diff --git a/dats/parser.c b/dats/parser.c
index f1a39fd..1f541a9 100644
--- a/dats/parser.c
+++ b/dats/parser.c
@@ -39,7 +39,7 @@ extern void print_all_nr_t(nr_t *nr);
 static token_t tok;
 static symrec_t *staff;
 static int rule_match = 0;
-dats_t *d;
+static dats_t *d;
 
 /* Returns 0 if success. Non-zero if failed. */
 static int parse_notes_rests() {
@@ -472,7 +472,7 @@ static symrec_t *parse_pcm16(char *id) {
             }
             break;
           } else if (driver->options[i + 1].option_name == NULL) {
-            C_ERROR(d, "No such option, %s\n", tok_identifier);
+            C_ERROR(d, "no such option, '%s'", tok_identifier);
             return NULL;
           }
         }
diff --git a/dats/scanner.c b/dats/scanner.c
index 3d2fa45..80b0e71 100644
--- a/dats/scanner.c
+++ b/dats/scanner.c
@@ -150,7 +150,7 @@ symrec_t *symrec_tcpy(symrec_t *const s) {
   return copy;
 }
 
-void print_debugging_info(const token_t tok, const dats_t *const d) {
+void print_debugging_info(const token_t tok, dats_t *d) {
   switch (tok) {
   case TOK_IDENTIFIER:
     ERROR(", '%s'\n", tok_identifier);
@@ -162,6 +162,16 @@ void print_debugging_info(const token_t tok, const dats_t *const d) {
     ERROR("\n");
   }
   char buff[1000] = {0};
+  if (d->scan_line[strlen(d->scan_line)-1] != '\n'){
+    int ls = strlen(d->scan_line);
+    d->scan_line[ls] = '\n';
+    d->scan_line[ls+1] = 0;
+  }
+  if (d->scan_line[strlen(d->scan_line)-2] != '\r'){
+    int ls = strlen(d->scan_line);
+    memcpy(d->scan_line+(ls-2), d->scan_line+(ls-1), 2);
+  }
+  
   int length = sprintf(buff, "    %d | %s", line_token_found, d->scan_line);
   ERROR("%s", buff);
   ERROR("%*s\n", column_token_found + (length - (int)strlen(d->scan_line)),
diff --git a/dats/scanner.h b/dats/scanner.h
index ade446e..68a2f88 100644
--- a/dats/scanner.h
+++ b/dats/scanner.h
@@ -23,7 +23,7 @@ EXTERN const char *token_t_to_str(const token_t t);
 EXTERN symrec_t *getsym(const dats_t *const t, char const *const id);
 EXTERN token_t read_next_tok_cur_dats_t(dats_t *const t);
 EXTERN void print_all_symrec_t_cur_dats_t(const dats_t *const t);
-EXTERN void print_debugging_info(const token_t tok, const dats_t *const d);
+EXTERN void print_debugging_info(const token_t tok, dats_t * d);
 
 EXTERN int line_token_found;
 EXTERN int column_token_found;
diff --git a/libsynth/s_kpa.c b/libsynth/s_kpa.c
index d1e9134..f98b3b0 100644
--- a/libsynth/s_kpa.c
+++ b/libsynth/s_kpa.c
@@ -45,7 +45,16 @@ static pcm16_t *synth(const symrec_t *restrict staff) {
                              i + total < staff->value.staff.numsamples;
              i++) {
           wavetable[cur] = ((wavetable[cur] / 2) + (prev / 2));
-          pcm[total + i] += wavetable[cur];
+          pcm[total + i] +=
+              (int16_t)
+              /* simple linear attack and linear decay filter */
+              (double)wavetable[cur] *
+              (i < (uint32_t)nn->attack
+                   ? (double)i / nn->attack
+                   : (i > nn->duration - (uint32_t)nn->release
+                          ? (-(double)i + (double)(nn->duration)) / nn->release
+                          : 1.0));
+          //pcm[total + i] += wavetable[cur];
           prev = wavetable[cur];
           cur++;
           cur %= (int)(44100.0 / nn->frequency);
diff --git a/libsynth/s_sin.c b/libsynth/s_sin.c
index 9e980e2..aa1851e 100644
--- a/libsynth/s_sin.c
+++ b/libsynth/s_sin.c
@@ -13,6 +13,12 @@ static DSOption options[] = {
    {DSOPTION_FLOAT, "vibrato_magnitude", "Vibrato magnitude", {.floatv = 0}},
    {DSOPTION_INT, "attack_type", "Attack type (linear=0, exponential=1)", {.intv = 0}},
    {DSOPTION_INT, "decay_type", "Decay type (linear=0, exponential=1)", {.intv = 0}},
+   {DSOPTION_INT, "sustain_type", "Sustain type (linear=0, exponential=1)", {.intv = 0}},
+   {DSOPTION_INT, "release_type", "Release type (linear=0, exponential=1)", {.intv = 0}},
+   {DSOPTION_FLOAT, "attack_exp_coeff", "Attack exponential coefficiant", {.floatv = 0.0}},
+   {DSOPTION_FLOAT, "decay_exp_coeff", "Attack exponential coefficiant", {.floatv = 0.0}},
+   {DSOPTION_FLOAT, "sustain_exp_coeff", "Attack exponential coefficiant", {.floatv = 0.0}},
+   {DSOPTION_FLOAT, "release_exp_coeff", "Decay exponential coefficiant", {.floatv = 0.0}},
    /*{DSOPTION_INT, "attack_s", "Attack ending in samples", {.intv = 0}},
    {DSOPTION_INT, "decay_s", "Decay begin in samples", {.intv=  0}},*/
    {.option_name = NULL}
@@ -30,7 +36,38 @@ static void free_string_options(void) {
   }
 }
 
