diff --git a/CMakeLists.txt b/CMakeLists.txt
index c6a2a15..703dc7d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -14,6 +14,14 @@ endif()
 
 add_subdirectory(xxhash)
 
+set(CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}")
+find_package(IPP)
+if (IPP_FOUND)
+  add_definitions(-DINTEL_IPP=1)
+  include_directories(${IPP_INCLUDE_DIRS})
+  list(APPEND _BOO_SYS_LIBS ${IPP_LIBRARIES})
+endif ()
+
 set(WITH_LSR_BINDINGS OFF)
 set(BUILD_TESTS OFF)
 set(BUILD_SHARED_LIBS OFF)
@@ -222,6 +230,7 @@ add_library(boo
             lib/inputdev/DeviceFinder.cpp include/boo/inputdev/DeviceFinder.hpp
             lib/inputdev/HIDParser.cpp include/boo/inputdev/HIDParser.hpp
             lib/inputdev/IHIDDevice.hpp
+            lib/audiodev/Common.hpp
             lib/audiodev/WAVOut.cpp
             lib/audiodev/AudioMatrix.hpp
             #lib/audiodev/AudioMatrix.cpp
@@ -232,6 +241,8 @@ add_library(boo
             lib/audiodev/AudioVoice.cpp
             lib/audiodev/AudioSubmix.hpp
             lib/audiodev/AudioSubmix.cpp
+            lib/audiodev/LtRtProcessing.hpp
+            lib/audiodev/LtRtProcessing.cpp
             lib/audiodev/MIDIEncoder.cpp
             lib/audiodev/MIDIDecoder.cpp
             lib/audiodev/MIDICommon.hpp
diff --git a/FindIPP.cmake b/FindIPP.cmake
new file mode 100644
index 0000000..dd6a19c
--- /dev/null
+++ b/FindIPP.cmake
@@ -0,0 +1,81 @@
+# - Find Intel IPP
+# Find the IPP libraries
+# Options:
+#
+#   IPP_STATIC: true if using static linking
+#   IPP_MULTI_THREADED: true if using multi-threaded static linking
+#
+# This module defines the following variables:
+#
+#   IPP_FOUND       : True if IPP_INCLUDE_DIR are found
+#   IPP_INCLUDE_DIR : where to find ipp.h, etc.
+#   IPP_INCLUDE_DIRS: set when IPP_INCLUDE_DIR found
+#   IPP_LIBRARIES   : the library to link against.
+
+set(IPP_STATIC ON)
+
+include(FindPackageHandleStandardArgs)
+
+set(IPP_ROOT /opt/intel/ipp CACHE PATH "Folder contains IPP")
+
+# Find header file dir
+find_path(IPP_INCLUDE_DIR ipp.h
+          PATHS ${IPP_ROOT}/include)
+
+# Find libraries
+
+# Handle suffix
+set(_IPP_ORIG_CMAKE_FIND_LIBRARY_SUFFIXES ${CMAKE_FIND_LIBRARY_SUFFIXES})
+
+if(WIN32)
+    set(CMAKE_FIND_LIBRARY_SUFFIXES .lib)
+else()
+    if(IPP_STATIC)
+        set(CMAKE_FIND_LIBRARY_SUFFIXES .a)
+    else()
+        set(CMAKE_FIND_LIBRARY_SUFFIXES .so)
+    endif()
+endif()
+
+if(IPP_STATIC)
+    if(IPP_MULTI_THREADED)
+        set(IPP_LIBNAME_SUFFIX _t)
+    else()
+        set(IPP_LIBNAME_SUFFIX _l)
+    endif()
+else()
+    set(IPP_LIBNAME_SUFFIX "")
+endif()
+
+set(IPP_LIBNAME_SUFFIX "")
+
+macro(find_ipp_library IPP_COMPONENT)
+    string(TOLOWER ${IPP_COMPONENT} IPP_COMPONENT_LOWER)
+
+    find_library(IPP_LIB_${IPP_COMPONENT} ipp${IPP_COMPONENT_LOWER}${IPP_LIBNAME_SUFFIX}
+            PATHS ${IPP_ROOT}/lib/ia32/ ${IPP_ROOT}/lib)
+endmacro()
+
+# IPP components
+# Core
+find_ipp_library(CORE)
+# Signal Processing
+find_ipp_library(S)
+# Vector Math
+find_ipp_library(VM)
+
+set(IPP_LIBRARY
+    ${IPP_LIB_CORE}
+    ${IPP_LIB_S}
+    ${IPP_LIB_VM})
+
+set(CMAKE_FIND_LIBRARY_SUFFIXES ${_IPP_ORIG_CMAKE_FIND_LIBRARY_SUFFIXES})
+
+find_package_handle_standard_args(IPP DEFAULT_MSG
+        IPP_INCLUDE_DIR IPP_LIBRARY)
+
+if (IPP_FOUND)
+    set(IPP_INCLUDE_DIRS ${IPP_INCLUDE_DIR})
+    set(IPP_LIBRARIES ${IPP_LIBRARY})
+endif()
+
diff --git a/include/boo/audiodev/IAudioVoiceEngine.hpp b/include/boo/audiodev/IAudioVoiceEngine.hpp
index a4ac8f7..3b7acf1 100644
--- a/include/boo/audiodev/IAudioVoiceEngine.hpp
+++ b/include/boo/audiodev/IAudioVoiceEngine.hpp
@@ -60,6 +60,9 @@ struct IAudioVoiceEngine
     /** Set total volume of engine */
     virtual void setVolume(float vol)=0;
 
