diff --git a/core/AmAdvancedAudio.cpp b/core/AmAdvancedAudio.cpp
index 6a41935c..78d9d935 100644
--- a/core/AmAdvancedAudio.cpp
+++ b/core/AmAdvancedAudio.cpp
@@ -223,7 +223,7 @@ int AmAudioDelay::write(unsigned int user_ts, unsigned int size) {
 }
 
 int AmAudioDelay::read(unsigned int user_ts, unsigned int size) { 
-  sarr.read((unsigned int) (user_ts  - delay*8000.0), (short*)  ((unsigned char*) samples), size >> 1); 
+  sarr.read((unsigned int) (user_ts  - delay*(float)SYSTEM_SAMPLERATE), (short*)  ((unsigned char*) samples), size >> 1); 
   return size;
 }
 
diff --git a/core/AmAudio.cpp b/core/AmAudio.cpp
index 594436c4..43613440 100644
--- a/core/AmAudio.cpp
+++ b/core/AmAudio.cpp
@@ -39,8 +39,6 @@
 
 #include <typeinfo>
 
-#define SYSTEM_SAMPLERATE 8000 // fixme: sr per session
-
 /** \brief structure to hold loaded codec instances */
 struct CodecContainer
 {
@@ -140,7 +138,7 @@ AmAudioSimpleFormat::AmAudioSimpleFormat(int codec_id)
   : AmAudioFormat(), codec_id(codec_id)
 {
   codec = getCodec();
-  rate = 8000;
+  rate = SYSTEM_SAMPLERATE;
   channels = 1;
 }
 
@@ -275,6 +273,7 @@ AmAudio::~AmAudio()
 }
 
 void AmAudio::setFormat(AmAudioFormat* new_fmt) {
+  DBG("set format to %p --------------------------\n", new_fmt);
   fmt.reset(new_fmt);
   fmt->resetCodec();
 }
@@ -377,10 +376,10 @@ int AmAudio::encode(unsigned int size)
 {
   int s = size;
 
-  //     if(!fmt.get()){
-  // 	DBG("no encode fmt\n");
-  // 	return 0;
-  //     }
+//   if(!fmt.get()){
+//     DBG("no encode fmt\n");
+//     return 0;
+//   }
 
   amci_codec_t* codec = fmt->getCodec();
   long h_codec = fmt->getHCodec();
diff --git a/core/AmAudio.h b/core/AmAudio.h
index cc8187bc..d26a74ff 100644
--- a/core/AmAudio.h
+++ b/core/AmAudio.h
@@ -47,6 +47,8 @@ using std::string;
 #define PCM16_B2S(b) ((b) >> 1)
 #define PCM16_S2B(s) ((s) << 1)
 
+#define SYSTEM_SAMPLERATE 8000 // fixme: sr per session
+
 class SdpPayload;
 class CodecContainer;
 
diff --git a/core/AmAudioMixIn.h b/core/AmAudioMixIn.h
index 28636974..fdb06a2c 100644
--- a/core/AmAudioMixIn.h
+++ b/core/AmAudioMixIn.h
@@ -33,8 +33,8 @@
 
 
 #define MAX_PACKETLENGTH_MS   30
-#define MAX_BUF_SAMPLES  8000 * MAX_PACKETLENGTH_MS / 1000
-#define DEFAULT_SAMPLE_RATE 8000 // eh...
+#define MAX_BUF_SAMPLES  SYSTEM_SAMPLERATE * MAX_PACKETLENGTH_MS / 1000
+#define DEFAULT_SAMPLE_RATE SYSTEM_SAMPLERATE // eh...
 
 /**
  * \brief \ref AmAudio to mix in every n seconds a file
diff --git a/core/AmDtmfDetector.cpp b/core/AmDtmfDetector.cpp
index 8006ceba..0116b308 100644
--- a/core/AmDtmfDetector.cpp
+++ b/core/AmDtmfDetector.cpp
@@ -462,7 +462,7 @@ AmSemsInbandDtmfDetector::AmSemsInbandDtmfDetector(AmKeyPressSink *keysink)
     m_last(' '),
     m_idx(0),
     m_count(0),
-    SAMPLERATE(8000)
+    SAMPLERATE(SYSTEM_SAMPLERATE)
 {
   /* precalculate 2 * cos (2 PI k / N) */
   for(unsigned i = 0; i < NELEMSOF(rel_cos2pik); i++) {
diff --git a/core/AmJitterBuffer.h b/core/AmJitterBuffer.h
index 30937ecf..65ae7392 100644
--- a/core/AmJitterBuffer.h
+++ b/core/AmJitterBuffer.h
@@ -29,11 +29,12 @@
 #define _AmJitterBuffer_h_
 
