If you or a colleague are familiar with Praat, you can use this Praat script to generate variations of your stimuli where there are manipulations of the pitch contour and the duration. You'll end up with your original sound, an versions where the pitch went up or down (three different pitch contours) and for each of those, a version with the original duration, as well as a shortened duration and lengthened duration. So 9 sounds total from each original sound you have. 
# Enter your sound directory here, within double quotes:
sound_dir$ = "C:\consonants"
# select your manipulations (these are multipliers of the pitch contour and duration)
pitch_up = 1.15
pitch_down = 0.85
duration_up = 1.2
duration_down = 0.8
# clear the info window
clearinfo
# list all the files in the folder
Create Strings as file list: "fileList", "'sound_dir$'\*.wav"
num_files = Get number of strings
# loop through the files
for index from 1 to num_files
 select Strings fileList
 filename$ = Get string: index
 name$ = "'filename$'" - ".wav"
 name$ = "'filename$'" - ".WAV"
 Read from file: "'sound_dir$'\'filename$'"
# make a manipulation object using some default pitch analysis parameters
 To Manipulation: 0.01, 75, 600
 # create various pitch tiers
   Extract pitch tier
   Copy: "'name$'_p2"
   Copy: "'name$'_p1"
   Multiply frequencies: 0, 1000, pitch_down
   select PitchTier 'name$'
   Copy: "'name$'_p3"
   Multiply frequencies: 0, 1000, pitch_up
 # create various duration tiers
   select Manipulation 'name$'
   Extract duration tier
   Copy: "'name$'_d2"
   Copy: "'name$'_d1"
   Add point: 0, duration_down
   select DurationTier 'name$'_d2
   Copy: "'name$'_d3"
   Add point: 0, duration_up
 for p_index from 1 to 3
   for d_index from 1 to 3
   select Manipulation 'name$'
   plus PitchTier 'name$'_p'p_index'
   Replace pitch tier
   
   select Manipulation 'name$'
   plus DurationTier 'name$'_d'd_index'
   Replace duration tier
      
   select Manipulation 'name$'
   Get resynthesis (overlap-add)
   Rename: "'name$'_p'p_index'_d'd_index'"
      
   endfor
 endfor
# cleanup
selectObject: "Sound 'name$'"
plusObject: "Manipulation 'name$'"
plusObject: "PitchTier 'name$'"
plusObject: "PitchTier 'name$'_p2"
plusObject: "PitchTier 'name$'_p1"
plusObject: "PitchTier 'name$'_p3"
plusObject: "DurationTier 'name$'"
plusObject: "DurationTier 'name$'_d2"
plusObject: "DurationTier 'name$'_d1"
plusObject: "DurationTier 'name$'_d3"
Remove
print finished with file: 'name$''newline$'
#pause finished with file: 'name$'
endfor