Below are 2 EPs recorded using commercially available piezoelectric contact microphones for my MFA thesis "Piezoelectric Microphones: Creative Applications of Lo-Fi Transducers" at Middle Tennessee State University. 

The "Utopia" EP by Christian Sager is an experimental/electronic exploration of the capabilities of piezo contact mics where all tracks (including vox) are recorded through piezoelectric microphones. "The Prelude" EP by Laura Short is an extrapolation of the experimental recording techniques into pop genres to assess viability of the piezoelectric contact microphone within commercial studio recordings.

The full scope of the project also involved some technical and material property characterization via impedance/capacitance testing, ESEM imaging, acoustic microscope imaging, SMAART Analysis, as well as EDS characterization. The following is the abstract from the final draft of the thesis: 

"The Curie’s discovery of the piezoelectric effect in 1880 led to the development of new transducer technologies that would become a staple in the recording industry between the 1930s and the 1960s. During this time period the marketplace became saturated with piezoelectric microphones, but the introduction of low-cost dynamic and electret aeroacoustic microphones quickly proved to be a preferable alternative. After the introduction of these aeroacoustic microphones, the piezoelectric was phased out of microphone manufacture due to inherent deviations from the technical and sonic qualities of aeroacoustic transducers. An analysis of these characteristics provides solutions for common user difficulties and reveals certain advantages in piezoelectric selection over aeroacoustic selection for both live and studio recording situations. Still an economical alternative to the traditional aeroacoustic microphone, music producers, recording engineers, and artists may elect to utilize a piezoelectric microphone to impart textures in their works, or may also attempt a more traditional recording approach. Both use of piezoelectric microphones with the traditional production approach as well as the experimental production approach are presented in a collection of musical works recorded using solely commercially available piezoelectric microphones.  A sonic library from which a potential user may reference sonic characteristics is also presented. In tandem with the sonic library, a user guide and generated specification sheet catalogue is offered to aid a user with recording techniques and provide technical data on commercially available piezoelectric transducers that is not readily available."

If you would like to read more on how these EPs were recorded and/or the results of any of the tests feel free to contact me and I can send you the full thesis paper.