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SPL question [message #33463] Sun, 24 June 2001 13:02 Go to next message
James W. Johnson is currently offline  James W. Johnson
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Registered: May 2009
Master
The JBL HLA 4895 3-way combined with the 4897 bass module are JBLs top of the line tour sound products, they are capable of producing 140dB from 34Hz on up from 1 meter....can a pair of these fill up a football stadium with sound? The reason I ask is that my current set-up can produce around 100dB from one meter so they are only 40dBs away from being able to fill up a football stadium with sound?
Basically what I have now is not loud enough for me, but I am pretty close , it seems to me that if I could turn up my volume knob just a couple of notches more I would be satisfied, certainly the Four Pis I am preparing to build should get me there.
So how does SPL perception work, is it that once you get to a certain point each decible becomes more powerful?..In other words does the sound seem twice as loud for each additional decibal after a certain point? How does this work?
Re: SPL question [message #33465 is a reply to message #33463] Sun, 24 June 2001 14:46 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18786
Registered: January 2001
Illuminati (33rd Degree)
Point sources falloff at 6dB each time distance is doubled and line sources falloff by 3dB each time distance is doubled. Small spaces can generally be adequately covered with a few number of speakers having wide angular coverage. Larger spaces usually require more speakers, each with narower coverage. And there is also a matter of whether the space is indoors or outdoors, because sound systems indoors act very differently than sound outdoors, so sound systems used in each have their own sets of requirements. This is a subject that really needs a book (or several) to properly address. There are lots of good books, and the link below is a pretty good one to get you started.
Re: SPL question [message #33466 is a reply to message #33465] Sun, 24 June 2001 20:21 Go to previous messageGo to next message
James W. Johnson is currently offline  James W. Johnson
Messages: 199
Registered: May 2009
Master
Where can I see a list of equipment professional bands use? I would love to hear what sort of equipment it takes to put on a show like Woodstock.
Re: SPL question [message #33467 is a reply to message #33466] Mon, 25 June 2001 01:25 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18786
Registered: January 2001
Illuminati (33rd Degree)
For big name acts, you'll most likely find JBL, EAW or Meyer, companies like that with big P&L statements. There is generally a rider that specifies a list of what equipment can be used, and it is a short list for the bigger acts. The list of vendors grows larger as the acts get smaller.
Re: SPL question [message #33468 is a reply to message #33467] Mon, 25 June 2001 10:30 Go to previous messageGo to next message
mikebake is currently offline  mikebake
Messages: 243
Registered: May 2009
Grand Master
Most non-pro audio people will not be that familiar with the associated electronics, which are such a part of the sound reinforcement scene. Several top line boxes require their own controllers in order to function correctly.

Saw The Three Tenors outdoors in Detroit 2 years ago, an all-Meyer system, sounded great. Turbosound has some pretty powerful boxes, the Flashlight and Floodlight series. I guy I know who uses Turbosound is raving about Funktion One speakers, from the guy who developed Turbosound. Check out their website at funktion-one.com. Also check out audiodirectory.nl for some more interesting pro audio manufacturers.

All the big names have web sites which pitch their particular solution and are pretty interesting. Certain truths in sound reinforcement have cropped up over the years, and are usually based on solid physics.

Re: SPL question [message #33469 is a reply to message #33466] Mon, 25 June 2001 14:31 Go to previous messageGo to next message
pickle is currently offline  pickle
Messages: 24
Registered: May 2009
Chancellor
Also, to see a partial sample equipment list for a company which does some pretty big shows (large national country or rock acts in a fairground setting; they did Def Leppard a few 2 years ago, routinely do first-rate large country acts at outdoor venues) see the URL below. Basically as the show grows they just add/rent more Meyer boxes and amps.................. lots of people seem to like the Yamaha boards........
MBB
Re: SPL question [message #33471 is a reply to message #33468] Mon, 25 June 2001 17:33 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18786
Registered: January 2001
Illuminati (33rd Degree)
Good links, Mike, thanks!
Re: SPL question [message #33474 is a reply to message #33471] Tue, 26 June 2001 09:27 Go to previous messageGo to next message
James W. Johnson is currently offline  James W. Johnson
Messages: 199
Registered: May 2009
Master
Thanks for the link Mike. I found another interesting link these folks cater to bands such as the Red Hot Chili Peppers.
Here is their take on horn loading... http://ratsound.com/concept.htm

Their Rat Trap Five speaker seems like a real winner, I wish I could hear a pair of them. Here is a link to their system configuration page , it kind of shows what it takes to fill a given area with sound... http://ratsound.com/sysconfig.htm

The pic is 24 of their Rat Trap Five speakers used at a Pearl Jam concert.


