diff --git a/firmware/application/apps/soundboard_app.cpp b/firmware/application/apps/soundboard_app.cpp
index 56933134..5d23dff8 100644
--- a/firmware/application/apps/soundboard_app.cpp
+++ b/firmware/application/apps/soundboard_app.cpp
@@ -116,11 +116,11 @@ void SoundBoardView::start_tx(const uint32_t id) {
 
     // TODO: Delete all this and use tx model.
     baseband::set_audiotx_config(
-        1536000 / 20,  // Update vu-meter at 20Hz
+        TONES_SAMPLERATE / 20,  // Update vu-meter at 20Hz
         transmitter_model.channel_bandwidth(),
         0,  // Gain is unused
         8,  // shift_bits_s16, default 8 bits, but  also unused
-        TONES_F2D(tone_key_frequency(tone_key_index), 1536000),
+        TONES_F2D(tone_key_frequency(tone_key_index), TONES_SAMPLERATE),
         0,  // AM
         0,  // DSB
         0,  // USB
@@ -132,7 +132,8 @@ void SoundBoardView::start_tx(const uint32_t id) {
 
     tx_view.set_transmitting(true);
 
-    audio::output::start();
+    if (tone_key_index == 0)
+        audio::output::start();
 }
 
 /*void SoundBoardView::show_infos() {
@@ -238,6 +239,7 @@ SoundBoardView::SoundBoardView(
                   //&text_duration,
                   //&progressbar,
                   &field_volume,
+                  &text_volume_disabled,
                   &page_info,
                   &check_loop,
                   &check_random,
@@ -263,6 +265,13 @@ SoundBoardView::SoundBoardView(
     tone_keys_populate(options_tone_key);
     options_tone_key.set_selected_index(0);
 
+    text_volume_disabled.hidden(true);
+    options_tone_key.on_change = [this](size_t index, OptionsField::value_t) {
+        bool tone_key_enabled = (index != 0);
+        text_volume_disabled.hidden(!tone_key_enabled);
+        field_volume.hidden(tone_key_enabled);
+    };
+
     check_loop.set_value(false);
     check_random.set_value(false);
 
diff --git a/firmware/application/apps/soundboard_app.hpp b/firmware/application/apps/soundboard_app.hpp
index 88dc3c20..52b1c96f 100644
--- a/firmware/application/apps/soundboard_app.hpp
+++ b/firmware/application/apps/soundboard_app.hpp
@@ -128,6 +128,9 @@ class SoundBoardView : public View {
 
     AudioVolumeField field_volume{
         {28 * 8, 180}};
+    Text text_volume_disabled{
+        {28 * 8, 180, 3 * 8, 16},
+        "--"};
 
     Checkbox check_loop{
         {0, 25 * 8 + 4},
diff --git a/firmware/baseband/audio_dma.cpp b/firmware/baseband/audio_dma.cpp
index df12ccfe..f493fd93 100644
--- a/firmware/baseband/audio_dma.cpp
+++ b/firmware/baseband/audio_dma.cpp
@@ -215,9 +215,12 @@ void disable() {
     gpdma_channel_i2s0_rx.disable();
 }
 
-void shrink_tx_buffer() {
-    single_tx_buffer = true;
-    lli_tx_loop[0].lli = lli_pointer(&lli_tx_loop[0]);
+void shrink_tx_buffer(bool shrink) {
+    single_tx_buffer = shrink;
+    if (single_tx_buffer)
+        lli_tx_loop[0].lli = lli_pointer(&lli_tx_loop[0]);
+    else
+        lli_tx_loop[0].lli = lli_pointer(&lli_tx_loop[1]);
 }
 
 buffer_t tx_empty_buffer() {
diff --git a/firmware/baseband/audio_dma.hpp b/firmware/baseband/audio_dma.hpp
index 2416b6cf..8634de82 100644
--- a/firmware/baseband/audio_dma.hpp
+++ b/firmware/baseband/audio_dma.hpp
@@ -47,7 +47,7 @@ void init();
 void configure();
 void enable();
 void disable();
-void shrink_tx_buffer();
+void shrink_tx_buffer(bool shrink);
 
 audio::buffer_t tx_empty_buffer();
 audio::buffer_t rx_empty_buffer();
diff --git a/firmware/baseband/audio_output.cpp b/firmware/baseband/audio_output.cpp
index 8a895a87..81cd2b3e 100644
--- a/firmware/baseband/audio_output.cpp
+++ b/firmware/baseband/audio_output.cpp
@@ -32,34 +32,34 @@
 #include <cstddef>
 #include <array>
 
-void AudioOutput::configure(
-    const bool do_proc) {
+void AudioOutput::configure(const bool do_proc) {
     do_processing = do_proc;
 }
 
-void AudioOutput::configure(
-    const iir_biquad_config_t& hpf_config,
-    const iir_biquad_config_t& deemph_config,
-    const float squelch_threshold) {
+void AudioOutput::configure(const iir_biquad_config_t& hpf_config, const iir_biquad_config_t& deemph_config, const float squelch_threshold) {
     hpf.configure(hpf_config);
     deemph.configure(deemph_config);
     squelch.set_threshold(squelch_threshold);
 }
 
