diff --git a/services/audiopolicy/common/include/Volume.h b/services/audiopolicy/common/include/Volume.h
index a4cc759..4205589 100755
--- a/services/audiopolicy/common/include/Volume.h
+++ b/services/audiopolicy/common/include/Volume.h
@@ -18,6 +18,10 @@
 
 #include <system/audio.h>
 #include <utils/Log.h>
+#include <math.h>
+
+// Absolute min volume in dB (can be represented in single precision normal float value)
+#define VOLUME_MIN_DB (-758)
 
 class VolumeCurvePoint
 {
@@ -32,7 +36,7 @@
     /**
      * 4 points to define the volume attenuation curve, each characterized by the volume
      * index (from 0 to 100) at which they apply, and the attenuation in dB at that index.
-     * we use 100 steps to avoid rounding errors when computing the volume in volIndexToAmpl()
+     * we use 100 steps to avoid rounding errors when computing the volume in volIndexToDb()
      *
      * @todo shall become configurable
      */
@@ -134,4 +138,20 @@
         }
     }
 
+    static inline float DbToAmpl(float decibels)
+    {
+        if (decibels <= VOLUME_MIN_DB) {
+            return 0.0f;
+        }
+        return exp( decibels * 0.115129f); // exp( dB * ln(10) / 20 )
+    }
+
+    static inline float AmplToDb(float amplification)
+    {
+        if (amplification == 0) {
+            return VOLUME_MIN_DB;
+        }
+        return 20 * log10(amplification);
+    }
+
 };
diff --git a/services/audiopolicy/common/managerdefinitions/include/AudioOutputDescriptor.h b/services/audiopolicy/common/managerdefinitions/include/AudioOutputDescriptor.h
index c6bb975..f1aee46 100644
--- a/services/audiopolicy/common/managerdefinitions/include/AudioOutputDescriptor.h
+++ b/services/audiopolicy/common/managerdefinitions/include/AudioOutputDescriptor.h
@@ -74,7 +74,7 @@
     audio_patch_handle_t mPatchHandle;
     uint32_t mRefCount[AUDIO_STREAM_CNT]; // number of streams of each type using this output
     nsecs_t mStopTime[AUDIO_STREAM_CNT];
-    float mCurVolume[AUDIO_STREAM_CNT];   // current stream volume
+    float mCurVolume[AUDIO_STREAM_CNT];   // current stream volume in dB
     int mMuteCount[AUDIO_STREAM_CNT];     // mute request counter
     bool mStrategyMutedByDevice[NUM_STRATEGIES]; // strategies muted because of incompatible
                                         // device selection. See checkDeviceMuteStrategies()
diff --git a/services/audiopolicy/common/managerdefinitions/src/AudioOutputDescriptor.cpp b/services/audiopolicy/common/managerdefinitions/src/AudioOutputDescriptor.cpp
index 0837a54..596aa1d 100644
--- a/services/audiopolicy/common/managerdefinitions/src/AudioOutputDescriptor.cpp
+++ b/services/audiopolicy/common/managerdefinitions/src/AudioOutputDescriptor.cpp
@@ -21,6 +21,7 @@
 #include "AudioOutputDescriptor.h"
 #include "IOProfile.h"
 #include "AudioGain.h"
+#include "Volume.h"
 #include "HwModule.h"
 #include <media/AudioPolicy.h>
 
@@ -354,11 +355,12 @@
     if (changed) {
         // Force VOICE_CALL to track BLUETOOTH_SCO stream volume when bluetooth audio is
         // enabled
+        float volume = Volume::DbToAmpl(mCurVolume[stream]);
         if (stream == AUDIO_STREAM_BLUETOOTH_SCO) {
             mClientInterface->setStreamVolume(
-                    AUDIO_STREAM_VOICE_CALL, mCurVolume[stream], mIoHandle, delayMs);
+                    AUDIO_STREAM_VOICE_CALL, volume, mIoHandle, delayMs);
         }
-        mClientInterface->setStreamVolume(stream, mCurVolume[stream], mIoHandle, delayMs);
+        mClientInterface->setStreamVolume(stream, volume, mIoHandle, delayMs);
     }
     return changed;
 }
diff --git a/services/audiopolicy/engine/interface/AudioPolicyManagerInterface.h b/services/audiopolicy/engine/interface/AudioPolicyManagerInterface.h
index eadaa77..db0573f 100755
--- a/services/audiopolicy/engine/interface/AudioPolicyManagerInterface.h
+++ b/services/audiopolicy/engine/interface/AudioPolicyManagerInterface.h
@@ -134,16 +134,16 @@
                                               audio_policy_dev_state_t state) = 0;
 
