While an application has the file open, you can use lsof to locate it. Note that this only works while the file is open at the operating system level, which may not always be the case while the application displays the file. For example a text or image editor typically opens the file to read or save it, but closes it immediately after each load or save operation. But I would expect a sound recorder to write progressively to the output file, and for that it would keep the file open as long as it's recording.