-void AudioOutput::write(
-    const buffer_s16_t& audio) {
+void AudioOutput::write_unprocessed(const buffer_s16_t& audio) {
+    block_buffer_s16.feed(
+        audio,
+        [this](const buffer_s16_t& buffer) {
+            audio_present = true;
+            fill_audio_buffer(buffer, audio_present);
+        });
+}
+
+void AudioOutput::write(const buffer_s16_t& audio) {
     std::array<float, 32> audio_f;
     for (size_t i = 0; i < audio.count; i++) {
         audio_f[i] = audio.p[i] * ki;
     }
-    write(buffer_f32_t{
-        audio_f.data(),
-        audio.count,
-        audio.sampling_rate});
+    write(buffer_f32_t{audio_f.data(), audio.count, audio.sampling_rate});
 }
 
-void AudioOutput::write(
-    const buffer_f32_t& audio) {
+void AudioOutput::write(const buffer_f32_t& audio) {
     block_buffer.feed(
         audio,
         [this](const buffer_f32_t& buffer) {
@@ -67,8 +67,7 @@ void AudioOutput::write(
         });
 }
 
-void AudioOutput::on_block(
-    const buffer_f32_t& audio) {
+void AudioOutput::on_block(const buffer_f32_t& audio) {
     if (do_processing) {
         const auto audio_present_now = squelch.execute(audio);
 
@@ -93,6 +92,18 @@ bool AudioOutput::is_squelched() {
     return !audio_present;
 }
 
+void AudioOutput::fill_audio_buffer(const buffer_s16_t& audio, const bool send_to_fifo) {
+    auto audio_buffer = audio::dma::tx_empty_buffer();
+    for (size_t i = 0; i < audio_buffer.count; i++) {
+        audio_buffer.p[i].left = audio_buffer.p[i].right = audio.p[i];
+    }
+    if (stream && send_to_fifo) {
+        stream->write(audio.p, audio_buffer.count * sizeof(int16_t));
+    }
+
+    feed_audio_stats(audio);
+}
+
 void AudioOutput::fill_audio_buffer(const buffer_f32_t& audio, const bool send_to_fifo) {
     std::array<int16_t, 32> audio_int;
 
@@ -110,6 +121,15 @@ void AudioOutput::fill_audio_buffer(const buffer_f32_t& audio, const bool send_t
     feed_audio_stats(audio);
 }
 
+void AudioOutput::feed_audio_stats(const buffer_s16_t& audio) {
+    audio_stats.feed(
+        audio,
+        [](const AudioStatistics& statistics) {
+            const AudioStatisticsMessage audio_stats_message{statistics};
+            shared_memory.application_queue.push(audio_stats_message);
+        });
+}
+
 void AudioOutput::feed_audio_stats(const buffer_f32_t& audio) {
     audio_stats.feed(
         audio,
diff --git a/firmware/baseband/audio_output.hpp b/firmware/baseband/audio_output.hpp
index 84104920..1b00a016 100644
--- a/firmware/baseband/audio_output.hpp
+++ b/firmware/baseband/audio_output.hpp
@@ -44,6 +44,7 @@ class AudioOutput {
         const iir_biquad_config_t& deemph_config = iir_config_passthrough,
         const float squelch_threshold = 0.0f);
 
+    void write_unprocessed(const buffer_s16_t& audio);
     void write(const buffer_s16_t& audio);
     void write(const buffer_f32_t& audio);
 
@@ -57,6 +58,7 @@ class AudioOutput {
     static constexpr float k = 32768.0f;
     static constexpr float ki = 1.0f / k;
 
+    BlockDecimator<int16_t, 32> block_buffer_s16{1};
     BlockDecimator<float, 32> block_buffer{1};
 
     IIRBiquadFilter hpf{};
@@ -73,7 +75,11 @@ class AudioOutput {
     bool do_processing = true;
 
     void on_block(const buffer_f32_t& audio);
+
+    void fill_audio_buffer(const buffer_s16_t& audio, const bool send_to_fifo);
     void fill_audio_buffer(const buffer_f32_t& audio, const bool send_to_fifo);
+
+    void feed_audio_stats(const buffer_s16_t& audio);
     void feed_audio_stats(const buffer_f32_t& audio);
 };
 
diff --git a/firmware/baseband/audio_stats_collector.cpp b/firmware/baseband/audio_stats_collector.cpp
index 5ed98391..4a5af3a2 100644
--- a/firmware/baseband/audio_stats_collector.cpp
+++ b/firmware/baseband/audio_stats_collector.cpp
@@ -23,6 +23,19 @@
 
 #include "utility.hpp"
 
