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Posts Tagged ‘technology’

What will give you the biggest bang for the buck in upgrading the Sound of your church?

Posted by jdbsound on May 2, 2018

This 300 seat church already had a reasonable high quality sound system.  It was properly designed for the room and professionally installed. The acoustics were not that bad.  At least it was thought that the acoustics were not such a problem.  The outstanding issues they were trying to solve or improve were:

  1. Gain before feedback,
  2. Elimination of the few deadspots that were not solved from the previous sound system when the current new JBL speakers were installed
  3. Reduce sound spill from floor monitors,
  4. Better control of the drums (when using acoustic drums) and
  5. They wanted 3dB more bass from the Sub-woofer.

These are all reasonable reasons to upgrade the sound system.

Good Speaker System setup_s

The church was considered the following upgrades.

  1. Replacing the professional designed and installed 12 year old JBL sound system.
  2. They considered going for IEM (in ear monitor) system for up to 8 people. (This would have included a new digital mixer)
  3. The church considered making an air conditioned drum booth or get an electronic drum kit.
  4. They also wanted to add a second twin 15 inch sub-woofer.
  5. Estimated total cost, almost $26,000.00 installed.

This is what the church actually did. They changed the acoustics of the room.  They installed an acoustical Tube Radiator system.

What did they gain by doing this?

  1. The sonic quality of the existing JBL speaker system was greatly improved. The improvement was noticeable better regardless how much equalization was added or when the EQ was bypassed. (Definite proof that the acoustics of the room changed the performance of the speaker system from the day they were installed.)
  2. All of the remaining deadspots were now gone. (This was never a speaker system problem as the right speaker system design was already installed.)
  3. The performance of the speaker system was such that picking up a person’s voice went from 12 inches to 35 inches with a Shure SM58 mic before feedback would show up. (Again, acoustics limits the performance of all sound system. Sure there are some very expensive gadgets that can improve gain before feedback, but such gadget can cost more than the material cost of the acoustical fix.)
  4. The floor monitors are now well behaved. No matter how loud the floor monitors get, you definitely need to and to add the front of house to hear clear sound. As it turns out, the overall stage mix dropped around 10dB without the performers even noticing as they were now able to hear the stage mix from the monitors so well at a lower volume. You could say that the monitor spill issue is eliminated.
  5. This eliminated the need for IEM’s.
  6. Since the drummer can hear himself now, he gradually started playing quieter after a few weeks. The need for a drum cage disappeared.
  7. The Single Sub-Woofer was now able to play 9dB louder without distortion. It would have taken 3 more sub-woofers to get the same loudness without distortion. That was equal to spending around $15,000.00. (Standing waves and bass buildup in the corners added air pressure onto the surface of the cones of the subs drivers. This added air pressure creates distortion. When the subs distort, the sound quality and maximum sound levels of what the sub is supposed to be able to do, can drop up to 15dB in many rooms.)

Aylmer EMC Church Pano 2017_ss

Other improvements

Congregation Singing.

  1. The participation of people singing went up from 30% to 75%. (When people can hear themselves and the other people around them, it encourage people to sing more.)  s a resulting, the congregation is singing 8 to 15dB louder. (The more people singing, the louder they will become.)
  2. No more distortion from the speaker system with playing louder which means the perception of loudness is greatly reduced. (Standing waves and bass buildup in the corners added air pressure onto the surface of the cones of the bass driver of full range speakers. This added air pressure creates distortion. When the bass drivers distort, the sound quality and maximum sound levels of what the full range speaker is supposed to be able to do, can drop up to 15dB in many rooms.)
  3. After two years, the congregation is starting to add harmonies to their singing. (That is what happens when people can hear each other.)
  4. Now when people stand up to give testimonies or prayer requests, people can hear them whenever they forget to use hand held wireless audience microphone.
  5. The front of house stage mix is so much better. Now you can hear all of the performers without having to blast the sound system. (A well diffused room can make the signal to noise ratio improve from 3dB to 25dB. As the signal to noise improves, the easier it is to settle into a high quality.)
  6. The worship space is now concert quality for any high SPL event, recitals, choirs or orchestral events.

Total cost of the acoustical system including painting the whole sanctuary. $1,400.00
Since this as a DIY project, the money saved went towards a better headset mic for the pastor and the new digital mixer. Total upgrade, $5,000.00. If the church contract out the installation of the Sono Tubes, add $5,200.00. That is still 60%of the cost of upgrading a perfectly good sound system if everything is contracted out or an 83% difference.

Conclusion

One can honestly say that fixing the acoustics had a far better return on investment verses just upgrading the speaker system alone. Upgrading the speaker system can never make the room sound better, improve congregational singing and it would have not be possible to delete the deadspots without add more speakers on delays around the room. This transformation is typical of the new worship experience when a church gets the acoustics they are supposed to have. In the battle between acoustics vs sound systems, acoustics always wins. It’s Physics. Try moving a wall with air? You can’t. Change the wall and hear what happens!

 

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Dead Spots – Sound System or Acoustics?

