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Posts Tagged ‘Powerful bass control’

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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Before and After results of a Real Multipurpose Hall

Posted by jdbsound on December 4, 2017

This is a before and after test results of a multipurpose room.  The room is a converter steel factory.  The purpose of the room is for multi use including banquets, acoustical and amplified musical performances, teaching and general meetings.  While the room has a fixed sound system, the  room performs equally well regardless of the orientation of the seating or event layout.

sandbox B-A results

From the graph, it shows the before and after.  Before the room had an average of 2.1 seconds of reverberation.  That said, at around 400 Hertz, the reverb time was 2.85 seconds. This made the room unacceptable for all uses.  It was hard to have a simple conversation with someone only 5 feet away.

The acoustical treatment in this case require 3 different acoustical system.  Tube Radiators were used for controlling sound from 200 to 2000 Hertz.  The tube radiators have only a profile depth of 4 and 6 inches and the idea that something so small can control sound down to 200 Hertz is amazing.  The tube radiators only covers 12% of the total wall space of the room.  

The second system was outround diffuser panels.  They covered another 10% of the available wall space.  These panels were used to manage sound from 100 to 500 Hertz.  By combining these two system with the limited wall space, we were able to cut the reverb time at 400 and 800 Hertz 1.8 seconds.  That is a massive amount considering that 400 Hertz is a wave length of about 33 inches long and 800 Hz is about 17 inches.

The third acoustical was a fiber absorber.  The fiber absorber covered 40% of the ceiling and 10% of the side walls.  The fiber panels covered the outrounds on the side walls.  It is rare to need absorption in such projects but when you have a concrete floor with no carpet, you have to replace the carpet with something similar.  Here is the thing about carpet.  Carpet, which is always within 4 to 7 feet of our ears works very efficiently.  The shallow angle of most sounds we hear in a large room event gives a 1/2 inch of carpet the acoustical performance of 2 inches of a typical wall panel absorber.  Since one of the requirements of this room is to include music that can reach 100dB, it was planned to have a reverb time of 1 second, +/- .2 tenths of a second.  That goal was met and the range it was met is typical of our acoustical fixes.  If you look at the before and after, the room now meets that goal from 150Hz to 4,000Hz.  Before, using the same criteria, the room had a average reverb time of 1.8 second with a +/- of 1.1 second variance.

percent alcons 4 sandbox

The critical question is, how does the room sound for speech, talking and for music.  For speech, the change was from 14% Alcon’s (rated as poor) to 4% Alcon’s.  At 4%, it means that you can talk to someone from end to end of the 55 ft long room with a slightly raise voice.  When you add a properly equalized sound system, you can better the speech intelligibility to 3.5%.  For talking across a table during banquet or social events is easy in this space.  You can talk to someone 15 ft away while the person next to you is talking to someone across the table without having to raise your voice to compete with other conversations.

As for music, so far, for the high energy high SPL events the room has been well received by musician and audience members.  That has meant fewer events with drum shields, fewer events with IEM (in ear monitors) and very little floor monitor spill that degrades the sound for the audience.

At the other end there have been a few recital type performances where the even was all acoustical.  One person who was a graduate of a royal conservatory of music remarked that the room was similar to recital rooms at a well known royal conservatory school in Toronto, Canada.  One violinist said that while she would have liked a longer reverb time, the quality of the sound of her expensive instrument was amazing.  The last time she heard her violin sound so great was at a high end recording studio that was  acoustical treated.  She was also stunned that it didn’t matter where in the room she performed, the violin sounded great.

There is one down side to the new room.  Since there is no carpet, when the room is empty, you do notice the reflection off the floor. This does make the room a little challenging for those who do rehearsals when the room empty and before any table and chairs are set up.  Once tables and chairs are setup, the room behaves well.

In the real world, there are a lot of rooms that are used as multi purposed spaces but perform poorly.  Most facility owners don’t worry about acoustics because they may have the only place in town that can accommodate such events.  That said, if they were to get 10 to 20% more bookings per year, they would recover the cost of investing in an acoustical fix in less than a year.  Furthermore, it would allow the facility owner to charge a hire fee if the place gets too busy.  There is no down side to having an acoustically friendly community center, convention hall, rental hall or banquet facility.

 

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