diff --git a/Makefile b/Makefile
index cfb137a..99fc279 100644
--- a/Makefile
+++ b/Makefile
@@ -31,11 +31,11 @@ default: $(TARGET)
 all: default
 
 SOURCES = src/algorithms.c src/amy.c src/envelope.c src/examples.c \
-	src/filters.c src/oscillators.c src/pcm.c src/partials.c \
+	src/filters.c src/oscillators.c src/pcm.c src/partials.c src/custom.c \
 	src/delay.c src/log2_exp2.c src/patches.c
 
 OBJECTS = $(patsubst %.c, %.o, src/algorithms.c src/amy.c src/envelope.c \
-	src/delay.c src/partials.c src/patches.c \
+	src/delay.c src/partials.c src/custom.c src/patches.c \
 	src/examples.c src/filters.c src/oscillators.c src/pcm.c src/log2_exp2.c \
 	src/libminiaudio-audio.c)
 
diff --git a/src/amy-example.c b/src/amy-example.c
index 8b186f2..4814e45 100644
--- a/src/amy-example.c
+++ b/src/amy-example.c
@@ -49,6 +49,10 @@ int main(int argc, char ** argv) {
     }
     uint32_t start = amy_sysclock();
     
+    #if AMY_HAS_CUSTOM == 1
+    example_init_custom();
+    #endif
+
     amy_start(/* cores= */ 1, /* reverb= */ 1, /* chorus= */ 1);
     
     ma_encoder_config config = ma_encoder_config_init(ma_encoding_format_wav, ma_format_s16, AMY_NCHANS, AMY_SAMPLE_RATE);
@@ -66,7 +70,6 @@ int main(int argc, char ** argv) {
 
 
     amy_reset_oscs();
-
     example_voice_chord(0);
 
     // Now just spin for 10s
@@ -74,7 +77,7 @@ int main(int argc, char ** argv) {
         if (output_filename) {
             int16_t * frames = amy_simple_fill_buffer();
             int num_frames = AMY_BLOCK_SIZE;
-            result = ma_encoder_write_pcm_frames(&encoder, frames, num_frames, NULL);
+            ma_encoder_write_pcm_frames(&encoder, frames, num_frames, NULL);
         }
         usleep(THREAD_USLEEP);
     }
diff --git a/src/amy.c b/src/amy.c
index 88cb6c6..e8c517d 100644
--- a/src/amy.c
+++ b/src/amy.c
@@ -175,7 +175,7 @@ void config_chorus(float level, int max_delay, float lfo_freq, float depth) {
             alloc_chorus_delay_lines();
         }
         // if we're turning on for the first time, start the oscillator.
-        if (synth[CHORUS_MOD_SOURCE].status == OFF) {  //chorus.level == 0) {
+        if (synth[CHORUS_MOD_SOURCE].status == STATUS_OFF) {  //chorus.level == 0) {
             // Setup chorus oscillator.
             synth[CHORUS_MOD_SOURCE].logfreq_coefs[COEF_CONST] = logfreq_of_freq(lfo_freq);
             synth[CHORUS_MOD_SOURCE].logfreq_coefs[COEF_NOTE] = 0;  // Turn off default.
@@ -592,7 +592,7 @@ void reset_osc(uint16_t i ) {
     synth[i].sample = F2S(0);
     synth[i].mod_value = F2S(0);
     synth[i].substep = 0;
-    synth[i].status = OFF;
+    synth[i].status = STATUS_OFF;
     AMY_UNSET(synth[i].chained_osc);
     AMY_UNSET(synth[i].mod_source);
     synth[i].mod_target = 0;
@@ -649,6 +649,9 @@ int8_t oscs_init() {
     if(pcm_samples) {
         pcm_init();
     }
+    if(AMY_HAS_CUSTOM == 1) {
+        custom_init();
+    }
     events = (struct delta*)malloc_caps(sizeof(struct delta) * AMY_EVENT_FIFO_LEN, EVENTS_RAM_CAPS);
     synth = (struct synthinfo*) malloc_caps(sizeof(struct synthinfo) * (AMY_OSCS+1), SYNTH_RAM_CAPS);
     msynth = (struct mod_synthinfo*) malloc_caps(sizeof(struct mod_synthinfo) * (AMY_OSCS+1), SYNTH_RAM_CAPS);
@@ -787,6 +790,9 @@ void osc_note_on(uint16_t osc, float initial_freq) {
         if(synth[osc].wave==PARTIAL)  partial_note_on(osc);
         if(synth[osc].wave==PARTIALS) partials_note_on(osc);
     }
+    if(AMY_HAS_CUSTOM == 1) {
+        if(synth[osc].wave==CUSTOM) custom_note_on(osc, initial_freq);
+    }
 }
 
