diff --git a/examples/tts/tts.cpp b/examples/tts/tts.cpp
index f402ba8a2..1fdf756d5 100644
--- a/examples/tts/tts.cpp
+++ b/examples/tts/tts.cpp
@@ -9,6 +9,7 @@
 #include <string>
 #include <vector>
 #include <fstream>
+#include <thread>
 
 //
 // Terminal utils
@@ -67,6 +68,45 @@ void fill_hann_window(int length, bool periodic, float * output) {
     }
 }
 
+// very poor-man fft
+void twiddle(float * real, float * imag, int k, int N) {
+    float angle = 2 * M_PI * k / N;
+    *real = cos(angle);
+    *imag = sin(angle);
+}
+
+void irfft(int n, float * inp_cplx, float * out_real) {
+    int N = n / 2 + 1;
+
+    std::vector<float> real_input(N);
+    std::vector<float> imag_input(N);
+    for (int i = 0; i < N; ++i) {
+        real_input[i] = inp_cplx[2 * i];
+        imag_input[i] = inp_cplx[2 * i + 1];
+    }
+
+    std::vector<float> real_output(n);
+    std::vector<float> imag_output(n);
+
+    for (int k = 0; k < n; ++k) {
+        real_output[k] = 0.0f;
+        imag_output[k] = 0.0f;
+        for (int m = 0; m < N; ++m) {
+            float twiddle_real;
+            float twiddle_imag;
+
+            twiddle(&twiddle_real, &twiddle_imag, k * m, n);
+
+            real_output[k] += real_input[m] * twiddle_real - imag_input[m] * twiddle_imag;
+            imag_output[k] += real_input[m] * twiddle_imag + imag_input[m] * twiddle_real;
+        }
+    }
+
+    for (int i = 0; i < n; ++i) {
+        out_real[i] = real_output[i] / N;
+    }
+}
+
 int main(int argc, char ** argv) {
     common_params params;
 
@@ -181,28 +221,93 @@ int main(int argc, char ** argv) {
     const int n_embd = llama_n_embd(model_cts);
     const float * embd = llama_get_embeddings(ctx_cts);
 
-    const int w = 1280;
-    std::vector<float> hann(w);
+    const int n     = prompt_inp.size();
+    const int n_fft = 1280;
+    const int n_hop = 320;
+    const int n_win = 1280;
+    const int n_pad = (n_win - n_hop)/2;
+
+    std::vector<float> hann(n_fft);
+
     fill_hann_window(hann.size(), true, hann.data());
 
+    int n_spec = n_embd*n;
 
-    int n = n_embd*261;
+    std::vector<float> E (n_spec);
+    std::vector<float> S (n_spec);
+    std::vector<float> ST(n_spec);
 
-    LOG("result:\n");
-    for (int i = 0; i < 10; ++i) {
-        LOG("%8.3f ", embd[i]);
+    for (int l = 0; l < n; ++l) {
+        for (int k = 0; k < n_embd; ++k) {
+            E[k*n + l] = embd[l*n_embd + k];
+        }
     }
-    LOG("\n");
-    for (int i = n - 10; i < n; ++i) {
-        LOG("%8.3f ", embd[i]);
+
+    for (int k = 0; k < n_embd/2; ++k) {
+        for (int l = 0; l < n; ++l) {
+            float mag = E[(k           )*n + l];
+            float phi = E[(k + n_embd/2)*n + l];
+
+            mag = exp(mag);
+
+            if (mag > 1e2) {
+                mag = 1e2;
+            }
+            S[2*(k*n + l) + 0] = mag*cosf(phi);
+            S[2*(k*n + l) + 1] = mag*sinf(phi);
+        }
+    }
+
+    for (int l = 0; l < n; ++l) {
+        for (int k = 0; k < n_embd/2; ++k) {
+            ST[l*n_embd + 2*k + 0] = S[2*(k*n + l) + 0];
+            ST[l*n_embd + 2*k + 1] = S[2*(k*n + l) + 1];
+        }
+    }
+
+    std::vector<float> res(n*n_fft);
+
+    const int n_thread = std::thread::hardware_concurrency();
+    std::vector<std::thread> workers(n_thread);
+    for (int i = 0; i < n_thread; ++i) {
+        workers[i] = std::thread([&, i]() {
+            for (int l = i; l < n; l += n_thread) {
+                irfft(n_fft, ST.data() + l*n_embd, res.data() + l*n_fft);
+            }
+        });
+    }
+    for (int i = 0; i < n_thread; ++i) {
+        workers[i].join();
+    }
+
+    LOG("result (%d):\n", res.size());
+    for (int i = 0; i < n_fft; ++i) {
+        LOG("%d - %8.5f\n", i, res[5*n_fft + i]);
     }
     LOG("\n");
     double sum = 0.0;
-    for (int i = 0; i < n; ++i) {
-        sum += embd[i];
+    for (int i = 0; i < n_fft; ++i) {
+        sum += res[5*n_fft + i];
     }
     LOG("sum: %f\n", sum);
 
+    {
+        LOG("result:\n");
+        for (int i = 0; i < 10; ++i) {
+            LOG("%8.3f ", S[i]);
+        }
+        LOG("\n");
+        for (int i = n_spec - 10; i < n_spec; ++i) {
+            LOG("%8.3f ", S[i]);
+        }
+        LOG("\n");
+        double sum = 0.0;
+        for (int i = 0; i < n_spec; ++i) {
+            sum += S[i];
+        }
+        LOG("sum: %f\n", sum);
+    }
+
     fprintf(stderr, "\n");
 
     llama_free(ctx_ttc);