+static double linear_attack(double x, double n){
+  return x / n;
+}
+
+static double linear_release(double x, double n){
+  return x / n;
+}
+
+static double exponential_attack(double x, double n){
+  return pow(M_E, x-n);
+}
+static double exponential_release(double x, double n){
+  return pow(M_E, (-x-n)+1.0);
+}
 static pcm16_t *synth(const symrec_t *staff) {
+
+  double (*attack_ret)(double, double) = NULL;
+  double (*release_ret)(double, double) = NULL;
+
+  switch (options[2].value.intv){
+    case 0: attack_ret = linear_attack; break;
+    case 1: attack_ret = exponential_attack; break;
+    default: fprintf(stderr, "unknown attack type: %d\n", options[2].value.intv);
+        return NULL;
+  }
+
+  switch (options[5].value.intv){
+    case 0: release_ret = linear_release; break;
+    case 1: release_ret = exponential_release; break;
+    default: fprintf(stderr, "unknown attack type: %d\n", options[5].value.intv);
+        return NULL;
+  }
   int16_t *pcm = calloc(sizeof(int16_t), (size_t)staff->value.staff.numsamples);
   pcm16_t *pcm_ctx = malloc(sizeof(pcm16_t));
   if (pcm_ctx == NULL || pcm == NULL)
@@ -54,9 +91,9 @@ static pcm16_t *synth(const symrec_t *staff) {
               /* simple linear attack and linear decay filter */
               (double)sample1 *
               (i < (uint32_t)nn->attack
-                   ? (double)i / nn->attack
+                   ? attack_ret((double)i, nn->attack)
                    : (i > nn->duration - (uint32_t)nn->release
-                          ? (-(double)i + (double)(nn->duration)) / nn->release
+                          ? release_ret(-(double)i+nn->duration, nn->release)
                           : 1.0));
         }
       }
diff --git a/libsynth/synth.h b/libsynth/synth.h
index a0bdebb..0d07fa7 100644
--- a/libsynth/synth.h
+++ b/libsynth/synth.h
@@ -28,7 +28,7 @@ struct DSSynth {
 
   /* Possible options to be set for your synth.
    * Set this to NULL if there are none */
-  DSOption *options;
+  DSOption *const options;
 
   /* Prints documentation on stdout.
    * This must always point to something, not NULL! */
diff --git a/test/canon-2.dats b/test/canon-2.dats
index 2c809ae..91af045 100644
--- a/test/canon-2.dats
+++ b/test/canon-2.dats
@@ -1,5 +1,5 @@
 staff m1 {
-  n 1, e4;
+  n 1, e4. ;
   n 1, d4;
   n 1, c4;
   n 1, b3;
diff --git a/test/happyhchristmas.dats b/test/happyhchristmas.dats
index d9de562..bf200a0 100644
--- a/test/happyhchristmas.dats
+++ b/test/happyhchristmas.dats
@@ -1,6 +1,6 @@
 staff m1 {
   bpm = 120;
-  octave = 0; // raise a 0 octave
+  octave = 1; // raise an octave
   semitone = 0; // raise a 0 semitone
 
 // part 1
@@ -111,7 +111,7 @@ staff m1 {
 staff m2 {
 // part 1
   octave = 0;
-  volume = 1200;
+  volume = 1100;
   n 12, d4;
   n 12, f#4;
   n 12, a4;
@@ -343,8 +343,8 @@ staff m3 {
 
 master {
   pcm16 tr1 = mix((synth.sin(m1)[
-    vibrato_frequency=8, vibrato_magnitude=2.0]),
-    (mix((synth.square(m2)),(mix((synth.sin(m2)), (synth.sin(m3)))))));
-  write("t.wav", tr1, tr1);
+    vibrato_frequency=8, vibrato_magnitude=3]),
+    (mix((synth.square(m2)),(synth.sin(m2)))));
+  write("t.wav", tr1);
 
 }
diff --git a/test/t.dats b/test/t.dats
index 54e2cc1..fa45381 100644
--- a/test/t.dats
+++ b/test/t.dats
@@ -191,7 +191,7 @@ master {
    ***
    hh */
   /* pcm16 tmp1 = synth.kpa(apple);*/
-   pcm16 track1 = synth.kpa(apple)[test="Al-buharie test l"], track1;
+   pcm16 track1 = synth.kpa(apple), track1;
    write("wj.wav", track1);
 }