replaygain uses the "gain" effect instead of "vol"

The `gain' effect seems superior as it can "see" across the effects
chain to take into account extra/lost headroom.

For example, this allows me to add the the "gain -h" effect at the
start of my effects chain before the RGFX placeholder in my source
command, so when I play a file requiring a -6dB ReplayGain adjustment,
I will only need an additional -4dB of headroom to accomodate the
10dB boost at 20Hz I use (for listening through headphones):

Before:
  RGFX='vol -6dB'
  sox "$INFILE" $SOXFMT - $TRIMFX $RGFX vol -10dB equalizer 20 0.7071q 10

After:
  RGFX='gain -6'
  sox "$INFILE" $SOXFMT - $TRIMFX gain -h $RGFX equalizer 20 0.7071q 10

1 files changed, 6 insertions, 4 deletions

diff --git a/test/test_rg_integration.rb b/test/test_rg_integration.rb
index f8e81c2..efc8f97 100644
--- a/test/test_rg_integration.rb
+++ b/test/test_rg_integration.rb
@@ -1,8 +1,10 @@
 # Copyright (C) 2013-2015 all contributors <dtas-all@nongnu.org>
 # License: GPLv3 or later (https://www.gnu.org/licenses/gpl-3.0.txt)
 require './test/player_integration'
+require 'dtas/util'
 class TestRgIntegration < Testcase
   include PlayerIntegration
+  include DTAS::Util
 
   def tmp_pluck(len = 5)
     pluck = Tempfile.open(%w(pluck .flac))
@@ -58,10 +60,10 @@ class TestRgIntegration < Testcase
       assert_match expect, cur["current"]["env"]["RGFX"]
     end
 
-    check_gain.call(%r{vol -3dB}, "album_gain")
-    check_gain.call(%r{vol -2dB}, "track_gain")
-    check_gain.call(%r{vol 1\.3}, "track_peak")
-    check_gain.call(%r{vol 1\.0}, "album_peak")
+    check_gain.call(%r{gain -3}, "album_gain")
+    check_gain.call(%r{gain -2}, "track_gain")
+    check_gain.call(%r{gain 0\.0}, "album_peak")
+    check_gain.call(%r{gain 2\.5}, "track_peak")
 
     s.req_ok("rg preamp+=1")
     rg = YAML.load(yaml = s.req("rg"))