increase the buffer size for hardware mixing a bit

stepmania/src/arch/Sound/RageSoundDriver_DSound.cpp

@@ -23,7 +23,10 @@ RageSoundManager *SOUNDMAN = NULL;
 const int channels = 2;
 const int samplesize = 2 * channels; /* 16-bit */
 const int samplerate = 44100;
-const int buffersize_frames = 1024*8;	/* in frames */
+/* With this driver, we want a large buffer size.  Since latency is detached
+ * from write-ahead, this won't cause lag.  Since we're filling every playing
+ * sound buffer separately, a larger buffer here means less overhead. */
+const int buffersize_frames = 1024*16;	/* in frames */
 const int buffersize = buffersize_frames * samplesize; /* in bytes */
 
 const int num_chunks = 8;