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Author Topic: Midsized festival -> Line Array  (Read 12124 times)

Stu McDoniel

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Re: Midsized festival -> Line Array
« Reply #30 on: December 31, 2013, 03:33:27 pm »

Hi all,

I'm in the organising team of a midsized festival (1500pl) in Belgium, recently whe received new regulations that require us to redesign our audio setup. LAeq,60min ≤ 100 dB(A) is the new benchmark, currently our setup is very basic, woofers and speakers blasting the sound in the crowd.

We want to keep our sound level in front of the stage @  LAeq,60min ≤ 100 dB(A) and keep the rest of the area more quiet to give the crowd the chance to rest and have a drink.

We have had numoures offers al presenting us a Line-array system. It is quite an investment but is it worth the money? What is your opinion? is it enough to just keep the current speakers and raise them of the floor or do we realy need the line array to give the crowd a desent sound quality?
A few ideas

Use the system you have.

Splay your tops more to minimize overlap.

Get those tops higher up in the air.

The recommendation of scaffolding is a good one.

Keep it simple.
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Brad Weber

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Re: Midsized festival -> Line Array
« Reply #31 on: January 01, 2014, 12:41:07 pm »

Thatís not how you add Leqs!
 
eg. if 100 dBA = 100% dose then 103 dBA = 200% dose.
 
Note -  Leq assumes an Exchange Rate of 3 dB and applies to all ISO and British Standard measurements. In some Countries, for example the USA OSHA Standards use a 5 dB exchange rate.
From varous sources the Leq is:
 
  • Equivalent continuous A-weighted sound pressure level is widely used around the world as an index for noise. It is defined as "the A-weighted sound pressure level of a noise fluctuating over a period of time, expressed as the amount of average energy."
  • The average sound level measurement over the run time.
  • The Equivalent Continuous Sound Level is the preferred single decibel value to describe Sound Levels that vary over time and would produce the same Sound Energy over the same period of time T.
I was not adding Leq values, rather showing a simplistic example of a one hour Leq consisting of two 30 minute periods with different levels.  To actually measure Leq or LAeq you genherally use an integrating sound level meter.  It integrates the levels (energy) measured over the defined time period and then divides that total value by the overall time period to determine the average or continuous equivaleant level over that period.
 
Dose relates to OSHA, ISO, etc. and where the Exchange Rate referenced relates a Leq or TWA to the related defined 8 hour Dose.   That is alsdo why those situtation are best approached through the use of dosimeters for any measurements.  However, there are numerous community, environmental and other noise guidelines and measurements that use Leq and/or TWA measurements, as well as other defined descriptors such as Ldn, Ln, etc., without any relation to OSHA, ISO, etc. or to the related Dose.
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Lee Buckalew

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Re: Midsized festival -> Line Array
« Reply #32 on: January 01, 2014, 01:37:57 pm »

Hi all,

I'm in the organising team of a midsized festival (1500pl) in Belgium, recently whe received new regulations that require us to redesign our audio setup. LAeq,60min ≤ 100 dB(A) is the new benchmark, currently our setup is very basic, woofers and speakers blasting the sound in the crowd.

We want to keep our sound level in front of the stage @  LAeq,60min ≤ 100 dB(A) and keep the rest of the area more quiet to give the crowd the chance to rest and have a drink.

We have had numoures offers al presenting us a Line-array system. It is quite an investment but is it worth the money? What is your opinion? is it enough to just keep the current speakers and raise them of the floor or do we realy need the line array to give the crowd a desent sound quality?

For your existing gear the suggestions of getting it up in the air and angles down are excellent.  It may mean using a pair each side up high angles down and the other two cabinets used as front fill either from the stage or from a slightly lower level on the scaffold.  Angle for appropriate coverage.  You should be able to provide much more even coverage and also limit some of the spill.

If you are wanting to hire in a system to see what can be done in a different way I would encourage you to check out the Martin MLA-C (for this size area the MLA would be overkill) system for its ability to control the evenness of coverage within the listening area and to limit SPL outside of the coverage area.

