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[Jim Russell]

Hi,

For the past couple of years we have been running a PA hire company in Scotland where we run two identical rigs using Mackie SA1530z and Yorkville LS 800p's.  

My dilemma is how to scale up our business from here. We tend to cater for events with audiences of up to 200 people. Recently we did an event in a large local hall which would probably hold 350+ with a high roof . We have four sets of 1530 Z is as well as four sets of subs. And what we found was although the sound at the front of the hall was great the speakers just did not have the ability to throw the sound to the back of the hall. And anywhere beyond about halfway (10/15 m from the stage) and generally the sound was really muddy with no definition or power.

Our systems are completely mobile and we basically have 1 to 3 hours setup time per event so one of the key considerations for us is keeping to this basic layout of a set of tops and a set of subs. For that reason we have never looked at line array (and certainly any ceiling mounted gear is out of the question). However I recently received a demonstration of the FBT Modus range. If you're not familiar with this it is based on the line array technology built inside a single cabinet (all active as well). Although slightly bigger and quite a bit heavier than the Mackie/Yorkville's these were still mobile units which stack on the stage. Although the demonstration was only playing music from a CD player it was in a huge car park and the sound was absolutely incredible and did not diminish as you moved further away from the speakers.

At this point I should mention I know nothing about line array technology (hence why to this point it was not a consideration for us) however as this FBT system takes this technology and encloses that the single cabinet. This in itself makes it very interesting to me. Is this something we should consider?

One of my key questions is scalability. Clearly this system would be fine for a small festival (I think it tops out at between 10 and 11kW). However would it be suitable for a smaller venue inside of say 300 to 500 people? As there is clearly different technologies within the speakers to throw the sound incredible distance would this work in an enclosed space where possibly the sound could bounce straight off the back wall? What are the potential PitFalls?

If I go ahead and purchased this FBT system it will represent a massive financial investment for us and to be truthful I have no idea what the alternatives are. Your comments and advice would be greatly appreciated.

Regards

Jim Russell

[Jeff Wheeler]

Jim Russell wrote on Thu, 15 April 2010 11:30

And what we found was although the sound at the front of the hall was great the speakers just did not have the ability to throw the sound to the back of the hall. And anywhere beyond about halfway (10/15 m from the stage) and generally the sound was really muddy with no definition or power.

This will probably be true for any wide-coverage speakers you try to deploy in that hall.  Reflections cause the sound to be unintelligible as distance from the PA increases.

IMO in a small hall like that and on a relatively low budget, the best thing to do is try to keep reflections off the walls and deal with it, or put a couple of delay speakers covering the rear part of the room.  You will want to allocate extra time to try a few different positions and adjust the delay time to get the best coverage available with the gear you bring.

Any long-throw solution will require front fills, and so you will be basically spending much more money per box on long-throw or array-able cabinets, and still have the complexity of more boxes to cover the area near the stage, which will not be within the coverage beam of a long-throw cabinet.

[Art Welter]

Listening outdoors is a completely different  environment than  a reverberant room.
Your experience in the large room was that after the critical distance, the point where direct sound was equaled by the reverberant sound, things got muddy.
Outdoors, with no reflections, speakers simply drop at 6 dB per doubling of distance. Once you are a ways away, you have to walk a long distance to notice a change.

A line array  of adequate length can be of benefit in that it reduces the reflected energy from the roof and floor.
The destructive interference in the near field reduces output, so a correctly set up line array will drop at 3 dB per doubling of distance until critical distance

The FBT MODUS 40A is not long enough to have pattern control  to a very low frequency, and the high horns are arranged to give 40 degree vertical dispersion, rather wide unless you get it way up in the air. At 205 pounds, that will require a major lift.

The FBT MODUS 40A will also suffer from a dip in the response caused by cancellation due to it’s side by side mid/high components. The dip will occur in the crossover region when off axis because of the path length difference between the two drivers reproducing the same frequency, and therefore is not correctable.

