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[Chris Grimshaw]

Next, because it is sealed, the driver does not move as much (excursion) as with a ported box-so the driver is not "flopping around".

Only below the port's tuning frequency. Over the range where the port is helping (a wider bandwidth than you might think - fire up Hornresp and have a look), cone excursion will be lower for a given SPL.

The rest of the post is fine. In theory, sealed boxes can go alllll the way down with enough EQ. In practice, that takes a lot of cone excursion and power input. For small shows, you might get away with pushing for 60Hz, taking the hit on maximum SPL as you noted.


FWIW, most 12-15" passive tops have their ports tuned around 50Hz, but they start rolling off around 100Hz. You can boost at or above the port tuning to get more LF extension, but there's always the headroom tradeoff.

Chris

[Ivan Beaver]

Only below the port's tuning frequency. Over the range where the port is helping (a wider bandwidth than you might think - fire up Hornresp and have a look), cone excursion will be lower for a given SPL.

The rest of the post is fine. In theory, sealed boxes can go alllll the way down with enough EQ. In practice, that takes a lot of cone excursion and power input. For small shows, you might get away with pushing for 60Hz, taking the hit on maximum SPL as you noted.


FWIW, most 12-15" passive tops have their ports tuned around 50Hz, but they start rolling off around 100Hz. You can boost at or above the port tuning to get more LF extension, but there's always the headroom tradeoff.

Chris

Agreed, there are limits.

Everything is a tradeoff of some some sorts in some way.

[Tom Danley]

Something two people with a van can deploy without the use of forklift :-)

Not trying to negate the benefit of big point source boxes, just from a small operator point of view several smaller boxes are easier to deploy then one huge box.

Hi Marjan, all
I hear that “oh they are so large” pretty often and I have to admit, stuff is usually bigger in person than on my computer screen, but I also don’t think a lot of those folks grasp what they are looking at. 

Some of our boxes are large but remember they are based on a different philosophy than prevalent in sound now.     
This is aimed at getting the most sound possible from each box using horn loading and radiating as if they had one full range driver and NOT selling the most boxes possible for a given job or using an approach which wastes about half the potential acoustic power in self cancelation.   
I may not be able to lift a J-3 for example but I also couldn’t lift the 12 to 16 large format line array boxes it equals in output.  And it does so with far more uniform coverage and frequency response and larger working distance and less energy lost to the sides and rear.                                                                                                   

So yes even a j3 is big but it’s also way smaller and lighter with better pattern control than what they usually replace in stadiums etc and sounds more like a studio monitor doing it and still does in the wind.

Then when you get out to say 800+ feet like the far end of a 100,000+ seat stadium and the requirement is say 105A, that takes horsepower and even if you had a wall of array boxes to get the level and it would sonically fall apart long before that distance.
 
THAT is why we make “big speakers”, here is the Caleb (which has been rented out for temporary use out to 2500 feet) at my lab at 100m and a different one installed at about 800 feet (speaker is behind the Hawkeye in the scoreboard).  Pop on some headphones.
 
https://www.dropbox.com/s/g61e95t8eve7gux/20160623090318.mts?dl=0

https://www.dropbox.com/s/lyjf0p46163q4es/20140805175937.mts?dl=0

Here is a much smaller system, I think only about 60,000 seats using the J-3’s, the one more like a big line array and J-4’s aimed at the far end to get more upper end there.   You can kind of make out the speaker in the scoreboards.  This is more like only 500-600 feet away
https://www.dropbox.com/s/lqeg3cf0daqv9ti/20120726114748.mts?dl=0

https://www.dropbox.com/s/tnsw5mb4v5vdlwq/20120726122124.mts?dl=0

When the speaker system radiates as a single source, there is no interference pattern, the wind has much less effect on sound,  the spectral balance doesn’t change with position or distance AND to the degree one can make it constant directivity, then when you move off axis (out of or under the pattern), the SPL goes down but it sounds the same.    In the old video below Mike walks from under the pattern down field to the far end. An old demo below at a stadium that had a 3yr old concert array until this demo.  After the new system was installed, Clair bros who installed it measured + - 2dB.

https://www.youtube.com/watch?v=e_usTlJi2NA

This is why we make big horns, the bigger the room, the worse the acoustics are, the more directivity you need, the more acoustic power you need, the more you need all of those, the more compromised in every single way the array of sources approach is, not to mention in a big system vastly it’s more expensive and power hungry.     So when you see a big “D” box, especially the J series, remember that while it’s big, for it’s size, it probably makes more sound than you imagine.
Best,
Tom

[Helge A Bentsen]

Hi Marjan, all
I hear that “oh they are so large” pretty often and I have to admit, stuff is usually bigger in person than on my computer screen, but I also don’t think a lot of those folks grasp what they are looking at. 


Best,
Tom

I think a lot of people grasp what they are looking at from a logistics perspective, namely if you can't lift it with a sensible number of people, it's too heavy.

Like today, we're setting up for a outdoor opera performance and the centre channel is two 6-box hangs of mid-size linearray cabs from a known manufacturer, suspended from a scaff tower in the middle of the set.

We needed to carry them there, so they we're a sensible choice.
If you go with one big box to replace all this you have, from a rental companys perspective, placed all your eggs in one basket and have to say no to jobs like this because you can't get the PA into position.

Having a "one size-box" is not very sensible for a lot of people with changing work conditions/locations.

 

[Mark Wilkinson]

it almost seems like a qualifier needs to be stated whenever we talk about speakers....

here's my stab...... "Given this rigging, and this manpower, what are the optimal power contenders for this coverage pattern.........?"


