the even coverage i think is the reason for arrays. i heard that it is illegal to have over 100dba at any spot in the crowd which is actually not a lot so the main concern these days isn't to reach 100dba but how not to blow by it on any hot spots like the front row ...
arrays are more than anything a tool to control the coverage to avoid these hot spots ...
this is why everything is flown now except maybe a few subs - to keep speakers at a safe distance from people to avoid frying their ears excessively
subs largely fall outside of the A-weighting curve on DBA SPL meters so they can be placed closer to people than full range boxes
it would be a lot easier to just put speakers on the side of the stage facing the crowd but the first row would be hit with like 120 dba, which would be very bad
of course the other benefit of arrays is the coupling of the elements next to each other boosting output - but this is only a benefit in lower frequencies - and high frequencies are actually a weakness of arrays ...
It's rented for a certain amount of time, which is generally how long the tour is. The rental companies also usually supply the technicians to deploy it.
Sometimes the PA is rented locally. It all depends on the band and their budget. It can also depend on the location of the shows. When you're doing a tour around Asia (as I currently am) you will use locally rented PA systems in every country because it's not realistic to fly it around. But we do fly around our mixing consoles, microphones, wireless gear and some other stuff so that we have consistency.
Yes and it has to withstand being pushed over bumps, long bumpy truck rides, extreme heat and humidity and they're often punished all day at festivals.
Install amp barrier strips allow for faster installation in a rack.
Measurements often tell a different story.
Hypex and Purifi would be my choice for this.
are systems always transported on trucks ? does that mean that a tour would have to be limited to a single continent ? or rather that if a tour spans several continents then gear would be rented separately on every continent ? i guess it would make sense since there might be compatibility issues otherwise.
i never thought about these logistics when hearing things like "North American Tour" ... that it's limited by the ability of gear to travel ... because the talent can fly but the gear has to go on a truck ...
i guess a week between tour dates is just enough time to move the system by truck from one city to another as long as they're within the same geographic region ...
yes
It's not illegal. Most shows go well over 100db, but some places have limits which is often measured as 100db average over 15 minutes.
Yes
Yes.
Kinda. Getting even coverage with subs is tricky, especially in arenas. It's helpful to have some of them flown and some on the floor. When some are flown, the floor subs don't have to be as loud so they won't pummel the people in the front.
It would ruin site lines and destroy any sense of even coverage. It's not difficult to fly a large PA system. I watch people do it in about 45 minutes to an hour (sometimes less).
Why do you think high frequencies would be a weakness? That's certainly not my experience.
They're almost always on trucks. It's cost prohibitive to fly a large format PA system on a plane. But we have those PA systems all over the world so we will get them locally. Often times, we will have the same PA for all of America and Canada. Then we get a different one for Europe. But when we're flying around, we will get it sourced locally. This brings along as many complications as you can imagine.
Yes, unless you scale down to a "control package" and carry less gear. But tours are booked by region for this reason.
We are used to the compatibility issues and we adjust accordingly.
The talent also often travels on buses just like the crew. The logistics are certainly a thing..........but the industry does well to move the gear around. a 10-15 semi-truck tour is not uncommon for arenas.
We load in during the early morning hours. Do a show the same night, then load it out onto trucks that night. We sleep on buses while they drive to the next city. The trucks drive to the next city and we load in again at 8am. If the tour is booked properly, we will do many days in a row like this. It only works in Europe and America/Canada. For Asia, South America and other parts of the world, we fly around.
yeah good point. three single phase amps isn't the same as one three phase amp. i should have been clear 3-phase is better when it is delivered as 3 phase straight to the amp, not when it is split to three single phase amps. amps that take 3 phase power of course are not cheap.
i guess it depends on how you define "high" frequencies.
i am reading this:
https://www.prosoundweb.com/examining-line-array-high-frequency-output-capability/
and according to that write up ( which i believe ) line arrays start to run into issues above 5 khz or so ...
which would still make for a bright sounding system, but not an "airy" one ...
it depends of course on how close to the limit the system is pushed. you can EQ the HF if the system isn't at the limit.
On my point about the weight issue I'm only referring to the arrays, subs, and other big cabs. A 200 pound sub vs a 100 pound sub; that sorta thing. The implication being a five ton rig vs. a ten ton rig, which is going to impact moving the gear from A to B, including what kind of trucks are involved. I can see why this might not matter all that much in a professional setting if everything is motorized, coordinated logistically, and so on. I'm making the mistake of imagining if I got to set up a NIN system and what sort of effort that would entail. Plus add to this scenario that I'm lazy and want it streamlined.
