Frequently Asked Questions
- I'm the organist at a church with a beautiful pipe organ in a historic stone church. I'm sure it sounded great in the old days they covered the floor with beautiful carpet years ago and lost the sanctuary lost its reverb. They won't remove the carpet to get the reverb back... Do you know of any clear paint I can use to remove the carpet's acoustics so I can get the reverb back into the sanctuary?
Carpets do absorb a lot of reverberation. Old school organ music is supposed to be played in highly reverberant rooms, where each note adds to the reverberant sound of the preceding note, creating chords without having to play all the notes at one time...... Modern organ music is written for electronic organs in modern, non reverberant spaces. You can hold all the keys down and not run out of "air" and no longer need the reverberation of the room to create chords.
I don't know of a carpet paint that improves the sound reflection of a carpet. Are you sure it is the carpet? Have there been any other changes in the building? Any remodeling work? Stain windows pulled out, replaced by Anderson windows? Why is the reverb of the sanctuary a problem now and it wasn't a problem 10 years ago?
I took the web site photo tour of the sanctuary..... I see: Red carpet downstairs, green pattern carpet upstairs and red cushions on all the wood seats. I think I see some sort of runner on aisles. There is a lot of sound absorption in this sanctuary already.
Which carpet is untouchable? The red downstairs or the green pattern one upstairs? I'll bet it's the red one downstairs. Can you get them to remove all the cushions and carpet out of the balconies? That way you'd have a reverberant top half to the sanctuary and an acoustic dead lower half.
Good luck and keep me posted...
- Our church is considering replacing the current carpeting. What are the various alternatives available and what impact do they have on the acoustics?
This is a classic question asked time and time again. Let's examine the impact of carpeting in the sanctuary. Carpets kill sibilance - the "tssss" "shhhh" sounds. This takes the life out of the sonic aire. Carpets have no effect on the vowel sounds - a, e, i, o, u. The issue with acoustics is, to a significant degree, the frequency response of the material. Carpet kills treble and does nothing to the bass.
Generally, carpeted floors are not good for congregational singing. They leave the singing space too dull and boomy. On the other hand, if you like the sound of your sanctuary with the current carpet, then you should replace the carpet with a like carpet. If it feels too dead, particularly for congregational singing, consider removing, rather than replacing, the carpet. As an alternative, you might consider Berber which has a very tight weave and does almost nothing to the sound, but it is rather expensive.
The point is that hard surfaces support congregational singing and, generally speaking, churches like to have bright and lively sounding congregational areas. Many churches have carpeted walkways and wood or concrete flooring under the pews. This way there is a quiet entry and exit path with a lively singing space.
Another carpet problem to consider is that 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. Choirs are plagued by the same problem. Putting a choir on a carpeted floor is like pulling out their vocal chords.
In contrast to this, putting carpet on the floors under the chairs in Sunday school and in office spaces is an excellent idea. The rooms tend to be smaller and there is a lot of "creature noises", such as shifting chairs, bodies, and papers. Carpet is great at quieting these noises.
Be sure you know the reasons why you want to change carpet before doing so. This will help you select the best solution for your situation. Remember, any change in the acoustics load will appear in the voice of the room. Carpet has lots of fibers which present acoustic friction. Removing carpet changes the amount of acoustic friction in the room, which changes the reverberation of the room.
- Our sound technician keeps complaining about echoes and feedback and always tries to fix them by buying new speakers and microphones and moving everything around, but the problem is never completely fixed. Is he doing something wrong?
This is exactly what people always try first. They generally exhaust themselves dealing with this very issue. They buy more and more electronic equipment without ever getting the improvement they need until they're finally ready to give up on the allure of electronics, sit down, and listen and learn about the world of acoustics.
Acoustics is a whole world, invisible to the eye, but very audible to the ear. Once the sound is launched in the air, only acoustics can help guide it to where it is supposed to go. That's what we do at ASC. We take over where the electronics leave off. Here is how we work: we get photos, floor plans, elevations, descriptions of the problem, and often times audio recordings from you. Then we estimate the probable cost for the "fix" for your particular situation. Now you have a budget to talk about. Once you decide that your ready to start working to fix the problem, we analyze the problem in detail, design and build the solution and you install it. You get to skip the middle man by purchasing the proper solution direct from the factory.
We can also work with your audio technician, train them to do the testing we need to analyze the room, provide appropriate photos, and conduct interviews. We do our homework before we invest any time in working up a design. We have to know what the rules are within the church so we can work within those guidelines.
