24-bit / 96kHz Mastering
The dawn of a new era of sound quality
A lot of pain for not much gain?
24/96: Better Sound Quality
More channel bandwidth: Maybe to 44kHz
Or a more relaxed filter response:
Eliminate ‘pre-echo’ problems
More dynamic range: 142dB or even more!
The jury’s still out!
Echoes in Brick-Wall Filters
Probably the most significant artifact left in
high-quality 48kHz digital audio systems
Where Do We Need 24/96?
Recorded sources should be archived at the
best possible quality
Mastering-processing is best done at 96kHz;
Produced master should be archived in a form
independent of delivery medium
DVD, surround and what next?
Comparison with DSD
DSD: DR and/or BW limited by 2.8224MHz fs
24/96: >142dB DR, 44kHz BW if required
Delivery compatibility (low sampling rates):
DSD & 24/96: High quality re-sampling possible
Channel data bandwidth:
DSD: 2.8244 Mb/s, cannot be losslessly coded
24/96: 2.304Mb/s, halved by lossless coding
Comparison with DSD
Analogue source compatibility:
DSD: Available directly from 1-bit modulators
Difficult to obtain from complex modulators
24/96: Requires decimation filtering
DSD: Requires silicon-intensive and obscure
processing, unless converted to PCM
24/96: Can be processed by conventional DSPs
How Do We DO IT?
The equipment is not available
The standards aren’t established
Not even the interface!
Double-speed or ‘Split96’?
And what about channel status?
There’s no test equipment
And anyway, we’ve got to produce surround
material now; and that’s another problem
Data Converters for 24/96
All the old issues of quality are even more
important: linearity, dynamic range, jitter etc.
96kHz is only one converter parameter, but
threatens to overshadow all others
24bit is now a meaningless parameter
Compatibility: Interface formats, status etc.
Versatility: Variable filter parameters, multiple
sampling rates, rate conversion etc.
But all converters will soon be 24/96, won’t
Recorders - Many work as Split96, but don’t
have channels for surround working at 24/96
Routers - Most only work as Split96
Digital mixers - Easily upgradeable, Sir!
Workstations - Market leaders 24/96 capable
Sample rate converters - Existing types can’t
handle 96kHz and don’t have high-quality
If we need to re-equip for surround working,
we should do so with a channel format that is
24/96 should give us all the quality we need;
scientific listening tests are needed to be sure
24/96 may be a lot of pain for not much gain
unless quality bottlenecks are dealt with
24/96 is the best choice of ‘beyond reproach’
sound channel for the future