AES Cincinnati, in coordination with Sonic Arts and the Corbett Studio (an audio recording and production facility of Cincinnati Public Radio), recently conducted a listening test for cross-compatibility of different surround sound encoding/decoding solutions proposed for HD Radio. Equipment used to encode and decode selected cross-genre audio samples was provided by Neural Audio, Dolby Laboratories and SRS Labs for tests run on September 9 and 10. The mission of the critical listening test was to objectively determine if any issues with cross-compatibility exist among the represented manufacturer's surround sound encoding/decoding systems. The specific systems under test were the Neural Audio 5225 Upmix and Downmix, Dolby DP563/564 using Dolby Pro Logic II and SRS Labs Circle Surround Digital encoder/decoders.
To insure objective results, the test was overseen by principals from NPR and AES Cincinnati. Audio selections were auditioned in calibrated 5.1 mix rooms at Sonic Arts. Each listening test session lasted from 60 to 90 minutes, with participants monitoring 16 music selections encoded as a Reference sample, an A sample and a B sample without knowing which encoder/decoder hardware was used to create them. As part of the test, the participants were asked to note overall satisfaction with the sound quality, audio imaging and sound field placement of each audio sample, as well as the observed difference between the Reference, A, and B samples.
Event organizer and sponsor Alex Kosiorek from the Corbett Studio says that, “The Cincinnati Chapter of the Audio Engineer Society was requested to initiate this test to determine the cross compatibility of various surround sound encode/decode solutions for broadcast applications. The results from this test will help further the understanding of the cross-compatibility of composite surround sound systems proposed for digital and various analog broadcast methods. The results will also shape future testing if and when that is needed."
Event host and president of Sonic Arts John McDaniel commented that "It was very interesting to get a glimpse of the possibilities of surround for HD radio. Our engineers put a lot of effort into the test setup; tweaking speaker angles and placement down to the ¼-inch. We all enjoyed hosting the event."
Dan Scherbarth, AES Cincinnati chairman and owner of dawstore.com adds that, "This critical listening test highlights the interest level and commitment of our members and other regional audio pros for the future of HD Radio in surround. We had participants from as far as Northern Ohio, ranging from professional mixers experienced in surround to musicians and many levels in between. An incredible amount of work from everyone involved provided objective and valuable input to the HD Radio community and made the test a rousing success!"