diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index ffe48ee15..149d234c1 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -11,7 +11,7 @@ defaults:
     shell: bash
 
 env:
-  BUILD_TYPE: Debug
+  BUILD_TYPE: Release
 
 jobs:
   build:
diff --git a/extern/vgsound_emu-modified/vgsound_emu/src/k007232/k007232.cpp b/extern/vgsound_emu-modified/vgsound_emu/src/k007232/k007232.cpp
index 3798f4c81..02aa34601 100644
--- a/extern/vgsound_emu-modified/vgsound_emu/src/k007232/k007232.cpp
+++ b/extern/vgsound_emu-modified/vgsound_emu/src/k007232/k007232.cpp
@@ -126,7 +126,7 @@ void k007232_core::voice_t::write(u8 address, u8 data)
 			m_start = (m_start & ~0x0ff00) | (u32(data) << 8);
 			break;
 		case 4:	 // start address bit 16
-			m_start = (m_start & ~0x10000) | (u32(bitfield(data, 16)) << 16);
+			m_start = (m_start & ~0x10000) | (u32(bitfield(data, 0)) << 16);
 			break;
 		case 5:	 // keyon trigger
 			keyon();
diff --git a/papers/format.md b/papers/format.md
index 492544ec5..25304378e 100644
--- a/papers/format.md
+++ b/papers/format.md
@@ -32,6 +32,8 @@ these fields are 0 in format versions prior to 100 (0.6pre1).
 
 the format versions are:
 
+- 129: Furnace dev129
+- 128: Furnace dev128
 - 127: Furnace dev127
 - 126: Furnace dev126
 - 125: Furnace dev125
@@ -1120,9 +1122,11 @@ size | description
      | - 16: 16-bit PCM
   1  | loop direction (>=123) or reserved
      | - 0: forward
-     | - 0: backward
-     | - 0: ping-pong
-  2  | reserved
+     | - 1: backward
+     | - 2: ping-pong
+  1  | flags (>=129) or reserved
+     | - 0: BRR emphasis
+  1  | reserved
   4  | loop start
      | - -1 means no loop
   4  | loop end
diff --git a/src/audio/sdlAudio.cpp b/src/audio/sdlAudio.cpp
index f1d0e1e9d..2915f0343 100644
--- a/src/audio/sdlAudio.cpp
+++ b/src/audio/sdlAudio.cpp
@@ -106,6 +106,13 @@ bool TAAudioSDL::init(TAAudioDesc& request, TAAudioDesc& response) {
     audioSysStarted=true;
   }
 
+  const char* audioDriver=SDL_GetCurrentAudioDriver();
+  if (audioDriver==NULL) {
+    logD("SDL audio driver: NULL!");
+  } else {
+    logD("SDL audio driver: %s",audioDriver);
+  }
+
   desc=request;
   desc.outFormat=TA_AUDIO_FORMAT_F32;
 
diff --git a/src/engine/brrUtils.c b/src/engine/brrUtils.c
index e3b20c26d..c4d07b398 100644
--- a/src/engine/brrUtils.c
+++ b/src/engine/brrUtils.c
@@ -21,6 +21,8 @@
  */
 
 #include "brrUtils.h"
+#include <stdio.h>
+#include <string.h>
 
 #define NEXT_SAMPLE buf[j]-(buf[j]>>3)
 
@@ -56,384 +58,257 @@
   last2=last1; \
   last1=nextDec; \
 
-long brrEncode(short* buf, unsigned char* out, long len, long loopStart) {
+void brrEncodeBlock(const short* buf, unsigned char* out, unsigned char range, unsigned char filter, short* last1, short* last2, int* errorSum) {
+  // encode one block using BRR
+  unsigned char nibble=0;
+  int preOut=0;
+  int pred=0;
+  int nextDec=0;
+  int nextError=0;
+  *errorSum=0;
+  for (int j=0; j<16; j++) {
+    short s=NEXT_SAMPLE;
+    switch (filter) {
+      case 0: // no filter
+        pred=s;
+        break;
+      case 1: // simple
+        pred=s-(((int)(*last1*2)*15)>>4);
+        break;
+      case 2: // complex
+        pred=s+(((int)(*last2*2)*15)>>4)-(((int)(*last1*2)*61)>>5);
+        break;
+      case 3:
+        pred=s+(((int)(*last2*2)*13)>>4)-(((int)(*last1*2)*115)>>6);
+        break;
+    }
+
+    if (pred<-32768) pred=-32768;
+    if (pred>32767) pred=32767;
+
+    preOut=pred>>range;
+    if (range) {
+      if (pred&(1<<(range>>1))) preOut++;
+      if (filter==0 && range>=12) if (preOut<-7) preOut=-7;
+    }
+    if (preOut>7) preOut=7;
+    if (preOut<-8) preOut=-8;
+
+    nibble=preOut&15;
+    if (j&1) {
+      out[j>>1]|=nibble;
+    } else {
+      out[j>>1]=nibble<<4;
+    }
+
+    // roll last1/last2
+    nextDec=nibble;
+    if (nextDec&8) nextDec|=0xfffffff0;
+
+    if (range>=13) { /* invalid shift */
+      nextDec=(nextDec<0)?0xfffff800:0;
+    } else {
+      nextDec<<=range; /* range */
+      nextDec>>=1;
+    }
+
+    switch (filter) { /* filter */
+      case 0:
+        break;
+      case 1:
+        nextDec+=(*last1)+((-(*last1))>>4);
+        break;
+      case 2:
+        nextDec+=(*last1)*2+((-(*last1)*3)>>5)-(*last2)+((*last2)>>4);
+        break;
+      case 3:
+        nextDec+=(*last1)*2+((-(*last1)*13)>>6)-(*last2)+(((*last2)*3)>>4);
+        break;
+    }
+
+    nextDec&=0x7fff;
+    if (nextDec&0x4000) nextDec|=0xffff8000;
+
+    nextError=s-(nextDec<<1);
+    if (nextError<0) nextError=-nextError;
+    *errorSum+=nextError;
+
+    *last2=*last1;
+    *last1=nextDec;
+  }
+}
+
+long brrEncode(short* buf, unsigned char* out, long len, long loopStart, unsigned char emphasis) {
   if (len==0) return 0;
 
