Sound generally begins from a central point and then radiates equally outwards - it’s something we experience everyday. However, directional speakers seem to turn this idea on its head. Using new technologies, sound can form into a beam of energy that focuses audio across a space allowing one person to hear a sound while someone nearby hears (almost) nothing. For this article we will focus on the most innovative and relevant directional speakers that we have deployed in projects and tested in our studio.
Holosonics are flat panel speakers that use “ultrasonic waves” to focus a tight beam of sound towards a listener. The result is uncanny. There are other ultrasonic speakers companies but Holosonics have been around the longest and we have partnered with them on several projects in the past. The speakers are very effective, however it is important to note the audio quality has limited bandwidth using this technology. There is not much low end response so sounds are thin and trebly without much bass. This means it works exceptionally well for things like voice, but certain musical sounds will translate better than others. Overall Holosonics’ speakers are great for installs where a compact focused sound source is needed.
Using a matrix of hundreds of small speaker drivers, Holoplot's X1 speaker system offers a completely innovative method of creating focused beams of sound. To explore these speakers we teamed up with Holoplot and to create a mock floor plan that demonstrated how focused audio can be used for environmental audio design. By combining multiple X1 units you can create up to 12 steerable sound beams as well as define areas for more broad coverage of audio. The sound quality from these speakers is amazing, and the steerable sound beams are very effective. One thing to consider is that these speakers take up a bigger footprint than the Holosonics so they require larger spaces where they can be suitably installed.
Sonible sent us a test unit of their uniquespeaker to perform some experiments for possible experiential audio applications. The IKO speaker uses a completely different approach by placing a multi-faceted sphere of speakers in the center of a physical space. Using either direct or physical reflections of sound that bounce off of walls and ceiling surfaces, the IKO can create a sense of directionality. However, these speakers are better suited for creating immersive acoustic spaces as the sound beams they produce are less focused than the Holoplot and Holosonics speakers.
One thing to keep in mind for all directional speakers is that they are most effective in larger spaces, or in spaces with substantial background noise. The speakers are indeed directional but the focused beam can bounce around making the sound audible at a low volume level throughout the space. There are a lot of factors that can influence this and make the speakers more or less effective. Speaker positioning, room acoustics, and background noise in the space can be harnessed to make the speakers much more effective. If used correctly, directional speakers can add layers of focused audio experiences into a physical space in new and exciting ways.