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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: Ryan Rife on March 28, 2013, 01:37:31 PM
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Greetings all,
I am currently assigned to a shop responsible for setting up and running sound systems for events on a USAF installation. One of the main problems I run into is that most of the larger events are held in hangars which if you didn't know, are giant concrete, steel, and aluminum boxes. Hardly the ideal acoustic enviroment.
The hands down biggest problem I have when trying to provide an audience sound is the amount of echo/reverb that occurs. Being that the space and crowds are so large I have to really crank the volume , yet I'm worried that if I add more speakers to the equation I am going to get even more signals bouncing off all the walls.
Does anyone have any experience with these enviroments that could offer some tips on how to optimize the set up? I usually have one mixer, two power amps, and up to 8 speakers available to me. I do have a feedback suppressor running, so that is not normally an issue.
Any help would be most appreciated.
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You may be out of luck on that type of environment. There are some portable "sound absorbing" walls that can provide some relief; they are used to line the parameter walls of a reflective area (usually in 4' x 8' sections). Adding more speakers to get "power" may work, but to have any noticeable amount of power would require the doubling of the number of cabinets you currently have. If you are running 8 speakers, you will need 16 to get a noticeable amount of "power". Though, the more people that fill the area should help with keeping reverb down.
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Greetings all,
Any help would be most appreciated.
Use speakers with pattern control which goes as low as possible.
Point them at the listeners.
Do not let them bounce sound off any walls, ceilings or flooring.
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Point them at the listeners.
This.
We do a lot of events in helicopter hangers and the acoustics are terrible. If you have speakers with angled pole sockets get them up high and point them down at the crowd. The rest you just have to do the best you can with.
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The good news is you have a low bar to clear. You don't need to make great sound, just better than the last guy.
The problem as you correctly identified is operating inside a highly reverberant space due to the reflective walls. The goal as others have mentioned is point sound at the meat in the seats since it won't reflect much off them. More speakers closer to and pointing down at the audience will put more sound energy into the audience and less into the room reverberation.
Simple to describe the problem, not so simple the solution.
JR
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What kind of material will be reinforced?
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What kind of material will be reinforced?
Concrete?
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Back in my navy days we would cycle from Vietnam to Guam, Japan, PI, etc., put the band together and party hardy. Everyone was invited, sailors and crabs alike, and the event was always in a hanger, and usually a very large hanger.
We didn't have anything more than our amps and a PA, usually a Vocal Master, and never once worried about the sound, reflections, or anything else as long as the stage mix was correct and not too loud. The ambience was great, the sound was great, and people had a good time. Get a good mix with what you have and you'll be fine.
PS - Nice one Dick. LMFAO
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Music with extra reverberation is not a show stopper (and probably helped Bob's sound), but if it's a comedian telling jokes, articulation and intelligibility is useful.
The big boys work to make the sound appear like it is coming from the stage, so delay a limited number of audience fill speakers to keep up the illusion. For good speech intelligibility I'd forget about the delay compensation and just throw as many small boxes as I can get my hands on, close and pointing directly at the audience. For music it's nice to have it seem like the pretty girl on stage is making the sound.
JR
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Greetings all,
I am currently assigned to a shop responsible for setting up and running sound systems for events on a USAF installation. One of the main problems I run into is that most of the larger events are held in hangars which if you didn't know, are giant concrete, steel, and aluminum boxes. Hardly the ideal acoustic enviroment.
The hands down biggest problem I have when trying to provide an audience sound is the amount of echo/reverb that occurs. Being that the space and crowds are so large I have to really crank the volume , yet I'm worried that if I add more speakers to the equation I am going to get even more signals bouncing off all the walls.
Does anyone have any experience with these enviroments that could offer some tips on how to optimize the set up? I usually have one mixer, two power amps, and up to 8 speakers available to me. I do have a feedback suppressor running, so that is not normally an issue.
Any help would be most appreciated.
Speaker model(s)?
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Another thing to consider is to see if you can put the speakers in one position. Don't do two speakers with one on each side of the stage. If pattern control is not an option than stacking the speakers in one column may reduce the problem a little.