+void AudioStatsCollector::consume_audio_buffer(const buffer_s16_t& src) {
+    auto src_p = src.p;
+    const auto src_end = &src.p[src.count];
+    while (src_p < src_end) {
+        const auto sample = *(src_p++);
+        const auto sample_squared = sample * sample;
+        squared_sum += sample_squared;
+        if (sample_squared > max_squared) {
+            max_squared = sample_squared;
+        }
+    }
+}
+
 void AudioStatsCollector::consume_audio_buffer(const buffer_f32_t& src) {
     auto src_p = src.p;
     const auto src_end = &src.p[src.count];
@@ -56,6 +69,12 @@ bool AudioStatsCollector::update_stats(const size_t sample_count, const size_t s
     }
 }
 
+bool AudioStatsCollector::feed(const buffer_s16_t& src) {
+    consume_audio_buffer(src);
+
+    return update_stats(src.count, src.sampling_rate);
+}
+
 bool AudioStatsCollector::feed(const buffer_f32_t& src) {
     consume_audio_buffer(src);
 
diff --git a/firmware/baseband/audio_stats_collector.hpp b/firmware/baseband/audio_stats_collector.hpp
index 527323d3..3a46b6b6 100644
--- a/firmware/baseband/audio_stats_collector.hpp
+++ b/firmware/baseband/audio_stats_collector.hpp
@@ -30,6 +30,13 @@
 
 class AudioStatsCollector {
    public:
+    template <typename Callback>
+    void feed(const buffer_s16_t& src, Callback callback) {
+        if (feed(src)) {
+            callback(statistics);
+        }
+    }
+
     template <typename Callback>
     void feed(const buffer_f32_t& src, Callback callback) {
         if (feed(src)) {
@@ -52,10 +59,12 @@ class AudioStatsCollector {
 
     AudioStatistics statistics{};
 
+    void consume_audio_buffer(const buffer_s16_t& src);
     void consume_audio_buffer(const buffer_f32_t& src);
 
     bool update_stats(const size_t sample_count, const size_t sampling_rate);
 
+    bool feed(const buffer_s16_t& src);
     bool feed(const buffer_f32_t& src);
     bool mute(const size_t sample_count, const size_t sampling_rate);
 };
diff --git a/firmware/baseband/proc_audiotx.cpp b/firmware/baseband/proc_audiotx.cpp
index 0965aef7..4e84977a 100644
--- a/firmware/baseband/proc_audiotx.cpp
+++ b/firmware/baseband/proc_audiotx.cpp
@@ -41,13 +41,17 @@ void AudioTXProcessor::execute(const buffer_c8_t& buffer) {
             }
         }
 
-        // Output to speaker too
-        uint32_t imod32 = i & (AUDIO_OUTPUT_BUFFER_SIZE - 1);
-        audio_data[imod32] = ((int16_t)audio_sample - 0x80) * (1.0f / 128.0f);
-        if (imod32 == (AUDIO_OUTPUT_BUFFER_SIZE - 1))
-            audio_output.write(audio_buffer);
+        sample = audio_sample - 0x80;
 
-        sample = tone_gen.process(audio_sample - 0x80);
+        // Output to speaker too
+        if (!tone_key_enabled) {
+            uint32_t imod32 = i & (AUDIO_OUTPUT_BUFFER_SIZE - 1);
+            audio_data[imod32] = sample * 256;
+            if (imod32 == (AUDIO_OUTPUT_BUFFER_SIZE - 1))
+                audio_output.write_unprocessed(audio_buffer);
+        }
+
+        sample = tone_gen.process(sample);
 
         // FM
         delta = sample * fm_delta;
@@ -102,7 +106,9 @@ void AudioTXProcessor::audio_config(const AudioTXConfigMessage& message) {
     progress_interval_samples = message.divider;
     resample_acc = 0;
     audio_output.configure(false);
-    audio::dma::shrink_tx_buffer();
+
+    tone_key_enabled = (message.tone_key_delta != 0);
+    audio::dma::shrink_tx_buffer(!tone_key_enabled);
 }
 
 void AudioTXProcessor::replay_config(const ReplayConfigMessage& message) {
diff --git a/firmware/baseband/proc_audiotx.hpp b/firmware/baseband/proc_audiotx.hpp
index d11be3cb..0791cd41 100644
--- a/firmware/baseband/proc_audiotx.hpp
+++ b/firmware/baseband/proc_audiotx.hpp
@@ -52,14 +52,15 @@ class AudioTXProcessor : public BasebandProcessor {
     int32_t sample{0}, delta{};
     int8_t re{0}, im{0};
 
-    float audio_data[AUDIO_OUTPUT_BUFFER_SIZE];
-    buffer_f32_t audio_buffer{audio_data, AUDIO_OUTPUT_BUFFER_SIZE, 48000};
+    int16_t audio_data[AUDIO_OUTPUT_BUFFER_SIZE];
+    buffer_s16_t audio_buffer{audio_data, AUDIO_OUTPUT_BUFFER_SIZE, 48000};
     AudioOutput audio_output{};
 
     size_t progress_interval_samples = 0, progress_samples = 0;
 
     bool configured{false};
     uint32_t bytes_read{0};
+    bool tone_key_enabled{false};
 
     void sample_rate_config(const SampleRateConfigMessage& message);
     void audio_config(const AudioTXConfigMessage& message);