   // encoding process:
   // 1. read next group of 16 samples
   // 2. is this the first block?
   //   - if yes, don't filter. output and then go to 1
-  // 3. is this the loop block?
-  //   - if yes, don't filter. output and then go to 1
-  // 4. try encoding using 4 filters
-  //   - perform linear prediction
-  //   - calculate range
-  //   - decode and apply correction to achieve low error
+  // 4. try encoding using 3 filters and 12 ranges (besides no filter)
   // 5. which one of these yields the least amount of error?
   // 6. output the one which does
-  // 7. is this the last block?
-  //   - if yes, mark end and finish
-  // 8. go to 1
+  // 7. do we still have more to encode?
+  //   - if so, go to 1
+  // 8. is loop point set?
+  //   - if not, end process here
+  // 9. is transition between last block and loop block smooth?
+  //   - if not, encode the loop block again and output it
   long total=0;
-  unsigned char next0[8];
-  unsigned char next1[8];
-  unsigned char next2[8];
-  unsigned char next3[8];
   unsigned char filter=0;
-  unsigned char range0=0;
-  unsigned char range1=0;
-  unsigned char range2=0;
-  unsigned char range3=0;
-  unsigned char o=0;
-  int pred1[16];
-  int pred2[16];
-  int pred3[16];
-  short o1=0;
-  short o2=0;
-  short o0=0;
-  short o1f1=0;
-  short o1f2=0;
-  short o1f3=0;
-  //short o2f1=0;
-  short o2f2=0;
-  short o2f3=0;
+  unsigned char range=0;
 
-  int last1=0;
-  int last2=0;
-  int nextDec=0;
-  int maxError[4];
-  int avgError[4];
+  short x0=0;
+  short x1=0;
+  short x2=0;
+  int emphOut=0;
+
+  short in[17];
+
+  short last1[4][13];
+  short last2[4][13];
+  int avgError[4][13];
+  unsigned char possibleOut[4][13][8];
+
+  memset(in,0,16*sizeof(short));
+  memset(last1,0,4*13*sizeof(short));
+  memset(last2,0,4*13*sizeof(short));
+  memset(avgError,0,4*13*sizeof(int));
+  memset(possibleOut,0,4*13*8);
 
