diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -232,3 +232,8 @@
 ## 0.24.3.0 -- 2020-04-06
 
 * Twenty-fourth version revised C. Fixed issue with being not compiled code because of the wrong type signature. 
+
+## 0.24.4.0 -- 2020-04-07
+
+* Twenty-fourth version revised D. Fixed issues with segmentation faults in some functions. Added two new functions to the DobutokO.Sound.Functional
+module. Improved stability.
diff --git a/DobutokO/Sound.hs b/DobutokO/Sound.hs
--- a/DobutokO/Sound.hs
+++ b/DobutokO/Sound.hs
@@ -327,8 +327,7 @@
           soxSynthHelpMain note0 note1
           overSoXSynthHelpN v0
           overSoXSynthHelpN2 v1
-          mixTest
-          renameFile "result.wav" $ "result" ++ prependZeroes zeroN (show j) ++ ".wav") vec0
+          mixTest2 zeroN j) vec0
  | otherwise = let ampL1 = ampL - (fromIntegral . truncate $ ampL) in
     if abs ampL1 < 0.01 then overSoXSynthN n 0.01 time3 zs vec0
     else overSoXSynthN n ampL1 time3 zs vec0
@@ -361,8 +360,7 @@
           soxSynthHelpMain note0 note1
           overSoXSynthHelpN v0
           overSoXSynthHelpN2 v1
-          mixTest
-          renameFile "result.wav" $ "result" ++ prependZeroes zeroN (show j) ++ ".wav") vec0
+          mixTest2 zeroN j) vec0
  | otherwise = let ampL1 = ampL - (fromIntegral . truncate $ ampL) in
     if abs ampL1 < 0.01 then overSoXSynthN2 n 0.01 time3 zs tts vec0
     else overSoXSynthN2 n ampL1 time3 zs tts vec0    
@@ -570,8 +568,7 @@
           soxSynthHelpMain note0 note1
           uniqOverSoXSynthHelpN v0
           uniqOverSoXSynthHelpN2 v1
-          mixTest
-          renameFile "result.wav" $ "result" ++ prependZeroes zeroN (show j) ++ ".wav") vec0
+          mixTest2 zeroN j) vec0
  | otherwise = let ampL1 = ampL - (fromIntegral . truncate $ ampL) in
     if abs ampL1 < 0.01 then uniqOverSoXSynthN n 0.01 time3 zs wws vec0
     else uniqOverSoXSynthN n ampL1 time3 zs wws vec0
@@ -608,8 +605,7 @@
           soxSynthHelpMain note0 note1
           uniqOverSoXSynthHelpN v0
           uniqOverSoXSynthHelpN2 v1
-          mixTest
-          renameFile "result.wav" $ "result" ++ prependZeroes zeroN (show j) ++ ".wav") vec0
+          mixTest2 zeroN j) vec0
  | otherwise = let ampL1 = ampL - (fromIntegral . truncate $ ampL) in
     if abs ampL1 < 0.01 then uniqOverSoXSynthN3 n 0.01 time3 zs wws tts vec0
     else uniqOverSoXSynthN3 n ampL1 time3 zs wws tts vec0    
@@ -660,8 +656,7 @@
                   ; soxSynthHelpMain1 (fromJust note1)
                   ; uniqOverSoXSynthHelpN v0
                   ; uniqOverSoXSynthHelpN2 v1}
-          mixTest
-          renameFile "result.wav" $ "result" ++ prependZeroes zeroN (show j) ++ ".wav") vec0
+          mixTest2 zeroN j) vec0
  | otherwise = let ampL1 = ampL - (fromIntegral . truncate $ ampL) in
     if abs ampL1 < 0.01 then uniqOverSoXSynthN4 n 0.01 time3 dAmpl zs wws tts vs vec0
     else uniqOverSoXSynthN4 n ampL1 time3 dAmpl zs wws tts vs vec0    
diff --git a/DobutokO/Sound/Functional.hs b/DobutokO/Sound/Functional.hs
--- a/DobutokO/Sound/Functional.hs
+++ b/DobutokO/Sound/Functional.hs
@@ -33,6 +33,7 @@
   , octavesT
   -- * Combining intermediate files
   , mixTest
+  , mixTest2
   -- * Working with files
   , freqsFromFile
   , endFromResult
@@ -73,6 +74,7 @@
   , overSoXSynthGen2FDN_Sf3G2G
   -- ** 2G generalized auxiliary functions
   , mixTest2G
+  , mixTest22G
   , endFromResult2G
   -- * Generalized functions with several functional parameters
   , soundGenF3
@@ -260,8 +262,30 @@
 mixTest2G ys = do
   paths0 <- listDirectory "."
   let paths = sort . filter (isPrefixOf "test") $ paths0
-  _ <- readProcessWithExitCode (fromJust (showE "sox")) (["--combine", "mix"] ++ paths ++ soxBasicParams ys ["result.wav","vol","0.3"]) ""
+  _ <- readProcessWithExitCode (fromJust (showE "sox")) (["--combine", "mix"] ++ paths ++ soxBasicParams ys ["","result.wav","vol","0.3"]) ""
   mapM_ removeFile paths
+
+-- | Combines (mixes) all \"test\*" files in the given directory. The files should be similar in parameters and must be sound files for SoX to work
+-- on them properly. Afterwards, the function deletes these combined files. The name of the resulting file depends on the first two command line
+-- arguments so that it is easy to produce unique names for the consequent call for the function.
+mixTest2 :: Int -> Int -> IO ()
+mixTest2 zeroN j = do
+  paths0 <- listDirectory "."
+  let paths = sort . filter (isPrefixOf "test") $ paths0
+  _ <- readProcessWithExitCode (fromJust (showE "sox")) (["--combine", "mix"] ++ paths ++ ["result" ++ prependZeroes zeroN (show j) ++ ".wav",
+    "vol","0.3"]) ""
+  mapM_ removeFile paths
+
+-- | Similar to 'mixTest', but allows to change the sound quality parameters for the resulting file. For more information, please, refer to
+-- 'soxBasicParams'. The name of the resulting file depends on the first two command line
+-- arguments so that it is easy to produce unique names for the consequent call for the function.
+mixTest22G :: Int -> Int -> String -> IO ()
+mixTest22G zeroN j ys = do
+  paths0 <- listDirectory "."
+  let paths = sort . filter (isPrefixOf "test") $ paths0
+  _ <- readProcessWithExitCode (fromJust (showE "sox")) (["--combine", "mix"] ++ paths ++ soxBasicParams ys ["","result" ++ prependZeroes zeroN (show j) ++
+      ".wav","vol","0.3"]) ""
+  mapM_ removeFile paths  
 
 -- | Gets an \"end.wav\" file from the intermediate \"result\*.wav\" files in the current directory. If it is not successful, produces the notification
 -- message and exits without error. If you would like to create the file if there are too many intermediate ones, please, run
diff --git a/dobutokO2.cabal b/dobutokO2.cabal
--- a/dobutokO2.cabal
+++ b/dobutokO2.cabal
@@ -2,7 +2,7 @@
 -- documentation, see http://haskell.org/cabal/users-guide/
 
 name:                dobutokO2
-version:             0.24.3.0
+version:             0.24.4.0
 synopsis:            A program and a library to create experimental music from a mono audio and a Ukrainian text
 description:         It can also create a timbre for the notes. Uses SoX inside.
 homepage:            https://hackage.haskell.org/package/dobutokO2
