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Flown line array angles?


ceecrb1

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Again, going back to the "I've never done a formal course"

 

Just wondering what the guys who have, have been taught on setting the "hanging angles" of line arrays?

 

also, having never been the person taking the decision, what makes it for you?

General layout and basic use of angles to cover the area or is there more to it?

 

Ta muchly.

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yeah been desperately trying to get the company to pay for me to attend a course that repeats itslef a lot here by DAS audio....

 

Truth is in a few weeks I have a small array of 4 seccions... for a very large square... it wont work and the client knows it but its still my job to make the best I can of the situation....

 

Hence trying to work out if there is more science to it than just aiming all the sections evenly over the area etc...

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What are the boxes?

Is it proper "line array" or just flown boxes (people are frequently mixing the two up sometimes)

If it's a real line array, scrimping on the correct amount of boxes for even coverage according to prediction analysis is going to be a complete waste of time. If it's a large area to cover evenly you will probably need in-fills, out-fills and possibly front fills....this will also apply even if you are flying a conventional box.

Always extremely irritating that the client knows that the system is going to be inadequate and it's the crew that takes the flack from irate punters :** laughs out loud **:

 

I guess this is a free event? If you can give a little more info that will help people here. Also what type of structure will you be flying this gear off? For obvious reasons this is not an area you can scrimp on whatever the client says.

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No luckily the structure is not being scrimped on....

 

 

the job is the arrival of the 3 kings (more important here in spain than santa) to a town near barcelona...

 

The job is in a large L shaped squre, however the show only takes place in one of the legs of the L.

The square where the staging will be is roughly 40x80mtrs with people stood apparently rather filled and crazy!!!

Sound sources are. one headmic for roaving around, 1 lectern with 2 mics and mp3s... simple enough.

 

I have 3 small arrays placed in the square where the main stage and walkway will be..

 

however, last year there was a "large" line array covering the entire 2nd leg of the L.. which we have financially had to remove, also during the client meeting

I asked if I was covering the entire square with sound and they said no, just where the staging is (ie in one leg only)

 

I will be also rigging 2 arrays at 90 degrees to each other to best fill the 2nd leg.

 

The 3 arrays in the square will each have 2 subs and 3 array sections.

The 2 which are for the "other part" will be 2 arrays each of 4 secions.

All systems will be rigged on staging/supports or flown so the arrays are over head height

 

The array system is..

http://www.tecno-star.com/upload/pdf/AX-210.pdf

self amped 1500W sections

With 120degree horizonal and vertical "as configuration"

The subs are equally powered

 

There are no more sections available (physically and financially)

I have total:

18 tops

8 subs

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I would speak with the manufacturer if you can. I am in the same boat as you to a certain extent as I have never been on a formal course. I have been working with a Martin Line Array and Martin Audio have been superb, they sent me all the information and software I needed via email and also offered phone support.

 

I have found most manufacturers want there equipment to be set-up and used corrctly as its a shop window for them.

 

Chris

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"Again, going back to the "I've never done a formal course"

 

Just wondering what the guys who have, have been taught on setting the "hanging angles" of line arrays?

 

also, having never been the person taking the decision, what makes it for you?

General layout and basic use of angles to cover the area or is there more to it?"

A few points, from a regular user of various line arrays (and an early qualified V-DOSC engineer) ...

 

Training courses are all very well, but they only teach you how to use the manufacturers' aiming sotware and to rig their systems safely and effectively. Consequently a lot of line arrays are regularly set up very badly by people who think that's all they need to know.

 

What they don't provide you with, is any understanding of the basics of acoustics and how sound propagates outdoors - without which you can't get it right. Partly this is because their marketing departments want you to think that their magic software is all you need to become one of the the big-time experts. But a lot of the oh-so--clever people who design this software have no real-world experience of this specialised field of work. The biggest problem is that they think sound waves always travel in straight lines.

 

The second biggest problem is the very naive modern conditioned belief that if something has been calculated by a clever computer spreadsheet, then it *must* be right. People don't realise that they need enough background technical knowledge, and experience, to be able to interpret what's on the computer and adapt it to prevailing conditions.

 

"Hence trying to work out if there is more science to it than just aiming all the sections evenly over the area etc..."

A "real" line array, ie one that behaves somewhat like a line source over a substantial part of its frequency range, is NOT just a an array of angled boxes. Rather, it is a single speaker, tall and thin, that can be broken down into modules for transportation. Much of its acoustical behaviour depends the size and shape of that single large loudspeaker. So yes, there is a lot more to it than the use of angles to cover an area (a technique that DOES work for small cluster type arrays)

 

 

----------------------------

 

As for your 3 Kings event:

 

From the spec sheet it is not clear whether that is just another of the many simple "vertically arrayable" systems now on the market, or whether it can be made to behave like a "real" line array from a major manufacturer. But given that your lines are too short to have much LF directivity, that doesn't really matter in this case. As you are aware, you will just have to be pragmatic and do the best with what you have available. Your system will have some attributes of a (vertical) angled cluster and (maybe) some attributes of a short line array.