-  len&=~15;
-  loopStart&=~15;
   for (long i=0; i<len; i+=16) {
-    range0=0;
-    // encode with no filter
-    for (int j=0; j<16; j++) {
-      short s=NEXT_SAMPLE;
-      if (s<0) s=-s;
-      while (range0<12 && s>((8<<range0)-1)) range0++;
-    }
-    for (int j=0; j<16; j++) {
-      short s=NEXT_SAMPLE;
-      o0=s>>range0;
-      if (range0) if (s&(1<<(range1>>1))) o0++;
-      if (o0>7) o0=7;
-      if (o0<-8) o0=-8;
-      if (range0>=12) if (o0<-7) o0=-7;
-      o=o0&15;
-      if (j&1) {
-        next0[j>>1]|=o;
-      } else {
-        next0[j>>1]=o<<4;
-      }
-    }
-
-    // encode with filter
-    if (i /*&& i!=loopStart*/) {
-      // 1: x = o0 - o1 * 15/16
-      // 2: x = o0 + o2 * 15/16 - o1 * 61/32
-      // 3: x = o0 + o2 * 13/16 - o1 * 115/64
-      range1=0;
-      range2=0;
-      range3=0;
-      //o2f1=o2;
-      o2f2=o2;
-      o2f3=o2;
-      o1f1=o1;
-      o1f2=o1;
-      o1f3=o1;
-      // first pass
-      for (int j=0; j<16; j++) {
-        int s=NEXT_SAMPLE;
-
-        pred1[j]=s-(((int)o1*15)>>4);
-        if (pred1[j]<-32768) pred1[j]=-32768;
-        if (pred1[j]>32767) pred1[j]=32767;
-
-        pred2[j]=s+(((int)o2*15)>>4)-(((int)o1*61)>>5);
-        if (pred2[j]<-32768) pred2[j]=-32768;
-        if (pred2[j]>32767) pred2[j]=32767;
-
-        pred3[j]=s+(((int)o2*13)>>4)-(((int)o1*115)>>6);
-        if (pred3[j]<-32768) pred3[j]=-32768;
-        if (pred3[j]>32767) pred3[j]=32767;
-        
-        o2=o1;
-        o1=s;
-      }
-      // calculate range of values
-      for (int j=0; j<16; j++) {
-        short s=pred1[j];
-        if (s<0) s=-s;
-        while (range1<12 && s>((8<<range1)-1)) range1++;
-
-        s=pred2[j];
-        if (s<0) s=-s;
-        while (range2<12 && s>((8<<range2)-1)) range2++;
-
-        s=pred3[j];
-        if (s<0) s=-s;
-        while (range3<12 && s>((8<<range3)-1)) range3++;
-      }
-      // second pass
-      int prevLast1=last1;
-      int prevLast2=last2;
-      filter=1;
-      for (int j=0; j<16; j++) {
-        int s=NEXT_SAMPLE;
-
-        pred1[j]=s-(((int)o1f1*15)>>4);
-        if (pred1[j]<-32768) pred1[j]=-32768;
-        if (pred1[j]>32767) pred1[j]=32767;
-
-        o0=pred1[j]>>range1;
-        if (range1) if (pred1[j]&(1<<(range1>>1))) o0++;
-        if (o0>7) o0=7;
-        if (o0<-8) o0=-8;
-        o=o0&15;
-        if (j&1) {
-          next1[j>>1]|=o;
+    if (i+17>len) {
+      long p=i;
+      for (int j=0; j<17; j++) {
+        if (p>=len) {
+          if (loopStart<0 || loopStart>=len) {
+            in[j]=0;
+          } else {
+            p=loopStart;
+            in[j]=buf[p++];
+          }
         } else {
-          next1[j>>1]=o<<4;
-        }
-
-        nextDec=o;
-        DO_ONE_DEC(range1);
-        //o2f1=last2<<1;
-        o1f1=last1<<1;
-      }
-      last1=prevLast1;
-      last2=prevLast2;
-      filter=2;
-      for (int j=0; j<16; j++) {
-        int s=NEXT_SAMPLE;
-        pred2[j]=s+(((int)o2f2*15)>>4)-(((int)o1f2*61)>>5);
-        if (pred2[j]<-32768) pred2[j]=-32768;
-        if (pred2[j]>32767) pred2[j]=32767;
-
-        o0=pred2[j]>>range2;
-        if (range2) if (pred2[j]&(1<<(range2>>1))) o0++;
-        if (o0>7) o0=7;
-        if (o0<-8) o0=-8;
-        o=o0&15;
-        if (j&1) {
-          next2[j>>1]|=o;
-        } else {
-          next2[j>>1]=o<<4;
-        }
-
-        nextDec=o;
-        DO_ONE_DEC(range2);
-        o2f2=last2<<1;
-        o1f2=last1<<1;
-      }
-      last1=prevLast1;
-      last2=prevLast2;
-      filter=3;
-      for (int j=0; j<16; j++) {
-        int s=NEXT_SAMPLE;
-        pred3[j]=s+(((int)o2f3*13)>>4)-(((int)o1f3*115)>>6);
-        if (pred3[j]<-32768) pred3[j]=-32768;
-        if (pred3[j]>32767) pred3[j]=32767;
-
-        o0=pred3[j]>>range3;
-        if (range3) if (pred3[j]&(1<<(range3>>1))) o0++;
-        if (o0>7) o0=7;
-        if (o0<-8) o0=-8;
-        o=o0&15;
-        if (j&1) {
-          next3[j>>1]|=o;
-        } else {
-          next3[j>>1]=o<<4;
-        }
-
-        nextDec=o;
-        DO_ONE_DEC(range3);
-        o2f3=last2<<1;
-        o1f3=last1<<1;
-      }
-      last1=prevLast1;
-      last2=prevLast2;
-
-      // find best filter
-      int error=0;
-
-      maxError[0]=0;
-      maxError[1]=0;
-      maxError[2]=0;
-      maxError[3]=0;
-      avgError[0]=0;
-      avgError[1]=0;
-      avgError[2]=0;
-      avgError[3]=0;
-
-      // test filter 0
-      filter=0;
-      for (int j=0; j<16; j++) {
-        int s=NEXT_SAMPLE;
-        if (j&1) {
-          nextDec=next0[j>>1]&15;
-        } else {
-          nextDec=next0[j>>1]>>4;
-        }
-        DO_ONE_DEC(range0);
-        error=s-(nextDec<<1);
-        if (error<0) error=-error;
-        avgError[0]+=error;
-        if (error>maxError[0]) maxError[0]=error;
-      }
-      last1=prevLast1;
-      last2=prevLast2;
-
-      // test filter 1
-      filter=1;
-      for (int j=0; j<16; j++) {
-        int s=NEXT_SAMPLE;
-        if (j&1) {
-          nextDec=next1[j>>1]&15;
-        } else {
-          nextDec=next1[j>>1]>>4;
-        }
-        DO_ONE_DEC(range1);
-        error=s-(nextDec<<1);
-        if (error<0) error=-error;
-        avgError[1]+=error;
-        if (error>maxError[1]) maxError[1]=error;
-      }
-      last1=prevLast1;
-      last2=prevLast2;
-
-      // test filter 2
-      filter=2;
-      for (int j=0; j<16; j++) {
-        int s=NEXT_SAMPLE;
-        if (j&1) {
-          nextDec=next2[j>>1]&15;
-        } else {
-          nextDec=next2[j>>1]>>4;
-        }
-        DO_ONE_DEC(range2);
-        error=s-(nextDec<<1);
-        if (error<0) error=-error;
-        avgError[2]+=error;
-        if (error>maxError[2]) maxError[2]=error;
-      }
-      last1=prevLast1;
-      last2=prevLast2;
-
-      // test filter 3
-      filter=3;
-      for (int j=0; j<16; j++) {
-        int s=NEXT_SAMPLE;
-        if (j&1) {
-          nextDec=next3[j>>1]&15;
-        } else {
-          nextDec=next3[j>>1]>>4;
-        }
-        DO_ONE_DEC(range3);
-        error=s-(nextDec<<1);
-        if (error<0) error=-error;
-        avgError[3]+=error;
-        if (error>maxError[3]) maxError[3]=error;
-      }
-      last1=prevLast1;
-      last2=prevLast2;
-
-      // pick best filter
-      int candError=0x7fffffff;
-      for (int j=0; j<4; j++) {
-        if (avgError[j]<candError) {
-          candError=avgError[j];
-          filter=j;
+          in[j]=buf[p++];
         }
       }
-      //printf("block %ld: %8d %8d %8d %8d -> %d\n",i>>4,avgError[0],avgError[1],avgError[2],avgError[3],filter);
     } else {
-      // don't filter on the first or loop block
+      memcpy(in,&buf[i],17*sizeof(short));
+    }
+    
+    // emphasis
+    if (emphasis) {
+      for (int j=0; j<17; j++) {
+        x0=x1;
+        x1=x2;
+        x2=in[j];
+
+        if (j==0) continue;
+        emphOut=((x1<<11)-x0*370-in[j]*374)/1305;
+        if (emphOut<-32768) emphOut=-32768;
+        if (emphOut>32767) emphOut=32767;
+        in[j-1]=emphOut;
+      }
+    }
+
+    // encode
+    for (int j=0; j<4; j++) {
+      for (int k=0; k<13; k++) {
+        brrEncodeBlock(in,possibleOut[j][k],k,j,&last1[j][k],&last2[j][k],&avgError[j][k]);
+      }
+    }
+
+    // find best filter/range
+    int candError=0x7fffffff;
+    if (i==0) {
       filter=0;
+      for (int k=0; k<13; k++) {
+        if (avgError[0][k]<candError) {
+          candError=avgError[0][k];
+          range=k;
+        }
+      }
+    } else {
+      for (int j=0; j<4; j++) {
+        for (int k=0; k<13; k++) {
+          if (avgError[j][k]<candError) {
+            candError=avgError[j][k];
+            filter=j;
+            range=k;
+          }
+        }
+      }
     }
 
