Choral shells - Making your riser into a choral shell

Improving the sound of your choir through means fair or foul Part 1 of 3

In a posting long ago, I explained how we of the Maple Leaf Singers made choral shells to help us better hear our riser-mates, and project a clearer sound to our audience. Here, at long last, are details on how to do make your own.

I have broken this advice into three parts:

Making a choral shell out of your risers; this posting.
This is the recommended first step: it’s easy to do, actually speeds your riser setup, and looks very professional. See below for the details.
Making an upper choral shell. See Here
This is more exotic, but is possible to try out a small version to see if it is effective for your group.
Simulating a choral shell with choral mikes. (another planned posting)
We (The Maple Leaf Singers) switched to this technique because :
    1) Very good choral mics recently became available at a reasonable price
    2) They are more portable than choral shells and can be set up in minutes, in many venues
    3) Our sound can be dynamically adjusted during a performance

How to make your choir’s risers into a choral shell

A choral shell covers our riser

"Choral-shelling" a riser is easy to do, actually speeds your riser setup (if you currently use black curtains), and the clean black panels look quite spiffy, as show on the right and above.

This change is also quite easy to try out before committing:

Buy 4 plastic sheets when you have an on-riser practice;
Put them on the riser and try songs or phrases with or without the sheets leaning on the risers
If you don't like the effect, or don't hear much difference, take the sheets back

What’s needed to cover a thirty-foot (7 - 8 sections) riser

Material

About 45 feet of black, 3/4“ wide Velcro (or equivalent), sticky-back, $75
Black Coroplast or equivalent 4’ X 8’ sheets, qty 4 $100
Optional: if you have a end-railings (We made ours) get an extra sheet
45 feet of high-quality 3/4” black vinyl tape, e.g. 3M $30
10 feet of duct tape (optional: to mark back of plastic sheet) $5
Optional: more sheets & tape for the riser-steps Total Cost: ~$200-$250

Tools

Sharp utility knife to cut plastic
Scissors to cut tape
4’ straight-edge and measuring tape
Cloths and strong grease-removing cleanser for cleaning the risers and plastic sheets

Procedure

The plastic sheets go on the inside of the riser railing, not behind. As sheets can overlap we don’t need an exact fit. The reflecting sheets are stuck to the riser with Velcro. Here's how to set it up:

Set up full riser.
Prepare and apply Velcro tape to inside of riser railings.
1. Clean off, with strong detergent, the
  upper bar of the riser railings, on the inside (forward-facing side); it will likely have a bit of grease from hands or manufacture
2. Apply the soft-feeling loop side Velcro tape to the railing, pressing down firmly for several seconds. It should lock in place like it has been glued.
  
  Why put the loop-side on the railing?: it feels a lot better than the "hook" side.
Cut, prepare and trim black plastic sheets
1. Put a plastic sheet on the riser and check how high you want it to come up – we chose about an inch higher. Note: we put the raw panels up and came to a consensus; this approach worked well.
2. Trim the sheets to this height.
  I think we trimmed off 5” or so,
  ending up 43” high.
  Save the trimmed plastic – it may be useful for covering the steps.
3. Take the black vinyl tape and tape along and over the edge that you want to be the top edge to smooth it. The top riser people will thank you: the idea is to prevent “paper” cuts.
4. Cut the sheets exactly in half: 4’ wide, so that the sheets can be stacked, carried and stored.
5. The corners will be sharp! Trim off round these corners a half-inch or so with a knife or scissors and put a bit of tape over them.
Prepare and apply Velcro tape to sheets.
1. Rest the sheets on the riser railing, top up, and decide which side will be the front.
  (Often there will be marks or price & UPC labels on one side).
2. The sheets may be dusty and may have grease on them. Clean off the dust and grease at the height of the Velcro strip that you have put on the riser.
3. Cut up the “hook” side (prickly feeling) Velcro tape into squares (long strips are not needed), and apply to the plastic sheet, back side, at the same height as the velcro on the railing, pressing the velcro onto the plastic firmly for several seconds. It should lock in place tightly.
  I suggest that you put the squares in about 1 inch in from the edge, one in the centre and two midway between the centre and the edge squares, You don’t need a lot of Velcro; if you use too much the plastic panels will be too hard to pull off the risers.
4. Cut squares of the loop Velcro and apply two squares on the front side of the panels, at the same spot as the two velcro squares near the edge on the back side.
  These extra squares are so that the plastic panels stack and stick together and are easy to carry and store; without this modification, the sheets slide like a deck of Teflon-coated cards.
Make the sheets easy to orient and mount
1. Finally, mark the back top of the panels with two 10”-long strips of duct tape arranged in the shape of an upside-down “V” (it will point out the top end). This shaves seconds off of riser setup time.
Test it out.
1. The appearance should be good
2. It should be faster to put up the sheets that it was to put up black curtains.
3. Last of all, try out a few songs with and without the panels in place.
4. Acoustically there should be a fairly slight to modest improvement for the top risers, more for the middle risers and more yet for the bottom riser and floor singers. Sound travels around people better than one would think.
5. I’d love it if someone could enlist a test “audience” to see what the change in sound is like. Ideally, blindfold the testers, but I expect this is asking for too much scientific rigor :) .
More: if you have end-railings (we made a pair) add plastic sheets to them too. They are more work to cut out but the effect is strong (think of them as sound-mirrors); creating an effect like adding 3 to 6 extra singers.