+    /** Enable or disable Lt/Rt surround encoding. If successful, getAvailableSet() will return Surround51 */
+    virtual bool enableLtRt(bool enable)=0;
+
     /** Get list of MIDI devices found on system */
     virtual std::vector<std::pair<std::string, std::string>> enumerateMIDIDevices() const=0;
 
diff --git a/lib/audiodev/AudioSubmix.cpp b/lib/audiodev/AudioSubmix.cpp
index 6d90ab4..bf8143a 100644
--- a/lib/audiodev/AudioSubmix.cpp
+++ b/lib/audiodev/AudioSubmix.cpp
@@ -95,7 +95,7 @@ int16_t* AudioSubmix::_getMergeBuf16(size_t frames)
     if (m_redirect16)
         return m_redirect16;
 
-    size_t sampleCount = frames * m_root.m_mixInfo.m_channelMap.m_channelCount;
+    size_t sampleCount = frames * m_root.clientMixInfo().m_channelMap.m_channelCount;
     if (m_scratch16.size() < sampleCount)
         m_scratch16.resize(sampleCount);
 
@@ -107,7 +107,7 @@ int32_t* AudioSubmix::_getMergeBuf32(size_t frames)
     if (m_redirect32)
         return m_redirect32;
 
-    size_t sampleCount = frames * m_root.m_mixInfo.m_channelMap.m_channelCount;
+    size_t sampleCount = frames * m_root.clientMixInfo().m_channelMap.m_channelCount;
     if (m_scratch32.size() < sampleCount)
         m_scratch32.resize(sampleCount);
 
@@ -119,7 +119,7 @@ float* AudioSubmix::_getMergeBufFlt(size_t frames)
     if (m_redirectFlt)
         return m_redirectFlt;
 
-    size_t sampleCount = frames * m_root.m_mixInfo.m_channelMap.m_channelCount;
+    size_t sampleCount = frames * m_root.clientMixInfo().m_channelMap.m_channelCount;
     if (m_scratchFlt.size() < sampleCount)
         m_scratchFlt.resize(sampleCount);
 
@@ -128,13 +128,13 @@ float* AudioSubmix::_getMergeBufFlt(size_t frames)
 
 size_t AudioSubmix::_pumpAndMix16(size_t frames)
 {
-    ChannelMap& chMap = m_root.m_mixInfo.m_channelMap;
+    const ChannelMap& chMap = m_root.clientMixInfo().m_channelMap;
     size_t chanCount = chMap.m_channelCount;
 
     if (m_redirect16)
     {
         if (m_cb && m_cb->canApplyEffect())
-            m_cb->applyEffect(m_redirect16, frames, chMap, m_root.m_mixInfo.m_sampleRate);
+            m_cb->applyEffect(m_redirect16, frames, chMap, m_root.clientMixInfo().m_sampleRate);
         m_redirect16 += chanCount * frames;
     }
     else
@@ -143,7 +143,7 @@ size_t AudioSubmix::_pumpAndMix16(size_t frames)
         if (m_scratch16.size() < sampleCount)
             m_scratch16.resize(sampleCount);
         if (m_cb && m_cb->canApplyEffect())
-            m_cb->applyEffect(m_scratch16.data(), frames, chMap, m_root.m_mixInfo.m_sampleRate);
+            m_cb->applyEffect(m_scratch16.data(), frames, chMap, m_root.clientMixInfo().m_sampleRate);
 
         size_t curSlewFrame = m_slewFrames;
         for (auto& smx : m_sendGains)
@@ -188,13 +188,13 @@ size_t AudioSubmix::_pumpAndMix16(size_t frames)
 
 size_t AudioSubmix::_pumpAndMix32(size_t frames)
 {
-    ChannelMap& chMap = m_root.m_mixInfo.m_channelMap;
+    const ChannelMap& chMap = m_root.clientMixInfo().m_channelMap;
     size_t chanCount = chMap.m_channelCount;
 
     if (m_redirect32)
     {
         if (m_cb && m_cb->canApplyEffect())
-            m_cb->applyEffect(m_redirect32, frames, chMap, m_root.m_mixInfo.m_sampleRate);
+            m_cb->applyEffect(m_redirect32, frames, chMap, m_root.clientMixInfo().m_sampleRate);
         m_redirect32 += chanCount * frames;
     }
     else
@@ -203,7 +203,7 @@ size_t AudioSubmix::_pumpAndMix32(size_t frames)
         if (m_scratch32.size() < sampleCount)
             m_scratch32.resize(sampleCount);
         if (m_cb && m_cb->canApplyEffect())
-            m_cb->applyEffect(m_scratch32.data(), frames, chMap, m_root.m_mixInfo.m_sampleRate);
+            m_cb->applyEffect(m_scratch32.data(), frames, chMap, m_root.clientMixInfo().m_sampleRate);
 
         size_t curSlewFrame = m_slewFrames;
         for (auto& smx : m_sendGains)
@@ -248,13 +248,13 @@ size_t AudioSubmix::_pumpAndMix32(size_t frames)
 
 size_t AudioSubmix::_pumpAndMixFlt(size_t frames)
 {
-    ChannelMap& chMap = m_root.m_mixInfo.m_channelMap;
+    const ChannelMap& chMap = m_root.clientMixInfo().m_channelMap;
     size_t chanCount = chMap.m_channelCount;
 
     if (m_redirectFlt)
     {
         if (m_cb && m_cb->canApplyEffect())
-            m_cb->applyEffect(m_redirectFlt, frames, chMap, m_root.m_mixInfo.m_sampleRate);
+            m_cb->applyEffect(m_redirectFlt, frames, chMap, m_root.clientMixInfo().m_sampleRate);
         m_redirectFlt += chanCount * frames;
     }
     else
@@ -263,7 +263,7 @@ size_t AudioSubmix::_pumpAndMixFlt(size_t frames)
         if (m_scratchFlt.size() < sampleCount)
             m_scratchFlt.resize(sampleCount);
         if (m_cb && m_cb->canApplyEffect())
-            m_cb->applyEffect(m_scratchFlt.data(), frames, chMap, m_root.m_mixInfo.m_sampleRate);
+            m_cb->applyEffect(m_scratchFlt.data(), frames, chMap, m_root.clientMixInfo().m_sampleRate);
 