 #include "amci/amci.h"
+#include "AmAudio.h"
 #include "AmThread.h"
 #include "SampleArray.h"
 
-#define INITIAL_JITTER	    640 // 80 miliseconds
-#define MAX_JITTER	    16000 // 2 seconds
+#define INITIAL_JITTER	    80 * SYSTEM_SAMPLERATE / 1000 // 80 miliseconds
+#define MAX_JITTER	    2  * SYSTEM_SAMPLERATE // 2 seconds
 #define RESYNC_THRESHOLD    2
 
 class Packet {
diff --git a/core/AmMediaProcessor.cpp b/core/AmMediaProcessor.cpp
index 8616aa19..7d2110cc 100644
--- a/core/AmMediaProcessor.cpp
+++ b/core/AmMediaProcessor.cpp
@@ -26,6 +26,7 @@
  */
 
 #include "AmMediaProcessor.h"
+#include "AmSession.h"
 #include "AmRtpStream.h"
 
 #include <assert.h>
@@ -212,7 +213,7 @@ void AmMediaProcessorThread::run()
     events.processEvents();
     processDtmfEvents();
 
-    ts += 80; // 10 ms
+    ts += 10 * SYSTEM_SAMPLERATE / 1000; // 10 ms
     timeradd(&tick,&next_tick,&next_tick);
   }
 }
diff --git a/core/AmMediaProcessor.h b/core/AmMediaProcessor.h
index d727860b..e32c1f19 100644
--- a/core/AmMediaProcessor.h
+++ b/core/AmMediaProcessor.h
@@ -28,8 +28,9 @@
 #ifndef _AmMediaProcessor_h_
 #define _AmMediaProcessor_h_
 
-#include "AmSession.h"
 #include "AmEventQueue.h"
+#include "amci/amci.h" // AUDIO_BUFFER_SIZE
+class AmSession;
 
 #include <set>
 using std::set;
diff --git a/core/AmMultiPartyMixer.cpp b/core/AmMultiPartyMixer.cpp
index 089b42a9..27f1640a 100644
--- a/core/AmMultiPartyMixer.cpp
+++ b/core/AmMultiPartyMixer.cpp
@@ -37,7 +37,7 @@
 
 // the internal delay of the mixer (between put and get)
 #define MIXER_DELAY_MS 20
-#define MIXER_DELAY    MIXER_DELAY_MS*8  // 8000/1000
+#define MIXER_DELAY    MIXER_DELAY_MS*SYSTEM_SAMPLERATE/1000
 
 AmMultiPartyMixer::AmMultiPartyMixer()
   : channels(),
diff --git a/core/AmPlayoutBuffer.cpp b/core/AmPlayoutBuffer.cpp
index 50e0317b..5c1a8055 100644
--- a/core/AmPlayoutBuffer.cpp
+++ b/core/AmPlayoutBuffer.cpp
@@ -42,7 +42,7 @@
 
 #define PI 3.14 
 
-#define MAX_DELAY 8000 /* 1 second */
+#define MAX_DELAY SYSTEM_SAMPLERATE*1 /* 1 second */
 
 AmPlayoutBuffer::AmPlayoutBuffer(AmPLCBuffer *plcbuffer)
   : r_ts(0),w_ts(0), 
diff --git a/core/AmPlayoutBuffer.h b/core/AmPlayoutBuffer.h
index 4d0fc2c0..d84322f2 100644
--- a/core/AmPlayoutBuffer.h
+++ b/core/AmPlayoutBuffer.h
@@ -42,18 +42,18 @@ using std::multiset;
 #define EXP_THRESHOLD 20
 #define SHR_THRESHOLD 180
 
-#define WSOLA_START_OFF  80
+#define WSOLA_START_OFF  10 * SYSTEM_SAMPLERATE / 1000
 #define WSOLA_SCALED_WIN 50
 