     /**
-     * Translate a volume index given by the UI to an amplification value for a stream type
+     * Translate a volume index given by the UI to an amplification value in dB for a stream type
      * and a device category.
      *
      * @param[in] deviceCategory for which the conversion is requested.
      * @param[in] stream type for which the conversion is requested.
      * @param[in] indexInUi index received from the UI to be translated.
      *
-     * @return amplification value matching the UI index for this given device and stream.
+     * @return amplification value in dB matching the UI index for this given device and stream.
      */
-    virtual float volIndexToAmpl(Volume::device_category deviceCategory, audio_stream_type_t stream,
+    virtual float volIndexToDb(Volume::device_category deviceCategory, audio_stream_type_t stream,
                                  int indexInUi) = 0;
 
     /**
diff --git a/services/audiopolicy/enginedefault/src/Engine.cpp b/services/audiopolicy/enginedefault/src/Engine.cpp
index 26a0d09..50f1609 100755
--- a/services/audiopolicy/enginedefault/src/Engine.cpp
+++ b/services/audiopolicy/enginedefault/src/Engine.cpp
@@ -63,13 +63,14 @@
     return (mApmObserver != NULL) ?  NO_ERROR : NO_INIT;
 }
 
-float Engine::volIndexToAmpl(Volume::device_category category, audio_stream_type_t streamType,
+float Engine::volIndexToDb(Volume::device_category category, audio_stream_type_t streamType,
                              int indexInUi)
 {
     const StreamDescriptor &streamDesc = mApmObserver->getStreamDescriptors().valueAt(streamType);
-    return Gains::volIndexToAmpl(category, streamDesc, indexInUi);
+    return Gains::volIndexToDb(category, streamDesc, indexInUi);
 }
 
+
 status_t Engine::initStreamVolume(audio_stream_type_t stream, int indexMin, int indexMax)
 {
     ALOGV("initStreamVolume() stream %d, min %d, max %d", stream , indexMin, indexMax);
diff --git a/services/audiopolicy/enginedefault/src/Engine.h b/services/audiopolicy/enginedefault/src/Engine.h
index f44556c..56a4748 100755
--- a/services/audiopolicy/enginedefault/src/Engine.h
+++ b/services/audiopolicy/enginedefault/src/Engine.h
@@ -101,10 +101,10 @@
         {
             return mPolicyEngine->initializeVolumeCurves(isSpeakerDrcEnabled);
         }
-        virtual float volIndexToAmpl(Volume::device_category deviceCategory,
+        virtual float volIndexToDb(Volume::device_category deviceCategory,
                                      audio_stream_type_t stream,int indexInUi)
         {
-            return mPolicyEngine->volIndexToAmpl(deviceCategory, stream, indexInUi);
+            return mPolicyEngine->volIndexToDb(deviceCategory, stream, indexInUi);
         }
     private:
         Engine *mPolicyEngine;
@@ -141,7 +141,7 @@
     audio_devices_t getDeviceForStrategy(routing_strategy strategy) const;
     audio_devices_t getDeviceForInputSource(audio_source_t inputSource) const;
 
-    float volIndexToAmpl(Volume::device_category category,
+    float volIndexToDb(Volume::device_category category,
                          audio_stream_type_t stream, int indexInUi);
     status_t initStreamVolume(audio_stream_type_t stream, int indexMin, int indexMax);
     void initializeVolumeCurves(bool isSpeakerDrcEnabled);
diff --git a/services/audiopolicy/enginedefault/src/Gains.cpp b/services/audiopolicy/enginedefault/src/Gains.cpp
index a684fdd..78f2909 100644
--- a/services/audiopolicy/enginedefault/src/Gains.cpp
+++ b/services/audiopolicy/enginedefault/src/Gains.cpp
@@ -197,10 +197,10 @@
 };
 
