SEGV in drumkv1_sample::ratio

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fffe85c4700 (LWP 29462)]
0x00007ffff72246d6 in drumkv1_sample::ratio (this=0x0) at drumkv1_sample.h:94
94                      { return m_ratio; }
(gdb) bt
#0  0x00007ffff72246d6 in drumkv1_sample::ratio (this=0x0) at drumkv1_sample.h:94
#1  0x00007ffff72247e6 in drumkv1_generator::next (this=0x68ab58, freq=73.4161987) at drumkv1_sample.h:162
#2  0x00007ffff72227db in drumkv1_impl::process (this=0x662d70, ins=0x7fffe85c38e0, outs=0x7fffe85c38c0, nframes=128) at drumkv1.cpp:1893
#3  0x00007ffff7223e2e in drumkv1::process (this=0x65b910, ins=0x7fffe85c38e0, outs=0x7fffe85c38c0, nframes=128) at drumkv1.cpp:2237
#4  0x000000000040a346 in drumkv1_jack::process (this=0x65b910, nframes=128) at drumkv1_jack.cpp:276
#5  0x0000000000409b44 in drumkv1_jack_process (nframes=128, arg=0x65b910) at drumkv1_jack.cpp:112
#6  0x00007ffff795ce2f in ?? () from /usr/lib/x86_64-linux-gnu/libjack.so.0
#7  0x00007ffff51a6064 in start_thread (arg=0x7fffe85c4700) at pthread_create.c:309
#8  0x00007ffff46b962d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111
(gdb)