-    switch (filter) {
-      case 0:
-        for (int j=0; j<8; j++) {
-          nextDec=next0[j]>>4;
-          DO_ONE_DEC(range0);
-          nextDec=next0[j]&15;
-          DO_ONE_DEC(range0);
-        }
-        o2=last2<<1;
-        o1=last1<<1;
-
-        out[0]=(range0<<4)|(filter<<2)|((i+16>=len)?((loopStart>=0)?3:1):0);
-        out[1]=next0[0];
-        out[2]=next0[1];
-        out[3]=next0[2];
-        out[4]=next0[3];
-        out[5]=next0[4];
-        out[6]=next0[5];
-        out[7]=next0[6];
-        out[8]=next0[7];
-        break;
-      case 1:
-        for (int j=0; j<8; j++) {
-          nextDec=next1[j]>>4;
-          DO_ONE_DEC(range1);
-          nextDec=next1[j]&15;
-          DO_ONE_DEC(range1);
-        }
-        o2=last2<<1;
-        o1=last1<<1;
-        out[0]=(range1<<4)|(filter<<2)|((i+16>=len)?((loopStart>=0)?3:1):0);
-        out[1]=next1[0];
-        out[2]=next1[1];
-        out[3]=next1[2];
-        out[4]=next1[3];
-        out[5]=next1[4];
-        out[6]=next1[5];
-        out[7]=next1[6];
-        out[8]=next1[7];
-        break;
-      case 2:
-        for (int j=0; j<8; j++) {
-          nextDec=next2[j]>>4;
-          DO_ONE_DEC(range2);
-          nextDec=next2[j]&15;
-          DO_ONE_DEC(range2);
-        }
-        o2=last2<<1;
-        o1=last1<<1;
-        out[0]=(range2<<4)|(filter<<2)|((i+16>=len)?((loopStart>=0)?3:1):0);
-        out[1]=next2[0];
-        out[2]=next2[1];
-        out[3]=next2[2];
-        out[4]=next2[3];
-        out[5]=next2[4];
-        out[6]=next2[5];
-        out[7]=next2[6];
-        out[8]=next2[7];
-        break;
-      case 3:
-        for (int j=0; j<8; j++) {
-          nextDec=next3[j]>>4;
-          DO_ONE_DEC(range3);
-          nextDec=next3[j]&15;
-          DO_ONE_DEC(range3);
-        }
-        o2=last2<<1;
-        o1=last1<<1;
-        out[0]=(range3<<4)|(filter<<2)|((i+16>=len)?((loopStart>=0)?3:1):0);
-        out[1]=next3[0];
-        out[2]=next3[1];
-        out[3]=next3[2];
-        out[4]=next3[3];
-        out[5]=next3[4];
-        out[6]=next3[5];
-        out[7]=next3[6];
-        out[8]=next3[7];
-        break;
+    // write
+    out[0]=(range<<4)|(filter<<2)|((i+16>=len && loopStart<0)?1:0);
+    for (int j=0; j<8; j++) {
+      out[j+1]=possibleOut[filter][range][j];
+    }
+
+    for (int j=0; j<4; j++) {
+      for (int k=0; k<13; k++) {
+        last1[j][k]=last1[filter][range];
+        last2[j][k]=last2[filter][range];
+      }
+    }
+    out+=9;
+    total+=9;
+  }
+  // encode loop block
+  if (loopStart>=0) {
+    long p=loopStart;
+    for (int i=0; i<17; i++) {
+      if (p>=len) {
+        p=loopStart;
+      }
+      in[i]=buf[p++];
+    }
+
+    if (emphasis) {
+      for (int j=0; j<17; j++) {
+        x0=x1;
+        x1=x2;
+        x2=in[j];
+
+        if (j==0) continue;
+        emphOut=((x1<<11)-x0*370-in[j]*374)/1305;
+        if (emphOut<-32768) emphOut=-32768;
+        if (emphOut>32767) emphOut=32767;
+        in[j-1]=emphOut;
+      }
+    }
+
+    // encode (filter 0/1 only)
+    for (int j=0; j<2; j++) {
+      for (int k=0; k<13; k++) {
+        brrEncodeBlock(in,possibleOut[j][k],k,j,&last1[j][k],&last2[j][k],&avgError[j][k]);
+      }
+    }
+
+    // find best filter/range
+    int candError=0x7fffffff;
+    for (int j=0; j<2; j++) {
+      for (int k=0; k<13; k++) {
+        if (avgError[j][k]<candError) {
+          candError=avgError[j][k];
+          filter=j;
+          range=k;
+        }
+      }
+    }
+
+    // write
+    out[0]=(range<<4)|(filter<<2)|3;
+    for (int j=0; j<8; j++) {
+      out[j+1]=possibleOut[filter][range][j];
+    }
+
+    for (int j=0; j<4; j++) {
+      for (int k=0; k<13; k++) {
+        last1[j][k]=last1[filter][range];
+        last2[j][k]=last2[filter][range];
+      }
     }
-    buf+=16;
     out+=9;
     total+=9;
   }
@@ -474,9 +349,11 @@ long brrEncode(short* buf, unsigned char* out, long len, long loopStart) {
   *out=next<<1; \
   out++;
 
-long brrDecode(unsigned char* buf, short* out, long len) {
+long brrDecode(unsigned char* buf, short* out, long len, unsigned char emphasis) {
   if (len==0) return 0;
 
+  short* outOrig=out;
+
   long total=0;
 
   int last1=0;
@@ -503,5 +380,20 @@ long brrDecode(unsigned char* buf, short* out, long len) {
     buf+=9;
   }
 
+  if (emphasis) {
+    short x0=0;
+    short x1=0;
+    short x2=0;
+    for (long i=0; i<=total; i++) {
+      x0=x1;
+      x1=x2;
+      x2=(i>=total)?0:outOrig[i];
+
+      if (i==0) continue;
+
+      outOrig[i-1]=(x0*370+x1*1305+x2*374)>>11;
+    }
+  }
+
   return total;
 }
diff --git a/src/engine/brrUtils.h b/src/engine/brrUtils.h
index 5cc898e1b..e4adc3a6d 100644
--- a/src/engine/brrUtils.h
+++ b/src/engine/brrUtils.h
@@ -30,21 +30,23 @@ extern "C" {
 /**
  * read len samples from buf, encode in BRR and output to out.
  * @param buf input data.
- * @param out output buffer. shall be at least 9*(len/16) shorts in size.
+ * @param out output buffer. shall be at least 9*((15+len)/16) shorts in size (9 more if loopStart is not -1!)
  * @param len input length (should be a multiple of 16. if it isn't, the output will be padded).
  * @param loopStart beginning of loop area (may be -1 for no loop). this is used to ensure the respective block has no filter in order to loop properly.
+ * @param emphasis apply filter to compensate for Gaussian interpolation high frequency loss.
  * @return number of written samples.
  */
-long brrEncode(short* buf, unsigned char* out, long len, long loopStart);
+long brrEncode(short* buf, unsigned char* out, long len, long loopStart, unsigned char emphasis);
 