 void apply_target_to_coefs(uint16_t osc, int target_val, int which_coef) {
@@ -954,6 +960,7 @@ void play_event(struct delta d) {
                     if(synth[synth[d.osc].mod_source].wave==TRIANGLE) triangle_mod_trigger(synth[d.osc].mod_source);
                     if(synth[synth[d.osc].mod_source].wave==PULSE) pulse_mod_trigger(synth[d.osc].mod_source);
                     if(synth[synth[d.osc].mod_source].wave==PCM) pcm_mod_trigger(synth[d.osc].mod_source);
+                    if(synth[synth[d.osc].mod_source].wave==CUSTOM) custom_mod_trigger(synth[d.osc].mod_source);
                 }
 
             }
@@ -977,6 +984,11 @@ void play_event(struct delta d) {
                 #endif
             }
             else if(synth[d.osc].wave==PCM) { pcm_note_off(d.osc); }
+            else if(synth[d.osc].wave==CUSTOM) {
+                #if AMY_HAS_CUSTOM == 1
+                custom_note_off(d.osc);
+                #endif
+            }
             else {
                 // osc note off, start release
                 AMY_UNSET(synth[d.osc].note_on_clock);
@@ -1051,7 +1063,7 @@ void hold_and_modify(uint16_t osc) {
         } else {
             if ( (total_samples - synth[osc].zero_amp_clock) >= MIN_ZERO_AMP_TIME_SAMPS) {
                 //printf("h&m: time %f osc %d OFF\n", total_samples/(float)AMY_SAMPLE_RATE, osc);
-                synth[osc].status = OFF;
+                synth[osc].status = STATUS_OFF;
                 AMY_UNSET(synth[osc].note_off_clock);
                 AMY_UNSET(synth[osc].zero_amp_clock);
             }
@@ -1125,6 +1137,9 @@ SAMPLE render_osc_wave(uint16_t osc, uint8_t core, SAMPLE* buf) {
             if(synth[osc].wave == PARTIALS) max_val = render_partials(buf, osc);
         }
     }
+    if(AMY_HAS_CUSTOM == 1) {
+        if(synth[osc].wave == CUSTOM) max_val = render_custom(buf, osc);
+    }
     AMY_PROFILE_STOP(RENDER_OSC_WAVE)
     return max_val;
 }
@@ -1140,7 +1155,7 @@ void amy_render(uint16_t start, uint16_t end, uint8_t core) {
             SAMPLE max_val = render_osc_wave(osc, core, per_osc_fb[core]);
             if (max_val > max_max) max_max = max_val;
             // check it's not off, just in case. todo, why do i care?
-            if(synth[osc].wave != OFF) {
+            if(synth[osc].wave != WAVE_OFF) {
                 // apply filter to osc if set
                 if(synth[osc].filter_type != FILTER_NONE) filter_process(per_osc_fb[core], osc, max_val);
                 mix_with_pan(fbl[core], per_osc_fb[core], msynth[osc].last_pan, msynth[osc].pan);
diff --git a/src/amy.h b/src/amy.h
index 8392875..b985487 100644
--- a/src/amy.h
+++ b/src/amy.h
@@ -23,8 +23,14 @@ typedef struct {
     uint8_t midinote;
 } pcm_map_t;
 
+#ifndef AMY_CONFIG_H
+#define AMY_CONFIG_H amy_config.h
+#endif
+
+#define QUOTED(x) #x
+#define INCLUDE(x) QUOTED(x)
 
-#include "amy_config.h"
+#include INCLUDE(AMY_CONFIG_H)
 
