Apogee AD-16X User manual

Apogee’s Symphony
system aims to bring
professional hardware to
users who want to work
with native digital audio
workstations on a Mac,
whether they’re in the
studio with a Mac Pro or
on the road with
a Macbook Pro.
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134
on test
computer
recording system
Mark Wherry
As computers have become more
powerful over the last few years,
especially with the introduction of
multi-core processors, it really has become
possible to do all of your audio processing,
recording, mixing, and playing virtual
instruments on one system, without the aid
of external processing power. Accordingly,
the market for higher-quality audio
hardware to be used with computer-based
workstations has grown tremendously,
although many of the products available are
targeted at home or project-level situations
rather than the demanding professional.
And by using the word ‘professional I m
talking about those who require a large
number of inputs and outputs (32 or more)
with high-quality analogue converters at
very low latency — and are willing to pay
for such a system.
It used to be that higher-end users
would buy Digidesign s Pro Tools system,
although often not necessarily for the Pro
Tools software itself. While many popular
products from developers such as MOTU,
Opcode and Steinberg supported Digidesign
hardware directly at one time or another,
perhaps the most popular example is the
way in which pro Logic users would run
Logic as front-end software for the Pro
Tools hardware. And although it s still
possible to use Pro Tools hardware in
conjunction with Logic, from my own
experience this seems to be a far less
desirable workflow than it was several
years ago.
Other than Pro Tools, if you need a large
number of inputs and outputs (Pro Tools
currently supports up to 160 inputs and
outputs) for a Mac-based audio workstation,
with low latency and quality converters, but
want to stay within the world of your
workstation s native abilities, there haven t
Apogee Symphony
pros
• Achieves very low latency while maintaining
native compatibility with Core Audio.
• Apogee’s converters are among the best
available.
• The VBus channel routing adds a feature that’s
sorely missing in many native audio
workstations.
• Symphony Mobile provides all the functionality
of a single Symphony PCI card.
cons
• If you want to take advantage of the Symphony
system’s feature set, but require more digital I/O
instead of high-quality analogue converters,
having to buy Apogee’s converters can work out
expensive.
• Fully understanding how all the parts of the
Symphony system work together can take a bit
of time.
summary
Apogee’s Symphony is an impressive system that
truly brings professional-quality audio converters,
combined with good performance and low
latency, to Core Audio-based applications on both
desktop and mobile platforms.
Apogee Symphony
Audio Interface System

been too many options. Planning to address
this need, Apogee, a respected
manufacturer of high-end audio converters,
realised that they already had half of the
solution: the converters. Since the
company s latest converters already had the
option of accommodating an expansion
card that would allow them to connect
directly to a Pro Tools system, it seemed
logical to create a system that would make
it possible to integrate Apogee converters
with native audio software instead. And
that s exactly what Apogee have done.
First Movement
Symphony is the name given to a number of
Apogee products used together to create
one system for high-quality, low-latency
audio input and output, designed
exclusively for Mac users — there s no
Windows version, and Apogee apparently
have no plans to release one either. The
heart of the Symphony system is the
Symphony PCI card, which has been
available in PCI Express (PCIe) and PCI
Extended (PCI-X) formats since last year.
Apogee also recently introduced a mobile
version (dubbed Symphony Mobile) that
plugs into the Express Card slot on
a Macbook Pro.
Each Symphony card
supports up to 32 channels
of input and 32 channels
of output
simultaneously,
and it s possible
to install up
to three
september 2007 • www.soundonsound.com 135
When the Symphony Mobile card is inserted in the
Macbook Pro, you’ll see this icon appear in the menu
bar. The pop-up menu provides a power-off option
that should be used before e ecting the card from the
system.
Symphony cards in your Mac, for a
maximum of 96 inputs and 96
outputs. Since a Macbook Pro only has
one Express Card slot, you can only
use one Symphony Mobile card in it,
for a maximum of 32 inputs and 32
outputs.
Installing the PCIe or PCI-X cards
inside a Mac Pro or older Power Mac
(you ll need at least a G5 to handle
Symphony) is fairly easy. As is usually
the case with PCI cards, Apogee
recommend that the first Symphony
card be installed in the
lowest-numbered slot available
(usually this will be as close to the
graphics card as possible), and if
you re installing additional cards,
these should be placed in adjacent
slots. The only thing to be aware of is
that each Symphony card has a set of
onboard jumpers that need to be
configured according to how many
cards you re going to use.