Adding panels to the steps

A surprising amount of recoverable sound escapes through the riser steps, as shown right.

This is a lot of lost sound, equivalent to a couple of 4X8' sheets! Further, sound lost under the steps is not lost, it bounces off the walls farther back in your venue and muddies the sound.

For this reason, and because putting those little curtains on the steps is a time-consuming pain, I recommend also putting sheets over the gaps between steps. About 2-3 extra panels are needed.

As you might expect, this is very similar to putting plastic sheets to the rise railings, with some important differences:

It’s important to never introduce a tripping hazard:
panels must never stick up above the step and ideally should be ½ inch below the step level
The panels must be cut to 4 different lengths, to match the riser widths at each level.
Make sure the corners are well rounded and the panels have no rough spots.
Make a couple of extra step cover panels for each size; this removes the need to hunt for the last matching panel.
Use blue vinyl tape (easy for the mounting person to see) to round the top of the panels. The blue is not visible from the audience, but is easy to position correctly.

It’s not hard to mount the panels on the matching riser steps, but it requires a bit of practice. You need a set of applicators that know what to do and can train newbies.

Introducing the new choral shell

The first time you introduce the panels, have everyone practice once before a show.
The application technique is not hard to learn, but requires practice without a deadline.

The applicators must be told that the panels have to match the steps.
(It’s surprising how many people take a long time to notice the size differences; those that don’t get very confused and frustrated).

The applicators must be aware of the importance of keeping the top edge of the panel below the step.

Safety first

A designated riser setup safety person should double-check the risers to make sure everything is set up, especially that the step-panels do not stick up above the step.

Once everyone was in the habit of setting up the shell, we found it was quick and easy.

Results

After all that work, you'll receive the biggest un-compliment of all; your audience won't notice any of your handiwork. It should be totally "part of the background".

Here’s a rough list to what to expect, sound-wise.

If you have a 4-row or five-row setup, the lower rows should hear each other noticeably better.
The director should hear the lower riser people better: whatever groups are on the top level will be asked to sing louder
The biggest effect we noticed was the people on each end could hear each other, e.g. our altos could hear our sopranos and vice-versa. Not surprising: this choral shell roughly doubles the sound energy going from end to end on the risers.
For the audience, the sound should not seem that much louder - the direct improvement should be just noticeable. However, the choral shell will stop sound leaking back-stage, and creating a muddy reflection off the back of the theatre. The two effects combined should make a difference.
As a consequence of point 4 above, the black choral shell seems to reduce the variation in the quality of the performance venue: a poor venue does not sound as bad to us.
As a consequence of all these "little" improvements, you should sing better; more in pitch; more in sync, with less strain.

Contact Me

I hope this helps your chorus. If it does, please let us know. Comments are appreciated.
If it does not, then we really need to know! Please send details to MusicScienceGuy.

For more about the Maple Leaf Singers, you are welcome to visit our site: www.MapleLeafSingers.com

Comments

Bryce, hope it works out! Ken.

Posted by: Ken Rushton | Oct 16, 2015 at 04:55 PM

Ken- I am just starting today. I will get you some photos and let you know how it turned out! I am not doing the entire shell yet- just the hanging portion for now.

Posted by: Bryce | Oct 16, 2015 at 02:10 PM

Aa/A1: how is the building of your choral shell going?

Posted by: Ken Rushton | Aug 25, 2015 at 01:31 PM