diff --git a/src/sfizz/Regexes.h b/src/sfizz/Regexes.h
index de323bb5..950ef3b3 100644
--- a/src/sfizz/Regexes.h
+++ b/src/sfizz/Regexes.h
@@ -5,7 +5,7 @@ namespace sfz
 namespace Regexes 
 {
 	static std::regex includes { R"V(#include\s*"(.*?)".*$)V", std::regex::optimize };
-	static std::regex defines { R"(#define\s*(\$[a-zA-Z0-9]+)\s+([a-zA-Z0-9]+)(?=\s|$))", std::regex::optimize };
+	static std::regex defines { R"(#define\s*(\$[a-zA-Z0-9_]+)\s+([a-zA-Z0-9-]+)(?=\s|$))", std::regex::optimize };
 	static std::regex headers { R"(<(.*?)>(.*?)(?=<|$))", std::regex::optimize };
 	static std::regex members { R"(([a-zA-Z0-9_]+)=([a-zA-Z0-9-_#.&\/\s\\\(\),\*]+)(?![a-zA-Z0-9_]*=))", std::regex::optimize };
 	static std::regex opcodeParameters { R"(([a-zA-Z0-9_]+?)([0-9]+)$)", std::regex::optimize };
diff --git a/tests/FilesT.cpp b/tests/FilesT.cpp
index 59a4522e..1a0e3179 100644
--- a/tests/FilesT.cpp
+++ b/tests/FilesT.cpp
@@ -127,10 +127,11 @@ TEST_CASE("[Files] Define test")
 {
     sfz::Synth synth;
     synth.loadSfzFile(fs::current_path() / "tests/TestFiles/defines.sfz");
-    REQUIRE(synth.getNumRegions() == 3);
+    REQUIRE(synth.getNumRegions() == 4);
     REQUIRE(synth.getRegionView(0)->keyRange == sfz::Range<uint8_t>(36, 36));
     REQUIRE(synth.getRegionView(1)->keyRange == sfz::Range<uint8_t>(38, 38));
     REQUIRE(synth.getRegionView(2)->keyRange == sfz::Range<uint8_t>(42, 42));
+    REQUIRE(synth.getRegionView(3)->volume == -12.0f);
 }
 
 TEST_CASE("[Files] Group from AVL")
diff --git a/tests/RegexT.cpp b/tests/RegexT.cpp
index 836c7637..d8dcaabd 100644
--- a/tests/RegexT.cpp
+++ b/tests/RegexT.cpp
@@ -22,6 +22,7 @@
 // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include "Regexes.h"
+#include <iostream>
 #include "catch2/catch.hpp"
 using namespace Catch::literals;
 
@@ -29,6 +30,8 @@ void includeTest(const std::string& line, const std::string& fileName)
 {
     std::smatch includeMatch;
     auto found = std::regex_search(line, includeMatch, sfz::Regexes::includes);
+    if (!found)
+        std::cerr << "Define test failed: " << line << '\n';
     REQUIRE(found);
     REQUIRE(includeMatch[1] == fileName);
 }
@@ -70,6 +73,9 @@ TEST_CASE("[Regex] #define")
     defineTest("#define $alphanum asr1t44", "$alphanum", "asr1t44");
     defineTest("#define  $whitespace   asr1t44   ", "$whitespace", "asr1t44");
     defineTest("#define $lazyMatching  matched  bfasd ", "$lazyMatching", "matched");
+    defineTest("#define $stircut  -12", "$stircut", "-12");
+    defineTest("#define $_ht_under_score_  3fd", "$_ht_under_score_", "3fd");
+    defineTest("#define $ht_under_score  3fd", "$ht_under_score", "3fd");
     defineFail("#define $symbols# 1");
     defineFail("#define $symbolsAgain $1");
     defineFail("#define $trailingSymbols 1$");
diff --git a/tests/TestFiles/defines.sfz b/tests/TestFiles/defines.sfz
index 81e5aa56..b1fb159f 100644
--- a/tests/TestFiles/defines.sfz
+++ b/tests/TestFiles/defines.sfz
@@ -2,7 +2,9 @@
 #define $KICKKEY 36
 #define $SNAREKEY 38
 #define $HATKEY 42
+#define $vol_db -12
 
 <region>key=$KICKKEY sample=kick.wav
 <region>key=$SNAREKEY sample=snare.wav
-<region>key=$HATKEY sample=closedhat.wav
\ No newline at end of file
+<region>key=$HATKEY sample=closedhat.wav
+<region>volume=$vol_db sample=*sine
\ No newline at end of file