 //static
-float Gains::volIndexToAmpl(audio_devices_t device, const StreamDescriptor& streamDesc,
-        int indexInUi)
+float Gains::volIndexToDb(Volume::device_category deviceCategory,
+                          const StreamDescriptor& streamDesc,
+                          int indexInUi)
 {
-    Volume::device_category deviceCategory = Volume::getDeviceCategory(device);
     const VolumeCurvePoint *curve = streamDesc.getVolumeCurvePoint(deviceCategory);
 
     // the volume index in the UI is relative to the min and max volume indices for this stream type
@@ -212,7 +212,7 @@
     // find what part of the curve this index volume belongs to, or if it's out of bounds
     int segment = 0;
     if (volIdx < curve[Volume::VOLMIN].mIndex) {         // out of bounds
-        return 0.0f;
+        return VOLUME_MIN_DB;
     } else if (volIdx < curve[Volume::VOLKNEE1].mIndex) {
         segment = 0;
     } else if (volIdx < curve[Volume::VOLKNEE2].mIndex) {
@@ -220,7 +220,7 @@
     } else if (volIdx <= curve[Volume::VOLMAX].mIndex) {
         segment = 2;
     } else {                                                               // out of bounds
-        return 1.0f;
+        return 0.0f;
     }
 
     // linear interpolation in the attenuation table in dB
@@ -231,17 +231,25 @@
                     ((float)(curve[segment+1].mIndex -
                             curve[segment].mIndex)) );
 
-    float amplification = exp( decibels * 0.115129f); // exp( dB * ln(10) / 20 )
-
-    ALOGVV("VOLUME vol index=[%d %d %d], dB=[%.1f %.1f %.1f] ampl=%.5f",
+    ALOGVV("VOLUME vol index=[%d %d %d], dB=[%.1f %.1f %.1f]",
             curve[segment].mIndex, volIdx,
             curve[segment+1].mIndex,
             curve[segment].mDBAttenuation,
             decibels,
-            curve[segment+1].mDBAttenuation,
-            amplification);
+            curve[segment+1].mDBAttenuation);
 
-    return amplification;
+    return decibels;
 }
 
+
+//static
+float Gains::volIndexToAmpl(Volume::device_category deviceCategory,
+                            const StreamDescriptor& streamDesc,
+                            int indexInUi)
+{
+    return Volume::DbToAmpl(volIndexToDb(deviceCategory, streamDesc, indexInUi));
+}
+
+
+
 }; // namespace android
diff --git a/services/audiopolicy/enginedefault/src/Gains.h b/services/audiopolicy/enginedefault/src/Gains.h
index b5601ca..7620b7d 100644
--- a/services/audiopolicy/enginedefault/src/Gains.h
+++ b/services/audiopolicy/enginedefault/src/Gains.h
@@ -29,8 +29,13 @@
 class Gains
 {
 public :
-    static float volIndexToAmpl(audio_devices_t device, const StreamDescriptor& streamDesc,
-                    int indexInUi);
+    static float volIndexToAmpl(Volume::device_category deviceCategory,
+                                const StreamDescriptor& streamDesc,
+                                int indexInUi);
+
+    static float volIndexToDb(Volume::device_category deviceCategory,
+                              const StreamDescriptor& streamDesc,
+                              int indexInUi);
 
     // default volume curve
     static const VolumeCurvePoint sDefaultVolumeCurve[Volume::VOLCNT];
diff --git a/services/audiopolicy/managerdefault/AudioPolicyManager.cpp b/services/audiopolicy/managerdefault/AudioPolicyManager.cpp
index b5ff9a9..686a0e1 100644
--- a/services/audiopolicy/managerdefault/AudioPolicyManager.cpp
+++ b/services/audiopolicy/managerdefault/AudioPolicyManager.cpp
@@ -4251,9 +4251,7 @@
                                             int index,
                                             audio_devices_t device)
 {
-    float volume = 1.0;
-
-    volume = mEngine->volIndexToAmpl(Volume::getDeviceCategory(device), stream, index);
+    float volumeDb = mEngine->volIndexToDb(Volume::getDeviceCategory(device), stream, index);
 
