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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => Audio Measurement and Testing => Topic started by: Kevin Maxwell on June 02, 2017, 10:57:52 PM
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Smaart with 3 mics and a line array question.
I am getting 2 new measurement mics, they are on their way to me now. I am anxious to get into using multiple mics with Smaart and this was the last piece of gear I needed. I am most likely going to be the BE for a show very soon that is at an outdoor venue with an installed line array. This is all lawn seating and the lawn is racked up from the stage. I have heard the system there sound great and I have heard it not sound so great, 2 different people mixing 2 different bands. I actually assume that the system is well tuned but I want to see how it measures. And I assume that I will have access to EQs in the digital console, if I need to make any changes. Is there a standard way to measure a line array outdoors with multiple mics? I am asking about basically mic placement. Do I put the mics in a straight line from the stage or is there some other trick that is recommended?
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Smaart with 3 mics and a line array question.
I am getting 2 new measurement mics, they are on their way to me now. I am anxious to get into using multiple mics with Smaart and this was the last piece of gear I needed. I am most likely going to be the BE for a show very soon that is at an outdoor venue with an installed line array. This is all lawn seating and the lawn is racked up from the stage. I have heard the system there sound great and I have heard it not sound so great, 2 different people mixing 2 different bands. I actually assume that the system is well tuned but I want to see how it measures. And I assume that I will have access to EQs in the digital console, if I need to make any changes. Is there a standard way to measure a line array outdoors with multiple mics? I am asking about basically mic placement. Do I put the mics in a straight line from the stage or is there some other trick that is recommended?
This is how I would do it on any system.
Turn off 1 side.
I would put the mics a little bit off axis. Some speaker have a "hotspot" right in the middle. And since there are more people off axis than on axis, you are tuning for the greater majority of the people
Put the first mic around the closest listener. The 2nd one at FOH and the 3rd towards the furthest listener of interest.
All in a row.
But BEFORE I put out any mics, you MUST calibrate the levels. I choose any position (it does not matter) and put the mic elements close together.
Then run some pink noise-It does NOT MATTER what the response is-don't waste time trying to flatten it out. ALL you are looking to do at this point is to adjust the gains of the mic pre so that all the mics read the same-or as close as possible.
DO NOT adjust the mic gains after this is done.
Now put the mics out-set the time for each one and adjust as needed.
Get ready for things you are not expecting-----
If you can't get the same response and level (which should be the goal) at all the seats, then settle for the same overall response shape-with lowering levels as you go back.
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Step 1- don't forget to mix your band
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Step 1- don't forget to mix your band
I was "assuming" the mics would be out during system alignment.
I don't like the idea of mics out in the audience during the performance.
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Step 1- don't forget to mix your band
Here is a real "No shiter".
Years ago (OK the late 80s), I worked with a band that had 2 "engineers".
This was an "arts festival".
I was running monitors and noticed the PA started sounding "odd"
I went to FOH to find 2 guys running sound.
1 guy was on the console-as usual.
The other guy (I could wring his neck) was "mixing the sound system".
What I mean is, he was constantly changing the house eq (to great extremes) AND the crossover levels and freq!!!! >:( >:( >:( >:( >:( >:(
And the console operator was also constantly changing eq quite a bit.
DO WHAT???
I am NOT kidding.
Of course everything was analog.
I reset the eq and xover to where I could remember it was and went back to monitor world.
A little while later he was doing it again
What a nightmare. I had brought plenty of PA, so nothing was damaged.
After that show, the xover was moved from FOH to the amp racks.
Yes, it was a weird show.
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Smaart with 3 mics and a line array question.
I am getting 2 new measurement mics, they are on their way to me now. I am anxious to get into using multiple mics with Smaart and this was the last piece of gear I needed. I am most likely going to be the BE for a show very soon that is at an outdoor venue with an installed line array. This is all lawn seating and the lawn is racked up from the stage. I have heard the system there sound great and I have heard it not sound so great, 2 different people mixing 2 different bands. I actually assume that the system is well tuned but I want to see how it measures. And I assume that I will have access to EQs in the digital console, if I need to make any changes. Is there a standard way to measure a line array outdoors with multiple mics? I am asking about basically mic placement. Do I put the mics in a straight line from the stage or is there some other trick that is recommended?
Kevin - you can also easily do this with one microphone. Hopefully you have a wireless setup, it makes it go quickly.
Ivan's advice is spot on, but I can offer a quicker method. The key is to average the measurements. Pick your measurement positions and capture them.
Then, adjust the amplitude of each captured measurement to match to the extent possible.
Now, average the measurements. You now have the average magnitude response of your chosen positions. Chances are you'll do 2-4 relatively broad cuts.
IMO spatial averaging upped the ante significantly.
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Kevin - you can also easily do this with one microphone. Hopefully you have a wireless setup, it makes it go quickly.
Ivan's advice is spot on, but I can offer a quicker method. The key is to average the measurements. Pick your measurement positions and capture them.
Then, adjust the amplitude of each captured measurement to match to the extent possible.
Now, average the measurements. You now have the average magnitude response of your chosen positions. Chances are you'll do 2-4 relatively broad cuts.
IMO spatial averaging upped the ante significantly.
I like this method as well. I prefer to look for the needed broad changes first.
Sent from my XT1254 using Tapatalk
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Kevin - you can also easily do this with one microphone. Hopefully you have a wireless setup, it makes it go quickly.
Ivan's advice is spot on, but I can offer a quicker method. The key is to average the measurements. Pick your measurement positions and capture them.
Then, adjust the amplitude of each captured measurement to match to the extent possible.
Now, average the measurements. You now have the average magnitude response of your chosen positions. Chances are you'll do 2-4 relatively broad cuts.
IMO spatial averaging upped the ante significantly.
I would agree that could work AS LONG AS the adjustments are done on the INPUT side of the overall loudspeaker system.
NOT on an individual box basis. One of the things that some people like to claim is how they can adjust the parameters of different parts of the line array to suit particular seating areas.
This can be done-HOWEVER-unless you have mics that are looking at ALL of the areas, you might be "fixing" one area, and making other areas worse-due to the lack of pattern control.
I have seen people set a mic in one place-adjust to where they like it, thenmove the mic to another place and adjust and do it again.
THE PROBLEM is that they never go back to the first positions and see what they look like.
They are completely different than when they first measured them.
That is were the multi live mics come in handy. You can see what is happening at all of the positions as you make adjustments to any part of the speaker system.
I know it was quite eye opening when I first started doing it.
What you "think" you are doing is often NOT what is happening-at least in more than 1 seat.
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NOT on an individual box basis. One of the things that some people like to claim is how they can adjust the parameters of different parts of the line array to suit particular seating areas.
This can be done-HOWEVER-unless you have mics that are looking at ALL of the areas, you might be "fixing" one area, and making other areas worse-due to the lack of pattern control.
What you "think" you are doing is often NOT what is happening-at least in more than 1 seat.
True!
Considering the interactions between elements of an array, changing EQ, level or delay on a box (s) will have an effect on the behaviour of the array.
Choose wisely ;)
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Unless you are using beamshaping of some sort you cannot do anything to frequency response below 1kHz or or higher depending on crossover points and horn design etc...
Keep that in mind when you EQ line arrays, they tend to follow antenna theory in the lower frequencies and act like poiby source boxes at the higher frequencies, I find I tend to actually decrease high end on the top boxes then compensate for air attenuation depending on the line array deployment, rolling off low mids on the bottom boxes will only make the already bad impulse response worse and not do anything to your overall frequency response.
Things like that are easily seen with multi mic setups but get overlooked with a one mic setup and not enough time.