This technical note compares the performance of Flora’s piezoelectric flat panel speaker to Bose SoundLink Revolve+ II Bluetooth speaker. To create the flat panel speaker, we attach two Dragonfly™ piezo exciters to the back side of a random ABS panel measuring approximately 24″ x 12″ x 0.24″. The Dragonfly™ units were powered by an off-the-shelf class AB audio amplifier Boss R1100M, and the output sound was recorded using a built-in microphone of a Canon DSLR camera placed 6ft away from the panel in an untreated listening room. The same sound tracks were played by the Bose speaker and recorded for comparison. We set the sound output level at 50% for both speakers, and all sound data are raw and unprocessed.
In addition, we measure sound pressure level (SPL) using an UMIK-1 microphone and REW software with 1/3 octave filters selected. It is noted that the SPL curve of the Dragonfly™ was equalized at the high frequency region (>5 kHz).
Conclusion
Although the SPL curves of the two speakers are similar, their sound characteristics differ. In our very subjective opinion, the Bose has better bass and a more boomer sound, and its soundstage is superior. This can be attributed to the fact that Bose’s cone has higher displacement and smaller size, while the Dragonfly™ has lower displacement but a much larger surface. However, the Dragonfly™ has better clarity, particularly for vocals, and a more transparent sound that doesn’t sound like it’s coming from a box. Its treble is also much clearer. In terms of directivity, both speakers perform well. The Bose seems to sound better with hip-hop and dance music, while the Dragonfly™ is better suited for pop, vocal, country, instrumental music, and news. Overall, both speakers are capable of providing high-quality and satisfying audio performance for listeners.
