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In Reply to: RE: Danley installation at the new Mercedes Benz stadium in Atlanta posted by BofService on April 03, 2017 at 11:41:06
Hi Paul, inmate, Guys
I don't mind explaining things when asked and there is time but arguing is what has made me lose my taste for posting on DIY forums.
If you don't have face book you can still see much of what's there, just google Danley sound labs facebook, at some point a join nag screen will pop up, just click "not now". It's much more current than the web page.
Near the middle at the center (sort of a running history) should be some pix of one of the systems being hung at the stadium, for the high efficiency folks, those 2 horn loaded subwoofers replaced what originally would have been 14 double 18 line array woofers.
Not only can they produce the same spl at the audience but they do it at a lesser percentage of rated power AND go down nearly an octave lower AND has forward directivity.
The other two high efficiency boxes, the J1 and J2 replace a 16 element large scale concert line array and should have at least 15dB of headroom at full tilt, the two are needed because of split level seating requiring different aim points
At the lower center, scroll down to Dec23 for a video fly through of the MB stadium, they mention us out of the blue and no we didn't pay them or even know about it.
Another fun thing has been Disney, if you have seen the Star wars spectacular or Rivers of Light, those are our speaker systems.
And so far as generation loss testing, the reason I have mentioned it more than once is because there are some people who build or modify their loudspeakers and they more than electronics can be /are somewhat mysterious.
Dick Heyser spent that last part of his life trying to build a bridge between what we measure and what we hear. Generation loss testing doesn't make that connection but it's useful because each generation is an increasingly grotesque sonic image of what's wrong, because to the degree it was faithful, there is no alteration.
Now, there is nothing like a red arrow that tells you what to fix, but it can sure point out the area you need to look.
Not only that but often once you hear the warts magnified this way, they are often now audible to you listening straight up.
The issue is again how we hear, part of that process is seeking the information and throwing away the noise so we may not have heard the flaw straight up until you hear it magnified and recognize it's signature. Hope that makes sense.
So why do generation loss recordings?
Well we did it mainly because I was unsure about what I was hearing, as the Unity and then especially Synergy Horns measured more and more like a single driver on a big horn, they also took on a odd quality I could not identify on the TEF. With a soft voice, it got harder and harder to tell how far away the speaker was if your eyes were closed AND the more a pair disappeared when producing a mono phantom or stereo. Until much farther down that road, I had never realized or experienced a mono phantom so strong you were not aware of the right or left speakers as the source. To me it looked better and better but the sound or lack of source depth localization was puzzling.
Initially I used a tower to remove any nearby reflections and a 24/96 MI grade multi channel recorder and m50 microphone. I used several parts of songs that I thought were most revealing and played that at 90dB at 1 meter, recording it with the microphone. Every successive generation the previously recorded mic signal is used as the playback source and recorded yet gain. As the speaker measured more like a single radiation in time, the greater it's survival in gen loss testing. It was also a way to compare competitor's speakers and after a few, we stopped doing it regularly.
The single point of acoustic radiation is part of it I think, one impulse in equals one impulse out not dependent on position and one property of even the largest Synergy horns today is you can stick your head insider while it's playing music and move up/down/left/right and never hear anything but one source of sound somewhere in front of you. You can't hear woofers, mids or tweeters, even when you walk inside the biggest one with a 10 foot tall mouth and 108 drivers.
This also means that in addition to no "minimum distance" and unlike a concert array, it sounds fine at any distance. To the degree they are CD, moving off axis only reduces spl, not the spectral balance so with the proper horn angle and mounting height, one can reduce the variation over a large stadium to about + - 2dB.
One other advantage of using a gen loss test to "point the way" so to speak, is that afterwards anyone can make nice sounding video's capturing the sound with a cheapo camera or iphone, in this case a canon vixia r300. If you have headphones handy, try a couple of these video's.
Here is the Caleb while it was at my shop being tested. This was taken at about 400 feet from the loudspeaker, about twice or three times the maximum usable distance of a large concert line array.
These are 10 foot tall horns are used in stadiums like (2@) FSU and (1@) Kinnick in Iowa. I was at the commissioning for Iowa, here is a video of the Caleb located behind the Hawkeye in the scoreboard. One of these addresses the far side, this video taken 800 feet from the speaker
Someone else's mic in a hall way captures a smaller system during set up
Here is what the far seats sound like;
Here is a really big stadium at LSU, you hear low bass because at the far seats it's still only -3dB at 27Hz;
Not all of them are "end zone or "scoreboard systems" some are distributed on roof tops where weather and stadium design are an issue such as in the Tundra of Greenbay. Here the speakers are in little cubes along the roof line.
Anyway, if you can't get on bookface, try the high efficiency video's.
Great post, Tom. Thanks for the links. Time for a bit more homework!
Will you be judging Midwest again this year?
Thanks again for adding to the body of horn knowledge, and for providing some entertaining distractions from looking for occult meanings and phantoms on the radar here.
Last night I attended the AES meet touring the facilities at he Old Town School here in Chicago. In a room full of platinum eared experts nobody argued, and nobody even disagreed with anyone! But nobody showed up masked either. This reminded me when you showed the Unitys at an AES meet back in 2007. The room used was difficult (to say the least!) and the bottom end was limited because you couldn't bring the subs, but the sound was very impressive. I brought a Stereophile reading friend with and even he liked it. It's interesting that while you are focused on coverage, there are some people going the other way. That same friend took me to a Magico demo at one of the local audiophile salons sometime back. The Magicos were in a heavily treated room and they had a very narrow one-seat sweet spot! My friend seemed oblivious to this, even after I asked him if he has ever heard half of the CSO disappear if you moved one seat left or right! My friend was still impressed with these one seat wonders however, and wanted to go back for another listen later. I heard the Magicos at the last Axpona here and they didn't have the one seat wonder effect, so I have to write it off to the room treatment and set up.
Richard Heyser was definitely one of the heavies in audio. One of his interests was the similarities of the paradoxes in the quantum/macro worlds in physics, and the paradoxes between what we hear and measure in audio. Doug Jones made Heyser's notebooks available online and I printed several out, but it's rough going trying to read Heyser's handwriting, and making corrections to make it a readable text. Hopefully some day these notebooks can be made into a readable book. I'd be happy to contribute what little I have.
And thanks again for the horn continuum concept, I had kind of thought of this, but you got there first by putting it into words here. And oh yeah, I've had to eat my pejorative comments on conical horns after hearing yours, but I'm not going to thank you for that lunch ; )
Hey, Tom, I have a question. In venues and in pro audio magazines, I often see speaker arrays being "flown" from the ceiling, and I often think "How do they know how much weight that structure will hold?". I 'get it' that they're often concave and so are pretty strong, but still, do they just cross their fingers and hope for the best, or are there weight limit specs which the tour sound companies get in the contract before setting up? I mean, seriously, when the sound crew is hanging literally tons of speakers from a ceiling, that's gotta be an issue.
Fortunately, I got out of the tour P.A. field while we were still doing floor and scaffolding setups, so I haven't had those nightmares to worry about!
They know in advance exactly how many hanging points there are and their load capacity for any given venue.
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