diff --git a/README.md b/README.md
index 0ce7ca8..f1b2e49 100644
--- a/README.md
+++ b/README.md
@@ -1,13 +1,13 @@
 # Piano
 
-This is a PHP extension to "play the piano" from PHP userland.
+This is a PHP extension to "play the piano" (beeps) from PHP userland.
 
-## How does it work
+## How does it work?
 
   - This only works on Linux.
   - This only works on PHP 7.
-  - This module uses the PC speaker, so make sure you have the Linux kernal module ```pcspkr``` loaded.
-  - This is not by default so check with ```lsmod``` and ```sudo insmod pcspkr``` if needed.
+  - This module uses the PC speaker, so make sure you have the Linux kernel module ```pcspkr``` loaded.
+  - This is not by default so check with ```lsmod``` and ``` sudo insmod /lib/modules/`uname -r`/kernel/drivers/input/misc/pcspkr.ko``` if needed.
   - Start php with sudo because we will try to write to ```/dev/console```.
 
 ## Build
diff --git a/piano.c b/piano.c
index 57665c0..ddee1da 100644
--- a/piano.c
+++ b/piano.c
@@ -34,7 +34,7 @@ ZEND_GET_MODULE(piano)
 
 /* Module init */
 PHP_MINIT_FUNCTION(piano) {
-    REGISTER_LONG_CONSTANT("PIANO_0",    1, CONST_CS | CONST_PERSISTENT);
+    REGISTER_LONG_CONSTANT("PIANO_0",    0, CONST_CS | CONST_PERSISTENT);
     REGISTER_LONG_CONSTANT("PIANO_C",  261, CONST_CS | CONST_PERSISTENT);
     REGISTER_LONG_CONSTANT("PIANO_D",  293, CONST_CS | CONST_PERSISTENT);
     REGISTER_LONG_CONSTANT("PIANO_E",  329, CONST_CS | CONST_PERSISTENT);
@@ -66,8 +66,12 @@ PHP_FUNCTION(play_piano) {
         exit(1);
     }
 
-    /* the PC uses a base rate of 1,193,180 Hz, generated by an oscillator chip */
-    ioctl(console_fd, KIOCSOUND, 1193180 / freq);
+    if (freq == 0) {
+        ioctl(console_fd, KIOCSOUND, 0);
+    } else {
+        /* the PC uses a base rate of 1,193,180 Hz, generated by an oscillator chip */
+        ioctl(console_fd, KIOCSOUND, 1193180 / freq);
+    }
     /* beep for given duration */
     usleep(ms * 1000);