The first card doesn t require any
jumpers and Apogee supply each
Symphony card with the jumper
attached to only the first pin, for
safekeeping — so if you re only using
one Symphony card there s nothing to
worry about. However, if you re
installing a second or third card you ll
need to make sure the jumper is
configured uniquely for each card, as
described in the manual. While the
jumper configuration isn t a big deal,
it does seem a shame that a more
automatic method of configuration
couldn t be found, although
you ll probably only
have to worry
about
it once.
Finally, as
with other
multi-card PCI
audio systems,
there s a ribbon
cable that tethers
together all the
Symphony cards in the
system.
Symphony Mobile is, of
course, slightly easier to install:
simply insert the card into the
Express Card slot on your MacBook
Pro. An Express Card icon will appear
in the menu bar, and if you want to
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▲
eject the card you need to choose the
‘Power off Card option first, from the
Express Card icon s pop-up menu, before
removing the card from the slot.
This was the first time I d used an
Express Card with my Macbook Pro, and
I was surprised at just how ineffective
Apple s spring-latch was for keeping the
Express Card in the slot. As you insert the
card you feel the spring-latch engage, but it
requires very little effort for the card to be
pulled from the slot without disengaging
the latch. To remove the card, you re
supposed to push it in again, to unlatch the
spring that releases the card, but again
I found it too easy to pull the card from the
slot without having to unlatch the spring.
You have to be careful when plugging in the
PC32 cable that connects the Symphony
Mobile card to your converters, since the
pressure of plugging in the cable will easily
unlatch the card. For this reason, you might
want to connect the lead to the card before
inserting it into your Macbook Pro.
This small criticism isn t Apogee s fault,
of course, but it is something to be aware
of when using Express Cards with
a Macbook Pro. Apogee do supply a little
rubber foot that can be attached to the
bottom of the card, to hold it in place and
prevent the weight of the cable pulling
down on the card in the slot.
‘X’ Marks The Converter
The Symphony PCI card can be used with
any of Apogee s converters that support
X-Series expansion cards, including the
AD16X and DA16X converters (which, as
their names suggest, offer 16 channels of
analogue-to-digital and digital-to-analogue
conversion respectively) and the Rosetta
800 and 200 (which give you either eight
channels of A-D and D-A conversion or
two). The really nice aspect of having
a choice of converters
available is that you
can also mix and
match them in a single
system, meaning that
you can start off with
a Rosetta 800 and one
Symphony card (giving you
eight ins and eight outs), and
later add either additional Rosetta
800s or AD16s or DA16s, as your
budget allows. For the review,
Apogee provided me with two AD16Xs
and two DA16Xs, details of which are
given in the box above. (Hugh Robjohns
has previously reviewed the Rosetta
converters; see the ‘Apogee Reviews in SOS
box for more information.)
The only down side to the X-Series
expansion cards is that you do have to buy
them separately and install them yourself,
although this is really simple and Apogee
provide clear and nicely illustrated
instructions. While on the subject of
instructions, all of Apogee s products are
supplied with good printed documentation
that s well written and provides plenty of
illustrations (PDF versions can be
downloaded from Apogee s web site), which
is always a pleasant surprise.
Once you ve installed the Symphony PCI
card (or cards) in your computer, the
X-Symphony cards in your converters, and
Apogee s supplied driver software on your
computer, it s time to wire everything up. If
you ve ever worked with a Pro Tools
system, wiring up a Symphony system is
pretty much the same, and very easy
to do. Each Symphony card has a
PC32 connector, and each X-
Symphony card has two PC32
connectors, marked Main and
Thru; so to connect your
first converter to the
Symphony system,
connect a PC32 cable
from the first
Symphony PCI card
to the Main PC32 connector on the
X-Symphony card of the converter.
Additional converters can be
daisy-chained from the first, via the Thru
PC32 connector, and you can keep on
daisy-chaining converters in this way until
you reach the maximum of 32 input and 32
output channels supported by the Symphony
PCI card to which all of the converters are
attached. To connect additional converters,
you would move onto the second or third
Symphony PCI cards in your system and
repeat the process until you d connected
on test
computer
recording system
APOGEE SYMPHONY
Maestro (see overleaf for details) provides access to the two hardware mixers on each Symphony PCI card that allow you to create low-latency monitor mixes when recording.