 // Rest of amy setup
 #define SAMPLE_MAX 32767
@@ -94,6 +100,8 @@ enum coefs{
 #define ALGO 8
 #define PARTIAL 9
 #define PARTIALS 10
+#define CUSTOM 11
+#define WAVE_OFF 12
 // synth[].status values
 #define EMPTY 0
 #define SCHEDULED 1
@@ -101,8 +109,7 @@ enum coefs{
 #define AUDIBLE 3
 #define IS_MOD_SOURCE 4
 #define IS_ALGO_SOURCE 5
-// Is this for .wave or .status?
-#define OFF 11
+#define STATUS_OFF 6
 
 #define true 1
 #define false 0
@@ -412,6 +419,16 @@ struct state {
     int16_t latency_ms;
 };
 
+// custom oscillator
+struct custom_oscillator {
+    void (*init)(void);
+    void (*note_on)(struct synthinfo* osc, float freq);
+    void (*note_off)(struct synthinfo* osc);
+    void (*mod_trigger)(struct synthinfo* osc);
+    SAMPLE (*render)(SAMPLE* buf, struct synthinfo* osc);
+    SAMPLE (*compute_mod)(struct synthinfo* osc);
+};
+
 // Shared structures
 extern uint32_t total_samples;
 extern struct synthinfo *synth;
@@ -441,8 +458,8 @@ void amy_stop();
 void amy_live_start();
 void amy_live_stop();
 void amy_reset_oscs();
-void amy_print_devices(); 
-
+void amy_print_devices();
+void amy_set_custom(struct custom_oscillator* custom);
 extern void reset_osc(uint16_t i );
 
 extern float render_am_lut(float * buf, float step, float skip, float incoming_amp, float ending_amp, const float* lut, int16_t lut_size, float *mod, float bandwidth);
@@ -451,6 +468,7 @@ extern void ks_deinit();
 extern void algo_init();
 extern void algo_deinit();
 extern void pcm_init();
+extern void custom_init();
 extern SAMPLE render_ks(SAMPLE * buf, uint16_t osc); 
 extern SAMPLE render_sine(SAMPLE * buf, uint16_t osc); 
 extern SAMPLE render_fm_sine(SAMPLE *buf, uint16_t osc, SAMPLE *mod, SAMPLE feedback_level, uint16_t algo_osc, SAMPLE mod_amp);
@@ -469,6 +487,7 @@ extern void patches_event_has_voices(struct event e);
 extern void patches_reset();
 
 extern SAMPLE render_partials(SAMPLE *buf, uint16_t osc);
+extern SAMPLE render_custom(SAMPLE *buf, uint16_t osc) ;
 
 extern SAMPLE compute_mod_pulse(uint16_t osc);
 extern SAMPLE compute_mod_noise(uint16_t osc);
@@ -477,6 +496,7 @@ extern SAMPLE compute_mod_saw_up(uint16_t osc);
 extern SAMPLE compute_mod_saw_down(uint16_t osc);
 extern SAMPLE compute_mod_triangle(uint16_t osc);
 extern SAMPLE compute_mod_pcm(uint16_t osc);
+extern SAMPLE compute_mod_custom(uint16_t osc);
 
 extern void sine_note_on(uint16_t osc, float initial_freq); 
 extern void fm_sine_note_on(uint16_t osc, uint16_t algo_osc); 
@@ -486,6 +506,8 @@ extern void triangle_note_on(uint16_t osc, float initial_freq);
 extern void pulse_note_on(uint16_t osc, float initial_freq); 
 extern void pcm_note_on(uint16_t osc);
 extern void pcm_note_off(uint16_t osc);
+extern void custom_note_on(uint16_t osc, float freq);
+extern void custom_note_off(uint16_t osc);
 extern void partial_note_on(uint16_t osc);
 extern void partial_note_off(uint16_t osc);
 extern void algo_note_on(uint16_t osc);
@@ -498,6 +520,7 @@ extern void saw_up_mod_trigger(uint16_t osc);
 extern void triangle_mod_trigger(uint16_t osc);
 extern void pulse_mod_trigger(uint16_t osc);
 extern void pcm_mod_trigger(uint16_t osc);
+extern void custom_mod_trigger(uint16_t osc);
 extern SAMPLE amy_get_random();
 //extern void algo_custom_setup_patch(uint16_t osc, uint16_t * target_oscs);
 
diff --git a/src/amy_config.h b/src/amy_config.h
index e0f6e1c..c75c9cc 100644
--- a/src/amy_config.h
+++ b/src/amy_config.h
@@ -9,6 +9,7 @@
 #define AMY_OSCS 120
 #define AMY_SAMPLE_RATE 44100 
 #define AMY_NCHANS 2
+#define AMY_USE_FIXEDPOINT
 