         size_t curSlewFrame = m_slewFrames;
         for (auto& smx : m_sendGains)
diff --git a/lib/audiodev/AudioVoice.cpp b/lib/audiodev/AudioVoice.cpp
index d0126f5..de7a5c4 100644
--- a/lib/audiodev/AudioVoice.cpp
+++ b/lib/audiodev/AudioVoice.cpp
@@ -146,14 +146,14 @@ size_t AudioVoiceMono::pumpAndMix16(size_t frames)
             {
                 AudioSubmix& smx = *reinterpret_cast<AudioSubmix*>(mtx.first);
                 m_cb->routeAudio(oDone, 1, dt, smx.m_busId, scratch16Pre.data(), scratch16Post.data());
-                mtx.second.mixMonoSampleData(m_root.m_mixInfo, scratch16Post.data(), smx._getMergeBuf16(oDone), oDone);
+                mtx.second.mixMonoSampleData(m_root.clientMixInfo(), scratch16Post.data(), smx._getMergeBuf16(oDone), oDone);
             }
         }
         else
         {
             AudioSubmix& smx = reinterpret_cast<AudioSubmix&>(m_root.m_mainSubmix);
             m_cb->routeAudio(oDone, 1, dt, m_root.m_mainSubmix.m_busId, scratch16Pre.data(), scratch16Post.data());
-            DefaultMonoMtx.mixMonoSampleData(m_root.m_mixInfo, scratch16Post.data(), smx._getMergeBuf16(oDone), oDone);
+            DefaultMonoMtx.mixMonoSampleData(m_root.clientMixInfo(), scratch16Post.data(), smx._getMergeBuf16(oDone), oDone);
         }
     }
 
@@ -183,14 +183,14 @@ size_t AudioVoiceMono::pumpAndMix32(size_t frames)
             {
                 AudioSubmix& smx = *reinterpret_cast<AudioSubmix*>(mtx.first);
                 m_cb->routeAudio(oDone, 1, dt, smx.m_busId, scratch32Pre.data(), scratch32Post.data());
-                mtx.second.mixMonoSampleData(m_root.m_mixInfo, scratch32Post.data(), smx._getMergeBuf32(oDone), oDone);
+                mtx.second.mixMonoSampleData(m_root.clientMixInfo(), scratch32Post.data(), smx._getMergeBuf32(oDone), oDone);
             }
         }
         else
         {
             AudioSubmix& smx = reinterpret_cast<AudioSubmix&>(m_root.m_mainSubmix);
             m_cb->routeAudio(oDone, 1, dt, m_root.m_mainSubmix.m_busId, scratch32Pre.data(), scratch32Post.data());
-            DefaultMonoMtx.mixMonoSampleData(m_root.m_mixInfo, scratch32Post.data(), smx._getMergeBuf32(oDone), oDone);
+            DefaultMonoMtx.mixMonoSampleData(m_root.clientMixInfo(), scratch32Post.data(), smx._getMergeBuf32(oDone), oDone);
         }
     }
 
@@ -220,14 +220,14 @@ size_t AudioVoiceMono::pumpAndMixFlt(size_t frames)
             {
                 AudioSubmix& smx = *reinterpret_cast<AudioSubmix*>(mtx.first);
                 m_cb->routeAudio(oDone, 1, dt, smx.m_busId, scratchFltPre.data(), scratchFltPost.data());
-                mtx.second.mixMonoSampleData(m_root.m_mixInfo, scratchFltPost.data(), smx._getMergeBufFlt(oDone), oDone);
+                mtx.second.mixMonoSampleData(m_root.clientMixInfo(), scratchFltPost.data(), smx._getMergeBufFlt(oDone), oDone);
             }
         }
         else
         {
             AudioSubmix& smx = reinterpret_cast<AudioSubmix&>(m_root.m_mainSubmix);
             m_cb->routeAudio(oDone, 1, dt, m_root.m_mainSubmix.m_busId, scratchFltPre.data(), scratchFltPost.data());
-            DefaultMonoMtx.mixMonoSampleData(m_root.m_mixInfo, scratchFltPost.data(), smx._getMergeBufFlt(oDone), oDone);
+            DefaultMonoMtx.mixMonoSampleData(m_root.clientMixInfo(), scratchFltPost.data(), smx._getMergeBufFlt(oDone), oDone);
         }
     }
 
@@ -349,14 +349,14 @@ size_t AudioVoiceStereo::pumpAndMix16(size_t frames)
             {
                 AudioSubmix& smx = *reinterpret_cast<AudioSubmix*>(mtx.first);
                 m_cb->routeAudio(oDone, 2, dt, smx.m_busId, scratch16Pre.data(), scratch16Post.data());
-                mtx.second.mixStereoSampleData(m_root.m_mixInfo, scratch16Post.data(), smx._getMergeBuf16(oDone), oDone);
+                mtx.second.mixStereoSampleData(m_root.clientMixInfo(), scratch16Post.data(), smx._getMergeBuf16(oDone), oDone);
             }
         }
         else
         {
             AudioSubmix& smx = reinterpret_cast<AudioSubmix&>(m_root.m_mainSubmix);
             m_cb->routeAudio(oDone, 2, dt, m_root.m_mainSubmix.m_busId, scratch16Pre.data(), scratch16Post.data());
-            DefaultStereoMtx.mixStereoSampleData(m_root.m_mixInfo, scratch16Post.data(), smx._getMergeBuf16(oDone), oDone);
+            DefaultStereoMtx.mixStereoSampleData(m_root.clientMixInfo(), scratch16Post.data(), smx._getMergeBuf16(oDone), oDone);
         }
     }
 
