<alter> (Semitones)

<measure number="11">
   <note>
      <pitch>
         <step>B</step>
         <alter>-2</alter>
         <octave>4</octave>
      </pitch>
      <duration>4</duration>
      <voice>1</voice>
      <type>eighth</type>
      <accidental>flat-flat</accidental>
      <stem default-y="-52">down</stem>
      <beam number="1">begin</beam>
   </note>
   <note>
      <pitch>
         <step>B</step>
         <alter>-1</alter>
         <octave>4</octave>
      </pitch>
      <duration>4</duration>
      <voice>1</voice>
      <type>eighth</type>
      <accidental>flat</accidental>
      <stem default-y="-52">down</stem>
      <beam number="1">continue</beam>
   </note>
   <note>
      <pitch>
         <step>B</step>
         <octave>4</octave>
      </pitch>
      <duration>4</duration>
      <voice>1</voice>
      <type>eighth</type>
      <accidental>natural</accidental>
      <stem default-y="-52">down</stem>
      <beam number="1">continue</beam>
   </note>
   <note>
      <pitch>
         <step>B</step>
         <alter>1</alter>
         <octave>4</octave>
      </pitch>
      <duration>4</duration>
      <voice>1</voice>
      <type>eighth</type>
      <accidental>sharp</accidental>
      <stem default-y="-52">down</stem>
      <beam number="1">end</beam>
   </note>
   <note>
      <pitch>
         <step>B</step>
         <alter>2</alter>
         <octave>4</octave>
      </pitch>
      <duration>8</duration>
      <voice>1</voice>
      <type>quarter</type>
      <accidental>double-sharp</accidental>
      <stem default-y="-55">down</stem>
   </note>
</measure>