narray not found by coreaudio, gem error Mac OSX

Question

I have installed coreAudio on my mac and I want to launch the outloop_sine.rb example:

ruby outloop_sine.rb

Then that return:

/usr/local/Cellar/ruby/2.1.1/lib/ruby/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:54:in `require': dlopen(/usr/local/Cellar/ruby/2.1.1/lib/ruby/gems/2.1.0/extensions/x86_64-darwin-13/2.1.0/narray-0.6.0.9/narray.bundle, 9): Library not loaded: /usr/local/opt/ruby/lib/libruby.2.1.0.dylib (LoadError)
  Referenced from: /usr/local/Cellar/ruby/2.1.1/lib/ruby/gems/2.1.0/extensions/x86_64-darwin-13/2.1.0/narray-0.6.0.9/narray.bundle
  Reason: image not found - /usr/local/Cellar/ruby/2.1.1/lib/ruby/gems/2.1.0/extensions/x86_64-darwin-13/2.1.0/narray-0.6.0.9/narray.bundle
    from /usr/local/Cellar/ruby/2.1.1/lib/ruby/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:54:in `require'
    from /usr/local/Cellar/ruby/2.1.1/lib/ruby/gems/2.1.0/gems/coreaudio-0.0.10/lib/coreaudio.rb:1:in `<top (required)>'
    from /usr/local/Cellar/ruby/2.1.1/lib/ruby/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:128:in `require'
    from /usr/local/Cellar/ruby/2.1.1/lib/ruby/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:128:in `rescue in require'
    from /usr/local/Cellar/ruby/2.1.1/lib/ruby/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:39:in `require'
    from outloop_sine.rb:1:in `<main>'

Then I install narray needed:

sudo gem install narray

That work but when I launch again the outloop_sine.rb example, the same error appear...

For your help:

ruby --version

ruby 2.1.1p76 (2014-02-24 revision 45161) [x86_64-darwin13.0]

and:

ls -l /usr/local/Cellar/ruby/2.1.1/lib/ruby/gems/2.1.0/extensions/x86_64-darwin-13/2.1.0/narray-0.6.0.9/

total 536
-rw-r--r--  1 root  admin       0  9 aoû 00:14 gem.build_complete
-rw-r--r--  1 root  admin    5441  9 aoû 00:14 gem_make.out
-rw-r--r--  1 root  admin    9883  9 aoû 00:14 mkmf.log
-rwxr-xr-x  1 root  admin  223684  9 aoû 00:04 narray.bundle
-rw-r--r--  1 root  admin    5104  9 aoû 00:04 narray.h
-rw-r--r--  1 root  admin     166  9 aoû 00:04 narray_config.h
-rw-r--r--  1 root  admin    7307  9 aoû 00:04 narray_ext.rb
-rw-r--r--  1 root  admin    5546  9 aoû 00:04 nmatrix.rb

and to conclude, I don't have libruby:

ls /usr/local/opt/ruby/lib/

ls: /usr/local/opt/ruby/lib/: No such file or directory

needed by the first error message:

Library not loaded: /usr/local/opt/ruby/lib/libruby.2.1.0.dylib (LoadError)

What's the problem of my coreAudio gem?