 /**
  * read len bytes from buf, decode BRR and output to out.
  * @param buf input data.
  * @param out output buffer. shall be at least 16*(len/9) shorts in size.
  * @param len input length (shall be a multiple of 9).
+ * @param emphasis apply filter to simulate Gaussian interpolation high frequency loss.
  * @return number of written bytes.
  */
-long brrDecode(unsigned char* buf, short* out, long len);
+long brrDecode(unsigned char* buf, short* out, long len, unsigned char emphasis);
 
 #ifdef __cplusplus
 }
diff --git a/src/engine/engine.h b/src/engine/engine.h
index ab028aca4..3b8881213 100644
--- a/src/engine/engine.h
+++ b/src/engine/engine.h
@@ -47,8 +47,8 @@
 #define BUSY_BEGIN_SOFT softLocked=true; isBusy.lock();
 #define BUSY_END isBusy.unlock(); softLocked=false;
 
-#define DIV_VERSION "dev128"
-#define DIV_ENGINE_VERSION 128
+#define DIV_VERSION "dev129"
+#define DIV_ENGINE_VERSION 129
 // for imports
 #define DIV_VERSION_MOD 0xff01
 #define DIV_VERSION_FC 0xff02
diff --git a/src/engine/platform/qsound.cpp b/src/engine/platform/qsound.cpp
index cc411fa5f..e513d5313 100644
--- a/src/engine/platform/qsound.cpp
+++ b/src/engine/platform/qsound.cpp
@@ -783,7 +783,7 @@ void DivPlatformQSound::renderSamples(int sysID) {
       for (int i=0; i<length; i++) {
         sampleMem[(memPos+i)]=s->dataQSoundA[i];
       }
-      sampleLoaded[i]=true;
+      sampleLoadedBS[i]=true;
     }
     offBS[i]=memPos;
     memPos+=length+16;
diff --git a/src/engine/platform/sms.cpp b/src/engine/platform/sms.cpp
index 0ce4c8361..1d51f56bd 100644
--- a/src/engine/platform/sms.cpp
+++ b/src/engine/platform/sms.cpp
@@ -125,6 +125,9 @@ double DivPlatformSMS::NOTE_SN(int ch, int note) {
   if (parent->song.linearPitch==2 || !easyNoise) {
     return NOTE_PERIODIC(note);
   }
+  int easyStartingPeriod=16;
+  //int easyThreshold=round(CHIP_CLOCK/(parent->song.tuning*0.0625*pow(2.0,(float)(nbase+384)/(128.0*12.0)))/CHIP_DIVIDER);
+  int easyThreshold=round(log((chipClock/(easyStartingPeriod*CHIP_DIVIDER))/parent->song.tuning)/log(2.0));
   if (note>easyThreshold) {
     return MAX(0,easyStartingPeriod-(note-easyThreshold));
   }
@@ -132,12 +135,16 @@ double DivPlatformSMS::NOTE_SN(int ch, int note) {
 }
 
 int DivPlatformSMS::snCalcFreq(int ch) {
-  if (parent->song.linearPitch==2 && easyNoise && chan[ch].baseFreq+chan[ch].pitch+chan[ch].pitch2>(easyThreshold<<7)) {
-    int ret=(((easyStartingPeriod<<7)+0x40)-(chan[ch].baseFreq+chan[ch].pitch+chan[ch].pitch2-(easyThreshold<<7)))>>7;
+  double CHIP_DIVIDER=toneDivider;
+  if (ch==3) CHIP_DIVIDER=noiseDivider;
+  int easyStartingPeriod=16;
+  int easyThreshold=round(128.0*log((chipClock/(easyStartingPeriod*CHIP_DIVIDER))/parent->song.tuning)/log(2.0));
+  if (parent->song.linearPitch==2 && easyNoise && chan[ch].baseFreq+chan[ch].pitch+chan[ch].pitch2>(easyThreshold)) {
+    int ret=(((easyStartingPeriod<<7))-(chan[ch].baseFreq+chan[ch].pitch+chan[ch].pitch2-(easyThreshold)))>>7;
     if (ret<0) ret=0;
     return ret;
   }
-  return parent->calcFreq(chan[ch].baseFreq,chan[ch].pitch,true,0,chan[ch].pitch2,chipClock,ch==3?noiseDivider:toneDivider);
+  return parent->calcFreq(chan[ch].baseFreq,chan[ch].pitch,true,0,chan[ch].pitch2,chipClock,CHIP_DIVIDER);
 }
 
 void DivPlatformSMS::tick(bool sysTick) {
@@ -464,40 +471,27 @@ void DivPlatformSMS::setFlags(const DivConfig& flags) {
   switch (flags.getInt("clockSel",0)) {
     case 1:
       chipClock=COLOR_PAL*4.0/5.0;
-      easyThreshold=84;
-      easyStartingPeriod=13;
       break;
     case 2:
       chipClock=4000000;
-      easyThreshold=86;
-      easyStartingPeriod=13;
       break;
     case 3:
       chipClock=COLOR_NTSC/2.0;
-      easyThreshold=72;
-      easyStartingPeriod=13;
       break;
     case 4:
       chipClock=3000000;
-      easyThreshold=81;
-      easyStartingPeriod=13;
       break;
     case 5:
       chipClock=2000000;
-      easyThreshold=74;
-      easyStartingPeriod=13;
       break;
     case 6:
       chipClock=COLOR_NTSC/8.0;
-      easyThreshold=48;
-      easyStartingPeriod=13;
       break;
     default:
       chipClock=COLOR_NTSC;
-      easyThreshold=84;
-      easyStartingPeriod=13;
       break;
   }
+  CHECK_CUSTOM_CLOCK;
   resetPhase=!flags.getBool("noPhaseReset",false);
   easyNoise=!flags.getBool("noEasyNoise",false);
   divider=16;
@@ -568,7 +562,7 @@ void DivPlatformSMS::setFlags(const DivConfig& flags) {
       stereo=false;
       break;
   }
-  CHECK_CUSTOM_CLOCK;
+
   rate=chipClock/divider;
   for (int i=0; i<4; i++) {
     oscBuf[i]->rate=rate;
diff --git a/src/engine/platform/sms.h b/src/engine/platform/sms.h
index ce3ee5e72..41f0efe48 100644
--- a/src/engine/platform/sms.h
+++ b/src/engine/platform/sms.h
@@ -65,8 +65,6 @@ class DivPlatformSMS: public DivDispatch {
   int divider=16;
   double toneDivider=64.0;
   double noiseDivider=64.0;
-  int easyThreshold;
-  int easyStartingPeriod;
   bool updateSNMode;
   bool resetPhase;
   bool isRealSN;
diff --git a/src/engine/platform/snes.cpp b/src/engine/platform/snes.cpp
index 2dd64de3a..2ab2c62cf 100644
--- a/src/engine/platform/snes.cpp
+++ b/src/engine/platform/snes.cpp
@@ -214,13 +214,13 @@ void DivPlatformSNES::tick(bool sysTick) {
           loop=start;
         } else if (chan[i].sample>=0 && chan[i].sample<parent->song.sampleLen) {
           start=sampleOff[chan[i].sample];
-          end=MIN(start+MAX(s->lengthBRR,1),getSampleMemCapacity());
+          end=MIN(start+MAX(s->lengthBRR+((s->loop && s->depth!=DIV_SAMPLE_DEPTH_BRR)?9:0),1),getSampleMemCapacity());
           loop=MAX(start,end-1);
           if (chan[i].audPos>0) {
             start=start+MIN(chan[i].audPos,s->lengthBRR-1)/16*9;
           }
           if (s->loopStart>=0) {
-            loop=start+s->loopStart/16*9;
+            loop=((s->depth!=DIV_SAMPLE_DEPTH_BRR)?9:0)+start+((s->loopStart/16)*9);
           }
         } else {
           start=0;
@@ -817,7 +817,7 @@ void DivPlatformSNES::renderSamples(int sysID) {
       continue;
     }
 