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Another thing to consider is to see if you can put the speakers in one position. Don't do two speakers with one on each side of the stage. If pattern control is not an option than stacking the speakers in one column may reduce the problem a little.
Huh? I think he'd be much better off with lots of speakers (each covering a small area - think bunches of delay stacks). That would keep the sound pointed at the water bags (and off of the surfaces), and less level would be needed from each speaker to be heard. That's a win/win. The only way to fight the reverberant field in a space like that is to avoid exciting it in the first place.
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Huh? I think he'd be much better off with lots of speakers (each covering a small area - think bunches of delay stacks). That would keep the sound pointed at the water bags (and off of the surfaces), and less level would be needed from each speaker to be heard. That's a win/win. The only way to fight the reverberant field in a space like that is to avoid exciting it in the first place.
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Huh? I think he'd be much better off with lots of speakers (each covering a small area - think bunches of delay stacks). That would keep the sound pointed at the water bags (and off of the surfaces), and less level would be needed from each speaker to be heard. That's a win/win. The only way to fight the reverberant field in a space like that is to avoid exciting it in the first place.
That would be fine if the user has multiple digital delay devices to set up and time align. Set up main and second line time align move to row three and time align move to row 4 and time align.
What about the cables for the power? If he used a wireless delivery. or the power and cable to each speaker.
In the basket ball gym at La Plata there is a 70v system with out time delay and has 12 speakers on the ceiling. The reverb extends well out past the 300 ms time on Home Theater REW room EQ wizard. Cheap rough program that shows some data mostly Did not do the RT60 with a baloon to give them the worst number.
Put a couple of those helocopters in the back to create sound defusers.
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That would be fun using assisted listening devices , Most of the military types have hearing loss from the jets, guns, and bombs.
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That would be fine if the user has multiple digital delay devices to set up and time align. Set up main and second line time align move to row three and time align move to row 4 and time align.
So, what's the problem? This is how it's done every day in convention centers around the world. This is what corporate event audio is all about, well that and no mistakes, lots of RF, wearing a headset all day.
Lots of speakers, distributed, aimed down at the audience, and properly delayed is the way to get the best STI in a big reverberant space like a large airplane hanger.
Mac
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That would be fine if the user has multiple digital delay devices.
I carry 5 Behringer Sharks. and these are still prone to failure but that is what I can afford.
I purchased them used on Ebay around 40 each. Some have the deep pockets to pay and the rest have to suffer and try and get by. Using a single source point is lower cost for the people that don't have the deep pockets and reduces the problems. Getting this single source of sound over their heads also reduces the problem. Getting the audience into the direct sound and out of the reverb.
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That would be fine if the user has multiple digital delay devices.
I carry 5 Behringer Sharks. and these are still prone to failure but that is what I can afford.
I purchased them used on Ebay around 40 each. Some have the deep pockets to pay and the rest have to suffer and try and get by. Using a single source point is lower cost for the people that don't have the deep pockets and reduces the problems. Getting this single source of sound over their heads also reduces the problem. Getting the audience into the direct sound and out of the reverb.
Go back to the OP and read the part about this being for the USAF. It really is standard operating procedure on every show I do. With 3 MY8-DA cards even an M7CL-32 can do 36 delay taps. With MY16-AE cards 64 delay outputs. A Meyer Galileo, 16 delay outs.
Delay is a common part of system optimization at all levels since it so easy to do. Even on a small show I will typically have at least 1 delay to match front fills to mains, 1 to match flown center fill to mains, and whatever may be needed for delay speakers farther out in the audience.
Mac
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And still the deep pockets and believing the milatary has money. Fort Meade will have a command go to VI to get a system and they come back with two speakers on sticks and a 50 foot mic cable with a mic. This they put in the hanger and call a speaker system.
Fort Meade has talent was going to try and do full band with 4 mics and a 16 channel analog mixer. No delay's or external processing. MWR reps were going to be running this. Sometimes it is a Sargent who has no clue. turn it up and keep it from squeel.
Not every base has the OLD Guard with the Honors Band from DC to support functions.
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And still the deep pockets and believing the milatary has money. Fort Meade will have a command go to VI to get a system and they come back with two speakers on sticks and a 50 foot mic cable with a mic. This they put in the hanger and call a speaker system.
