diff --git a/common/JackCallbackNetIOAdapter.cpp b/common/JackCallbackNetIOAdapter.cpp
index 374b67db..0d3089c0 100644
--- a/common/JackCallbackNetIOAdapter.cpp
+++ b/common/JackCallbackNetIOAdapter.cpp
@@ -38,6 +38,8 @@ int JackCallbackNetIOAdapter::Process(jack_nframes_t frames, void* arg)
     
     if (!adapter->fIOAdapter->IsRunning())
         return 0;
+        
+    adapter->fIOAdapter->SetCallbackTime(jack_get_time());
     
     for (i = 0; i < adapter->fCaptureChannels; i++) {
     
@@ -45,7 +47,7 @@ int JackCallbackNetIOAdapter::Process(jack_nframes_t frames, void* arg)
         size_t len = jack_ringbuffer_read_space(adapter->fCaptureRingBuffer);
         
         if (len < frames * sizeof(float)) {
-            jack_error("JackCallbackNetIOAdapter::Process : consumer too slow, skip frames = %d", (frames * sizeof(float)) - len);
+            jack_error("JackCallbackNetIOAdapter::Process : consumer too slow, skip frames = %d", frames - len / sizeof(float));
             jack_ringbuffer_read(adapter->fCaptureRingBuffer, buffer, len);
         } else {
             jack_ringbuffer_read(adapter->fCaptureRingBuffer, buffer, frames * sizeof(float));
@@ -58,7 +60,7 @@ int JackCallbackNetIOAdapter::Process(jack_nframes_t frames, void* arg)
         size_t len = jack_ringbuffer_write_space(adapter->fPlaybackRingBuffer);
         
          if (len < frames * sizeof(float)) {
-            jack_error("JackCallbackNetIOAdapter::Process : producer too slow, missing frames = %d", (frames * sizeof(float)) - len);
+            jack_error("JackCallbackNetIOAdapter::Process : producer too slow, missing frames = %d", frames - len / sizeof(float));
             jack_ringbuffer_write(adapter->fPlaybackRingBuffer, buffer, len);
         } else {
             jack_ringbuffer_write(adapter->fPlaybackRingBuffer, buffer, frames * sizeof(float));
diff --git a/common/JackIOAdapter.h b/common/JackIOAdapter.h
index 211e194a..96f3af9e 100644
--- a/common/JackIOAdapter.h
+++ b/common/JackIOAdapter.h
@@ -21,6 +21,8 @@ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 #define __JackIOAdapter__
 
 #include "ringbuffer.h"
+#include "jack.h"
+#include "JackError.h"
 
 namespace Jack
 {
@@ -34,6 +36,8 @@ namespace Jack
             int fPlaybackChannels;
             int fBufferSize;
             float fSampleRate;
+            jack_time_t fCallbackTime;
+            jack_time_t fFirstCallbackTime;
           
             jack_ringbuffer_t* fCaptureRingBuffer;
             jack_ringbuffer_t* fPlaybackRingBuffer;
@@ -46,6 +50,7 @@ namespace Jack
                 fPlaybackChannels(output), 
                 fBufferSize(buffer_size), 
                 fSampleRate(sample_rate),
+                fCallbackTime(0),
                 fRunning(false)
             {}
 			virtual ~JackIOAdapterInterface()
@@ -66,6 +71,11 @@ namespace Jack
             {
                 fBufferSize = buffer_size;
             }
+            
+            virtual void SetCallbackTime(jack_time_t usec)
+            {
+                fCallbackTime = usec;
+            }
         
 	};
 }
diff --git a/windows/JackPortAudioIOAdapter.cpp b/windows/JackPortAudioIOAdapter.cpp
index 268bccf0..c8987ea3 100644
--- a/windows/JackPortAudioIOAdapter.cpp
+++ b/windows/JackPortAudioIOAdapter.cpp
@@ -34,7 +34,12 @@ int JackPortAudioIOAdapter::Render(const void* inputBuffer, void* outputBuffer,
     float** paBuffer;
     char* buffer;
     
-    adapter->fRunning = true;
+    if (!adapter->fRunning) {
+        adapter->fRunning = true;
+        adapter->fFirstCallbackTime = jack_get_time();
+    }
+    
+    jack_log("Coef %f", double(jack_get_time() - adapter->fFirstCallbackTime) / double( adapter->fCallbackTime - adapter->fFirstCallbackTime));
     
     paBuffer = (float**)inputBuffer;
     for (int i = 0; i < adapter->fCaptureChannels; i++) {
@@ -43,7 +48,7 @@ int JackPortAudioIOAdapter::Render(const void* inputBuffer, void* outputBuffer,
         size_t len = jack_ringbuffer_write_space(adapter->fCaptureRingBuffer);
         
         if (len < framesPerBuffer * sizeof(float)) {
-            jack_error("JackPortAudioIOAdapter::Process : producer too slow, missing frames = %d", (framesPerBuffer * sizeof(float)) - len);
+            jack_error("JackPortAudioIOAdapter::Process : producer too slow, missing frames = %d", framesPerBuffer - len / sizeof(float));
             jack_ringbuffer_write(adapter->fCaptureRingBuffer, buffer, len);
         } else {
             jack_ringbuffer_write(adapter->fCaptureRingBuffer, buffer, framesPerBuffer * sizeof(float));
@@ -57,7 +62,7 @@ int JackPortAudioIOAdapter::Render(const void* inputBuffer, void* outputBuffer,
         size_t len = jack_ringbuffer_read_space(adapter->fPlaybackRingBuffer);
          
         if (len < framesPerBuffer * sizeof(float)) {
-            jack_error("JackPortAudioIOAdapter::Process : consumer too slow, skip frames = %d", (framesPerBuffer * sizeof(float)) - len);
+            jack_error("JackPortAudioIOAdapter::Process : consumer too slow, skip frames = %d", framesPerBuffer - len / sizeof(float));
             jack_ringbuffer_read(adapter->fPlaybackRingBuffer, buffer, len);
         } else {
             jack_ringbuffer_read(adapter->fPlaybackRingBuffer, buffer, framesPerBuffer * sizeof(float));