-    int length=s->lengthBRR;
+    int length=s->lengthBRR+((s->loop && s->depth!=DIV_SAMPLE_DEPTH_BRR)?9:0);
     int actualLength=MIN((int)(getSampleMemCapacity()-memPos)/9*9,length);
     if (actualLength>0) {
       sampleOff[i]=memPos;
diff --git a/src/engine/platform/vic20.cpp b/src/engine/platform/vic20.cpp
index 52a08836e..20ff0c8b4 100644
--- a/src/engine/platform/vic20.cpp
+++ b/src/engine/platform/vic20.cpp
@@ -80,7 +80,7 @@ void DivPlatformVIC20::calcAndWriteOutVol(int ch, int env) {
 }
 
 void DivPlatformVIC20::writeOutVol(int ch) {
-  if (!isMuted[ch]) {
+  if (!isMuted[ch] && chan[ch].active) {
     rWrite(14,chan[ch].outVol);
   }
 }
diff --git a/src/engine/sample.cpp b/src/engine/sample.cpp
index 5460aed32..148e63fb5 100644
--- a/src/engine/sample.cpp
+++ b/src/engine/sample.cpp
@@ -52,8 +52,8 @@ void DivSample::putSampleData(SafeWriter* w) {
   w->writeI(centerRate);
   w->writeC(depth);
   w->writeC(loopMode);
+  w->writeC(brrEmphasis);
   w->writeC(0); // reserved
-  w->writeC(0);
   w->writeI(loop?loopStart:-1);
   w->writeI(loop?loopEnd:-1);
 
@@ -125,9 +125,13 @@ DivDataErrors DivSample::readSampleData(SafeReader& reader, short version) {
       reader.readC();
     }
 
+    if (version>=129) {
+      brrEmphasis=reader.readC();
+    } else {
+      reader.readC();
+    }
     // reserved
     reader.readC();
-    reader.readC();
 
     loopStart=reader.readI();
     loopEnd=reader.readI();
@@ -490,8 +494,8 @@ bool DivSample::initInternal(DivSampleDepth d, int count) {
     case DIV_SAMPLE_DEPTH_BRR: // BRR
       if (dataBRR!=NULL) delete[] dataBRR;
       lengthBRR=9*((count+15)/16);
-      dataBRR=new unsigned char[lengthBRR];
-      memset(dataBRR,0,lengthBRR);
+      dataBRR=new unsigned char[lengthBRR+9];
+      memset(dataBRR,0,lengthBRR+9);
       break;
     case DIV_SAMPLE_DEPTH_VOX: // VOX
       if (dataVOX!=NULL) delete[] dataVOX;
@@ -1041,7 +1045,7 @@ void DivSample::render(unsigned int formatMask) {
         }
         break;
       case DIV_SAMPLE_DEPTH_BRR: // BRR
-        brrDecode(dataBRR,data16,lengthBRR);
+        brrDecode(dataBRR,data16,lengthBRR,brrEmphasis);
         break;
       case DIV_SAMPLE_DEPTH_VOX: // VOX
         oki_decode(dataVOX,data16,samples);
@@ -1100,7 +1104,7 @@ void DivSample::render(unsigned int formatMask) {
   }
   if (NOT_IN_FORMAT(DIV_SAMPLE_DEPTH_BRR)) { // BRR
     if (!initInternal(DIV_SAMPLE_DEPTH_BRR,samples)) return;
-    brrEncode(data16,dataBRR,(samples+15)&(~15),loop?loopStart:-1);
+    brrEncode(data16,dataBRR,samples,loop?loopStart:-1,brrEmphasis);
   }
   if (NOT_IN_FORMAT(DIV_SAMPLE_DEPTH_VOX)) { // VOX
     if (!initInternal(DIV_SAMPLE_DEPTH_VOX,samples)) return;
@@ -1174,9 +1178,9 @@ DivSampleHistory* DivSample::prepareUndo(bool data, bool doNotPush) {
       duplicate=new unsigned char[getCurBufLen()];
       memcpy(duplicate,getCurBuf(),getCurBufLen());
     }
-    h=new DivSampleHistory(duplicate,getCurBufLen(),samples,depth,rate,centerRate,loopStart,loopEnd,loop,loopMode);
+    h=new DivSampleHistory(duplicate,getCurBufLen(),samples,depth,rate,centerRate,loopStart,loopEnd,loop,brrEmphasis,loopMode);
   } else {
-    h=new DivSampleHistory(depth,rate,centerRate,loopStart,loopEnd,loop,loopMode);
+    h=new DivSampleHistory(depth,rate,centerRate,loopStart,loopEnd,loop,brrEmphasis,loopMode);
   }
   if (!doNotPush) {
     while (!redoHist.empty()) {
diff --git a/src/engine/sample.h b/src/engine/sample.h
index 0e233843c..86beea2d2 100644
--- a/src/engine/sample.h
+++ b/src/engine/sample.h
@@ -60,10 +60,10 @@ struct DivSampleHistory {
   unsigned int length, samples;
   DivSampleDepth depth;
   int rate, centerRate, loopStart, loopEnd;
-  bool loop;
+  bool loop, brrEmphasis;
   DivSampleLoopMode loopMode;
   bool hasSample;
-  DivSampleHistory(void* d, unsigned int l, unsigned int s, DivSampleDepth de, int r, int cr, int ls, int le, bool lp, DivSampleLoopMode lm):
+  DivSampleHistory(void* d, unsigned int l, unsigned int s, DivSampleDepth de, int r, int cr, int ls, int le, bool lp, bool be, DivSampleLoopMode lm):
     data((unsigned char*)d),
     length(l),
     samples(s),
@@ -73,9 +73,10 @@ struct DivSampleHistory {
     loopStart(ls),
     loopEnd(le),
     loop(lp),
+    brrEmphasis(be),
     loopMode(lm),
     hasSample(true) {}
-  DivSampleHistory(DivSampleDepth de, int r, int cr, int ls, int le, bool lp, DivSampleLoopMode lm):
+  DivSampleHistory(DivSampleDepth de, int r, int cr, int ls, int le, bool lp, bool be, DivSampleLoopMode lm):
     data(NULL),
     length(0),
     samples(0),
@@ -85,6 +86,7 @@ struct DivSampleHistory {
     loopStart(ls),
     loopEnd(le),
     loop(lp),
+    brrEmphasis(be),
     loopMode(lm),
     hasSample(false) {}
   ~DivSampleHistory();
@@ -106,7 +108,7 @@ struct DivSample {
   // - 10: VOX ADPCM
   // - 16: 16-bit PCM
   DivSampleDepth depth;
-  bool loop;
+  bool loop, brrEmphasis;
   // valid values are:
   // - 0: Forward loop
   // - 1: Backward loop
@@ -306,6 +308,7 @@ struct DivSample {
     loopOffP(0),
     depth(DIV_SAMPLE_DEPTH_16BIT),
     loop(false),
+    brrEmphasis(true),
     loopMode(DIV_SAMPLE_LOOP_FORWARD),
     data8(NULL),
     data16(NULL),
diff --git a/src/gui/dataList.cpp b/src/gui/dataList.cpp
index 0948743d4..71bfe03d1 100644
--- a/src/gui/dataList.cpp
+++ b/src/gui/dataList.cpp
@@ -688,20 +688,48 @@ void FurnaceGUI::actualWaveList() {
 