It sounds like the band will lug the rental gear around on tour, as previously mentioned, so the little things will start to add up into nice-to-haves over the duration. The whole scenario is sort of funny because a big name act is essentially a group of talent moving around entirely in the rental sphere. Every vehicle, every bed, every woofer, every stage. I'd have a hard time getting comfortable in that environment. Edit: hard to blame a band for doing the nonstop party routine in light of certain realities. There aren't a lot of options that address such a unique situation.
The VHF is always a limiting factor at distance due to atmospheric losses in addition to inverse distance losses. At a football field distance, the SPL delivered above 10kHz may drop between 10 and 60dB compared to frequencies below 1200Hz, the typical lower range of a high frequency driver in a line array.
Obviously, the high frequency system transducers can't handle several orders of magnitude more power, so we live with the losses.
https://sengpielaudio.com/calculator-air.htm
As evident in the above calculations, humidity and temperature make huge variations in losses.
When I first moved to the high, dry desert conditions of New Mexico from the humid summers in Minnesota, thought I'd lost my hearing when I started mixing again, the VHF was literally less than half as loud at 100 feet than I was used to.
I remember the first time I'd actually seen dozens of 2x18" subs used in end-fire arrays was at Tingley Coliseum, in Albuquerque on 3/11/2006 when an old friend invited me to see KoRn, who he was production managing at the time.
Shortly in to their set, the FOH sound power died.
We first ran to the sound power distribution expecting to find a tripped breaker, but Wally found an entire phase dead. He checked the 4/0 power cables back to the disconnect and found one of the 400 amp 3 phase mains fuses had blown.
Had to track down the house electrician to get a replacement fuse, seemed like forever, though probably around 15 minutes. Definite vibe kill...
In the interim, the sound guys blamed the light guys (who had a separate 600 amp 120/208 three phase service) for the power outage because a 30 amp projector had been plugged into the sound power distribution.
Art
the article i linked suggests limiting coverage to distances where absorption by air is not a huge factor, then using additional arrays on delay after that.
the loss of HF discussed is instead due to 2 factors:
1 - mass break point of compression drivers around 3 khz
2 - out of phase summation of different array elements
absorption by air is in addition to that and then there may be even further factors for example Dave Rat explained that the heat from the crowd can cause a sort of an acoustical mirage:
that ends up reflecting high frequencies so they don't reach the crowd ...
a lot of factors conspiring against HF in prosound ... we have it easy at home !
The article ended saying: "The future will bring improved transducer technology to provide the output we need to provide a full, high-level, very-high-frequency listening experience out to a distance of 200 to 250 feet, with an acceptable, although lower, experience to 300 feet. Beyond that distance, air propagation losses are very significant, and additional delay clusters will continue to be required for full fidelity."
There has been no improvement evident in over 100 years of transducer technology advancement that could compensate for air absorption VHF losses.
I don't expect any breakthroughs until teleportation becomes commonplace.
As far as delay systems, they can only be aligned to a single position, under a specific environmental condition which is subject to constant change, and are too expensive to deploy for around an octave that most of the audience won't miss.
They will continue to used, but won't solve the VHF problem.
We spec systems to have plenty of "headroom" so we're not running them into limit. I'm not saying that it doesn't happen, because there are certainly issues but we like to always have more PA than we need. The PA manufacturers know how to deal with any high frequency issues that are described in that paper. The software does the math on how the line array is set up. We model the arenas, stadiums, etc. in the software and they compensate. We take a multitude of measurements to get even coverage from the front to back as much as possible. We use a lot of EQ.......but we aren't usually limited in the top end. When you combine the array boxes at the top to shoot further, they are flatter so the top end couples more. The array works with the software to accomplish all of it.
Delays are needed in stadiums and for the lawn in amphitheaters but we can cover most arenas just fine with a normal array. You get a little bit of top end loss in the very back but it's often not much.
D&B amplifiers compensate for temperature outside so they change the response based on it. The PA manufacturers are all aware of these issues and they have plenty of tools to deal with it.
oops, you're right. it sounded wrong to me as well because i knew it takes more than one show for the system to pay for itself but when we are wrong we tend to just rationalize it away instead of questioning ourselves. i make dumb mistakes like this a lot and usually too lazy to double check. GRRR
Still, nothing bad ever became of giant sound systems, even if they only ticked off your neighbours for miles around. 😉
Count me in.
Count me in.
The thing is; giant sound systems are not louder or better sounding than what we use now. Line arrays are far more effective at giving even coverage and can easily be as loud as any old baffle PA system. Modern amplifiers and speaker drivers are so much better.