Posted by jdbsound on April 9, 2018

An unwelcomed guest in any church is Mr. Deadspots. Unfortunately, deadspots in churches are more common than you think. There are two main types of deadspots. Some are frequency related/comb filtering interference and others are dips in sound levels greater that 6dB created by the room.

It is common to see frequency related deadspots in Left/Right sound system regardless if they are Line Arrays or point and shoot speakers. These deadspots are created by interference patterns in a mono speech system as a persons voice is always mono.  These deadspots are where you shift from one foot to another and notice a sound change. In these cases it becomes a problem when on one foot you hear the highs but not the lows. When you shift your position onto the other foot, you hear the lows and the highs disappear. People with hearing aids or early stages of hearing lose notice this the most. People with good hearing notice the change too but learn quickly to put up with it. Some young people think of it as a passive noise filter. If the music is too bright, stand to one side of your seating position. If the music is too boomy, shift to the other side of your seating position. Really! Isn’t that like buying a headset and controlling the sound changes with what angle you tilt your head. It might sound like a great idea until you find yourself with a lot of neck pain. No thank you.

Sound level dips are usually acoustically related. These are created with standing waves, bass building up, hollow walls, room corners, and parallel surfaces that include walls, ceilings and floors and concaved surfaces. In all of these cases, often mid and bass energy build up and the highs are absorbed with carpets, padded pews and people. By the nature of churches and how they are used, carpeted floors and padded seating often represents how the church sounds when it is 50% full. That means that if your attendance is often over 50%, the effects of padded seating and carpeted floors has little to no impact. If church attendance is often over 70% a carpeted floor makes the room more intimate during times of prayer and solemn reverence. In the end, carpets and padded seating is a good thing.

However, because of people in the room, once that room attendance is above 50% the people absorb enough highs that extra mids and bass energy is left behind as is being amplified between parallel surfaces. This excess energy automatically masks the highs. When the highs are masked, speech and music intelligibility drops. The kicker is, if you go around the room with a sound level meter, often the sound levels don’t drop much, even when you stand in a spot where the highs (when you measure just the highs) drop off over 6dB. That is because the excess bass energy is so strong that it fools the sound meter as the meter is reading an average sound level. When you take sound level readings by frequency, then you notice the high number of deadspots in the room. Get a tone generator in a cell phone or computer app and play a constant tone at 55dB at 500 Hertz, 1000 Hertz and 3000 Hertz and then start walking around. At 500 Hertz you shouldn’t notice much of change until you get close to walls. At 1000 Hertz you will notice more changes. At 3000 Hertz, if you are hearing a lot of changes, imagine what 25% of your church audience is experiencing.

Here is a church that had both acoustical and sound system created deadspots, with a central cluster. By nature of a central cluster, in a good room, it gives the best coverage and performance for speech. There is no better way to design a church sound system unless your ceiling is less than 14 ft. high. Choice of speakers, coverage patterns and speaker placement impacts sound too but these are mainly tone qualities and gain before feedback related. It may have up to a 2 or 3% impact on overall intelligibility as well.

corner view pano Ebeneezer Church_s

In this church example, it already has a fairly good quality speaker system in the ideal location for the room. It is designed as a central cluster and by nature, in this setup, it should perform well. However, it didn’t matter if you used the main speaker system or used portable speakers on stands, with any sound amplified you could find deadspots all over the room. On top of that, if you raised your voice in the room, once you were more than 18 feet from someone, understand what was being said was difficult to impossible depending on dictions of the person talking and how good is one’s hearing. When the proper acoustical fix was applied, all of those problems went away and the church didn’t need to upgrade the speaker system.

The church decided to leave the sound system alone as the gain before feedback improved and all of the deadspots disappeared. Since this is a traditional church that has no intentions to do anything contemporary, the acoustical fix was designed to not change the overall reverb time. Before and after reverb time remained about the same. 1.7 seconds.  It was the frequency response of the room that saw a major change. As the graphs shows below, where the mixer for the worship space was located, it was also one of many spots where weird measurements were recorded before. We found dozens of spots where the room measurements went squirrely. This is typical of the results of measuring a Left/Right speaker system, not a cluster system. These weird results were a result of room acoustics and not the sound system.  We used our own test speaker for all room testing.

Sound Booth Before and After

After checking our test equipment for errors, it was then realized that by just moving the mic over a few inches, you would get a very different result. In some places, the sound was perfectly fine but move over a few inches and it was not. Our ears are about 8 inches apart. In one row of seating, the largest distance we could move the test mic between a good spot and bad spot was 14 inches. Pew seating is 18 inches.  Every seating position had both good and bad sound. What we were measuring was sound masking in the mids and lows.  The energy was so strong that it masked the highs.  Not only that but the highs were most likely also being canceled from nearby wall reflection between 1800 to 5000 Hertz.  It gave the impression that there was something wrong with the sound system.

In this church, people marked their seating positions by placing personal pillows in spots where the sound was better. Sure enough, testing these spots showed better sound before the acoustical treatment was applied. After the acoustical system was installed, the sound was the same no matter where you sat including the sound booth.