 void FurnaceGUI::actualSampleList() {
   for (int i=0; i<(int)e->song.sample.size(); i++) {
+    bool memWarning=false;
+
     DivSample* sample=e->song.sample[i];
     ImGui::TableNextRow();
     ImGui::TableNextColumn();
+    for (int j=0; j<e->song.systemLen; j++) {
+      DivDispatch* dispatch=e->getDispatch(j);
+      if (dispatch==NULL) continue;
+
+      for (int k=0; k<4; k++) {
+        if (dispatch->getSampleMemCapacity(k)==0) continue;
+        if (!dispatch->isSampleLoaded(k,i) && sample->renderOn[k][j]) {
+          memWarning=true;
+          break;
+        }
+      }
+      if (memWarning) break;
+    }
+    if (memWarning) ImGui::PushStyleColor(ImGuiCol_Text,uiColors[GUI_COLOR_SAMPLE_CHIP_WARNING]);
     if (ImGui::Selectable(fmt::sprintf("%d: %s##_SAM%d",i,sample->name,i).c_str(),curSample==i)) {
       curSample=i;
       samplePos=0;
       updateSampleTex=true;
     }
-    if (wantScrollList && curSample==i) ImGui::SetScrollHereY();
     if (ImGui::IsItemHovered() && !mobileUI) {
+      ImGui::PushStyleColor(ImGuiCol_Text,uiColors[GUI_COLOR_TEXT]);
       ImGui::SetTooltip("Bank %d: %s",i/12,sampleNote[i%12]);
       if (ImGui::IsMouseDoubleClicked(ImGuiMouseButton_Left)) {
         sampleEditOpen=true;
       }
+      ImGui::PopStyleColor();
     }
+    if (memWarning) {
+      ImGui::SameLine();
+      ImGui::Text(ICON_FA_EXCLAMATION_TRIANGLE);
+      if (ImGui::IsItemHovered() && !mobileUI) {
+        ImGui::PushStyleColor(ImGuiCol_Text,uiColors[GUI_COLOR_TEXT]);
+        ImGui::SetTooltip("out of memory for this sample!");
+        ImGui::PopStyleColor();
+      }
+      ImGui::PopStyleColor();
+    }
+    if (wantScrollList && curSample==i) ImGui::SetScrollHereY();
   }
 }
diff --git a/src/gui/editControls.cpp b/src/gui/editControls.cpp
index a7582ff38..05c5d4c9f 100644
--- a/src/gui/editControls.cpp
+++ b/src/gui/editControls.cpp
@@ -23,19 +23,29 @@
 