@@ -388,14 +388,14 @@ size_t AudioVoiceStereo::pumpAndMix32(size_t frames)
             {
                 AudioSubmix& smx = *reinterpret_cast<AudioSubmix*>(mtx.first);
                 m_cb->routeAudio(oDone, 2, dt, smx.m_busId, scratch32Pre.data(), scratch32Post.data());
-                mtx.second.mixStereoSampleData(m_root.m_mixInfo, scratch32Post.data(), smx._getMergeBuf32(oDone), oDone);
+                mtx.second.mixStereoSampleData(m_root.clientMixInfo(), scratch32Post.data(), smx._getMergeBuf32(oDone), oDone);
             }
         }
         else
         {
             AudioSubmix& smx = reinterpret_cast<AudioSubmix&>(m_root.m_mainSubmix);
             m_cb->routeAudio(oDone, 2, dt, m_root.m_mainSubmix.m_busId, scratch32Pre.data(), scratch32Post.data());
-            DefaultStereoMtx.mixStereoSampleData(m_root.m_mixInfo, scratch32Post.data(), smx._getMergeBuf32(oDone), oDone);
+            DefaultStereoMtx.mixStereoSampleData(m_root.clientMixInfo(), scratch32Post.data(), smx._getMergeBuf32(oDone), oDone);
         }
     }
 
@@ -427,14 +427,14 @@ size_t AudioVoiceStereo::pumpAndMixFlt(size_t frames)
             {
                 AudioSubmix& smx = *reinterpret_cast<AudioSubmix*>(mtx.first);
                 m_cb->routeAudio(oDone, 2, dt, smx.m_busId, scratchFltPre.data(), scratchFltPost.data());
-                mtx.second.mixStereoSampleData(m_root.m_mixInfo, scratchFltPost.data(), smx._getMergeBufFlt(oDone), oDone);
+                mtx.second.mixStereoSampleData(m_root.clientMixInfo(), scratchFltPost.data(), smx._getMergeBufFlt(oDone), oDone);
             }
         }
         else
         {
             AudioSubmix& smx = reinterpret_cast<AudioSubmix&>(m_root.m_mainSubmix);
             m_cb->routeAudio(oDone, 2, dt, m_root.m_mainSubmix.m_busId, scratchFltPre.data(), scratchFltPost.data());
-            DefaultStereoMtx.mixStereoSampleData(m_root.m_mixInfo, scratchFltPost.data(), smx._getMergeBufFlt(oDone), oDone);
+            DefaultStereoMtx.mixStereoSampleData(m_root.clientMixInfo(), scratchFltPost.data(), smx._getMergeBufFlt(oDone), oDone);
         }
     }
 
diff --git a/lib/audiodev/AudioVoiceEngine.cpp b/lib/audiodev/AudioVoiceEngine.cpp
index 15948cc..f47e5e2 100644
--- a/lib/audiodev/AudioVoiceEngine.cpp
+++ b/lib/audiodev/AudioVoiceEngine.cpp
@@ -1,5 +1,5 @@
 #include "AudioVoiceEngine.hpp"
-#include <string.h>
+#include "LtRtProcessing.hpp"
 
 namespace boo
 {
@@ -15,7 +15,17 @@ BaseAudioVoiceEngine::~BaseAudioVoiceEngine()
 void BaseAudioVoiceEngine::_pumpAndMixVoices(size_t frames, int16_t* dataOut)
 {
     memset(dataOut, 0, sizeof(int16_t) * frames * m_mixInfo.m_channelMap.m_channelCount);
-    m_mainSubmix.m_redirect16 = dataOut;
+    if (m_ltRtProcessing)
+    {
+        size_t sampleCount = m_5msFrames * 5;
+        if (m_ltRtIn16.size() < sampleCount)
+            m_ltRtIn16.resize(sampleCount);
+        m_mainSubmix.m_redirect16 = m_ltRtIn16.data();
+    }
+    else
+    {
+        m_mainSubmix.m_redirect16 = dataOut;
+    }
 
     if (m_submixesDirty)
     {
@@ -50,6 +60,12 @@ void BaseAudioVoiceEngine::_pumpAndMixVoices(size_t frames, int16_t* dataOut)
         for (auto it = m_linearizedSubmixes.rbegin() ; it != m_linearizedSubmixes.rend() ; ++it)
             (*it)->_pumpAndMix16(thisFrames);
 
+        if (m_ltRtProcessing)
+        {
+            m_ltRtProcessing->Process(m_ltRtIn16.data(), dataOut, int(thisFrames));
+            m_mainSubmix.m_redirect16 = m_ltRtIn16.data();
+        }
+
         size_t sampleCount = thisFrames * m_mixInfo.m_channelMap.m_channelCount;
         for (size_t i=0 ; i<sampleCount ; ++i)
             dataOut[i] *= m_totalVol;
@@ -65,7 +81,17 @@ void BaseAudioVoiceEngine::_pumpAndMixVoices(size_t frames, int16_t* dataOut)
 void BaseAudioVoiceEngine::_pumpAndMixVoices(size_t frames, int32_t* dataOut)
 {
     memset(dataOut, 0, sizeof(int32_t) * frames * m_mixInfo.m_channelMap.m_channelCount);
-    m_mainSubmix.m_redirect32 = dataOut;
+    if (m_ltRtProcessing)
+    {
+        size_t sampleCount = m_5msFrames * 5;
+        if (m_ltRtIn32.size() < sampleCount)
+            m_ltRtIn32.resize(sampleCount);
+        m_mainSubmix.m_redirect32 = m_ltRtIn32.data();
+    }
+    else
+    {
+        m_mainSubmix.m_redirect32 = dataOut;
+    }
 
     if (m_submixesDirty)
     {
@@ -100,6 +126,12 @@ void BaseAudioVoiceEngine::_pumpAndMixVoices(size_t frames, int32_t* dataOut)
         for (auto it = m_linearizedSubmixes.rbegin() ; it != m_linearizedSubmixes.rend() ; ++it)
             (*it)->_pumpAndMix32(thisFrames);
 
