Available Online Recordings for Acoustic Echo Identifiablity I am trying to add a few samples for a publication on identification of clean signal from the one which has echo on it. For this purpose I need data set that includes playback of an already available signal in a big room/hall and the recording of the signal with a mic in this hall that includes the echo.

Does anybody know of any available online source for such data samples.
I don't know of any online recordings, but you could try using the Silophone player to create some.  Play your original file, then record what the silophone plays back.
Silophone homepage

The Silophone uses an old grain silo as an echo chamber.  It also plays the echoed audio locally over a speaker outside the silo, so you might want to avoid using anything obnoxious or private or copyrighted.