Transformative Engineering Audio Injector Allows Signal Substitution in HDMI Path Transformative Engineering's HAI-1 Audio Injector is a patent-pending device that allows a user to substitute audio in an HDMI signal path.By RS Staff Published: September 29, 2015 ⋅ Updated: April 15, 2019 Transformative Engineering’s HAI-1 Audio Injector is a patent-pending device that allows a user to substitute audio in an HDMI signal path. Typical applications, according to the company, include injecting the center channel information so a TV’s speakers can be used as the center channel. The resulting effect eliminates the need for a separate center-channel speaker. Another use may be injecting a local microphone preamp signal in an educational or corporate environment to utilize the TV’s internal amplifier and speakers. This eliminates the need and cost of a separate amplifier, speakers, and installation. The HAI-1 has one HDMI input and one output, stereo RCA line-level inputs, and high-level speaker audio inputs. In center-channel applications, speaker input would be connected to an AV receiver’s center-channel output. The RCA jacks are used to inject line-level mono or stereo signals into the HDMI signal, and may be used to play independent audio sources such as a local microphone for narration or CD/MP3 player for background music through the TV’s audio system. The HAI-1 also has a USB port for firmware updates. SubscribeFor more stories like this, and to keep up to date with all our market leading news, features and analysis, sign up to our newsletter here.