+        if (m_ltRtProcessing)
+        {
+            m_ltRtProcessing->Process(m_ltRtIn32.data(), dataOut, int(thisFrames));
+            m_mainSubmix.m_redirect32 = m_ltRtIn32.data();
+        }
+
         size_t sampleCount = thisFrames * m_mixInfo.m_channelMap.m_channelCount;
         for (size_t i=0 ; i<sampleCount ; ++i)
             dataOut[i] *= m_totalVol;
@@ -115,7 +147,17 @@ void BaseAudioVoiceEngine::_pumpAndMixVoices(size_t frames, int32_t* dataOut)
 void BaseAudioVoiceEngine::_pumpAndMixVoices(size_t frames, float* dataOut)
 {
     memset(dataOut, 0, sizeof(float) * frames * m_mixInfo.m_channelMap.m_channelCount);
-    m_mainSubmix.m_redirectFlt = dataOut;
+    if (m_ltRtProcessing)
+    {
+        size_t sampleCount = m_5msFrames * 5;
+        if (m_ltRtInFlt.size() < sampleCount)
+            m_ltRtInFlt.resize(sampleCount);
+        m_mainSubmix.m_redirectFlt = m_ltRtInFlt.data();
+    }
+    else
+    {
+        m_mainSubmix.m_redirectFlt = dataOut;
+    }
 
     if (m_submixesDirty)
     {
@@ -150,6 +192,12 @@ void BaseAudioVoiceEngine::_pumpAndMixVoices(size_t frames, float* dataOut)
         for (auto it = m_linearizedSubmixes.rbegin() ; it != m_linearizedSubmixes.rend() ; ++it)
             (*it)->_pumpAndMixFlt(thisFrames);
 
+        if (m_ltRtProcessing)
+        {
+            m_ltRtProcessing->Process(m_ltRtInFlt.data(), dataOut, int(thisFrames));
+            m_mainSubmix.m_redirectFlt = m_ltRtInFlt.data();
+        }
+
         size_t sampleCount = thisFrames * m_mixInfo.m_channelMap.m_channelCount;
         for (size_t i=0 ; i<sampleCount ; ++i)
             dataOut[i] *= m_totalVol;
@@ -216,9 +264,24 @@ void BaseAudioVoiceEngine::setVolume(float vol)
     m_totalVol = vol;
 }
 
+bool BaseAudioVoiceEngine::enableLtRt(bool enable)
+{
+    if (enable && m_mixInfo.m_channelMap.m_channelCount == 2 &&
+        m_mixInfo.m_channels == AudioChannelSet::Stereo)
+        m_ltRtProcessing = std::make_unique<LtRtProcessing>(m_5msFrames, m_mixInfo);
+    else
+        m_ltRtProcessing.reset();
+    return m_ltRtProcessing.operator bool();
+}
+
 const AudioVoiceEngineMixInfo& BaseAudioVoiceEngine::mixInfo() const
 {
     return m_mixInfo;
 }
 
+const AudioVoiceEngineMixInfo& BaseAudioVoiceEngine::clientMixInfo() const
+{
+    return m_ltRtProcessing ? m_ltRtProcessing->inMixInfo() : m_mixInfo;
+}
+
 }
diff --git a/lib/audiodev/AudioVoiceEngine.hpp b/lib/audiodev/AudioVoiceEngine.hpp
index e68d0c0..bed47d6 100644
--- a/lib/audiodev/AudioVoiceEngine.hpp
+++ b/lib/audiodev/AudioVoiceEngine.hpp
@@ -2,6 +2,8 @@
 #define BOO_AUDIOVOICEENGINE_HPP
 
 #include "boo/audiodev/IAudioVoiceEngine.hpp"
+#include "LtRtProcessing.hpp"
+#include "Common.hpp"
 #include "AudioVoice.hpp"
 #include "AudioSubmix.hpp"
 #include <functional>
@@ -9,17 +11,6 @@
 namespace boo
 {
 
-/** Pertinent information from audio backend about optimal mixed-audio representation */
-struct AudioVoiceEngineMixInfo
-{
-    double m_sampleRate;
-    soxr_datatype_t m_sampleFormat;
-    unsigned m_bitsPerSample;
-    AudioChannelSet m_channels;
-    ChannelMap m_channelMap;
-    size_t m_periodFrames;
-};
-
 /** Base class for managing mixing and sample-rate-conversion amongst active voices */
 class BaseAudioVoiceEngine : public IAudioVoiceEngine
 {
@@ -44,6 +35,12 @@ protected:
     std::vector<int32_t> m_scratch32Post;
     std::vector<float> m_scratchFltPost;
 
