How to build a choral shell
As described here, We found a choral shell was very effective in a number of ways, and seemed to have no downside:
- The intra-choral sound was excellent: we could hear each other, didn’t yell, stayed on pitch
- The shell focused the audience attention on the choir
- We could hear the audience a bit better
- the cost was low - $400 for 10 sheets of Coroplast, lots of Velcro, and some wood.
I wrote the following as a script for a video I ran out of time to finish. It should, however, be useful. I will add pictures shortly, I hope.
First, the choral shell in my design has 2 parts: Pic of Show
- 1. The choral riser back – the safety rail covering
important but it’s not very visible but don’t forget it. Pic of it being built
- 2. The elevated choral shell – the visible part
It gives people on the lower risers get a better sound environment.
The choral riser back
Black sheets look good, set up faster than curtains, and greatly
improves your choral sound
To build this system you need:
- Sheets of black corrugated plastic (called Coroplast for short), I used 4’ by 8’ sheets. For this Demo I’m using 4’ by 2” sheets. You can cut them down to make them more convenient to handle, store and mount. Most riser and back railing sections are 6’ wide, so you may want to cut them to match.
- 20 or so squares of 3/4” wide black Velcro, the “hook” side. I’ve used white here so that you can see it against the black Coroplast.
- A roll of black vinyl tape, to prevent the sharp edges of the Coroplast from giving people paper-cuts
- A sharp knife, or better an exacto-knife and a long straight-edge for making straight cuts
- Optionally, some white or gray tape – I recommend duct tape for marking the back side of the sheet
- Note that our riser railings have velco already on them, the soft “loop” side, not the prickly “hook” side, formerly to facilitate putting up riser curtains quickly
- Put the panels in place on the riser railing and mark where the plastic comes on the top of the riser
- Trim all your sheets to the same height, - typically a 4” sheet will be trimmed down to 3 ½ feet. Keep the trim for filling in between the steps on the riser.
- Decide on the top edge and which side will be the back, and put on the riser
- Protect hands from the sharp upper edge by taping over this edge with the black vinyl tape
- Clean well the panels – in the store and in handling they can pick up grease. You want the velcro to stay in place.
- Put the black Velcro squares on the back of the panels where they will stick to the velcro on the back railing every 12 to 18 inches or so. Put it far enough part so the panels can be pulled off easily, but are not too loose
- On the back of each panel, put a big arrow pointing up to the top. This marks both the back and the top edge with the velcro squares.
- Try it out – it should be easy to put up the panels on the back of the risers and remove them. If velcro squares come off, make sure the panels are really clean and use fresh squares.
- Repeat between the riser steps – it’s worth doing because of both the improved sound and the good appearance.
If you have side railings, I strongly recommend covering them too
Elevated Choral Shell
If the lower choral shell works out, to build the upper riser back:
You will need to (1) bend the panels, (2) join the panels together and (3) suspend the panels
To build this system you need:
- Sheets of white Coroplast, I used 4’ by 8’ sheets. You may prefer 4 x 4 sheets for easier handling and storage
- Lots of white heavy-duty 2” wide Velcro, available in hardware stores
- Small drill with a 1/16” drill bit, for drilling holes in plastic
- Fishing line – I used 20lb test. It should be strong enough to not stretch
- Wood (2”x1”x8’, enough to back the shell from end to end twice , wood glue, and screws or nails and a small saw. This will make the batten to hold up the shell.
- a suspension system –microphone
stands with a wide base and a long boom works indoors.
Outdoors it would need bracing against wind, on a stage with a fly system the batten will be attached to the fly system
- some screws and washers to fasten the plastic sheets to to
- Making a bendable sheet of plastic
- Drill holes in the sheet as shown, eight holes in all, in 2 rows of 4, about 8 inches from the top and bottom edges,
- String the fishing line through the sheets
- Tie the fishing line snug, with a non-slip knot – e.g. the fisherman’s knot.
- Test it by pulling on the back – the sheet should bend. Warning – do not over bend it, it will kink permanently
- Preparing to join the sheets together
- Put 4” long x2” wide rectangles of velcro, the soft “loop” side, on the ends of each sheet as shown: top and bottom corners, and in the exact middle. The complementary “hook” side you want to have in 8” long by 2” wide sections
Making the batten, the stiff rod you attach the plastic to
Take the wood, pair up pieces and fasten (Nail or screw) them together to make a “L beam”, but offset the ends by exactly 6” so that they can be fastened together, end to end.
I also put white glue between the wood pieces to ensure they were rigidly joined. In the ends I predrilled holes and put screws in them so I could join them together in just seconds when on stage.
Joining the sheet together.
- Put the soft "loop" velcro on the ends of each sheet as shown (parallel to the edge), then add the "hook " strip so that the two sheets are bridged. If you pull the hook strip tight, the two sheets will be bound tightly.
Suspending the system
To be continued ... It's not hard: connect the batten to the suspension system, and secure the batten to the sheets, about 1/3rd of the way from the top edge. I used velcro pads to make it easy to place the battens and have them stay in place, then because we did not trust 100% the velcro, we screwed the sheets to the batten with screws and washers, then covered the washers with white tape.