I mean this thread started out looking for lounge-level, horn loaded, high spl boxes....SOS, or maybe on small lifts, ...probably trap kinda boxes ..

And then it moves to L-arrays and large co-entrant horns....not sure why, or even how they are relevant....

[Tom Danley]

I think a lot of people grasp what they are looking at from a logistics perspective, namely if you can't lift it with a sensible number of people, it's too heavy.

Like today, we're setting up for a outdoor opera performance and the centre channel is two 6-box hangs of mid-size linearray cabs from a known manufacturer, suspended from a scaff tower in the middle of the set.

We needed to carry them there, so they we're a sensible choice.
If you go with one big box to replace all this you have, from a rental companys perspective, placed all your eggs in one basket and have to say no to jobs like this because you can't get the PA into position.

Having a "one size-box" is not very sensible for a lot of people with changing work conditions/locations.

Well you can’t beat that instance, if you have to carry them one at a time by hand.   

Most folks put sets of boxes on carts in which each cart full often weigh as much or more and keep in mind you’re talking about a speaker strong enough to fill foot ball stadiums to the far end with just a few.

“If you go with one big box to replace all this you have, from a rental companys perspective, placed all your eggs in one basket and have to say no to jobs like this because you can't get the PA into position.”

Well if one were to go this route, for mains they would need probably three different sets of speakers and some fills to cover from the largest to the smallest use and use the volume control to scale the output to what’s needed.  I think Ivan has looked at this in some detail and in total it’s considerably smaller than one big array system.

So far this ignores the fact that they sound much clearer which is very important in large scales sound like stadiums, Disney etc …….BUT ARE NOT on any riders.   
There are some folks in Europe that have tried them and are starting to be used for live sound over there.  Here is a review from 5 years ago at a classical performance using a J-1, somewhat less powerful than a J-3 but has a subwoofer built in.

https://www.youtube.com/watch?v=AkrZplo9xgM

Maybe this puts it in better perspective
Best
Tom

[Marjan Milosevic]

Tom, dont get me wrong, i admire your work and you are one of a very few people in this business that i truly have unreserved respect for.
But you need to understand that most often people on the road are challenged in logistics way and they must compromise.
No need to debate the sound difference between a good point source and a line array. This is a question of practicality and logistics. Two people can easy deploy 16 per side of any line array box you can think of. But they will never be able to deploy your big horns. I can send two guys with a van and they can set 8 line array per side and some subs all by them self.
Especially in Europe logistic is more costly (gas is way more expensive then there) towns are like 15 centuries old and most things are happening in the old part of town. Infrastructure is different, streets way narrower. And so on. When i think harder, i dont think any rental company in 300 miles radius from me has a forklift.

[Ivan Beaver]

No need to debate the sound difference between a good point source and a line array. This is a question of practicality and logistics. Two people can easy deploy 16 per side of any line array box you can think of. But they will never be able to deploy your big horns. I can send two guys with a van and they can set 8 line array per side and some subs all by them self.
Especially in Europe logistic is more costly (gas is way more expensive then there) towns are like 15 centuries old and most things are happening in the old part of town. Infrastructure is different, streets way narrower. And so on. When i think harder, i dont think any rental company in 300 miles radius from me has a forklift.

But comparing a 8 element line array to a J series horn is not exactly.

You need to compare 16-20 large format line arrays to a J3-not 8 smaller ones.

For somebody needing a large system-the line arrays are not carried individually.  They are on a cart that is larger and weighs more than a J3.

With a hook in place, I can have a J3 wired and in the air in a less than a minute.

It also depends on the particular venue.  In most larger venues one person can push a J3 into place.

I don't see many venues that you need to carry 20 large format line arrays per side up steps.  Unless you have a lot of people.

In that case- there is no way 2 people are going to do that

For the smaller shows, there are cabinets that are smaller and lighter than the J3.  Those are the shows you are talking about-not the large shows.

A forklift is not much help on steps.  And since you don't need to actually lift the J3, it is not important.  Just push it in place-hook up the motor and plug in and go.  No lifting needed

[Mac Kerr]

For somebody needing a large system-the line arrays are not carried individually.  They are on a cart that is larger and weighs more than a J3.

Generally yes, occasionally no. Recently in Hawaii we had stacked V-DOSC on 6' high biljax decks. On the load out we could not use the fork we used to stack them, so they had to be individually unstacked by hand and carried onto the 4' high stage and then to the ground and then 30' to the plywood roadway so we could roll them the 300' to the truck. Everything was individual V-DOSC dollies.

Mac

[Ivan Beaver]

Generally yes, occasionally no. Recently in Hawaii we had stacked V-DOSC on 6' high biljax decks. On the load out we could not use the fork we used to stack them, so they had to be individually unstacked by hand and carried onto the 4' high stage and then to the ground and then 30' to the plywood roadway so we could roll them the 300' to the truck. Everything was individual V-DOSC dollies.

Mac

And there are exceptions all over the place.

I remember seeing one from a Beach Boys gig on a beach.

They had to carry everything down something like 200 or more steps zig zagging down the side of a cliff.

Then across plywood laid on the sand for hundreds of feet.

This included the full stage-with a top-PA-lights etc.  The consoles were PM5Ds.

I think it was for a 16 yr olds birthday party.

Yes-the daddy was not in the audio business.

A friend of mine was mixing monitors.  He carried his USB stick

He said it was a real bitch-but "for somebody else"-not his problem.

[ProSoundWeb Community]