+    /* LtRt processing if enabled */
+    std::unique_ptr<LtRtProcessing> m_ltRtProcessing;
+    std::vector<int16_t> m_ltRtIn16;
+    std::vector<int32_t> m_ltRtIn32;
+    std::vector<float> m_ltRtInFlt;
+
     AudioSubmix m_mainSubmix;
     std::list<AudioSubmix*> m_linearizedSubmixes;
     bool m_submixesDirty = true;
@@ -71,8 +68,10 @@ public:
     void setCallbackInterface(IAudioVoiceEngineCallback* cb);
 
     void setVolume(float vol);
+    bool enableLtRt(bool enable);
     const AudioVoiceEngineMixInfo& mixInfo() const;
-    AudioChannelSet getAvailableSet() {return m_mixInfo.m_channels;}
+    const AudioVoiceEngineMixInfo& clientMixInfo() const;
+    AudioChannelSet getAvailableSet() {return clientMixInfo().m_channels;}
     void pumpAndMixVoices() {}
     size_t get5MsFrames() const {return m_5msFrames;}
 };
diff --git a/lib/audiodev/Common.hpp b/lib/audiodev/Common.hpp
new file mode 100644
index 0000000..6ac6386
--- /dev/null
+++ b/lib/audiodev/Common.hpp
@@ -0,0 +1,22 @@
+#ifndef BOO_AUDIOCOMMON_HPP
+#define BOO_AUDIOCOMMON_HPP
+
+#include <soxr.h>
+
+namespace boo
+{
+
+/** Pertinent information from audio backend about optimal mixed-audio representation */
+struct AudioVoiceEngineMixInfo
+{
+    double m_sampleRate;
+    soxr_datatype_t m_sampleFormat;
+    unsigned m_bitsPerSample;
+    AudioChannelSet m_channels;
+    ChannelMap m_channelMap;
+    size_t m_periodFrames;
+};
+
+}
+
+#endif // BOO_AUDIOCOMMON_HPP
diff --git a/lib/audiodev/LtRtProcessing.cpp b/lib/audiodev/LtRtProcessing.cpp
new file mode 100644
index 0000000..1c4d302
--- /dev/null
+++ b/lib/audiodev/LtRtProcessing.cpp
@@ -0,0 +1,270 @@
+#include "LtRtProcessing.hpp"
+#include <cmath>
+
+namespace boo
+{
+
+template <typename T>
+inline T ClampFull(float in)
+{
+    if(std::is_floating_point<T>())
+    {
+        return std::min<T>(std::max<T>(in, -1.f), 1.f);
+    }
+    else
+    {
+        constexpr T MAX = std::numeric_limits<T>::max();
+        constexpr T MIN = std::numeric_limits<T>::min();
+
+        if (in < MIN)
+            return MIN;
+        else if (in > MAX)
+            return MAX;
+        else
+            return in;
+    }
+}
+
+#if INTEL_IPP
+
+WindowedHilbert::WindowedHilbert(int windowSamples)
+: m_windowSamples(windowSamples), m_halfSamples(windowSamples / 2),
+  m_inputBuf(new Ipp32f[m_windowSamples * 2 + m_halfSamples]),
+  m_outputBuf(new Ipp32fc[m_windowSamples * 4]),
+  m_hammingTable(new Ipp32f[m_halfSamples])
+{
+    memset(m_inputBuf.get(), 0, sizeof(Ipp32fc) * m_windowSamples * 2 + m_halfSamples);
+    memset(m_outputBuf.get(), 0, sizeof(Ipp32fc) * m_windowSamples * 4);
+    m_output[0] = m_outputBuf.get();
+    m_output[1] = m_output[0] + m_windowSamples;
+    m_output[2] = m_output[1] + m_windowSamples;
+    m_output[3] = m_output[2] + m_windowSamples;
+    int sizeSpec, sizeBuf;
+    ippsHilbertGetSize_32f32fc(m_windowSamples, ippAlgHintNone, &sizeSpec, &sizeBuf);
+    m_spec = (IppsHilbertSpec*)ippMalloc(sizeSpec);
+    m_buffer = (Ipp8u*)ippMalloc(sizeBuf);
+    ippsHilbertInit_32f32fc(m_windowSamples, ippAlgHintNone, m_spec, m_buffer);
+
+    for (int i=0 ; i<m_halfSamples ; ++i)
+        m_hammingTable[i] = Ipp32f(std::cos(M_PI * (i / double(m_halfSamples) + 1.0)) * 0.5 + 0.5);
+}
+
+WindowedHilbert::~WindowedHilbert()
+{
+    ippFree(m_spec);
+    ippFree(m_buffer);
+}
+
+void WindowedHilbert::_AddWindow()
+{
+    if (m_bufIdx)
+    {
+        /* Mirror last half of samples to start of input buffer */
+        Ipp32f* bufBase = &m_inputBuf[m_windowSamples * 2];
+        for (int i=0 ; i<m_halfSamples ; ++i)
+            m_inputBuf[i] = bufBase[i];
+        ippsHilbert_32f32fc(&m_inputBuf[m_windowSamples],
+                            m_output[2], m_spec, m_buffer);
+        ippsHilbert_32f32fc(&m_inputBuf[m_windowSamples + m_halfSamples],
+                            m_output[3], m_spec, m_buffer);
+    }
+    else
+    {
+        ippsHilbert_32f32fc(&m_inputBuf[0],
+                            m_output[0], m_spec, m_buffer);
+        ippsHilbert_32f32fc(&m_inputBuf[m_halfSamples],
+                            m_output[1], m_spec, m_buffer);
+    }
+    m_bufIdx ^= 1;
+}
+
+void WindowedHilbert::AddWindow(const float* input, int stride)
+{
+    Ipp32f* bufBase = &m_inputBuf[m_windowSamples * m_bufIdx + m_halfSamples];
+    for (int i=0 ; i<m_windowSamples ; ++i)
+        bufBase[i] = input[i * stride];
+    _AddWindow();
+}
+
+void WindowedHilbert::AddWindow(const int32_t* input, int stride)
