diff --git a/fft.h b/fft.h
index 954b4b3..f721fa1 100644
--- a/fft.h
+++ b/fft.h
@@ -26,6 +26,8 @@
 #include <math.h>
 #include <stdint.h>
 
+// Use table increase transform speed from 6500 tick to 2025, increase code size on 700 bytes
+// Use compact table, increase code size on 208 bytes, and not decrease speed
 #define FFT_USE_SIN_COS_TABLE
 
 static uint16_t reverse_bits(uint16_t x, int n) {
@@ -43,6 +45,7 @@ static const float sin_table[] = {
 			printf("% .8f,%c", sin(2 * M_PI * i / FFT_SIZE), i % 8 == 7 ? '\n' : ' ');
 		}
 	*/
+	 // for FFT_SIZE = 256
 	 0.00000000,  0.02454123,  0.04906767,  0.07356456,  0.09801714,  0.12241068,  0.14673047,  0.17096189,
 	 0.19509032,  0.21910124,  0.24298018,  0.26671276,  0.29028468,  0.31368174,  0.33688985,  0.35989504,
 	 0.38268343,  0.40524131,  0.42755509,  0.44961133,  0.47139674,  0.49289819,  0.51410274,  0.53499762,
@@ -51,7 +54,7 @@ static const float sin_table[] = {
 	 0.83146961,  0.84485357,  0.85772861,  0.87008699,  0.88192126,  0.89322430,  0.90398929,  0.91420976,
 	 0.92387953,  0.93299280,  0.94154407,  0.94952818,  0.95694034,  0.96377607,  0.97003125,  0.97570213,
 	 0.98078528,  0.98527764,  0.98917651,  0.99247953,  0.99518473,  0.99729046,  0.99879546,  0.99969882,
-	 1.00000000,  0.99969882,  0.99879546,  0.99729046,  0.99518473,  0.99247953,  0.98917651,  0.98527764,
+	 1.00000000,/*  0.99969882,  0.99879546,  0.99729046,  0.99518473,  0.99247953,  0.98917651,  0.98527764,
 	 0.98078528,  0.97570213,  0.97003125,  0.96377607,  0.95694034,  0.94952818,  0.94154407,  0.93299280,
 	 0.92387953,  0.91420976,  0.90398929,  0.89322430,  0.88192126,  0.87008699,  0.85772861,  0.84485357,
 	 0.83146961,  0.81758481,  0.80320753,  0.78834643,  0.77301045,  0.75720885,  0.74095113,  0.72424708,
@@ -66,9 +69,19 @@ static const float sin_table[] = {
 	-0.70710678, -0.72424708, -0.74095113, -0.75720885, -0.77301045, -0.78834643, -0.80320753, -0.81758481,
 	-0.83146961, -0.84485357, -0.85772861, -0.87008699, -0.88192126, -0.89322430, -0.90398929, -0.91420976,
 	-0.92387953, -0.93299280, -0.94154407, -0.94952818, -0.95694034, -0.96377607, -0.97003125, -0.97570213,
-	-0.98078528, -0.98527764, -0.98917651, -0.99247953, -0.99518473, -0.99729046, -0.99879546, -0.99969882,
+	-0.98078528, -0.98527764, -0.98917651, -0.99247953, -0.99518473, -0.99729046, -0.99879546, -0.99969882,*/
 };
-const float* const cos_table = &sin_table[64];
+// full size table:
+//   sin = sin_table[i   ]
+//   cos = sin_table[i+64]
+//#define SIN(i) sin_table[(i)]
+//#define COS(i) sin_table[(i)+64]
+
+// for size use only 0-64 indexes
+//   sin = i > 64 ? sin_table[128-i] : sin_table[   i];
+//   cos = i > 64 ?-sin_table[ i-64] : sin_table[64-i];
+#define SIN(i) ((i) > 64 ? sin_table[128-(i)] : sin_table[   (i)])
+#define COS(i) ((i) > 64 ?-sin_table[ (i)-64] : sin_table[64-(i)])
 #endif
 
 /***
@@ -104,8 +117,10 @@ static void fft256(float array[][2], const uint8_t dir) {
 			uint16_t j, k;
 			for (j = i, k = 0; j < i + halfsize; j++, k += tablestep) {
 				uint16_t l = j + halfsize;
-				float tpre =  array[l][real] * cos_table[k] + array[l][imag] * sin_table[k];
-				float tpim = -array[l][real] * sin_table[k] + array[l][imag] * cos_table[k];
+				float s = SIN(k);
+				float c = COS(k);
+				float tpre =  array[l][real] * c + array[l][imag] * s;
+				float tpim = -array[l][real] * s + array[l][imag] * c;
 				array[l][real] = array[j][real] - tpre;
 				array[l][imag] = array[j][imag] - tpim;
 				array[j][real] += tpre;