Like Jeff says, you are probably better off simply employing delay speakers when you are in large reverberant places.

Art Welter

[Jim Russell]

Thank you for the insight and advise.  It was the 15 degree Modus Tops (rather than the 40 degree you mentioned) we were looking at with the idea of putting them on the stage like a "regular" PA. Elevating the cabinets in any way is completely impractical for us.

Regardless of the technical difference regarding indoor and outdoor events (which as you have explained will exist with any type of speakers).  How would you advise me in terms of going to the next level with our PA system.  The FBT system is going to cost 3 or 4 times more that our existing Mackies SA1530z/Yorkville LS800P setup.

Would it be money well spent? and would it give us significantly more head room to do larger gigs.

At the demo we received the rig was on a wheeled trolley.  I am presuming that the cabs will be a relatively straight forward 2 man lift?

Cheers

Jim

[Dick Rees]

Jim Russell wrote on Thu, 15 April 2010 12:58

Elevating the cabinets in any way is completely impractical for us. Jim

And elevating whatever cabinets you use is one of the keys to getting the sound out over the audience.  You need to have the sound sources well above the heads (and bodies) of the listeners.

Before jumping into spending $$$$ on another system, you need to learn to get the maximum out of what you have.  Without the knowledge gained in learning proper deployment of the existing gear you'd be spending a serious amount of money without the knowledge requisite for the use of the gear you purchase.

Learn how to use what you have.  Then you'll know what and if you need to go further.  Save your money and study up.

Edit:

Pay particular attention to what Art said about the critical distance.....the distance at which the reverberative sound is equal to or greater than the direct sound.  To set up sound indoors you really need to know about this.  Beyond learning this you'll need to have a unit capable of providing you with delay appropriate to synching up secondary speakers to extend the critical distance (indoors) or to reinforce and extend the sound field outdoors.

[Jim Russell]

Thanks for that - I understand the principals and the existing  speakers (I presume the tops are the important element here)are above the audience as they are elevated by the subs and the stage so will be above the audience by a fair amount -  I was refering to using rigging etc or ceiling mounted.

Cheers

Jim

[Art Welter]

Jim Russell wrote on Thu, 15 April 2010 11:58

Thank you for the insight and advise.  It was the 15 degree Modus Tops (rather than the 40 degree you mentioned) we were looking at with the idea of putting them on the stage like a "regular" PA. Elevating the cabinets in any way is completely impractical for us. Regardless of the technical difference regarding indoor and outdoor events (which as you have explained will exist with any type of speakers).  How would you advise me in terms of going to the next level with our PA system.  The FBT system is going to cost 3 or 4 times more that our existing Mackies SA1530z/Yorkville LS800P setup. Would it be money well spent? and would it give us significantly more head room to do larger gigs. At the demo we received the rig was on a wheeled trolley.  I am presuming that the cabs will be a relatively straight forward 2 man lift? Cheers Jim

Without knowing your market, I have no way to tell what investments you should make.

The Modus 15 is the starter cabinet. The Modus 40 continues as  the bottom of a “J” array.
The HF pattern of 15 degrees would be better for a reverberant room, but you still need to elevate the 183 pound cabinet well above peoples heads and angle the stack down.

After lifting cabinets most  all my life, I still can’t press more than 90 pounds (with a barbell- cabinets are worse) without my shoulders complaining.

Lifting that weight definitely would require either scaffold, a pair of crank lifts and a truss, or a large crank lift like a Genie ST 24, or chain motors and rigging.

The large number of 8 inch cones gets the sensitivity and power handeling up over a speaker on a stick.

If you want to increase your output level and clarity, the Modus 15 would be one way to do it, if you are willing to add the equipment needed to get it up where it needs to be.

If you want to get a more capable system but don’t want all the rigging, check this out:

http://srforums.prosoundweb.com/index.php/t/50266/19717/

Might be a bit expensive to ship to Scotland, however   .

Since Yorkville seems to be available to you, the Unity or VTC lines would be a step up and be more amenable to stacking.

Art Welter