+{
+    Ipp32f* bufBase = &m_inputBuf[m_windowSamples * m_bufIdx + m_halfSamples];
+    for (int i=0 ; i<m_windowSamples ; ++i)
+        bufBase[i] = input[i * stride] / (float(INT32_MAX) + 1.f);
+    _AddWindow();
+}
+
+void WindowedHilbert::AddWindow(const int16_t* input, int stride)
+{
+    Ipp32f* bufBase = &m_inputBuf[m_windowSamples * m_bufIdx + m_halfSamples];
+    for (int i=0 ; i<m_windowSamples ; ++i)
+        bufBase[i] = input[i * stride] / (float(INT16_MAX) + 1.f);
+    _AddWindow();
+}
+
+template <typename T>
+void WindowedHilbert::Output(T* output, float lCoef, float rCoef) const
+{
+    int first, middle, last;
+    if (m_bufIdx)
+    {
+        first = 3;
+        middle = 0;
+        last = 1;
+    }
+    else
+    {
+        first = 1;
+        middle = 2;
+        last = 3;
+    }
+
+    int i, t;
+    for (i=0, t=0 ; i<m_halfSamples ; ++i, ++t)
+    {
+        float tmp = m_output[first][i].im * (1.f - m_hammingTable[t]) +
+                    m_output[middle][i].im * m_hammingTable[t];
+        output[i*2] = ClampFull<T>(output[i*2] + tmp * lCoef);
+        output[i*2+1] = ClampFull<T>(output[i*2+1] + tmp * rCoef);
+    }
+    for (; i<m_windowSamples-m_halfSamples ; ++i)
+    {
+        float tmp = m_output[middle][i].im;
+        output[i*2] = ClampFull<T>(output[i*2] + tmp * lCoef);
+        output[i*2+1] = ClampFull<T>(output[i*2+1] + tmp * rCoef);
+    }
+    for (t=0 ; i<m_windowSamples ; ++i, ++t)
+    {
+        float tmp = m_output[middle][i].im * (1.f - m_hammingTable[t]) +
+                    m_output[last][i].im * m_hammingTable[t];
+        output[i*2] = ClampFull<T>(output[i*2] + tmp * lCoef);
+        output[i*2+1] = ClampFull<T>(output[i*2+1] + tmp * rCoef);
+    }
+}
+
+template void WindowedHilbert::Output<int16_t>(int16_t* output, float lCoef, float rCoef) const;
+template void WindowedHilbert::Output<int32_t>(int32_t* output, float lCoef, float rCoef) const;
+template void WindowedHilbert::Output<float>(float* output, float lCoef, float rCoef) const;
+
+#endif
+
+template <> int16_t* LtRtProcessing::_getInBuf<int16_t>() { return m_16Buffer.get(); }
+template <> int32_t* LtRtProcessing::_getInBuf<int32_t>() { return m_32Buffer.get(); }
+template <> float* LtRtProcessing::_getInBuf<float>() { return m_fltBuffer.get(); }
+
+template <> int16_t* LtRtProcessing::_getOutBuf<int16_t>() { return m_16Buffer.get() + m_outputOffset; }
+template <> int32_t* LtRtProcessing::_getOutBuf<int32_t>() { return m_32Buffer.get() + m_outputOffset; }
+template <> float* LtRtProcessing::_getOutBuf<float>() { return m_fltBuffer.get() + m_outputOffset; }
+
+LtRtProcessing::LtRtProcessing(int _5msFrames, const AudioVoiceEngineMixInfo& mixInfo)
+: m_inMixInfo(mixInfo), m_5msFrames(_5msFrames), m_5msFramesHalf(_5msFrames / 2),
+  m_outputOffset(m_5msFrames * 5 * 2), m_hilbertSL(_5msFrames), m_hilbertSR(_5msFrames)
+{
+    m_inMixInfo.m_channels = AudioChannelSet::Surround51;
+    m_inMixInfo.m_channelMap.m_channelCount = 5;
+    m_inMixInfo.m_channelMap.m_channels[0] = AudioChannel::FrontLeft;
+    m_inMixInfo.m_channelMap.m_channels[1] = AudioChannel::FrontRight;
+    m_inMixInfo.m_channelMap.m_channels[2] = AudioChannel::FrontCenter;
+    m_inMixInfo.m_channelMap.m_channels[3] = AudioChannel::RearLeft;
+    m_inMixInfo.m_channelMap.m_channels[4] = AudioChannel::RearRight;
+
+    int samples = m_5msFrames * (5 * 2 + 2 * 2);
+    switch (mixInfo.m_sampleFormat)
+    {
+    case SOXR_INT16_I:
+        m_16Buffer.reset(new int16_t[samples]);
+        memset(m_16Buffer.get(), 0, sizeof(int16_t) * samples);
+        break;
+    case SOXR_INT32_I:
+        m_32Buffer.reset(new int32_t[samples]);
+        memset(m_32Buffer.get(), 0, sizeof(int32_t) * samples);
+        break;
+    case SOXR_FLOAT32_I:
+        m_fltBuffer.reset(new float[samples]);
+        memset(m_fltBuffer.get(), 0, sizeof(float) * samples);
+        break;
+    default:
+        break;
+    }
+}
+
+template <typename T>
+void LtRtProcessing::Process(const T* input, T* output, int frameCount)
+{
+    int outFramesRem = frameCount;
+    T* inBuf = _getInBuf<T>();
+    T* outBuf = _getOutBuf<T>();
+    int tail = std::min(m_5msFrames * 2, m_bufferTail + frameCount);
+    int samples = (tail - m_bufferTail) * 5;
+    memmove(&inBuf[m_bufferTail * 5], input, samples * sizeof(float));
+    input += samples;
+    frameCount -= tail - m_bufferTail;
+
+    int bufIdx = m_bufferTail / m_5msFrames;
+    if (tail / m_5msFrames > bufIdx)