Fort Meade has talent was going to try and do full band with 4 mics and a 16 channel analog mixer. No delay's or external processing. MWR reps were going to be running this. Sometimes it is a Sargent who has no clue. turn it up and keep it from squeel.
Not every base has the OLD Guard with the Honors Band from DC to support functions.
Jerome, why are you being so argumentative? This thread has good advice. The OP has to decide how to use it.
Sent from my iPad using Tapatalk HD
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So, what's the problem? This is how it's done every day in convention centers around the world. This is what corporate event audio is all about, well that and no mistakes, lots of RF, wearing a headset all day.
Lots of speakers, distributed, aimed down at the audience, and properly delayed is the way to get the best STI in a big reverberant space like a large airplane hanger.
Mac
Read and heed.
Lifting devices using base resources might be an option.
Aim them at the audience, put more listeners in the direct field, and enjoy the benefits.
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Read and heed.
Lifting devices using base resources might be an option.
Aim them at the audience, put more listeners in the direct field, and enjoy the benefits.
crank high, tilt down. it just works.
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crank high, tilt down. it just works.
Nothing says folk music like straw bales and corn stalks........
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Well thanks everyone for all the advice.
As for setting up various delay's I do not have the equipment to do that.
I will definitely try to get the speakers raised higher and oriented more towards the audience the next go round.
On another topic I was told I should have used the "RTA" mic and eq pink noise for the last set up. Anyone have a clue what that is? One problem with being a radio troop is getting everything related to a frequency thrown at you as if you know what you are doing.
Thanks for all your help.
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As for setting up various delay's I do not have the equipment to do that.
What equipment do you have? Whenever asking questions like this it gets rid of a lot of confusion if you fully describe the situation. There may be other ways to help you maximize your results if we know exactly what you have.
Mac
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On another topic I was told I should have used the "RTA" mic and eq pink noise for the last set up.
Yes and no......but mostly no.
There are easier and more effective ways to maximize your system capability by simply using your graphic EQ. If you don't have a graphic EQ, you're kind of crippled.
If you'd like a PDF of how to "ring out" your system, send me your email address in a PM and I'll send it to you. I cannot attach PDF's here or to PM's.
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Well thanks everyone for all the advice.
As for setting up various delay's I do not have the equipment to do that.
I will definitely try to get the speakers raised higher and oriented more towards the audience the next go round.
On another topic I was told I should have used the "RTA" mic and eq pink noise for the last set up. Anyone have a clue what that is? One problem with being a radio troop is getting everything related to a frequency thrown at you as if you know what you are doing.
Thanks for all your help.
Uh what's your MOS troop?
If you don't have delay, no problem one less thing to adjust. 8)
The way to think of this is that the sound coming out of the speakers forms a cone. You don't want the top of that cone putting energy into the ceiling to bounce off and create reverberation. So point the speakers down, and starting from higher up lets you point them down and at more seats.
The delay for extra speakers is to fool the audience into thinking all the sound is coming from the stage.. For spoken word (like comedians) it is better to get the speakers closer to the troops, so they can understand the words, than fooling them about where the sound is coming from.
RTA (real time analyzer) is to help adjust frequency response... Not your major malfunction which is room acoustics, For now worry about how you point the speakers.
JR
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Nothing says folk music like straw bales and corn stalks........
Children of the corn.
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Nothing says folk music like straw bales and corn stalks........
As i recall.... those cornstalks were full of live bugs.
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I have done a bunch of Corporate meetings for a high profile personal
jet company in there smaller maintenance hanger 125'x400'+ 400-800pps.
I use Ev X-Array cabs flown and pointed right on the seats. Keeping the energy off the walls and ceiling is the name of the game hear. I had experimented with different heights and placements before I came to mostly covering the first 20 rows with direct sound and the rest where getting the indirect bounce best compromise.
I mix these shows on an SC48 so using groups to EQ the Vox and Music separate keeps the music sounding more full and the Vox band limited then your house EQ is for problems and quick show fixes.. Rolling your HP up till it just starts taking the balls out is advisable.
