I see there are lots of open reed moose calls on the market. I think if you found some recorded moose sounds you might be able to make up a soundboard. All the pictures I seen looked like a wide and flat at the tip reed. Or you could use the old coffee can and a string. I have been reading about it and alot of people seem to swear by the can and a string call. Here's the instructions. ;D
Using a hammer and nail, punch a small hole in middle of the base of an empty coffee can.
Tie a knot in one end of a shoelace, and insert the other end in the hole. Pull the shoelace through the other side until the knot hits outside of the coffee can (the shoelace should now be inside the can).
Use some water to moisten the shoelace. Hold the can under one arm, and grab the shoelace with the other hand. Pull hard. The vibrations on the wet shoestring are amplified by the coffee can to produce the sound a moose makes.
If the sound is too metallic, put some wet leaves in the can to dampen the metal sound.
I thought it was funny but there sure seem to be alot of people who actually use it.
John