+    {
+        T* in = &inBuf[bufIdx * m_5msFrames * 5];
+        T* out = &outBuf[bufIdx * m_5msFrames * 2];
+        m_hilbertSL.AddWindow(in + 3, 5);
+        m_hilbertSR.AddWindow(in + 4, 5);
+
+        // x(:,1) + sqrt(.5)*x(:,3) + sqrt(19/25)*x(:,4) + sqrt(6/25)*x(:,5)
+        // x(:,2) + sqrt(.5)*x(:,3) - sqrt(6/25)*x(:,4) - sqrt(19/25)*x(:,5)
+        if (bufIdx)
+        {
+            int delayI = -m_5msFramesHalf;
+            for (int i=0 ; i<m_5msFrames ; ++i, ++delayI)
+            {
+                out[i * 2] = ClampFull<T>(in[delayI * 5] + 0.7071068f * in[delayI * 5 + 2]);
+                out[i * 2 + 1] = ClampFull<T>(in[delayI * 5 + 1] + 0.7071068f * in[delayI * 5 + 2]);
+            }
+        }
+        else
+        {
+            int delayI = m_5msFrames * 2 - m_5msFramesHalf;
+            int i;
+            for (i=0 ; i<m_5msFramesHalf ; ++i, ++delayI)
+            {
+                out[i * 2] = ClampFull<T>(in[delayI * 5] + 0.7071068f * in[delayI * 5 + 2]);
+                out[i * 2 + 1] = ClampFull<T>(in[delayI * 5 + 1] + 0.7071068f * in[delayI * 5 + 2]);
+            }
+            delayI = 0;
+            for (; i<m_5msFrames ; ++i, ++delayI)
+            {
+                out[i * 2] = ClampFull<T>(in[delayI * 5] + 0.7071068f * in[delayI * 5 + 2]);
+                out[i * 2 + 1] = ClampFull<T>(in[delayI * 5 + 1] + 0.7071068f * in[delayI * 5 + 2]);
+            }
+        }
+#if INTEL_IPP
+        m_hilbertSL.Output(out, 0.8717798f, 0.4898979f);
+        m_hilbertSR.Output(out, -0.4898979f, -0.8717798f);
+#endif
+    }
+    m_bufferTail = tail;
+
+    if (frameCount)
+    {
+        samples = frameCount * 5;
+        memmove(inBuf, input, samples * sizeof(float));
+        m_bufferTail = frameCount;
+    }
+
+    int head = std::min(m_5msFrames * 2, m_bufferHead + outFramesRem);
+    samples = (head - m_bufferHead) * 2;
+    memmove(output, outBuf + m_bufferHead * 2, samples * sizeof(float));
+    output += samples;
+    outFramesRem -= head - m_bufferHead;
+    m_bufferHead = head;
+    if (outFramesRem)
+    {
+        samples = outFramesRem * 2;
+        memmove(output, outBuf, samples * sizeof(float));
+        m_bufferHead = outFramesRem;
+    }
+}
+
+template void LtRtProcessing::Process<int16_t>(const int16_t* input, int16_t* output, int frameCount);
+template void LtRtProcessing::Process<int32_t>(const int32_t* input, int32_t* output, int frameCount);
+template void LtRtProcessing::Process<float>(const float* input, float* output, int frameCount);
+
+}
diff --git a/lib/audiodev/LtRtProcessing.hpp b/lib/audiodev/LtRtProcessing.hpp
new file mode 100644
index 0000000..7f08fa2
--- /dev/null
+++ b/lib/audiodev/LtRtProcessing.hpp
@@ -0,0 +1,65 @@
+#ifndef BOO_LTRTPROCESSING_HPP
+#define BOO_LTRTPROCESSING_HPP
+
+#include "boo/System.hpp"
+#include "boo/audiodev/IAudioVoice.hpp"
+#include "Common.hpp"
+#include <memory>
+
+#if INTEL_IPP
+#include "ipp.h"
+#endif
+
+namespace boo
+{
+
+#if INTEL_IPP
+class WindowedHilbert
+{
+    IppsHilbertSpec* m_spec;
+    Ipp8u* m_buffer;
+    int m_windowSamples, m_halfSamples;
+    int m_bufIdx = 0;
+    int m_bufferTail = 0;
+    std::unique_ptr<Ipp32f[]> m_inputBuf;
+    std::unique_ptr<Ipp32fc[]> m_outputBuf;
+    Ipp32fc* m_output[4];
+    std::unique_ptr<Ipp32f[]> m_hammingTable;
+    void _AddWindow();
+public:
+    explicit WindowedHilbert(int windowSamples);
+    ~WindowedHilbert();
+    void AddWindow(const float* input, int stride);
+    void AddWindow(const int32_t* input, int stride);
+    void AddWindow(const int16_t* input, int stride);
+    template <typename T>
+    void Output(T* output, float lCoef, float rCoef) const;
+};
+#endif
+
+class LtRtProcessing
+{
+    AudioVoiceEngineMixInfo m_inMixInfo;
+    int m_5msFrames;
+    int m_5msFramesHalf;
+    int m_outputOffset;
+    int m_bufferTail = 0;
+    int m_bufferHead = 0;
+    std::unique_ptr<int16_t[]> m_16Buffer;
+    std::unique_ptr<int32_t[]> m_32Buffer;
+    std::unique_ptr<float[]> m_fltBuffer;
+#if INTEL_IPP
+    WindowedHilbert m_hilbertSL, m_hilbertSR;
+#endif
+    template <typename T> T* _getInBuf();
+    template <typename T> T* _getOutBuf();
+public:
+    LtRtProcessing(int _5msFrames, const AudioVoiceEngineMixInfo& mixInfo);
+    template <typename T>
+    void Process(const T* input, T* output, int frameCount);
+    const AudioVoiceEngineMixInfo& inMixInfo() const { return m_inMixInfo; }
+};
+
+}
+
+#endif // BOO_LTRTPROCESSING_HPP