Had a bud who was in a blind and since there was only room for one - he stuck his hands out and freaked the birds out.
Now for all these years - I have never worried about callin from the outside of the blind. If you can hear that Tom - that tom can hear you and hear you better than you think! I fI am worried about volume I use a trumpet or wingbone call for long distance - If on my box or slate hold it up higher near the window - but I never stick my call outside.
Start soft as you can always go louder. if that Tom is interested he will tell you.
And I have had birds peck the blind - more like - knock-knock - anyone home!
JW