diff --git a/beets/util/__init__.py b/beets/util/__init__.py
index c2d5c9334..642298c25 100644
--- a/beets/util/__init__.py
+++ b/beets/util/__init__.py
@@ -723,7 +723,7 @@ def cpu_count():
             num = 0
     elif sys.platform == 'darwin':
         try:
-            num = int(command_output([b'/usr/sbin/sysctl', b'-n', b'hw.ncpu']))
+            num = int(command_output(['/usr/sbin/sysctl', '-n', 'hw.ncpu']))
         except (ValueError, OSError, subprocess.CalledProcessError):
             num = 0
     else:
diff --git a/beets/util/artresizer.py b/beets/util/artresizer.py
index bc9f4409b..4c2e92532 100644
--- a/beets/util/artresizer.py
+++ b/beets/util/artresizer.py
@@ -91,8 +91,8 @@ def im_resize(maxwidth, path_in, path_out=None):
     # compatibility.
     try:
         util.command_output([
-            b'convert', util.syspath(path_in, prefix=False),
-            b'-resize', b'{0}x^>'.format(maxwidth),
+            'convert', util.syspath(path_in, prefix=False),
+            '-resize', '{0}x^>'.format(maxwidth),
             util.syspath(path_out, prefix=False),
         ])
     except subprocess.CalledProcessError:
@@ -119,7 +119,7 @@ def pil_getsize(path_in):
 
 
 def im_getsize(path_in):
-    cmd = [b'identify', b'-format', b'%w %h',
+    cmd = ['identify', '-format', '%w %h',
            util.syspath(path_in, prefix=False)]
     try:
         out = util.command_output(cmd)
@@ -233,7 +233,7 @@ def get_im_version():
     Try invoking ImageMagick's "convert".
     """
     try:
-        out = util.command_output([b'convert', b'--version'])
+        out = util.command_output(['convert', '--version'])
 
         if b'imagemagick' in out.lower():
             pattern = br".+ (\d+)\.(\d+)\.(\d+).*"
diff --git a/beetsplug/keyfinder.py b/beetsplug/keyfinder.py
index 77312e25b..34a4abca4 100644
--- a/beetsplug/keyfinder.py
+++ b/beetsplug/keyfinder.py
@@ -52,14 +52,14 @@ class KeyFinderPlugin(BeetsPlugin):
 
     def find_key(self, items, write=False):
         overwrite = self.config['overwrite'].get(bool)
-        bin = util.bytestring_path(self.config['bin'].as_str())
+        bin = self.config['bin'].as_str()
 
         for item in items:
             if item['initial_key'] and not overwrite:
                 continue
 
             try:
-                output = util.command_output([bin, b'-f',
+                output = util.command_output([bin, '-f',
                                               util.syspath(item.path)])
             except (subprocess.CalledProcessError, OSError) as exc:
                 self._log.error(u'execution failed: {0}', exc)
diff --git a/beetsplug/replaygain.py b/beetsplug/replaygain.py
index 884339387..a3f94bd2e 100644
--- a/beetsplug/replaygain.py
+++ b/beetsplug/replaygain.py
@@ -102,9 +102,9 @@ class Bs1770gainBackend(Backend):
             'method': 'replaygain',
         })
         self.chunk_at = config['chunk_at'].as_number()
-        self.method = b'--' + config['method'].as_str().encode('ascii')
+        self.method = '--' + config['method'].as_str()
 
-        cmd = b'bs1770gain'
+        cmd = 'bs1770gain'
         try:
             call([cmd, self.method])
             self.command = cmd
@@ -195,7 +195,7 @@ class Bs1770gainBackend(Backend):
         # Construct shell command.
         cmd = [self.command]
         cmd = cmd + [self.method]
-        cmd = cmd + [b'-p']
+        cmd = cmd + ['-p']
 
         # Workaround for Windows: the underlying tool fails on paths
         # with the \\?\ prefix, so we don't use it here. This
@@ -267,9 +267,9 @@ class CommandBackend(Backend):
                 )
         else:
             # Check whether the program is in $PATH.
-            for cmd in (b'mp3gain', b'aacgain'):
+            for cmd in ('mp3gain', 'aacgain'):
                 try:
-                    call([cmd, b'-v'])
+                    call([cmd, '-v'])
                     self.command = cmd
                 except OSError:
                     pass
@@ -308,9 +308,9 @@ class CommandBackend(Backend):
     def format_supported(self, item):
         """Checks whether the given item is supported by the selected tool.
         """
-        if b'mp3gain' in self.command and item.format != 'MP3':
+        if 'mp3gain' in self.command and item.format != 'MP3':
             return False
-        elif b'aacgain' in self.command and item.format not in ('MP3', 'AAC'):
+        elif 'aacgain' in self.command and item.format not in ('MP3', 'AAC'):
             return False
         return True
 
@@ -334,14 +334,14 @@ class CommandBackend(Backend):
         # tag-writing; this turns the mp3gain/aacgain tool into a gain
         # calculator rather than a tag manipulator because we take care
         # of changing tags ourselves.
-        cmd = [self.command, b'-o', b'-s', b's']
+        cmd = [self.command, '-o', '-s', 's']
         if self.noclip:
             # Adjust to avoid clipping.
-            cmd = cmd + [b'-k']
+            cmd = cmd + ['-k']
         else:
             # Disable clipping warning.
-            cmd = cmd + [b'-c']
-        cmd = cmd + [b'-d', str(self.gain_offset).encode('ascii')]
+            cmd = cmd + ['-c']
+        cmd = cmd + ['-d', str(self.gain_offset)]
         cmd = cmd + [syspath(i.path) for i in items]
 
         self._log.debug(u'analyzing {0} files', len(items))
diff --git a/test/test_keyfinder.py b/test/test_keyfinder.py
index 8befd750c..57e2bcd9c 100644
--- a/test/test_keyfinder.py
+++ b/test/test_keyfinder.py
@@ -44,7 +44,7 @@ class KeyFinderTest(unittest.TestCase, TestHelper):
         item.load()
         self.assertEqual(item['initial_key'], 'C#m')
         command_output.assert_called_with(
-            [b'KeyFinder', b'-f', util.syspath(item.path)])
+            ['KeyFinder', '-f', util.syspath(item.path)])
 
     def test_add_key_on_import(self, command_output):
         command_output.return_value = 'dbm'