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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 => LAB: The Classic Live Audio Board => Topic started by: Mark Edwards on February 10, 2018, 12:04:13 PM
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With 3D prediction software now the norm, I was wondering what approaches people have for taking venue measurements? I'm looking at this from a touring, get off the bus, mark out, measure up and load in perspective, rather than drawing venues in pre-production from a CAD.
Whilst I find it easy and quick to measure up a 'standard' rectangular style arena, I'm interested in what people are doing for other shapes of venue, particularly 'clam shell' and curved shaped ones. My instinct here tells me to measure from a central position (say DSC), and measure a series of points with both X and Y distance and angles that I can quickly translate to the design software, but I don't currently have the ability to take the horizontal angle measurements required to make this work. In this instance I currently tend to take a series of cut slices at predefined spots across the width of the venue, but this takes time which when touring is a precious resource!
What are peoples strategies for this, and are there any handy tools I don't know about? I've seen the Leica S910 Pro Pack, which seems to be ideal, but are there any cheaper alternatives?
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Laser 'tape' measure and a protractor?
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Laser 'tape' measure and a protractor?
Needs to be a little more accurate than that, a 1 degree error over 80m is nearly 1.5m!
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With 3D prediction software now the norm, I was wondering what approaches people have for taking venue measurements? I'm looking at this from a touring, get off the bus, mark out, measure up and load in perspective, rather than drawing venues in pre-production from a CAD.
Are venues not making 3D models available to visiting acts? If this isn't commonplace yet, perhaps there's a business model for a 3D Scanning service to survey venues.
Back when I was involved with an arena, we published PDF and CAD files in advance.
Dave
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There is a HUGE difference between doing 3D modeling and acoustic modeling.
With most 3D programs, they do not do acoustic modeling, just direct coverage.
You can often draw a room around the listening plane, but the ONLY thing that does is to give the customer an idea of how it looks in their room, but does not affect the coverage maps in any way.
A couple of the most popular are EASE, CATT, Modeler. you can also do simple direct coverage with them.
But to answer the question, what do you put it? It depends on what information you want out of the model. In other words, how accurate do you want it to be?
A general rule is you should model (put in) anything that is 1/2 of the highest freq of interest.
For example, lets say you want to go up to 4Khz. That is around 3". So 1/2 of that is 1.5" (around 38mm).
So everything that is that size or larger needs to be put into the model.
Nobody is coming even close to that sort of detail.
If you are lucky you might model to 500Hz. So details of 1' need to be modeled.
It takes A LONG time put in details like that. PLUS, the time it takes to do acoustic calculations is much longer, the more faces you put in.
So, once again, it depends on what you want out of the model.
And even if you did model to that fine degree, is the data for the surfaces accurate?
On on of Doug Jones classes, a student did a study of carpet used in models. She found out that the data for any of the carpet did not come close to what modern carpet actually measured. The data was 30yrs old and limited.
So the acoustic model would be off with the data supplied.
It gets A LOT more complicated, the deeper you dig into what is REALLY going on.
That being said, I (personally) have not done an acoustic model in over a decade. A direct 3D model (audience planes only) is usually "good enough".
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Are venues not making 3D models available to visiting acts? If this isn't commonplace yet, perhaps there's a business model for a 3D Scanning service to survey venues.
Back when I was involved with an arena, we published PDF and CAD files in advance.
Dave
Some do, some don't. Not something to rely on generally!
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Leica E7500i - bad assed.
Please learn how to do an embedded link
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For example, lets say you want to go up to 4Khz. That is around 3". So 1/2 of that is 1.5" (around 12mm).
1" = 25.4mm, or 2.54cm, so 1.5" is around 38mm.
When I'm not sure which way a conversion should go, I figure out which unit is bigger, and then decide whether the converted number should be smaller or larger.
I grew up with imperial units at home and metric at school. I use miles, metres, feet, inches and millimetres. The latter for anything precise, but day-to-day measurements (if I'm describing the size of an object over the phone, for example) are imperial.
Chris
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1" = 25.4mm, or 2.54cm, so 1.5" is around 38mm.
OOPS, Thanks for the catch, I had a brain fart---, was thinking about 1".
