diff --git a/app/build.gradle b/app/build.gradle
index f1dfa17..f81bdfa 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -55,5 +55,5 @@ android {
 dependencies {
     compile fileTree(dir: 'libs', include: ['*.jar'])
     testCompile 'junit:junit:4.12'
-    compile 'com.github.axet:android-audio-library:1.0.89' // compile project(':android-audio-library')
+    compile 'com.github.axet:android-audio-library:1.0.91' // compile project(':android-audio-library')
 }
diff --git a/app/src/main/java/com/github/axet/audiorecorder/activities/RecordingActivity.java b/app/src/main/java/com/github/axet/audiorecorder/activities/RecordingActivity.java
index a091f4b..02e11d0 100644
--- a/app/src/main/java/com/github/axet/audiorecorder/activities/RecordingActivity.java
+++ b/app/src/main/java/com/github/axet/audiorecorder/activities/RecordingActivity.java
@@ -47,6 +47,8 @@ import com.github.axet.audiolibrary.encoders.EncoderInfo;
 import com.github.axet.audiolibrary.encoders.Factory;
 import com.github.axet.audiolibrary.encoders.FileEncoder;
 import com.github.axet.audiolibrary.encoders.OnFlyEncoding;
+import com.github.axet.audiolibrary.filters.AmplifierFilter;
+import com.github.axet.audiolibrary.filters.VoiceFilter;
 import com.github.axet.audiolibrary.widgets.PitchView;
 import com.github.axet.audiorecorder.BuildConfig;
 import com.github.axet.audiorecorder.R;
@@ -990,6 +992,12 @@ public class RecordingActivity extends AppCompatThemeActivity {
 
         encoder = new FileEncoder(this, in, fly);
 
+        if (shared.getBoolean(MainApplication.PREFERENCE_VOICE, false))
+            encoder.filters.add(new VoiceFilter(getInfo().hz));
+        float amp = shared.getFloat(MainApplication.PREFERENCE_VOLUME, 0);
+        if (amp > 0)
+            encoder.filters.add(new AmplifierFilter(1 + amp));
+
         RecordingService.startService(this, Storage.getDocumentName(targetUri), thread != null, encoder != null);
 
         final ProgressDialog d = new ProgressDialog(this);
diff --git a/app/src/main/java/com/github/axet/audiorecorder/activities/SettingsActivity.java b/app/src/main/java/com/github/axet/audiorecorder/activities/SettingsActivity.java
index ec74514..9876176 100644
--- a/app/src/main/java/com/github/axet/audiorecorder/activities/SettingsActivity.java
+++ b/app/src/main/java/com/github/axet/audiorecorder/activities/SettingsActivity.java
@@ -24,11 +24,13 @@ import android.support.v7.preference.PreferenceManager;
 import android.support.v7.preference.PreferenceScreen;
 import android.view.MenuItem;
 import android.widget.ProgressBar;
+import android.widget.SeekBar;
 import android.widget.Toast;
 
 import com.github.axet.androidlibrary.widgets.AppCompatSettingsThemeActivity;
 import com.github.axet.androidlibrary.widgets.NameFormatPreferenceCompat;
 import com.github.axet.androidlibrary.widgets.OpenFileDialog;
+import com.github.axet.androidlibrary.widgets.SeekBarPreference;
 import com.github.axet.androidlibrary.widgets.SilencePreferenceCompat;
 import com.github.axet.androidlibrary.widgets.StoragePathPreferenceCompat;
 import com.github.axet.androidlibrary.widgets.ThemeUtils;
@@ -77,7 +79,9 @@ public class SettingsActivity extends AppCompatSettingsThemeActivity implements
             String stringValue = value.toString();
             String key = preference.getKey();
 
-            if (preference instanceof NameFormatPreferenceCompat) {
+            if (preference instanceof SeekBarPreference) {
+                preference.setSummary(((SeekBarPreference) preference).format(Float.valueOf(stringValue)));
+            } else if (preference instanceof NameFormatPreferenceCompat) {
                 preference.setSummary(((NameFormatPreferenceCompat) preference).getFormatted(stringValue));
             } else if (preference instanceof ListPreference) {
                 // For list preferences, look up the correct display value in
@@ -127,7 +131,7 @@ public class SettingsActivity extends AppCompatSettingsThemeActivity implements
         sBindPreferenceSummaryToValueListener.onPreferenceChange(preference,
                 PreferenceManager
                         .getDefaultSharedPreferences(preference.getContext())
-                        .getString(preference.getKey(), ""));
+                        .getAll().get(preference.getKey()));
     }
 
     @Override
@@ -213,6 +217,10 @@ public class SettingsActivity extends AppCompatSettingsThemeActivity implements
             NameFormatPreferenceCompat.show(caller, pref.getKey());
             return true;
         }
+        if (pref instanceof SeekBarPreference) {
+            SeekBarPreference.show(caller, pref.getKey());
+            return true;
+        }
         return false;
     }
 
@@ -250,6 +258,7 @@ public class SettingsActivity extends AppCompatSettingsThemeActivity implements
             bindPreferenceSummaryToValue(pm.findPreference(MainApplication.PREFERENCE_THEME));
             bindPreferenceSummaryToValue(pm.findPreference(MainApplication.PREFERENCE_CHANNELS));
             bindPreferenceSummaryToValue(pm.findPreference(MainApplication.PREFERENCE_FORMAT));
+            bindPreferenceSummaryToValue(pm.findPreference(MainApplication.PREFERENCE_VOLUME));
 
             StoragePathPreferenceCompat s = (StoragePathPreferenceCompat) pm.findPreference(MainApplication.PREFERENCE_STORAGE);
             s.setStorage(new Storage(getContext()));
diff --git a/app/src/main/res/xml/pref_general.xml b/app/src/main/res/xml/pref_general.xml
index 0aa8f3f..2656418 100644
--- a/app/src/main/res/xml/pref_general.xml
+++ b/app/src/main/res/xml/pref_general.xml
@@ -57,7 +57,18 @@
             android:summary="2015-12-31 22:11:34"
             android:title="@string/pref_nameformat_title" />
     </PreferenceCategory>
-
+    <PreferenceCategory android:title="@string/pref_filters">
+        <SwitchPreferenceCompat
+            android:defaultValue="false"
+            android:key="voice"
+            android:summary="@string/pref_voice_summary"
+            android:title="@string/pref_voice_title" />
+        <com.github.axet.androidlibrary.widgets.SeekBarPreference
+            android:defaultValue="0"
+            android:key="volume"
+            android:summary=""
+            android:title="@string/pref_volume_title" />
+    </PreferenceCategory>
     <PreferenceCategory android:title="@string/pref_application">
         <SwitchPreferenceCompat
             android:defaultValue="false"