diff --git a/module_usb_audio/audio_io/audio_io.xc b/module_usb_audio/audio_io/audio_io.xc
index 57512d1b..c002d218 100755
--- a/module_usb_audio/audio_io/audio_io.xc
+++ b/module_usb_audio/audio_io/audio_io.xc
@@ -58,16 +58,27 @@ static unsigned samplesIn[2][MAX(NUM_USB_CHAN_IN, IN_CHAN_COUNT)];
 #endif
 
 static int inDownsamplingCounter = 0;
-#if (I2S_DOWNSAMPLE_FACTOR_IN > 1)
+static int outDownsamplingCounter = 0;
+#if (I2S_DOWNSAMPLE_FACTOR_IN > 1) || (I2S_DOWNSAMPLE_FACTOR_OUT > 1)
 #include "src.h"
 static union ds3Data
 {
     long long doubleWordAlignmentEnsured;
-    /* [Number of I2S channels][Number of samples/phases][Taps per phase] */
+    /* delay lines = [Number of I2S channels][Number of samples/phases][Taps per phase] */
+#if (I2S_DOWNSAMPLE_FACTOR_IN > 1)
     int32_t inputDelayLine[I2S_DOWNSAMPLE_CHANS_IN][I2S_DOWNSAMPLE_FACTOR_IN][24];
+#endif // (I2S_DOWNSAMPLE_FACTOR_IN > 1)
+#if (I2S_DOWNSAMPLE_FACTOR_OUT > 1)
+    int32_t outputDelayLine[I2S_DOWNSAMPLE_CHANS_OUT][I2S_DOWNSAMPLE_FACTOR_OUT][24];
+#endif // (I2S_DOWNSAMPLE_FACTOR_OUT > 1)
 } ds3Data;
+#if (I2S_DOWNSAMPLE_FACTOR_IN > 1)
 static int64_t inputDs3Sum[I2S_DOWNSAMPLE_CHANS_IN];
 #endif // (I2S_DOWNSAMPLE_FACTOR_IN > 1)
+#if (I2S_DOWNSAMPLE_FACTOR_OUT > 1)
+static int64_t outputDs3Sum[I2S_DOWNSAMPLE_CHANS_OUT];
+#endif // (I2S_DOWNSAMPLE_FACTOR_OUT > 1)
+#endif // (I2S_DOWNSAMPLE_FACTOR_IN > 1) || (I2S_DOWNSAMPLE_FACTOR_OUT > 1)
 
 #if (DSD_CHANS_DAC != 0)
 extern buffered out port:32 p_dsd_dac[DSD_CHANS_DAC];
@@ -723,20 +734,22 @@ unsigned static deliver(chanend c_out, chanend ?c_spd_out,
 #pragma xta endpoint "i2s_output_l"
 
 #if (I2S_CHANS_DAC != 0) && (NUM_USB_CHAN_OUT != 0)
-                index = 0;
-#pragma loop unroll
-                /* Output "even" channel to DAC (i.e. left) */
-                for(int i = 0; i < I2S_CHANS_DAC; i+=I2S_CHANS_PER_FRAME)
+                if ((I2S_DOWNSAMPLE_FACTOR_OUT - 1) == outDownsamplingCounter)
                 {
-                    p_i2s_dac[index++] <: bitrev(samplesOut[frameCount +i]);
-                }
+                    index = 0;
+#pragma loop unroll
+                    /* Output "even" channel to DAC (i.e. left) */
+                    for(int i = 0; i < I2S_CHANS_DAC; i+=I2S_CHANS_PER_FRAME)
+                    {
+                        p_i2s_dac[index++] <: bitrev(samplesOut[frameCount +i]);
+                    }
 #endif
 
 #ifndef CODEC_MASTER
-                /* Clock out the LR Clock, the DAC data and Clock in the next sample into ADC */
-                doI2SClocks(divide);
+                    /* Clock out the LR Clock, the DAC data and Clock in the next sample into ADC */
+                    doI2SClocks(divide);
 #endif
-
+                }
 #ifdef ADAT_TX
                  TransferAdatTxSamples(c_adat_out, samplesOut, adatSmuxMode, 1);
 #endif
@@ -857,19 +870,24 @@ unsigned static deliver(chanend c_out, chanend ?c_spd_out,
                 index = 0;
 #pragma xta endpoint "i2s_output_r"
 #if (I2S_CHANS_DAC != 0) && (NUM_USB_CHAN_OUT != 0)
-                /* Output "odd" channel to DAC (i.e. right) */
-#pragma loop unroll
-                for(int i = 1; i < I2S_CHANS_DAC; i+=I2S_CHANS_PER_FRAME)
+                if ((I2S_DOWNSAMPLE_FACTOR_OUT - 1) == outDownsamplingCounter)
                 {
-                    p_i2s_dac[index++] <: bitrev(samplesOut[frameCount + i]);
-                }
+                    /* Output "odd" channel to DAC (i.e. right) */
+#pragma loop unroll
+                    for(int i = 1; i < I2S_CHANS_DAC; i+=I2S_CHANS_PER_FRAME)
+                    {
+                        p_i2s_dac[index++] <: bitrev(samplesOut[frameCount + i]);
+                    }
 #endif
 
 #ifndef CODEC_MASTER
-                doI2SClocks(divide);
+                    doI2SClocks(divide);
 #endif
-
-
+                }
+                else
+                {
+                    ++outDownsamplingCounter;
+                }
 
             }  // !dsdMode
 #if (DSD_CHANS_DAC != 0) && (NUM_USB_CHAN_OUT > 0)
diff --git a/module_usb_audio/devicedefines.h b/module_usb_audio/devicedefines.h
index b88d334b..4ea7137f 100644
--- a/module_usb_audio/devicedefines.h
+++ b/module_usb_audio/devicedefines.h
@@ -134,6 +134,19 @@
     #endif
 #endif
 
+/**
+ * @brief Output I2S (host to device) channels can be downsampled by a factor of 3.
+ *
+ * Default: 1 i.e. downsampling is disabled.
+ */
+#ifndef I2S_DOWNSAMPLE_FACTOR_OUT
+#define I2S_DOWNSAMPLE_FACTOR_OUT (1)
+#else
+    #if (I2S_DOWNSAMPLE_FACTOR_OUT != 3) && (I2S_DOWNSAMPLE_FACTOR_OUT != 1)
+        #error Unsupported I2S output downsampling configuration
+    #endif
+#endif
+
 /**
  * @brief Only downsample one channel per input I2S frame.
  *
@@ -157,6 +170,13 @@
 #define I2S_DOWNSAMPLE_CHANS_IN I2S_CHANS_ADC
 #endif
 
+/**
+ * @brief Number of output (host to device) I2S channels to downsample.
+ *
+ * Default: The number of I2S output channels.
+ */
+#define I2S_DOWNSAMPLE_CHANS_OUT I2S_CHANS_ADC
+
 /**
  * @brief Max supported sample frequency for device (Hz). Default: 192000
  */