 void FurnaceGUI::drawMobileControls() {
   float timeScale=1.0f/(60.0f*ImGui::GetIO().DeltaTime);
-  if (mobileMenuOpen) {
-    if (mobileMenuPos<0.999f) {
-      WAKE_UP;
-      mobileMenuPos+=MIN(0.1,(1.0-mobileMenuPos)*0.65)*timeScale;
+  if (dragMobileMenu) {
+    if (portrait) {
+      mobileMenuPos=(dragMobileMenuOrigin.y-ImGui::GetMousePos().y)/(canvasH*0.65);
     } else {
-      mobileMenuPos=1.0f;
+      mobileMenuPos=(ImGui::GetMousePos().x-dragMobileMenuOrigin.x)/(canvasW*0.65);
     }
+    if (mobileMenuPos<0.0f) mobileMenuPos=0.0f;
+    if (mobileMenuPos>1.0f) mobileMenuPos=1.0f;
   } else {
-    if (mobileMenuPos>0.001f) {
-      WAKE_UP;
-      mobileMenuPos-=MIN(0.1,mobileMenuPos*0.65)*timeScale;
+    if (mobileMenuOpen) {
+      if (mobileMenuPos<0.999f) {
+        WAKE_UP;
+        mobileMenuPos+=MIN(0.1,(1.0-mobileMenuPos)*0.65)*timeScale;
+      } else {
+        mobileMenuPos=1.0f;
+      }
     } else {
-      mobileMenuPos=0.0f;
+      if (mobileMenuPos>0.001f) {
+        WAKE_UP;
+        mobileMenuPos-=MIN(0.1,mobileMenuPos*0.65)*timeScale;
+      } else {
+        mobileMenuPos=0.0f;
+      }
     }
   }
   ImGui::SetNextWindowPos(portrait?ImVec2(0.0f,((1.0-mobileMenuPos*0.65)*canvasH)-(0.16*canvasW)):ImVec2(0.5*canvasW*mobileMenuPos,0.0f));
@@ -54,7 +64,20 @@ void FurnaceGUI::drawMobileControls() {
       }
     }
     if (ImGui::Button(mobButtonName,buttonSize)) {
-      mobileMenuOpen=!mobileMenuOpen;
+      if (!dragMobileMenu) {
+        mobileMenuOpen=!mobileMenuOpen;
+      }
+    }
+    if (ImGui::IsItemActive() && ImGui::GetIO().MouseDragMaxDistanceSqr[ImGuiMouseButton_Left]>ImGui::GetIO().ConfigInertialScrollToleranceSqr*2.0f) {
+      if (!dragMobileMenu) {
+        dragMobileMenu=true;
+        dragMobileMenuOrigin=ImGui::GetMousePos();
+        if (portrait) {
+          dragMobileMenuOrigin.y+=mobileMenuPos*canvasH*0.65f;
+        } else {
+          dragMobileMenuOrigin.x-=mobileMenuPos*canvasW*0.65f;
+        }
+      }
     }
 
     if (!portrait) ImGui::Separator();
diff --git a/src/gui/gui.cpp b/src/gui/gui.cpp
index f0d96ee21..8c5264c52 100644
--- a/src/gui/gui.cpp
+++ b/src/gui/gui.cpp
@@ -2931,6 +2931,14 @@ void FurnaceGUI::pointUp(int x, int y, int button) {
   }
   orderScrollLocked=false;
   orderScrollTolerance=false;
+  if (dragMobileMenu) {
+    dragMobileMenu=false;
+    if (mobileMenuOpen) {
+      mobileMenuOpen=(mobileMenuPos>=0.85f);
+    } else {
+      mobileMenuOpen=(mobileMenuPos>=0.15f);
+    }
+  }
   if (selecting) {
     if (!selectingFull) cursor=selEnd;
     finishSelection();
@@ -5785,6 +5793,7 @@ FurnaceGUI::FurnaceGUI():
   keepLoopAlive(false),
   orderScrollLocked(false),
   orderScrollTolerance(false),
+  dragMobileMenu(false),
   curWindow(GUI_WINDOW_NOTHING),
   nextWindow(GUI_WINDOW_NOTHING),
   curWindowLast(GUI_WINDOW_NOTHING),
@@ -5877,6 +5886,7 @@ FurnaceGUI::FurnaceGUI():
   orderScroll(0.0f),
   orderScrollSlideOrigin(0.0f),
   orderScrollRealOrigin(0.0f,0.0f),
+  dragMobileMenuOrigin(0.0f,0.0f),
   layoutTimeBegin(0),
   layoutTimeEnd(0),
   layoutTimeDelta(0),
diff --git a/src/gui/gui.h b/src/gui/gui.h
index 24e3ba1bb..75b87c0e6 100644
--- a/src/gui/gui.h
+++ b/src/gui/gui.h
@@ -1436,7 +1436,7 @@ class FurnaceGUI {
   SelectionPoint selStart, selEnd, cursor, cursorDrag, dragStart, dragEnd;
   bool selecting, selectingFull, dragging, curNibble, orderNibble, followOrders, followPattern, changeAllOrders, mobileUI;
   bool collapseWindow, demandScrollX, fancyPattern, wantPatName, firstFrame, tempoView, waveHex, waveSigned, waveGenVisible, lockLayout, editOptsVisible, latchNibble, nonLatchNibble;
-  bool keepLoopAlive, orderScrollLocked, orderScrollTolerance;
+  bool keepLoopAlive, orderScrollLocked, orderScrollTolerance, dragMobileMenu;
   FurnaceGUIWindows curWindow, nextWindow, curWindowLast;
   std::atomic<FurnaceGUIWindows> curWindowThreadSafe;
   float peak[2];
@@ -1582,6 +1582,7 @@ class FurnaceGUI {
   float nextScroll, nextAddScroll, orderScroll, orderScrollSlideOrigin;
 
   ImVec2 orderScrollRealOrigin;
+  ImVec2 dragMobileMenuOrigin;
 
   int layoutTimeBegin, layoutTimeEnd, layoutTimeDelta;
   int renderTimeBegin, renderTimeEnd, renderTimeDelta;
diff --git a/src/gui/sampleEdit.cpp b/src/gui/sampleEdit.cpp
index fb50fd567..a953742b6 100644
--- a/src/gui/sampleEdit.cpp
+++ b/src/gui/sampleEdit.cpp
@@ -190,6 +190,31 @@ void FurnaceGUI::drawSampleEdit() {
             ImGui::EndCombo();
           }
 
+          bool isThereSNES=false;
+          for (int i=0; i<e->song.systemLen; i++) {
+            if (e->song.system[i]==DIV_SYSTEM_SNES) {
+              isThereSNES=true;
+              break;
+            }
+          }
+          if (sample->depth==DIV_SAMPLE_DEPTH_BRR || isThereSNES) {
+            bool be=sample->brrEmphasis;
+            if (ImGui::Checkbox("BRR emphasis",&be)) {
+              sample->prepareUndo(true);
+              sample->brrEmphasis=be;
+              e->renderSamplesP();
+              updateSampleTex=true;
+              MARK_MODIFIED;
+            }
+            if (ImGui::IsItemHovered()) {
+              if (sample->depth==DIV_SAMPLE_DEPTH_BRR) {
+                ImGui::SetTooltip("this is a BRR sample.\nenabling this option will muffle it (only affects non-SNES chips).");
+              } else {
+                ImGui::SetTooltip("enable this option to slightly boost high frequencies\nto compensate for the SNES' Gaussian filter's muffle.");
+              }
+            }
+          }
+
           ImGui::TableNextColumn();
           ImGui::Text("C-4 (Hz)");
           ImGui::SameLine();