Deadspots in churches are more often a result of worship space design and not a result of sound system design (unless you have the wrong speaker system design for your room). When a church replaces a well-designed sound within 10 years, and have little to no overall improvement after an upgrade, that should be a BIG RED FLAG that you most likely have a serious acoustical problem and no amount of money spent on the sound system can make those problems go away. Besides, these days, acoustical fixes cost less than sound system fixes. As a caveat, our experience has been this. Churches that have fixed their acoustics and then wanted on to expand their music programs, they were able to upscale their sound system with a much higher budget as they upgraded, it actually lead to better performance rather than an exchange of one set of problems for another.

Bottom line is, get your church properly tested. Have someone who knows how to properly diagnose the data, and then design your church a proper acoustical management system. Install the acoustical system and watch the congregation respond and grow. Don’t be surprised if other churches want to use your church for musical and recording events. Your property value may go up too.

Note – The acoustical system is made up of 8 and 12 inch half round plaster covered foam diffusers on 3 walls.  The side walls use a gradient pattern to maximize room performance. On the back wall there are 24 units of 7 ft. x 2 ft. x 18 inch plaster covered foam diffusers that are hollow which allows for additional passive room equalizing in the near future. Project completed by church members.

By Joseph De Buglio
JdB Sound Acoustics

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Church Ceiling Height Chart

Posted by jdbsound on May 26, 2017

Churches these days are building lower and lower building.  I guess when so many churches have experienced only poor quality acoustics, many wonder what is the point of building a taller worship space.  As it turns out, existing worship space acoustics is doing fine and a lot of churches are are getting their acoustics fixed, sounding better today than they ever did before.

When a church builds a low ceiling, it limits congregational singing and it makes you more dependant on technology, but guess what!  The same things that limits congregational singing is what also limits the performance of all sound systems.  So, instead of getting 100% out of your high quality over priced expensive sound system, your getting only 40 to 60% of the sound systems true performance abilities.  It is actually cheaper to build higher than the added cost of audio technology to make up the difference.   The chart below should clear the air as to the minimum height your next church should be.  Also, a taller worship space does not mean being stuck with longer reverb times. A higher ceiling means natural room reverberation is adjustable and tuneable.  With a taller ceiling you can change the frequency response of the whole room without needing a sound system or equalizer.

Minimum Church Ceiling height Chart.JPG

Church height is important for a worship space.  One of the biggest parts of worship is singing.  Congregational singing to be specific.  When singing as a group, several elements are required for a good and healthy worship experience.  There is chorusing, harmony, sound volume or loudness of the singing and being able to hear yourself as well as the people around you.  When all of these elements are in balance, the worship experience is like no other.  The majority of people get a lot of satisfaction from the singing experience during worshiping in rooms that have ceiling heights that matches the size of the seating capacity of the worship space. The above chart are minimum heights.  If you want to build higher, you can as the singing experience gets even better but the improvement is more subtle.
High ceilings allow better and less expensive sound systems to be used.  Higher ceiling permit better gain before feedback and it becomes easier to isolate drums and floor monitor. The performance of the sound system is much better too when that is coupled with a good quality acoustical management system.
There are economic advantages too.  The higher the ceiling, the cheaper it is to heat and cool when using a vertical displacement HVAC type system which is specifically designed for large gathering spaces for people.  Such systems cost less to install, they use smaller HVAC components and cost about 30 to 40% less to operate.  In addition, the cooling systems last 2 to 3 times longer before needing to be replaced.
Another thing to consider. If building new, don’t build a flat ceiling that is parallel to the floor. (and it doesn’t count of you put in a sloping floor.)  Many churches that are moving into commercial buildings are learning the hard way that flat ceilings limit the quality of live musical performances and congregational singing.  Sure, there are acoustical panels that can slightly improve the room for amplified sound, but the cost doesn’t justify the returns.  There is little that can help congregational singing even if you have the height. Vertical standing waves are hard to manage than horizontal standing wave. If you know what you are doing, horizontal standing waves can be controlled to create an outstanding room.  It is part of the formula for the almost perfect worship space.  Funny though, most concert musicians that perform in a church that I have fixed, they often make comments like, “I wish our concert hall sounded and performed as well.”  That is almost like saying, “concert halls make for lousy worship space but worship spaces can perform better than a concert hall.”
*Note* In any country that has freedom of religion laws, the worship space portion of a church building has no roof heights limits regardless of local city building height restrictions. 

**Note** The data is based on 2800 churches from North America, Europe, Philippines and Central America. 

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All Sound Systems are like magnifying glasses of the room acoustics

Posted by jdbsound on December 10, 2012

Is your sound system making the right impression?  Are the acoustics of your church allowing your sound system to make that great first, second and third impression at your church?

Once again the subject of getting more performance out of the next sound system upgrade keeps coming up. When a church is constantly seeking to get more performance out of a sound system at every upgrade and not be  enjoying the best sound possible then it’s time to fix the room instead of putting it off and investing into more equipment. This is the message your sound system is broadcasting.  Are you listening or are you waiting for the next technology breakthrough for that sliver of improvement?

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