Re: SPL question [message #33475 is a reply to message #33471] Tue, 26 June 2001 09:36 Go to previous messageGo to next message
James W. Johnson is currently offline  James W. Johnson
Messages: 199
Registered: May 2009
Master
Thanks for the link Mike , I found an interesting link, these guys cater to bands such as the Red Hot Chili Peppers.

Here is their take on Horn loading......
Minimize the use of horn loading.
Horn loading increases output volume at the expense of sound quality.

How many home stereos and recording studios use folded horns or any kind of horn loaded cone drivers?
Why don't home stereo speakers use horn loaded speakers?
Like talking through cupped hands for volume. Certain frequencies are louder than others, adding a honky or nasally sound.
To correct this, equalization is used to reduce the volume of those frequencies.
The bigger, more efficient horns, need more EQ.
Cutting the loudest frequencies with EQ partially negates extra gain realized by horn loading and does not thoroughly solve the sound quality problem.

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Making a excellent sounding system loud, rather than attempt to make a loud system sound good.
In order to get horn loaded volumes from a reflex/infinite baffle system, every little bit counts. It is like fine tuning a race car engine. A lot of interrelated factors all sum together to reach the goal of reproducing sound with extreme accuracy at amazing volumes .
Minimize facial area. Reducing the baffle size to the absolute minimum keeps the drivers close together within the cabinet and box to box. This increases driver coupling, minimizes phase interference and therefore, increases system efficiency.
High Density. More components per box maximizes power handling per cubic foot for better coupling and more headroom.
Precise component selection. We use several different manufactures in order to achieve the optimum balance between sound quality, power handling and efficiency.
5 way. Every component is utilized in its optimum operating range, where it sounds best and is most efficient.
Matched and balanced power. Amplifier power is accurately matched to the components.
Proper system protection. Our systems are protected by precision limiters that allow the cabinets to reach absolute maximum volume and then seamlessly engage to prevent component damage.
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Smooth coverage of the audience.
The Rat Trap 5 Array exhibits extremely well behaved coverage patterns.
The small baffle/cabinet size minimizes the array size, reducing phase interference between drivers.
The fly array is a spherical segment with variable angles in both the horizontal and vertical axis for smooth, even coverage of the entire audience area.
Trapezoidal cabinets allow for minimum spaces between boxes in the fly array. Reducing gaps between cabinets increases coupling efficiency and reduces phase interference.
The 18"s are in separate cabinets coupled to the floor, not in the fly array, keeping the system compact, improving sight lines.
4 different Rat Trap configurations: short throw, long throw, flyable subs, and ultra long throws. The Rat array is extremely versatile and can be configured to provide optimum coverage anywhere from clubs and theaters to arenas and stadiums.


Their Rat trap Five seems like a real winner , I wish I could hear a pair of them.
The Pic is 24 of their Rat Trap Five speakers used at a Pearl Jam concert.

Re: SPL question [message #33476 is a reply to message #33475] Tue, 26 June 2001 12:00 Go to previous messageGo to previous message
Wayne Parham is currently offline  Wayne Parham
Messages: 18786
Registered: January 2001
Illuminati (33rd Degree)
Thanks for the link, James. Can't agree with them about horn loading though. You can always screw up anything, and horns are no exception. But a well built horn provides high output, smooth response, low distortion and controlled directivity. To be honest, the only valid argument I can see against horns is their size. But in a prosound environment, this vanishes. You're dealing with large spaces, so you can make large cabinets. In this case, the size of horns isn't a problem. In fact, the end result is smaller, because a horn produces more sound per cubic foot than a direct radiator does.
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