Update the ambisonic coefficients for HRTF

This uses an AllRAD-derived decoder matrix for the high frequencies, which
seems to improve positioning response. It also switches back to dual-band.
The low frequencies appear to be unexpectedly quiet by comparison, but it's not
that bad and can be tweaked later.

1 files changed, 15 insertions, 15 deletions

diff --git a/Alc/hrtf.c b/Alc/hrtf.c
index 34070792..87a119a0 100644
--- a/Alc/hrtf.c
+++ b/Alc/hrtf.c
@@ -195,26 +195,26 @@ ALuint BuildBFormatHrtf(const struct Hrtf *Hrtf, ALfloat (*coeffs)[HRIR_LENGTH][
         { DEG2RAD(-90.0f), DEG2RAD(   0.0f) },
     };
     static const ALfloat Ambi3DMatrix[14][2][MAX_AMBI_COEFFS] = {
-        { { 0.071428392f,  0.000000000f,  0.071428392f,  0.000000000f }, { 0.0269973975f,  0.0000000000f,  0.0467610443f,  0.0000000000f } },
-        { { 0.071428392f,  0.041239332f,  0.041239332f,  0.041239332f }, { 0.0269973975f,  0.0269973975f,  0.0269973975f,  0.0269973975f } },
-        { { 0.071428392f, -0.041239332f,  0.041239332f,  0.041239332f }, { 0.0269973975f, -0.0269973975f,  0.0269973975f,  0.0269973975f } },
-        { { 0.071428392f, -0.041239332f,  0.041239332f, -0.041239332f }, { 0.0269973975f, -0.0269973975f,  0.0269973975f, -0.0269973975f } },
-        { { 0.071428392f,  0.041239332f,  0.041239332f, -0.041239332f }, { 0.0269973975f,  0.0269973975f,  0.0269973975f, -0.0269973975f } },
-        { { 0.071428392f,  0.000000000f,  0.000000000f,  0.071428392f }, { 0.0269973975f,  0.0000000000f,  0.0000000000f,  0.0467610443f } },
-        { { 0.071428392f, -0.071428392f,  0.000000000f,  0.000000000f }, { 0.0269973975f, -0.0467610443f,  0.0000000000f,  0.0000000000f } },
-        { { 0.071428392f,  0.000000000f,  0.000000000f, -0.071428392f }, { 0.0269973975f,  0.0000000000f,  0.0000000000f, -0.0467610443f } },
-        { { 0.071428392f,  0.071428392f,  0.000000000f,  0.000000000f }, { 0.0269973975f,  0.0467610443f,  0.0000000000f,  0.0000000000f } },
-        { { 0.071428392f,  0.041239332f, -0.041239332f,  0.041239332f }, { 0.0269973975f,  0.0269973975f, -0.0269973975f,  0.0269973975f } },
-        { { 0.071428392f, -0.041239332f, -0.041239332f,  0.041239332f }, { 0.0269973975f, -0.0269973975f, -0.0269973975f,  0.0269973975f } },
-        { { 0.071428392f, -0.041239332f, -0.041239332f, -0.041239332f }, { 0.0269973975f, -0.0269973975f, -0.0269973975f, -0.0269973975f } },
-        { { 0.071428392f,  0.041239332f, -0.041239332f, -0.041239332f }, { 0.0269973975f,  0.0269973975f, -0.0269973975f, -0.0269973975f } },
-        { { 0.071428392f,  0.000000000f, -0.071428392f,  0.000000000f }, { 0.0269973975f,  0.0000000000f, -0.0467610443f,  0.0000000000f } },
+        { { 0.078851598f,  0.000000000f,  0.070561967f,  0.000000000f }, { 0.0269973975f,  0.0000000000f,  0.0467610443f,  0.0000000000f } },
+        { { 0.124051278f,  0.059847972f,  0.059847972f,  0.059847972f }, { 0.0269973975f,  0.0269973975f,  0.0269973975f,  0.0269973975f } },
+        { { 0.124051278f, -0.059847972f,  0.059847972f,  0.059847972f }, { 0.0269973975f, -0.0269973975f,  0.0269973975f,  0.0269973975f } },
+        { { 0.124051278f, -0.059847972f,  0.059847972f, -0.059847972f }, { 0.0269973975f, -0.0269973975f,  0.0269973975f, -0.0269973975f } },
+        { { 0.124051278f,  0.059847972f,  0.059847972f, -0.059847972f }, { 0.0269973975f,  0.0269973975f,  0.0269973975f, -0.0269973975f } },
+        { { 0.078851598f,  0.000000000f,  0.000000000f,  0.070561967f }, { 0.0269973975f,  0.0000000000f,  0.0000000000f,  0.0467610443f } },
+        { { 0.078851598f, -0.070561967f,  0.000000000f,  0.000000000f }, { 0.0269973975f, -0.0467610443f,  0.0000000000f,  0.0000000000f } },
+        { { 0.078851598f,  0.000000000f,  0.000000000f, -0.070561967f }, { 0.0269973975f,  0.0000000000f,  0.0000000000f, -0.0467610443f } },
+        { { 0.078851598f,  0.070561967f,  0.000000000f,  0.000000000f }, { 0.0269973975f,  0.0467610443f,  0.0000000000f,  0.0000000000f } },
+        { { 0.124051278f,  0.059847972f, -0.059847972f,  0.059847972f }, { 0.0269973975f,  0.0269973975f, -0.0269973975f,  0.0269973975f } },
+        { { 0.124051278f, -0.059847972f, -0.059847972f,  0.059847972f }, { 0.0269973975f, -0.0269973975f, -0.0269973975f,  0.0269973975f } },
+        { { 0.124051278f, -0.059847972f, -0.059847972f, -0.059847972f }, { 0.0269973975f, -0.0269973975f, -0.0269973975f, -0.0269973975f } },
+        { { 0.124051278f,  0.059847972f, -0.059847972f, -0.059847972f }, { 0.0269973975f,  0.0269973975f, -0.0269973975f, -0.0269973975f } },
+        { { 0.078851598f,  0.000000000f, -0.070561967f,  0.000000000f }, { 0.0269973975f,  0.0000000000f, -0.0467610443f,  0.0000000000f } },
     };
 /* Change this to 2 for dual-band HRTF processing. May require a higher quality
  * band-splitter, or better calculation of the new IR length to deal with the
  * tail generated by the filter.
  */
-#define NUM_BANDS 1
+#define NUM_BANDS 2
     BandSplitter splitter;
     ALfloat temps[3][HRIR_LENGTH];
     ALuint lidx[14], ridx[14];