     // if a headset is connected, apply the following rules to ring tones and notifications
     // to avoid sound level bursts in user's ears:
@@ -4271,26 +4269,26 @@
                 || ((stream_strategy == STRATEGY_ENFORCED_AUDIBLE) &&
                     (mEngine->getForceUse(AUDIO_POLICY_FORCE_FOR_SYSTEM) == AUDIO_POLICY_FORCE_NONE))) &&
             mStreams.canBeMuted(stream)) {
-        volume *= SONIFICATION_HEADSET_VOLUME_FACTOR;
+        volumeDb += SONIFICATION_HEADSET_VOLUME_FACTOR_DB;
         // when the phone is ringing we must consider that music could have been paused just before
         // by the music application and behave as if music was active if the last music track was
         // just stopped
         if (isStreamActive(AUDIO_STREAM_MUSIC, SONIFICATION_HEADSET_MUSIC_DELAY) ||
                 mLimitRingtoneVolume) {
             audio_devices_t musicDevice = getDeviceForStrategy(STRATEGY_MEDIA, true /*fromCache*/);
-            float musicVol = computeVolume(AUDIO_STREAM_MUSIC,
-                               mStreams.valueFor(AUDIO_STREAM_MUSIC).getVolumeIndex(musicDevice),
+            float musicVolDB = computeVolume(AUDIO_STREAM_MUSIC,
+                                 mStreams.valueFor(AUDIO_STREAM_MUSIC).getVolumeIndex(musicDevice),
                                musicDevice);
-            float minVol = (musicVol > SONIFICATION_HEADSET_VOLUME_MIN) ?
-                                musicVol : SONIFICATION_HEADSET_VOLUME_MIN;
-            if (volume > minVol) {
-                volume = minVol;
-                ALOGV("computeVolume limiting volume to %f musicVol %f", minVol, musicVol);
+            float minVolDB = (musicVolDB > SONIFICATION_HEADSET_VOLUME_MIN_DB) ?
+                    musicVolDB : SONIFICATION_HEADSET_VOLUME_MIN_DB;
+            if (volumeDb > minVolDB) {
+                volumeDb = minVolDB;
+                ALOGV("computeVolume limiting volume to %f musicVol %f", minVolDB, musicVolDB);
             }
         }
     }
 
-    return volume;
+    return volumeDb;
 }
 
 status_t AudioPolicyManager::checkAndSetVolume(audio_stream_type_t stream,
@@ -4320,12 +4318,12 @@
         device = outputDesc->device();
     }
 
-    float volume = computeVolume(stream, index, device);
+    float volumeDb = computeVolume(stream, index, device);
     if (outputDesc->isFixedVolume(device)) {
-        volume = 1.0f;
+        volumeDb = 0.0f;
     }
 
-    outputDesc->setVolume(volume, stream, device, delayMs, force);
+    outputDesc->setVolume(volumeDb, stream, device, delayMs, force);
 
     if (stream == AUDIO_STREAM_VOICE_CALL ||
         stream == AUDIO_STREAM_BLUETOOTH_SCO) {
diff --git a/services/audiopolicy/managerdefault/AudioPolicyManager.h b/services/audiopolicy/managerdefault/AudioPolicyManager.h
index 9baeeb6..11fd5ff 100644
--- a/services/audiopolicy/managerdefault/AudioPolicyManager.h
+++ b/services/audiopolicy/managerdefault/AudioPolicyManager.h
@@ -49,8 +49,11 @@
 
 // Attenuation applied to STRATEGY_SONIFICATION streams when a headset is connected: 6dB
 #define SONIFICATION_HEADSET_VOLUME_FACTOR 0.5
+#define SONIFICATION_HEADSET_VOLUME_FACTOR_DB (-6)
 // Min volume for STRATEGY_SONIFICATION streams when limited by music volume: -36dB
 #define SONIFICATION_HEADSET_VOLUME_MIN  0.016
+#define SONIFICATION_HEADSET_VOLUME_MIN_DB  (-36)
+
 // Time in milliseconds during which we consider that music is still active after a music
 // track was stopped - see computeVolume()
 #define SONIFICATION_HEADSET_MUSIC_DELAY  5000