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enough I/O channels to cover the supported
96 inputs and 96 outputs.
If you have a master clock in your
system (such as Apogee s own Big Ben), you
can obviously slave all of the converters to
that clock. However, if you don t have
a master clock you can use the first
converter as your master, and slave the
other converters by connecting the
word-clock output from the first converter
to the word-clock input of the additional
converters, using T-connectors and
terminating after the last one. As a rule of
thumb, if the converters in use in the
Symphony system are the only digital
devices in your studio requiring a clock
input, using the first converter as the
master will be absolutely fine; but if you re
going to be connecting other devices, via
a digital interface, to your converters, such
as an effects unit or the output from
another computer s soundcard, it would
definitely be worth investing in a master
clock to avoid potential problems.
If You Please, Maestro
Apogee supply both a Core Audio driver
and a software application called Maestro
that allows you to configure the Symphony
system and make use of the onboard
routing and mixing features on the
Symphony PCI card itself. The Maestro
software consists of two windows:
a Settings window that allows you to
configure the Symphony PCI card and
attached converters, and a Routing/Mixer
window that lets you assign which
hardware inputs and outputs are routed to
the Core Audio inputs and outputs.
The routing part of the Routing/Mixer
window is laid out in a familiar-looking grid,
and by default hardware channel one is
routed to software channel one, hardware
channel two is routed to software channel
two, and so on. There are separate pages
for Input and Output, and if you re used to
the I/O Setup window in Pro Tools the
Maestro Input and Output pages feel a little
bit quirky initially, but provide mostly the
same functionality. Channels have a stereo
mode where pairs of outputs are moved
together, although you can also ungroup
these pairs to assign mono channels
individually. However, instead of dragging
the channel routing elements around, you
click where you want them to go. One thing
that would be nice in the Outputs page of
Maestro would be the ability to route
a software output to more than one
hardware output, as you can with RME s
Total Mix system.
The Mixer page provides access to the
two hardware monitor mixers available on
each Symphony PCI card, which allow you
to create latency-free monitor mixes when
recording. Each mixer allows you to set
how much of the input signals are sent to
a mix output of your choosing, and you
also have the option to blend in a stereo
output from your audio workstation
software as well. Because these mixers are
provided on the Symphony PCI card, you
can route inputs from one converter to
outputs on another, so long as both
converters are attached to the same card. If
you re using multiple Symphony cards, you
can t route inputs from a converter attached
to one card to the outputs of a converter
attached to a different card. This is perhaps
a shame, but one of the goals of Symphony
is, of course, to allow you to work with
your audio workstation at low latencies,
which means you might be able to create
your monitor mixes from within software
like Logic Pro, enabling you to route
anything anywhere.
One of the neatest parts of the whole
Symphony system is the VBus channels that
allow you to route audio channels within
the Symphony card itself. This can be pretty
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APOGEE SYMPHONY
Released in 2004, the AD16X and DA16X were the successors to Apogee’s
previously popular 24-bit AD16 and DA16 converters, with the ‘X’ in the
names denoting support for the X-Series cards that were originally introduced
for the Rosetta 800. Other significant improvements included support for
192kHz sampling and the inclusion of the same C777 clock technology used
in Apogee’s Big Ben digital master clock, famous for its low jitter.
The AD16X and DA16X each support either 16 channels of A-D or D-A
conversion, respectively, and, accordingly, each unit has 16 analogue
connections (from two 25-pin D-connectors that require breakout cables),
along with both ADAT and AES connections (the latter via a 25-pin
D-connector). Each converter has four ADAT ports (only two are used at
44.1/48kHz rates) to support S/MUX (sample multiplex) modes that allow
either 16 channels at 88.2/96kHz or eight channels at 192kHz. To allow all
16-channels of A-D or D-A conversion to operate at 192kHz you either need to
use the AES ports in stand-alone mode, or an X-Series card, such as an
X-Symphony, as described in the main text.