 
 // These are overriden for you if you include pcm_X.h {tiny, small, large}
@@ -22,6 +23,7 @@ extern const uint16_t pcm_samples;
 #define AMY_MAX_DRIFT_MS 20000   // ms of time you can schedule ahead before synth recomputes time base
 #define AMY_KS_OSCS 1            // How many karplus-strong oscillators to keep track of (0 disables KS)
 #define AMY_HAS_PARTIALS 1       // 1 = Make partials available
+#define AMY_HAS_CUSTOM 0         // 1 = Make custom oscillators available
 #define PCM_AMY_SAMPLE_RATE 22050
 #define AMY_EVENT_FIFO_LEN 2000
 
diff --git a/src/amy_fixedpoint.h b/src/amy_fixedpoint.h
index aa764a9..75da1d5 100644
--- a/src/amy_fixedpoint.h
+++ b/src/amy_fixedpoint.h
@@ -51,7 +51,6 @@
 // #define MUL_KK mul4_k12k11(a, b)
 // #define MUL_KKS mul4_k16k7(a, b)  // the second arg is "sensitive".
 
-#define AMY_USE_FIXEDPOINT
 
 #ifndef AMY_USE_FIXEDPOINT
 
diff --git a/src/custom.c b/src/custom.c
new file mode 100644
index 0000000..35ab475
--- /dev/null
+++ b/src/custom.c
@@ -0,0 +1,42 @@
+// custom.c
+
+#include "amy.h"
+#include <assert.h>
+
+struct custom_oscillator* custom_osc;
+
+void amy_set_custom(struct custom_oscillator* custom) {
+    assert(custom_osc == NULL);
+    custom_osc = custom;
+}
+
+void custom_init() {
+    if (custom_osc != NULL) {
+        custom_osc->init();
+    }
+}
+
+void custom_note_on(uint16_t osc, float freq) {
+    assert(custom_osc != NULL);
+    custom_osc->note_on(&synth[osc], freq);
+}
+
+void custom_note_off(uint16_t osc) {
+    assert(custom_osc != NULL);
+    custom_osc->note_off(&synth[osc]);
+}
+
+void custom_mod_trigger(uint16_t osc) {
+    assert(custom_osc != NULL);
+    custom_osc->mod_trigger(&synth[osc]);
+}
+
+SAMPLE render_custom(SAMPLE* buf, uint16_t osc) {
+    assert(custom_osc != NULL);
+    return custom_osc->render(buf, &synth[osc]);
+}
+
+SAMPLE compute_mod_custom(uint16_t osc) {
+    assert(custom_osc != NULL);
+    return custom_osc->compute_mod(&synth[osc]);
+}
diff --git a/src/envelope.c b/src/envelope.c
index 3d45508..de97b01 100644
--- a/src/envelope.c
+++ b/src/envelope.c
@@ -25,6 +25,9 @@ SAMPLE compute_mod_value(uint16_t mod_osc) {
     if(synth[mod_osc].wave == SINE) value = compute_mod_sine(mod_osc);
     if(pcm_samples)
         if(synth[mod_osc].wave == PCM) value = compute_mod_pcm(mod_osc);
+    if(AMY_HAS_CUSTOM == 1) {
+        if(synth[mod_osc].wave == CUSTOM) value = compute_mod_custom(mod_osc);
+    }
     synth[mod_osc].mod_value = value;
     return value;
 }
diff --git a/src/examples.c b/src/examples.c
index f2c6921..c0e915d 100644
--- a/src/examples.c
+++ b/src/examples.c
@@ -272,4 +272,61 @@ void example_drums(uint32_t start, int loops) {
             AMY_UNSET(e.midi_note);
         }
     }
-}
\ No newline at end of file
+}
+
+// Minimal custom oscillator
+
+#if AMY_HAS_CUSTOM == 1
+
+void beeper_init(void) {
+    printf("Beeper init\n");
+}
+
+void beeper_note_on(struct synthinfo* osc, float freq) {
+    saw_down_note_on(osc->osc, freq);
+}
+
+void beeper_note_off(struct synthinfo* osc) {
+    osc->note_off_clock = total_samples;
+}
+
+void beeper_mod_trigger(struct synthinfo* osc) {
+    saw_down_mod_trigger(osc->osc);
+}
+
+SAMPLE beeper_render(SAMPLE* buf, struct synthinfo* osc) {
+    return render_saw_down(buf, osc->osc);
+}
+
+SAMPLE beeper_compute_mod(struct synthinfo* osc) {
+    return compute_mod_saw_down(osc->osc);
+}
+
+struct custom_oscillator beeper = {
+    beeper_init,
+    beeper_note_on,
+    beeper_note_off,
+    beeper_mod_trigger,
+    beeper_render,
+    beeper_compute_mod
+};
+
+void example_init_custom() {
+    amy_set_custom(&beeper);
+}
+
+void example_custom_beep() {
+    struct event e = amy_default_event();
+    e.osc = 50;
+    e.time = amy_sysclock();
+    e.freq_coefs[0] = 880;
+    e.wave = CUSTOM;
+    e.velocity = 1;
+    amy_add_event(e);
+
+    e.velocity = 0;
+    e.time += 500;
+    amy_add_event(e);
+}
+
+#endif
diff --git a/src/examples.h b/src/examples.h
index 5ffebee..a920c07 100644
--- a/src/examples.h
+++ b/src/examples.h
@@ -13,6 +13,8 @@ void example_fm(uint32_t start) ;
 void example_multimbral_fm();
 void example_drums(uint32_t start, int loops);
 void example_sine(uint32_t start);
+void example_init_custom();
+void example_custom_beep();
 void example_patches();
 void example_voice_chord(uint16_t patch);
 void example_voice_alloc();
diff --git a/src/oscillators.c b/src/oscillators.c
index d38f817..0f460ce 100644
--- a/src/oscillators.c
+++ b/src/oscillators.c
@@ -536,7 +536,7 @@ void partial_note_off(uint16_t osc) {
     AMY_UNSET(synth[osc].note_on_clock);
     synth[osc].note_off_clock = total_samples;   
     synth[osc].last_amp = 0;
-    synth[osc].status = OFF;
+    synth[osc].status = STATUS_OFF;
 }
 