Lee
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Ivan Beaver

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Re: Midsized festival -> Line Array
« Reply #33 on: January 01, 2014, 02:15:16 pm »

For your existing gear the suggestions of getting it up in the air and angles down are excellent.  It may mean using a pair each side up high angles down and the other two cabinets used as front fill either from the stage or from a slightly lower level on the scaffold.  Angle for appropriate coverage.  You should be able to provide much more even coverage and also limit some of the spill.

If you are wanting to hire in a system to see what can be done in a different way I would encourage you to check out the Martin MLA-C (for this size area the MLA would be overkill) system for its ability to control the evenness of coverage within the listening area and to limit SPL outside of the coverage area.

Lee
But if I was reading it right-the SPL limit was to be measured WITHIN the coverage area-kinda specifically the FOH position.

So it appears they are not so concerned with the spillage, but rather the SPL exposure of the people in attendance.

QUITE a different thing than trying to not annoy the neighbors.

Unless they put FOH outside the coverage area-but we don't want to go there.
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Lee Buckalew

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Re: Midsized festival -> Line Array
« Reply #34 on: January 01, 2014, 02:33:45 pm »

But if I was reading it right-the SPL limit was to be measured WITHIN the coverage area-kinda specifically the FOH position.

So it appears they are not so concerned with the spillage, but rather the SPL exposure of the people in attendance.

QUITE a different thing than trying to not annoy the neighbors.

Unless they put FOH outside the coverage area-but we don't want to go there.

Yes, the new regs posted are about audience area but, unless this is very different from many other areas around Europe there are existing strict limitations for spill as well.  Perhaps not.
Either way they can get more even coverage with their existing system with many of the suggestions provided or, if they want to hire in a system just to try it out, they can get exceptionally even coverage throughout the listening area with any of the MLA variants plus realize the added benefit of better control over off-site spill and better control of bleed on the stage.

Lee
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Peter Morris

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Re: Midsized festival -> Line Array
« Reply #35 on: January 01, 2014, 08:07:25 pm »

For your existing gear the suggestions of getting it up in the air and angles down are excellent.  It may mean using a pair each side up high angles down and the other two cabinets used as front fill either from the stage or from a slightly lower level on the scaffold.  Angle for appropriate coverage.  You should be able to provide much more even coverage and also limit some of the spill.

If you are wanting to hire in a system to see what can be done in a different way I would encourage you to check out the Martin MLA-C (for this size area the MLA would be overkill) system for its ability to control the evenness of coverage within the listening area and to limit SPL outside of the coverage area.
Lee

+1 ... Iíve been lucky enough to have a play with MLC Ö its sound quality and ability to maintain even coverage and control SPLs outside the listening area is fantastic.
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Peter Morris

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Re: Midsized festival -> Line Array
« Reply #36 on: January 01, 2014, 08:36:35 pm »

From varous sources the Leq is:
 
  • Equivalent continuous A-weighted sound pressure level is widely used around the world as an index for noise. It is defined as "the A-weighted sound pressure level of a noise fluctuating over a period of time, expressed as the amount of average energy."
  • The average sound level measurement over the run time.
  • The Equivalent Continuous Sound Level is the preferred single decibel value to describe Sound Levels that vary over time and would produce the same Sound Energy over the same period of time T.
I was not adding Leq values, rather showing a simplistic example of a one hour Leq consisting of two 30 minute periods with different levels.  To actually measure Leq or LAeq you genherally use an integrating sound level meter.  It integrates the levels (energy) measured over the defined time period and then divides that total value by the overall time period to determine the average or continuous equivaleant level over that period.
 
Dose relates to OSHA, ISO, etc. and where the Exchange Rate referenced relates a Leq or TWA to the related defined 8 hour Dose.   That is alsdo why those situtation are best approached through the use of dosimeters for any measurements.  However, there are numerous community, environmental and other noise guidelines and measurements that use Leq and/or TWA measurements, as well as other defined descriptors such as Ldn, Ln, etc., without any relation to OSHA, ISO, etc. or to the related Dose.

 :-\ well you did say ..."Say you had 30 minutes at 120dBA and 30 minutes at 80dBA, that would represent a LAeq(60mins) of 100dBA."
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Re: Midsized festival -> Line Array
¬ę Reply #36 on: January 01, 2014, 08:36:35 pm ¬Ľ


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