diff --git a/tools/chatgui/src/audio_buffer_tuning.h b/tools/chatgui/src/audio_buffer_tuning.h
index 71c63554..2a3ce5f2 100644
--- a/tools/chatgui/src/audio_buffer_tuning.h
+++ b/tools/chatgui/src/audio_buffer_tuning.h
@@ -9,7 +9,7 @@
  * Состояние живёт до смены устройства/сессии; begin() сохраняет подобранный размер при reopen. */
 struct AudioBufferTuning {
     enum Result { Unchanged, Increase, Limit };
-    unsigned requestedMs = 0, actualMs = 0, periods = 1;
+    unsigned requestedMs = 0, baseMs = 0, actualMs = 0, periods = 1;
     int64_t settleUntil = 0, changeAfter = 0, firstFaultAt = -1;
     unsigned faultPolls = 0;
 
@@ -24,7 +24,7 @@ struct AudioBufferTuning {
         faultPolls = std::min(faultPolls + 1, 2u);
         if (faultPolls < 2 || now < changeAfter) return Unchanged;
         firstFaultAt = -1; faultPolls = 0; changeAfter = now + 5000;
-        unsigned current = std::max(actualMs, requestedMs), maximum = 100 / periods;
+        unsigned current = std::max({actualMs, requestedMs, baseMs}), maximum = 100 / periods;
         if (!current || current >= maximum) return Limit;
         requestedMs = std::min(current + 5, maximum);
         return Increase;
diff --git a/tools/chatgui/src/audio_device.cpp b/tools/chatgui/src/audio_device.cpp
index 96d8a8dc..d124f362 100644
--- a/tools/chatgui/src/audio_device.cpp
+++ b/tools/chatgui/src/audio_device.cpp
@@ -48,6 +48,8 @@ bool AudioDevice::init(ma_context* context, ma_device_config config, const char*
     m_bufferKeyValid = true; m_bufferBackend = context->backend; m_bufferType = config.deviceType;
     m_bufferSession = session; m_bufferSelected = selected != nullptr;
     if (selected) m_bufferDeviceId = *selected;
+    m_bufferTuning.baseMs = config.periodSizeInFrames && config.sampleRate
+        ? unsigned((uint64_t(config.periodSizeInFrames) * 1000 + config.sampleRate - 1) / config.sampleRate) : config.periodSizeInMilliseconds;
     if (m_bufferTuning.requestedMs) {
         config.periodSizeInFrames = 0; config.periodSizeInMilliseconds = m_bufferTuning.requestedMs;
     }
diff --git a/tools/chatgui/tests/test_audio_timing.c b/tools/chatgui/tests/test_audio_timing.c
index f6adf0e5..0bb05c39 100644
--- a/tools/chatgui/tests/test_audio_timing.c
+++ b/tools/chatgui/tests/test_audio_timing.c
@@ -6,6 +6,15 @@
 static int64_t times[64];
 static unsigned counts[64], seen;
 static int capture_missing;
+static unsigned overruns, underruns;
+static void notification(const ma_device_notification* event) {
+    if (event->type == ma_device_notification_type_capture_overrun) overruns++;
+    if (event->type == ma_device_notification_type_playback_underrun) underruns++;
+}
+static int fake_hole(const void* stream, const void** data, size_t* bytes) {
+    (void)stream; *data = NULL; *bytes = 64 * 2 * sizeof(float); return 0;
+}
+static int fake_drop(void* stream) { (void)stream; return 0; }
 static int fake_latency(const void* stream, uint64_t* latency, int* negative) {
     (void)stream; *latency = 100000; *negative = 0; return 0;
 }
@@ -52,6 +61,16 @@ int main(void) {
     after = time_us();
     assert(seen == 1 && times[0] >= now - 100000 + 2500 && times[0] <= after - 100000 + 2500);
     assert(!audio_stream_capture_missing(&device)); // Hint действует только внутри dispatch.
+    device.onNotification = notification;
+    ma_device__set_state(&device, ma_device_state_started);
+    context.pulse.pa_stream_peek = (ma_proc)fake_hole; context.pulse.pa_stream_drop = (ma_proc)fake_drop;
+    seen = 0;
+    ma_device_on_read__pulse(device.pulse.pStreamCapture, 64 * 2 * sizeof(float), &device);
+    assert(overruns == 1 && underruns == 0 && seen == 4); // Один hole, четыре converter callbacks.
+    audio_diag_pulse_overflow(device.pulse.pStreamCapture, &device);
+    assert(overruns == 2 && underruns == 0);
+    audio_diag_pulse_underflow(NULL, &device);
+    assert(overruns == 2 && underruns == 1);
     ma_data_converter_uninit(&device.capture.converter, NULL);
-    puts("audio timing: capture read index, converter offsets, explicit hole PASS");
+    puts("audio timing: capture read index, converter offsets, hole/overrun/underrun notifications PASS");
 }