To answer some of your specific concerns, you should know that it is the echoes that create feedback. Sound technicians are always fighting "gain before feedback". Improving the on-stage acoustics is one way to improve this. Eliminating echoes also helps to improve the mic problems. Of course, it is always a good idea to first check to make sure the sound system is set up properly and not aimed directly at the microphones. Beyond this, it is the acoustics that can make the necessary improvements.
- My church is undergoing an interior restoration/rennovation project. There are many things we are considering in our endeavor, but the one major object involves the placement of our church organ and choir. I have heard that the best acoustical position for the organ is on the main axis of the church. Can you confirm this or shed some light on this theory? What would be the best acoustical positions for the choir and organ?
First, it's important to note that the physical location of the organ keyboard is one thing and the locations of the pipes or speakers is another. The type of organ or keyboard can make a difference as to where to best place it.
An organ is typically played in a reverberant space. Organ music is written so that the reverberation left over from the prior note mixes with the sound of the next note to form a chord. It is important to protect the reverberant part of the sanctuary for the sake of the organ. The organ is usually located in a position that easily and loudly stimulates the reverberation of the hall in which it is located. If you move the organ, you change the relationship between the sound generated by the organ and the reverberation of the hall. The ceiling often has impact on how the sound is stored and diffused throughout the space. If you move the organ, it will change how the sound is fed to the ceiling, changing the way it sounds in the hall. Organs are often located along the centerline of a church so that they can stimulate as much reverberation in the room as possible.
It's a good idea to contact the organ manufacturer or installer before moving the organ. They usually have a lot of experience matching the organ to the hall.
Everything pertaining to the organ also applies to the choir. Except that the choir must also be able to hear themselves. Placing the choir in a gallery allows some of the sound to be held within the gallery. The choir sound heard by the congregation is "pre-blended" by the walls, ceiling, and floor of the gallery. This makes their sound sweeter, more full, and almost larger than life. The people in the choir can hear themselves and each other because they are essentially singing in a room that happens to have a large door (the opening to the rest of the church). Choir members who can hear themselves and each other better stay in tune and on tempo better.
If you move the choir too far out into the open they struggle against the thinness of their sound. However, there are some churches who tire of the old world sounds of worship. The reverberant organ and choir may no longer be a valued part of their service. Perhaps the organ is being moved forward to join a contemporary praise band. Likewise, the choir may be being turned into the backup vocalists for the lead voices in the band. In this case, gut the old gallery, turn it into a spotlight deck and get on with the show. But, be aware that now their is a whole new issue of acoustics to deal with: the interaction of amplified sound within your reverberant hall. (See FAQ above.)
- We are building a new sanctuary and we're trying to decide between flat or vaulted ceiling. Which would be better for the acoustics?
A shallow vaulted ceiling is better than a flat ceiling. Most churches build their vaults running front to back so that there is a high wall section at the front. However, a shallow vaulted ceiling actually sounds better if the vault runs side to side. This is because the sound is stored in the high volume part of the space, which is located under the peak of the vault. So, the sound is stored side to side in the area where the people sit.
Furthermore, people's ears are separated sideways so we are more sensitive to side to side sounds. People tend to like the spacious effect of side to side sound storage. A slightly sloped ceiling at the front of the church moves sound away from the front towards the congregation, keeping the launched sound clear and unmuddled. A slightly sloped ceiling towards the back of the seating area compresses the sound coming from the front making it louder for people sitting further away, which is good, too.
A slightly sloped ceiling still keeps the sound of congregational singing within the congregation, where it belongs, just like a flat ceiling does, which is good.
Flat ceilings are not good, though. All sounds that hit the flat ceiling are reflected back down to the floor at the same time. The timing for floor-ceiling reflections is the same everywhere in the church. This creates a horrible droning tone problem.
Remember that, no matter whether you build your church with flat ceiling or sloped ceiling, or which direction you aim your vault, you will still need to address the acoustics of the space. This means you will typically need ASC acoustical treatment on the back wall and on the side walls.
The front of the church is usually built with a raised stage that is carpeted. You'll want to make sure the stage is quieted from drumming and thudding sounds by building it with ASC WallDamp between the joints and filling the cavity under the stage with ASC SonicSnow. The front of most churches can be left fairly reflective.
Choir areas need proper design. Don't put them out in the open, they need reflections returned to them so they can hear themselves and stay in tune. Don't use carpet under the piano or choir. Carpet the speaking area and, if there is a praise band, you'll need additional ASC acoustics to get the loudness under control and to get the mics working right.
Use one central cluster for speech and two side mains for music. Only the soloist should sing through the central cluster.
Things always work best if you design the church from the beginning around the acoustics. After all, if people can't hear what's being said, they stop coming.