Front fill idea as DIY project

K

kristianjohnsen

Senior
Mar 13, 2011
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Lillehammer, Norway
www.partyfabrikken.no
Hello all.

My company's standard "big box" PA these days is the HK Audio Projector.

Link:
Products - PROJECTOR - HK Audio Portable Sound

It's designed to typically be stacked on a stage riser or similar to make sure the high-mids reach the proper height. This is especially important due to the driver for the highs being situated in the middle of the top box. Please see "exploded view" picture attached.

Lately, we have sometimes used an empty flightcase between the subs and the high-mid box to elevate tha top box. This gives us the proper height but saves us the trouble of bringing risers just to elevate the stacks. I guess there possibly is a benefit from having the subs on the floor, as well. It also saves floor space.

First, I got the idea to build some custom cable boxes to fit perfectly and stable between the subs and the high-mids for a sleeker look and more stable stacking.

Then I got the idea to ramp it up one notch to make a front fill box of sorts:
On gigs where we use two stacks on either side of the stage we already implement a front fill solution. The splay opening between the stacks is just big enough for us to fit a small flightcase inbetween, with one of our standard wedges on top. The idea is to "brighten up" the sound somewhat for the people right in front of the stacks, especially when they are seated, but there are people standing further back so that we need to stack the PA pretty high.
Link to HK Audio DART wedge:
Products - D.A.R.T - HK Audio Portable Sound
This has put the wedge at about the same height as the top of the second sub and does seem to help intelligibility and such while being very close to the stack.

My idea would be to make cable boxes to double as "spacers", but here's the twist: There would be a front compartment housing a horn driver, possibly the same horn driver as the top end of the Projector box, as well as a small amp module with a simple crossover. The Projector system is active so power and signal is already present.
Please see my rough sketch that I have enclosed.

It would be great to get some people's opinion of the validity of this idea as well as any contributions to make this a viable project.

PS: The mid-to-high X-over frequency is 900Hz and the high end module of the Projector is rated at 300 watts. The specs say that the X-over is passive, but I guess that's a typo as the high-mid module does contain two amps with separate limiters, etc.

Best regards,

Kristian Johnsen

HK Audio projector exploded view.jpgSpacer box with driver.jpg
 
Re: Front fill idea as DIY project

I think there is a lot of room for development in the front fill department. I always had to get pretty high output boxes, because by the time I added EQ and a HPF all the output from the box was at frequencies where it was not originally optimized to work. An enclosure tuned in the low 100Hz range, with very wide horizontal dispersion, and plenty of balls from 500Hz to 12khz would do really well. Some of these are available commercially, but you'll see that a lot of the big houses are building their own solutions and there is a reason for that.

I always thought that a box based off a pair of 6.5" or at most 8" drivers, with a capable 1" or 1.5" in between would be a real winner. 9" height is about as much as you can get away with, really, and with flat sides and a simple passive crossover plus some in-amp processing that thing could really tear. Depth is pretty much unlimited, so there's plenty of enclosure volume there.
 
Re: Front fill idea as DIY project

I can see a front fill designed like that could be very useful in your situation.

As this is the DIY forum, maybe I shouldn't suggest it, but what about asking HK to make one for you using their exact HF design? Having the HF sound the same, just gained differently, would be a big selling point to me.

We have the Turbosound Aspect TA-880H point source boxes, as well as the TA-880HM which is the same box without the dual LF drivers. The TA-880HM has the same dimensions as the Aspect except it is much shorter, just as your ideal stacking box would be. Typically these are used as downfills on a flown array. They are less useful as individual front fills unless you have a lot of them as they have the same narrow pattern as the full size boxes.

We do find them very handy for balcony fills, though, put them on top and kick them up. Maybe another use for your design?

Jason
 
Re: Front fill idea as DIY project

Hello guys.

Thanks for your ideas earlier!

I never took the front fill speaker idea any further, but I did make the "spacer boxes" and have been very happy with them.

They save us from taking out the previously used speaker platforms that hardly fit into many venues besides being a pain to handle.

The boxes house stuff like cables, etc, in transit, usually things that get unpacked right away when we arrive at the venue, and don't need to go back into their case before the load-out. Cable drums to connect FOH to stage, patch cables for the PA itself, etc, are typical candidates.

In transit, the boxes are made to fit snugly into our already existing packing system in the van/trailer.

When the PA is stacked, the covers go into the spacer boxes. Keeps them dry and tidy and, I guess, prevent resonance building up within the boxes.

I'm also thinking that I'm hearing a benefit from having the subs on the floor/ground, as opposed to up on risers.

Anyway, if you're interested in checking them out, here are some photos.

PS: The height of the boxes is such that entire top cabinet typically sits well above the heads of the audience members.

CIMG6391.jpg

CIMG6402.jpg

CIMG6404.jpgCIMG6403.jpgCIMG6405.jpgCIMG6406.jpgCIMG6407.jpg
 

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