Fluency in older readers

In the past few weeks I have been working closely with some fourth grade students that are struggling readers.  They have made some growth this year, but not near enough growth to bridge the gap.  They can't really comprehend what they are reading as they are still having difficulties decoding, therefore are having fluency difficulties.  Last year when some of my second grade students were having fluency difficulties I decided to break out the microphones.  I had them record some of their reading and then we would play back their passage, discussing what they felt they did well as a reader, and what they would like to work on.  This really seemed to help my younger readers and they began focusing more on their areas of difficulty.  I began to see some nice growth.  The fourth graders weren't as keen to read into a microphone and listen to their own reading.  I have used voki, as a method to engage them a little more.  I have used audacity for them to see the visual for when their voice breaks in the recording, and compare the length of first readings and second readings.  Any one have any other suggestions?