Making Sausage in Audioland

So here it is…a detailed report on the provenance of The Rolling Stones High Fidelity Pure Audio Blu-ray disc. I happened to notice it on a website while I was looking around for yesterday’s article on the conflict between advocates for “Pure Audio” Blu-ray discs…or I prefer to call them “half-baked Blu-rays” because they don’t include any video.

This is the production path for the Stones BD disc:

“DSD flat transferred from UK original analogue master tapes by Mick McKenna and Richard Whittaker at FX Copyroom, London, in 2011.

Edited in DSD by Masaru Takagi (SIProject) at Sunrise Studio, Tokyo in 2011.

176.4 kHz/24-bit transferred from DSD by Yumetoki Suzuki at Universal Music Studios, Tokyo, in 2013.

HR (High Resolution) cutting from 176.4 kHz/24-bit at Victor Creative Media, in 2013.”

Figure 1 – A description of the provenance of the Rolling Stones GRRR BD.

And here’s the description of the title from the UK Amazon site:

“This High Fidelity Pure Audio release contains all 50 tracks on one high capacity Blu-ray disc. Material is taken from original 24 bit master tapes and delivered in PCM, Dolby True HD and DTS audio formats – so you can enjoy the music in its purest form.”

Geez…no wonder it’s hard to figure out what’s going one with regards to the audio provenance. Let’s start by parsing the information from the website. It’s great that there are 50 tracks on a single Blu-ray disc…no problem there. But it then it says the tracks have been taken from the “original 24-bit master tapes”. I’m not sure what that actually means?

Analog tapes don’t have bits! They are analog not digital…and we know that analog tapes can provide about 10 bits of dynamic range (maybe more if they masters used noise reduction). I doubt whether the masters from the Rolling Stones used anywhere close to all 10 bits but let’s say the mastering engineer had that much to work with. But the site brags about the “original 24-bit master tapes”. If the information in the first quote above is accurate the analog tapes were transferred to DSD not to PCM as the Amazon information segment states.

A correct description of the provenance of the GRRR HFPABD (High Fidelity Pure Audio Blu-ray Disc) can be determined by reading the top quote.

The engineers at a London were supplied an analog master tape. We don’t know if it was the EQ’d master, the dupe master, the CD master or the flat master…and it does make a difference…a huge difference. It would be safe to assumed it was the CD master and went through the usual heavy handed mastering associated with commercial pop/rock records.

It was played back on an analog deck to DSD 64. We don’t know the type or condition of the analog machine and we don’t know the type or quality of the analog to DSD converters. Let’s give them the benefit of the doubt and say that the studio was well equipped.

The DSD 64 new digital master (which we know is very good in the 20-20 kHz “audio band” but full of noise above that) was then edited at a studio in Tokyo. That’s about all they could do with the new DSD master. Simple editing is possible but any additional processing is not…not without going into the world of PCM/DXD.

Then they transferred from the DSD 64 edited master to a 176.4 kHz/24-bit PCM file to use as the high-resolution audio file for high-resolution digital downloads. How they got to 96 or 192 kHz for the Pure Audio Blu-ray disc is not discussed.

This is where we are stuck.

To be continued…