-// the maximum packet size that will be processed
-//   640 is 80ms @ 8khz
-#define MAX_PACKET_SAMPLES 640
-// search segments of size TEMPLATE_SEG samples 
-#define TEMPLATE_SEG   80
+// the maximum packet size that will be processed (80ms)
+#define MAX_PACKET_SAMPLES 80 * SYSTEM_SAMPLERATE / 1000
+// search segments of size TEMPLATE_SEG samples (10 ms)
+#define TEMPLATE_SEG   10 * SYSTEM_SAMPLERATE / 1000
 
 // Maximum value: AUDIO_BUFFER_SIZE / 2
 // Note: plc result get stored in our back buffer
-#define PLC_MAX_SAMPLES (160*4) 
+// maximum of 80ms PLC
+#define PLC_MAX_SAMPLES (4*20*SYSTEM_SAMPLERATE / 1000) 
 
 class AmPLCBuffer;
 
diff --git a/core/AmPlugIn.cpp b/core/AmPlugIn.cpp
index 53760acf..055ee2ac 100644
--- a/core/AmPlugIn.cpp
+++ b/core/AmPlugIn.cpp
@@ -92,7 +92,7 @@ amci_codec_t _codec_tevent = {
 amci_payload_t _payload_tevent = { 
   -1,
   "telephone-event",
-  8000,
+  8000, // telephone-event has always SR 8000 
   -1,
   CODEC_TELEPHONE_EVENT,
   -1 
diff --git a/core/AmRingTone.cpp b/core/AmRingTone.cpp
index fc0df291..17e28bb8 100644
--- a/core/AmRingTone.cpp
+++ b/core/AmRingTone.cpp
@@ -34,9 +34,9 @@ int AmRingTone::read(unsigned int user_ts, unsigned int size)
   for(unsigned int i=0; i<PCM16_B2S(size); i++, s++, t++){
 
     if(t < on_period<<3){
-      float fs = sin((float(t*freq)/8000.0)*2.0*PI)*15000.0;
+      float fs = sin((float(t*freq)/(float)SYSTEM_SAMPLERATE)*2.0*PI)*15000.0;
       if(freq2 != 0)
-	fs += sin((float(t*freq2)/8000.0)*2.0*PI)*15000.0;
+	fs += sin((float(t*freq2)/(float)SYSTEM_SAMPLERATE)*2.0*PI)*15000.0;
       *s = (short)(fs);
     }
     else
diff --git a/core/LowcFE.h b/core/LowcFE.h
index a24c6464..b52c452b 100644
--- a/core/LowcFE.h
+++ b/core/LowcFE.h
@@ -28,6 +28,7 @@
 #ifndef _LowcFE_h_
 #define _LowcFE_h_
 
+#include "AmAudio.h"
 
 typedef float Float;
 
@@ -37,13 +38,13 @@ typedef float Float;
 #define POVERLAPMAX   (PITCH_MAX >> 2)              /* maximum pitch OLA window */
 #define HISTORYLEN    (PITCH_MAX * 3 + POVERLAPMAX) /* history buff length*/
 #define NDEC          2                             /* 2:1 decimation */
-#define CORRLEN       160                           /* 20 msec correlation length */
+#define CORRLEN       20 * SYSTEM_SAMPLERATE / 1000 /* 20 msec correlation length */
 #define CORRBUFLEN    (CORRLEN + PITCH_MAX)         /* correlation buffer length */
 #define CORRMINPOWER  ((Float)250.)                 /* minimum power */
 #define EOVERLAPINCR  32                            /* end OLA increment per frame,4 ms */
-#define FRAMESZ       80                            /* 10 msec at 8 KHz */
+#define FRAMESZ       (10 * SYSTEM_SAMPLERATE / 1000) /* 10 msec */
 #define ATTENFAC      ((Float).2)                   /* attenu. factor per 10 ms frame */
-#define ATTENINCR     (ATTENFAC/FRAMESZ)            /* attenuation per sample */
+#define ATTENINCR     (ATTENFAC/(Float)(FRAMESZ))   /* attenuation per sample */
 
 /** \brief LowcFE erased frame generator for fec (plc) */
 class LowcFE {