Add mic ON/OFF toggle, headphone and studio output busses

- Channels 0-1 are now dedicated Mic 1/Mic 2 with mic_on toggle
- Mic audio only routes to main when mic_on=True, never to headphone
- New headphone_out_L/R JACK ports (all channels except mics)
- New studio_out_L/R JACK ports (copies main, mutes when any mic is on)
- Mic ON/OFF toggle button in mixer UI (hidden on non-mic channels)
- Session save/load includes mic_on state

audio_engine.py

@@ -15,8 +15,8 @@ FFMPEG_FORMATS    = {'.mp3', '.m4a', '.mp4', '.opus', '.aac', '.wma'}
 
 NUM_MIXER_CHANNELS = 8
 DEFAULT_CHANNEL_NAMES = [
-    "Turntable 1", "Turntable 2", "Mic", "Aux 1",
-    "Aux 2", "Aux 3", "Aux 4", "Aux 5",
+    "Mic 1", "Mic 2", "Aux 1",
+    "Aux 2", "Aux 3", "Aux 4", "Aux 5", "Aux 6",
 ]
 
 
@@ -163,6 +163,7 @@ class MixerChannel:
         self.muted    = False
         self.solo     = False
         self.pfl     = False
+        self.mic_on   = False
         self.vu_peak  = 0.0
         self.in_port_L = None
         self.in_port_R = None
@@ -285,6 +286,18 @@ class AudioEngine:
             self.client.outports.register("master_out_R"),
         )
 
+        # Headphone output ports (all channels except mics)
+        self.headphone_out = (
+            self.client.outports.register("headphone_out_L"),
+            self.client.outports.register("headphone_out_R"),
+        )
+
+        # Studio output ports (same as main, mutes when any mic is on)
+        self.studio_out = (
+            self.client.outports.register("studio_out_L"),
+            self.client.outports.register("studio_out_R"),
+        )
+
         # PFL output ports
         self.pfl_out = (
             self.client.outports.register("pfl_out_L"),
@@ -325,6 +338,15 @@ class AudioEngine:
         if 0 <= index < NUM_MIXER_CHANNELS:
             self.mixer['channels'][index].pfl = pfl
 
+    def set_channel_mic_on(self, index: int, on: bool):
+        if 0 <= index < NUM_MIXER_CHANNELS:
+            self.mixer['channels'][index].mic_on = on
+
+    def get_channel_mic_on(self, index: int) -> bool:
+        if 0 <= index < NUM_MIXER_CHANNELS:
+            return self.mixer['channels'][index].mic_on
+        return False
+
     def _fill_port(self, port_L, port_R, deck: DeckState, frames: int):
         buf_L = port_L.get_array()
         buf_R = port_R.get_array()
@@ -423,7 +445,18 @@ class AudioEngine:
         master_buf_L.fill(0.0)
         master_buf_R.fill(0.0)
 
+        headphone_buf_L = self.headphone_out[0].get_array()
+        headphone_buf_R = self.headphone_out[1].get_array()
+        headphone_buf_L.fill(0.0)
+        headphone_buf_R.fill(0.0)
+
+        studio_buf_L = self.studio_out[0].get_array()
+        studio_buf_R = self.studio_out[1].get_array()
+        studio_buf_L.fill(0.0)
+        studio_buf_R.fill(0.0)
+
         any_solo = any(ch.solo for ch in self.mixer['channels'])
+        any_mic_on = any(ch.mic_on for ch in self.mixer['channels'][:2])
 
         # PFL bus
         pfl_buf_L = self.pfl_out[0].get_array()
@@ -436,6 +469,7 @@ class AudioEngine:
             in_R = ch.in_port_R.get_array()
 
             mute = ch.muted or (any_solo and not ch.solo)
+            is_mic = ch.index < 2
 
             # PFL: pre-fader, pre-mute signal to PFL bus
             if ch.pfl:
@@ -447,16 +481,31 @@ class AudioEngine:
                 continue
 
             vol = ch.volume
+            goes_to_main = not is_mic or ch.mic_on
+            goes_to_headphone = not is_mic
+
             peak = 0.0
             for i in range(frames):
                 s_L = in_L[i] * vol
                 s_R = in_R[i] * vol
-                master_buf_L[i] += s_L
-                master_buf_R[i] += s_R
+                if goes_to_main:
+                    master_buf_L[i] += s_L
+                    master_buf_R[i] += s_R
+                if goes_to_headphone:
+                    headphone_buf_L[i] += s_L
+                    headphone_buf_R[i] += s_R
                 peak = max(peak, abs(s_L), abs(s_R))
 
             ch.vu_peak = peak
 
+        # ── Studio bus: same as main, muted when any mic is on ────────
+        if any_mic_on:
+            studio_buf_L.fill(0.0)
+            studio_buf_R.fill(0.0)
+        else:
+            studio_buf_L[:] = master_buf_L[:]
+            studio_buf_R[:] = master_buf_R[:]
+
         # ── Master DSP ──────────────────────────────────────────────────
         master_audio = np.array([master_buf_L, master_buf_R])
 
@@ -466,6 +515,20 @@ class AudioEngine:
         master_buf_L[:] = master_audio[0]
         master_buf_R[:] = master_audio[1]
 
+        # Apply same DSP to headphone (without mics)
+        hp_audio = np.array([headphone_buf_L, headphone_buf_R])
+        self.mixer['master'].compressor.process(hp_audio)
+        self.mixer['master'].limiter.process(hp_audio)
+        headphone_buf_L[:] = hp_audio[0]
+        headphone_buf_R[:] = hp_audio[1]
+
+        # Apply same DSP to studio
+        studio_audio = np.array([studio_buf_L, studio_buf_R])
+        self.mixer['master'].compressor.process(studio_audio)
+        self.mixer['master'].limiter.process(studio_audio)
+        studio_buf_L[:] = studio_audio[0]
+        studio_buf_R[:] = studio_audio[1]
+
         master_peak = max(np.max(np.abs(master_audio[0])), np.max(np.abs(master_audio[1])))
         self.mixer['master'].vu_peak = master_peak