diff --git a/app/src/main/cpp/sox/CmakeLists.txt b/app/src/main/cpp/sox/CmakeLists.txt
index 4b18b01..3135cd9 100644
--- a/app/src/main/cpp/sox/CmakeLists.txt
+++ b/app/src/main/cpp/sox/CmakeLists.txt
@@ -97,7 +97,6 @@ set(formats_srcs
         g723_40.c
         g72x.c
         g72x.h
-        htk.c
         ima-fmt.c
         ima_rw.h
         ima_rw.c
diff --git a/app/src/main/cpp/sox/formats.h b/app/src/main/cpp/sox/formats.h
index da45a11..cba5b09 100644
--- a/app/src/main/cpp/sox/formats.h
+++ b/app/src/main/cpp/sox/formats.h
@@ -31,7 +31,7 @@
   FORMAT(f8)
 //  FORMAT(gsrt)
 //  FORMAT(hcom)
-  FORMAT(htk)
+//  FORMAT(htk)
   FORMAT(ima)
   FORMAT(la)
   FORMAT(lu)
diff --git a/app/src/main/cpp/sox/htk.c b/app/src/main/cpp/sox/htk.c
deleted file mode 100644
index 6390616..0000000
--- a/app/src/main/cpp/sox/htk.c
+++ /dev/null
@@ -1,80 +0,0 @@
-/* libSoX file format: HTK   (c) 2008 robs@users.sourceforge.net
- *
- * See http://labrosa.ee.columbia.edu/doc/HTKBook21/HTKBook.html
- *
- * This library is free software; you can redistribute it and/or modify it
- * under the terms of the GNU Lesser General Public License as published by
- * the Free Software Foundation; either version 2.1 of the License, or (at
- * your option) any later version.
- *
- * This library is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser
- * General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public License
- * along with this library; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
- */
-
-#include "sox_i.h"
-
-typedef enum {
-  Waveform, Lpc, Lprefc, Lpcepstra, Lpdelcep, Irefc,
-  Mfcc, Fbank, Melspec, User, Discrete, Unknown} kind_t;
-static char const * const str[] = {
-  "Sampled waveform", "Linear prediction filter", "Linear prediction",
-  "LPC cepstral", "LPC cepstra plus delta", "LPC reflection coef in",
-  "Mel-frequency cepstral", "Log mel-filter bank", "Linear mel-filter bank",
-  "User defined sample", "Vector quantised data", "Unknown"};
-
-static int start_read(sox_format_t * ft)
-{
-  uint32_t period_100ns, num_samples;
-  uint16_t bytes_per_sample, parmKind;
-
-  if (lsx_readdw(ft, &num_samples     ) ||
-      lsx_readdw(ft, &period_100ns    ) ||
-      lsx_readw (ft, &bytes_per_sample) ||
-      lsx_readw (ft, &parmKind        )) return SOX_EOF;
-  if (parmKind != Waveform) {
-    int n = min(parmKind & 077, Unknown);
-    lsx_fail_errno(ft, SOX_EFMT, "unsupported HTK type `%s' (0%o)", str[n], parmKind);
-    return SOX_EOF;
-  }
-  return lsx_check_read_params(ft, 1, 1e7 / period_100ns, SOX_ENCODING_SIGN2,
-      (unsigned)bytes_per_sample << 3, (uint64_t)num_samples, sox_true);
-}
-
-static int write_header(sox_format_t * ft)
-{
-  double period_100ns = 1e7 / ft->signal.rate;
-  uint64_t len = ft->olength? ft->olength:ft->signal.length;
-
-  if (len > UINT_MAX)
-  {
-    lsx_warn("length greater than 32 bits - cannot fit actual length in header");
-    len = UINT_MAX;
-  }
-  if (!ft->olength && floor(period_100ns) != period_100ns)
-    lsx_warn("rounding sample period %f (x 100ns) to nearest integer", period_100ns);
-  return lsx_writedw(ft, (unsigned)len)
-      || lsx_writedw(ft, (unsigned)(period_100ns + .5))
-      || lsx_writew(ft, ft->encoding.bits_per_sample >> 3)
-      || lsx_writew(ft, Waveform) ? SOX_EOF : SOX_SUCCESS;
-}
-
-LSX_FORMAT_HANDLER(htk)
-{
-  static char const * const names[] = {"htk", NULL};
-  static unsigned const write_encodings[] = {SOX_ENCODING_SIGN2, 16, 0, 0};
-  static sox_format_handler_t handler = {
-    SOX_LIB_VERSION_CODE,
-    "PCM format used for Hidden Markov Model speech processing",
-    names, SOX_FILE_BIG_END | SOX_FILE_MONO | SOX_FILE_REWIND,
-    start_read, lsx_rawread, NULL,
-    write_header, lsx_rawwrite, NULL,
-    lsx_rawseek, write_encodings, NULL, 0
-  };
-  return &handler;
-}