diff --git a/firmware/drivers/audio/imx233-codec.c b/firmware/drivers/audio/imx233-codec.c
index 357aa33bb5..d56eb44d57 100644
--- a/firmware/drivers/audio/imx233-codec.c
+++ b/firmware/drivers/audio/imx233-codec.c
@@ -93,9 +93,7 @@ void audiohw_set_recvol(int left, int right, int type)
 
 void audiohw_set_depth_3d(int val)
 {
-    /* input is raw value ranging from 0dB to 6dB in tenth of dB
-     * convert to value in 1.5dB steps */
-    imx233_audioout_set_3d_effect(val / 15);
+    imx233_audioout_set_3d_effect(val);
 }
 
 void audiohw_set_monitor(bool enable)
diff --git a/firmware/export/imx233-codec.h b/firmware/export/imx233-codec.h
index 10500f15b9..040a829284 100644
--- a/firmware/export/imx233-codec.h
+++ b/firmware/export/imx233-codec.h
@@ -21,12 +21,12 @@
 #ifndef __IMX233_CODEC_H_
 #define __IMX233_CODEC_H_
 
-/* i.MX233 can boost up to 6dB in DAC mode and 12dB in line mode. Since mic/line
- * already have adjustable gain, keep lowest of both. With chained DAC volume
- * and headphone volume, the i.MX233 can achieve < -100dB but stay at -100dB. */
 #define AUDIOHW_CAPS    (DEPTH_3D_CAP | BASS_CAP | TREBLE_CAP | \
                          LIN_GAIN_CAP | MIC_GAIN_CAP)
 
+/* i.MX233 can boost up to 6dB in DAC mode and 12dB in line mode. Pretend we can
+ * do 12dB (but we cap at 6dB in DAC mode). With chained DAC volume
+ * and headphone volume, the i.MX233 can achieve < -100dB but stay at -100dB. */
 AUDIOHW_SETTING(VOLUME,     "dB", 0, 1, -100,  12,  -25)
 /* HAVE_SW_TONE_CONTROLS */
 #ifdef HAVE_RECORDING
@@ -38,7 +38,16 @@ AUDIOHW_SETTING(LEFT_GAIN,  "dB", 0, 1, -100,  22,   0)
 AUDIOHW_SETTING(RIGHT_GAIN, "dB", 0, 1, -100,  22,   0)
 AUDIOHW_SETTING(MIC_GAIN,   "dB", 0, 1, -100,  60,  20)
 #endif /* HAVE_RECORDING */
-/* i.MX233 has four settings: 0dB, 3dB, 4.5dB, 6dB so fake 1.5dB steps */
-AUDIOHW_SETTING(DEPTH_3D,   "dB", 1,15,   0,   60,   0)
+/* i.MX233 has four settings: 0dB, 3dB, 4.5dB, 6dB */
+/* depth_3d setting: 0=0dB, 1=3dB, 2=4.5dB, 3=6dB. Return value in tenth of dB */
+static inline int imx233_depth_3d_val2phys(int val)
+{
+    if(val == 0)
+        return 0; /* 0dB */
+    else
+        return 15 * (val + 1); /* 3dB + 1.5dB per step */
+}
+AUDIOHW_SETTING(DEPTH_3D,   "dB", 1, 1,    0,   3,   0, imx233_depth_3d_val2phys(val))
+
 
 #endif /* __IMX233_CODEC_H_ */
diff --git a/firmware/target/arm/imx233/audioout-imx233.h b/firmware/target/arm/imx233/audioout-imx233.h
index c819fdb294..4c27ae2375 100644
--- a/firmware/target/arm/imx233/audioout-imx233.h
+++ b/firmware/target/arm/imx233/audioout-imx233.h
@@ -60,7 +60,7 @@ void imx233_audioout_set_hp_vol(int vol_l, int vol_r);
 void imx233_audioout_set_freq(int fsel);
 /* select between DAC and Line1 */
 void imx233_audioout_select_hp_input(bool line1);
-/* value in 1.5dB steps, from 0dB to 6dB */
+/* value is uses register encoding: 0=Off, 1=3dB, 2=4.5dB, 3=6dB */
 void imx233_audioout_set_3d_effect(int val);
 /* enable/disable speaker amplifier */
 void imx233_audioout_enable_spkr(bool en);