 

Just remember that the smaller the intercabinet angle, the tighter the HF beaming will be, so the angles need to get smaller as you go higher in the stack.

You should get hold of a pair of the boxes in advance and get a feel for the effects of coupling. Put them together on their sides, feed them with low level pink noise and walk around and listen to the effect, on high and high-mid frequencies, of varying the intercabinet angle . As you increase the angle, you will reach a point where a hole in the middle occurs. This will first appear at the highest frequencies, and then begin to affect the high-mids as the angle is increased further. From this you can decide on the maximum allowable angle for the lowest two boxes depending on your view of what's an acceptable compromise.

You should also be aware that stacking the boxes close together will increase LF and low-mid efficiency, even if there are angles between the boxes. So don't expect a stack of four to sound the same as a single box or a pair.

 

As with any speaker system, getting them up high and angling down onto the audience will be better than having them too low and skimming across the crowd. A crowd of people generates a lot of warm air and the sound will be refracted upwards by a surprisingly large amount, resulting in no coverage at the back if you aren't careful. This is, of course, also the reason why you can't just follow what some manufacturer's line array spreadsheet has calculated based on the assumption that sound always travels in straight lines...

 

Hoping this is helpful.

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Yeah the website does supply for "ease" but as its need paid for..... not too much an option..

 

thanks.

 

Phone the company, tell them it's a bit of a unique coverage scenario and say you'd like the software AND phone support if neccessary, BECAUSE (and this is the important bit to state) "you wouldn't want to run the risk of THEIR system being compromised and possibly affecting THEIR rep unneccessarily".

 

They should give you the software for free and also offer to help you as much as they can - after all, their badges will no doubt be more prominent than your companies logo's all over the flightcases hidden from view!

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Given that you have so few boxes and apparently rather deep area to cover, why not consider hanging a larger centre cluster to cover each leg.

 

The greater number of boxes you could allocate to such a cluster would allow you to design a system to actually have appropriate vertical coverage and even level front to back.

 

The boxes have a very wide horizontal coverage, so you ought to get all the audience side to side, except those very close to the stage and off to the side. Some side fill may be necessary to cover this. A centre cluster will probably aid clarity of the system where you have large buildings defining the perimeter of the space. Since the programme is primarily voice reinforcement there should be no artistic directive for stereo (or surround, or ...).

 

It is not easy to give advice regarding the setting of splay angles whilst being unfamiliar with the space and the system (though reading Bob's book is always good advice). I would not hesitate to contact the manufacturer, I imagine they would be happy to advise an on an appropriate system design. I would not use the tone and line advocated by Stagemanagement, you might be mistaken for a jerk, when in fact you were just following some bad advice found on the internet

 

Good luck,

 

Phillip

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If you could find a Meyer box that is similar to the one you are using you could give MAPP a go. It’s free and depending on how close a match you can find in the Meyer line up it should be accurate enough for this type of coverage prediction

 

 

 

www.meyersound.com/mapponlinepro

 

 

 

A good starting point would be something from the MILO range like a MILO-120 or MICA etc. Sorry I don’t have the time to compare the spec sheets

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incase anyone can give further insight...

here is a google-earth modd'ed layout of the line arrays (note, done in paint not 100% accurate.....)

http://www.telefonica.net/web2/colinbone/gavaarial.jpg

The black is a small stage and walkway where an "anouncer" will roam with a wireless headmic and where the 3 kings will arrive and leave from..

 

The red signifies line arrays with the "leg" (not gonna put a phalic word) extending towards (rough, it was done in paint) rigged direction with the number of array sections beside the array.

Each array section is 1500W and will have 2 subs with each stack.

The array on the southern point will be flown at 6mtrs as will the pair to the east.

 

I have been told the whole square will be FULL of people like any street party.

The positions cannot alter too much as they are all placed with lighting scaff towers and for crowd purposes.. thats where they go!

 

I'm just having to hope I'm gonna cover the crowd well enough now.

 

There is no money to hire more, I cant see anything else I can do to improve the situation.

I have ONE more array seccion which I will place on one of the 3 stacks of 3, which is lacking or use as an infill for stage left area.. using it as a little room to play with once everything is rigged as it can be hung from the bottom of each array by hand.

 

Comments/guidance etc?

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Your "delay array" (!cheers copyrighted!) of 3 Stage Right, looks slightly uneccessary and may give you some phase problems from your SL array.

 

I'd be tempted to dump that and run the SL and SR arrays straight down your crowd (as opposed to the way the SL is angled with the "catwalk"), with one delay at the edge of the building and another at the end of the catwalk, rather than have them in the middle and fanned outwards.

What's your distance from stage to the edge of the building?

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yeah I do agree.. unfortunately.. the array positions are set by the client.. not for sound reasons but for public/people reasons.

The client wants the absolute minimum of groundspace occupied by gear..

 

so my arrays are with/under etc lights and cameras.

 

thanks for the comment though.

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