time and suddenly I had enough knowledge to be dangerous. All I needed was my digital recorder, a free piece of software called Room EQ Wizard, a balloon and a pin! I quickly found a willing assistant and we set to bursting balloons all over town.
Drapes, carpets and cushions at AFUMC
Here is what we found:
Screenshot of Room EQ Wizard in action.
With the sanctuary empty, AFUMC has a reverb of 1.453 seconds. Standing at the front (where the musicians are) the reverb drops to 1.367 (my guess is that the reverb time is quite a bit lower on a Sunday morning with the congregation there). 

What does this mean? After scratching my head over some complicated papers by acoustic engineers I found this chart that I could understand.
"What is a desirable reverberation time?" from Georgia State University's Hyper Physics site

So, even empty, by my amateur measurements AFUMC's reverb of 1.453 seconds falls into the "not a desirable place for music" category. And for the musicians at the front the 1.367 seconds of reverb puts us in the least desirable place in the whole sanctuary!

Perhaps my measurements were way off. I took my balloons to the university chapel which I know is a wonderful space in which to sing -- big hall, bare wooden pews, wooden stage.


2.883 seconds

We are in "fuller richer musical sound" territory. I am starting to develop sanctuary envy.


Shiny hard surfaces at CUMC
What can a church like AFUMC with its carpets, drapes and cushions do? The answer lies across town at Christ United Methodist Church. A few years ago they reappointed the front of their sanctuary. Away went the carpet and in came a laminate floor, and tasteful wooden choral risers. I have sung there on a number of occasions -- the choir has a full sound and the congregation sings with gusto.

On Tuesday afternoon I went in with my last two balloons (there had been 20 in the pack from Dollar General).


1.647 seconds

Back at Ashland First, the old worn carpet at the front of the sanctuary is coming out. The new carpet has already been purchased. It will, I am told, blend well with the carpet in the aisle.

It is time for me to say the serenity prayer and hope God will give me the wisdom to know which carpets I cannot change. The problem is that I prefer my serenity with lots of natural reverb.