The Word,
Nate
KDS&L
Yo Where the spell check at? I'm not a professor I'm a sound goof!
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i agree with all, that best way to go is a lot of speakers nearer to the audience.
but if there is no money for a delay, i doubt that there is any money for extra speaker or even amps which you will need for a delay.
maybe there is another option.
hangar are big. and most events donīt need this much space.
so why not start with a better sound befor the event starts, with a right planing.
think about where to place the event in this hangar.
i think that the positon of the audience and the stage in the hangar will help also.
havenīt tried it yet, i can imagine that this is the better way
********************
* s aaaaaaa*
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than that
********************
*s aaaaaaa *
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... for the audience, not the band (for them it will be better the other way)
maybe this is worth a thought.
carsten
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My AFSC is 3d1x3, RF Transmissions Tech.
As for equipment available I'll have to get back with you all for specifics. The rack I use has a mackie mixer, then a compressor, a DSP with auto feedback suppression, that RTA input, and various patches to set up crossovers, Shure wireless microphones, and two crown poweramps. I can probably get 1 more power amp from another rack if I need it.
Speakers are all JBL. There are two cabinents with a 10' and a tweeter, and 4 with 12' and a tweeter. We have more speakers in storage, but I think they are all massive cabinets and subs. Not anything I can put on a speaker stand.
As for raising the speakers higher than a stand, I don't have the clout to pull that off on a regular basis, but if we ever have an event in the future that is really high profile I'll see if I can get help with it.
EDIT: The Compressor is a DBX 1066, and the DSP is a DBX Driverack 260.
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My AFSC is 3d1x3, RF Transmissions Tech.
35E20 40+ years ago so I don't even remember what that is. Something electronic that was awarded to me for civilian experience before I was drafted.
As for equipment available I'll have to get back with you all for specifics. The rack I use has a mackie mixer, then a compressor, a DSP with auto feedback suppression, that RTA input, and various patches to set up crossovers, Shure wireless microphones, and two crown poweramps. I can probably get 1 more power amp from another rack if I need it.
Speakers are all JBL. There are two cabinents with a 10' and a tweeter, and 4 with 12' and a tweeter. We have more speakers in storage, but I think they are all massive cabinets and subs. Not anything I can put on a speaker stand.
Old speakers doesn't mean they are bad... More speakers closer to the meat in the seats, is better than a few speakers far away. More amps would be useful too but you can probably double up similar speakers on amp channels of modern amps. (observe speaker impedance and amp drive capability).
As for raising the speakers higher than a stand, I don't have the clout to pull that off on a regular basis, but if we ever have an event in the future that is really high profile I'll see if I can get help with it.
You can only do what you can do...
EDIT: The Compressor is a DBX 1066, and the DSP is a DBX Driverack 260.
You just need to do the best you can do with the tools you have. Understanding the problem is a start... sending sound at the peeps and not spilling over into walls and ceiling is a start.
JR
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Yes and no......but mostly no.
There are easier and more effective ways to maximize your system capability by simply using your graphic EQ. If you don't have a graphic EQ, you're kind of crippled.
If you'd like a PDF of how to "ring out" your system, send me your email address in a PM and I'll send it to you. I cannot attach PDF's here or to PM's.
Dick-
Please post your suggestion(s) in plain text. If pictures are included in your PDF, and we are still interested after reading the text, we may then request the "whole enchilada".
-Dennis
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What's this "we" thing? Do you have a turd in your pocket?
Carry on Dick.
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Dick-
Please post your suggestion(s) in plain text. If pictures are included in your PDF, and we are still interested after reading the text, we may then request the "whole enchilada".
-Dennis
I've posted the method a half-dozen times. If you don't know how to ring out a room with a graphic, I'll happily send you the method. It's nothing novel and I suspect that 90% of the folks who have been doing sound for more than a couple of years already know how to do it. But it's just easier to do an Email dialogue with GEQ noobs than futz around with a thread.
In a nutshell:
Raise each band slider one at a time starting with the low end of the GEQ to identify hot frequencies. Attenuate as needed. Lather, rinse, repeat.
More than that, send me a PM and I'll happily guide you through it more thoroughly.
Bob....
Thanks, as usual.