Echos

I've both ridden a number of steam engines and watched many videos of steam engines.  Here's a good example:

https://www.youtube.com/watch?v=QlhY0J5-ftg

There are two distinctive features of steam whistles that most model railroads don't capture well.  The first is whistle quills.  As I understand it, PBL's foreground sound system had a whistle quill feature in it.  There are some DCC manufacturers like NCE who are adding a "playable whistle" feature that are beginning to appear on the market.  Some decoder manufacturers like TCS include a pre-recorded quill on their sound decoders.  So it at least looks like there is some direction towards making quills a reality for model railroaders even if they aren't quite there yet.

The other distinctive feature is the echo caused by the whistle.  There are a couple good examples of this in the video I linked above, one in particular towards the end (here: http://youtu.be/QlhY0J5-ftg?t=4m21s).  He hits the whistle and an echo can be clearly heard around a second later.

I was originally wondering if this was possible to do with a second DCC sound decoder, similar to how Lance Mindheim used an off-train decoder with headphones.  The more I thought about it however the more I began to think this might be achievable by having a computer simulate the echo of sounds that it hears.

This is the idea:  Have one or two microphones located somewhere in the layout room connected to a computer.  Whenever a sound is heard, the computer plays back that sound back a second later on speakers located around the layout room, creating an echo effect that surrounds the whole room.  The software should filter out anything that isn't in the pitch range of a whistle ideally avoiding having the system echo voices and other noises of a lower pitch.  Another tricky part of this idea is if you listen closely, the echo keeps repeating as it bounces off of different mountains and such.

The difficult piece is finding the software to do this.  I've started looking at "live DJ" software.  Most of those allow input via microphone and have built-in echo effects.  No hits yet, but I think this is a solid idea.