I purchased this Blu-ray and it presents a stellar performance by the band.
However, upon playing the disc, using the Dolby Digital 5.1 option setting, I noticed Ronnie James Dio's vocals came out of the Front Left and Right speaker channels (I'm using a 5.1 surround speaker system supplemented with a sub-woofer), but not the Centre speaker thus in fact giving a 4.1 surround sound mix. The surround sound mix in Blu-ray discs is normally calibrated so the main voice track will come out of the Centre speaker. Strangely, the sound comes out of the Centre speaker for the Eagle Rock introductory brand animation sequence and the similarly the voice track in all the bonus features on the disc comes out of the Centre speaker.
I contacted Eagle Rock and their production person in London confirmed that "4.1 audio is intentional - the audio was supplied mixed from the band."