command line - Executing the same batch file in all subfolders with spaces in the subfolder names -

i have many sub-folders in root folder , want run same batch file in each sub-folder.
sub-folders might have spaces in names.
batch file want run appends of mp3 files in sub-folder 1 larger mp3 file , deletes individual mp3 files , have batch file , run manually in each sub-folder now.
there varying number of sub-folders , varying number of mp3 files in each sub-folder

the root folder is: d:\audioedit , existing batch file append , delete named mm.bat

my last (of many) attempts, running command line was:

for / f %f in<'dir /ad /b'> start mm.bat 

which not work. i've tried follow related threads here, not programmer , of flies on head.

this should work: reduce %% % if want run command line.

for /r /d "d:\audioedit" %%a in (*) pushd "%%a" & call mm.bat & popd 

a comment task: if mp3s have different bitrates , sampling rates etc may not play properly. if share same parameters there can still dislocation in audio @ join. may @ freemake audio converter free gui software, , autoit run in stack of folders. sox command line audio converter.