I have edited my post.
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For get off the bus, measure the room, mark the floor type of work, I use two different devices. I use an off the shelf, Bosch laser distance tape measure from Home Depot. I also use a TruPulse 200 (https://www.benmeadows.com/laser-technology-trupulse-laser-rangefinders_37258712/?gclid=CjwKCAiAk4XUBRB5EiwAHBLUMYB8SoHY9JgW6YYyxH4yQo2XtYwApIPCfLvvocjzkW1N0OaYOEJ3OhoCO0AQAvD_BwE&selectedsku=219804&CID=BMPL10&s_kwcid=AL!3210!3!181721379285!!!g!130343117338!&ef_id=WWizgwAAAHcx3iXo:20180212133212:s) for "rise and run" elevation type measurements. We are a JBL house so I'm working with Performance Manager and JBL's Line Array Calculator only; not a terribly detailed prediction program but it does what I need it to do.
In a theatre, I'm interested in essentially plotting a cross section diagram of the venue's seating planes. I use the DS edge of the stage as my zero reference. Measure rise and run of the floor plane, measure distance to the face of the 1st balcony and that elevation, 2nd balcony same same etc. I find the most important measurements are those defining the farthest top seat, and that of what my trim height limitation will be in a given room.
One thing to mention because I've seen this mistake made over and over again, is to remember that whatever device you may use to measure with, is most likely a certain distance above your reference (0,0) point. For example if I measure a room and I'm standing on the deck in a theatre using my TruPulse contraption and I see that the top seat has a horizontal distance of 135' and a vertical distance of 45', I need to add 9.5' to my vertical since I'm standing 3.5' above the floor plane and the device is at my eye (another 6').
The Bosch I use for quick and dirty distance measurements: how far to FOH, how far to the first seat on my side hangs, what are my low/high steel heights etc. I have had better luck with units like the TruPulse which has the eye sight because I am color blind and have a hard time picking up the laser dot if the enviroment isn't darkish. I simply use what works best for me. YMMV.
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With 3D prediction software now the norm
Is it? It is often pretty onscreen, but is it pretty reliable in use?
This is similar to RF: We can use intermod software, best practices, etc., but none of it will tell us what is truly present in the atmosphere. You gotta measure
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Is it? It is often pretty onscreen, but is it pretty reliable in use?
This is similar to RF: We can use intermod software, best practices, etc., but none of it will tell us what is truly present in the atmosphere. You gotta measure
The only prediction software I use is L-Acoustic SoundVision, and it is very good. If the software says the coverage is good, it is. While I rarely use it, Meyer Sound's MAPP is also very good, but, at least the last time I used it it was not 3D.
As Ivan said products like SoundVision do not model the room, they model listening planes. You do not need all the measurements of the building, only the surfaces of the audience seating area.
Mac
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It sounds like you are asking about a shed/amphitheater type venue. Here's a way to figure out the "described angle" of the seating area:
Find the spot up stage center where the lines of the edge of the seating area house left and house right meet. The distance from DSC to this point is the adjacent side of the triangle. Walk along the line of the edge of the seating area (the hypotenuse) toward DSR or DSL. Measure the distance from the point on the DS edge to DSC. This is the opposite side of the triangle. tan^(-1) of opposite divided by adjacent is half of the angle of the seating area.
With 3D prediction software now the norm, I was wondering what approaches people have for taking venue measurements? I'm looking at this from a touring, get off the bus, mark out, measure up and load in perspective, rather than drawing venues in pre-production from a CAD.
Whilst I find it easy and quick to measure up a 'standard' rectangular style arena, I'm interested in what people are doing for other shapes of venue, particularly 'clam shell' and curved shaped ones. My instinct here tells me to measure from a central position (say DSC), and measure a series of points with both X and Y distance and angles that I can quickly translate to the design software, but I don't currently have the ability to take the horizontal angle measurements required to make this work. In this instance I currently tend to take a series of cut slices at predefined spots across the width of the venue, but this takes time which when touring is a precious resource!
What are peoples strategies for this, and are there any handy tools I don't know about? I've seen the Leica S910 Pro Pack, which seems to be ideal, but are there any cheaper alternatives?