 
diff --git a/src/pcm.c b/src/pcm.c
index 6b8fbc4..c84dd9f 100644
--- a/src/pcm.c
+++ b/src/pcm.c
@@ -64,7 +64,7 @@ SAMPLE render_pcm(SAMPLE* buf, uint16_t osc) {
         synth[osc].phase = P_WRAPPED_SUM(synth[osc].phase, step);
         base_index = INT_OF_P(synth[osc].phase, PCM_INDEX_BITS);
         if(base_index >= patch->length) { // end
-            synth[osc].status = OFF;// is this right? 
+            synth[osc].status = STATUS_OFF;// is this right? 
             sample = 0;
         } else {
             if(msynth[osc].feedback > 0) { // loop       
@@ -94,7 +94,7 @@ SAMPLE compute_mod_pcm(uint16_t osc) {
     uint32_t base_index = INT_OF_P(synth[osc].phase, PCM_INDEX_BITS);
     SAMPLE sample;
     if(base_index >= patch->length) { // end
-        synth[osc].status = OFF;// is this right? 
+        synth[osc].status = STATUS_OFF;// is this right? 
         sample = 0;
     } else {
         sample = L2S(table[base_index]);
diff --git a/src/setup.py b/src/setup.py
index b5276d7..a221fe9 100644
--- a/src/setup.py
+++ b/src/setup.py
@@ -2,7 +2,7 @@
 import glob
 import os
 # the c++ extension module
-sources = ['algorithms.c', 'amy.c', 'delay.c', 'envelope.c', 'filters.c', 'patches.c', 'libminiaudio-audio.c', 'oscillators.c', 'partials.c', 'pcm.c', 'pyamy.c', 'log2_exp2.c']
+sources = ['algorithms.c', 'amy.c', 'delay.c', 'envelope.c', 'filters.c', 'custom.c', 'patches.c', 'libminiaudio-audio.c', 'oscillators.c', 'partials.c', 'pcm.c', 'pyamy.c', 'log2_exp2.c']
 os.environ["CC"] = "gcc"
 os.environ["CXX"] = "g++"