Once you use an AD16X or DA16X with an X-Series card, the
digital ports effectively become redundant, because either the
digital input to or output from the converter will being handled by
the X-series card instead of the converter’s own digital interface. To
take advantage of this redundancy, Apogee added an extra mode of
operation to the converters, called Advanced mode — the regular,
default mode is referred to as Standard mode — that allows you to
make use of both the digital and analogue connections simultaneously when
the converter is using an X-Series card. With the AD16X, for example, you can
get 16 channels of A-D (input) conversion, and 16 channels of digital output
via the onboard digital connections. With the DA16X you get 16 channels of
D-A (output) conversion with 16 channels of digital input.
As you can imagine, Advanced mode is pretty useful when these converters
form part of a Symphony system; if you don’t require analogue input and
output for every channel in the system, using the AD16X and DA16X
converters in Advanced mode provides a number of digital inputs or outputs
for connecting to other digital devices in your studio. It also means you need
fewer converters. In Standard mode each converter provides either
16 channels of input or 16 channels of output, so four converters (two
AD16Xs and two DA16Xs) are required to handle the 32 channels of input and
output supported by a single Symphony PCI card. In Advanced mode, however,
because each converter now offers both 16 channels of input and 16 channels
of output, only two converters are required to provide 32 channels of input
and output.
Sonically, the AD16 and DA16 converters are, as you would imagine and
hope given Apogee’s pedigree, pretty good. Judging A-D and D-A converters is
always highly subjective, especially at the higher end of the market, and
having listened to many converter shoot-outs over the years, one thing you
notice about high-end converters is that, quite honestly, the differences
between competing units can be very small indeed. Personally, I’ve found the
AD16 gives a certain clarity to the sound that I like, especially at higher
sampling rates, maintaining the detail of what’s being recorded in a very
flattering way.
Talking about the high end of the market, it’s worth noting that the AD16
and DA16 converters are priced quite affordably compared to far more
expensive models from companies like Prism and Genex, and many engineers
I know prefer the AD16s to more expensive offerings from other companies.
A friend of mine recently did a blind test on a scoring stage with the AD16s
competing against more expensive converters from another reputable
company, and everyone on the stage apparently preferred the Apogees. While
the quality of converters can be highly subjective, and other engineers may
disagree with my assessment and anecdotes, that the AD16 and DA16s fall
into the category where we can discuss them subjectively rather than
technically is perhaps the highest compliment.
The AD16X & DA16X Converters
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useful, since one of the big limitations of
the mixer found in many native
workstations, such as Logic Pro and Cubase
or Nuendo, is that it s impossible to route
the output of a bus or group to the input of
an audio track. There are many situations
where you would want to do this; for
example, in the media world it s quite
common to submit your final mix as
a series of so-called ‘stems , where, instead
of supplying the whole mix as one stereo
file, you provide a number of stereo mixes
for the different groups that make up the
track. While it s possible to do this in any
program, by using the bounce or export
feature to record each stem one pass at
a time, with a more flexible bussing system
you can create all of your stems in a single
pass. Apogee s VBus channels give you
exactly this feature.
Each Symphony card provides up to 32
VBus channels that show up as additional
physical audio inputs and outputs in your
audio workstation. And because the VBus
channels are part of the Core Audio driver,
you can easily use them to route audio
between different applications as well,
which could be useful. Logic users might
want to switch to the driver s own I/O label
via the Audio Configuration window, so the
VBus channels can easily be differentiated
from the actual hardware inputs and
outputs on the converters.
Perhaps the best thing about the VBus
channels is that it s possible to make
a sample-accurate recording from the ouput
of one track to the input of another. I tested
this in Logic Pro, recording the output of
a mono track via a VBus to the input of
another mono track; and when I looked at
both recordings in Logic s Sample Editor
window (see the diagram above) both audio
files started at exactly the same sample.
How Low Can You Go
One of Apogee s big claims for the
Symphony system is its performance,
especially with regard to latency. To test
this, I used Logic Pro 7.2.3 with
a Symphony system installed in a Mac Pro
(featuring two dual-core 3GHz processors,
3GB memory, and a 500GB SATA-II drive)
and also with a Symphony Mobile system
on a first-generation Macbook Pro (with
a 2.16GHz Core Duo processor, 2GB
memory and a 100GB, 7200rpm drive). The
test was kept fairly simple: I created 32
mono audio tracks and used Activity
Monitor to measure Logic s CPU usage when
all 32 tracks were enabled, and then when
all 32 tracks were in record. It should be
noted that the Mac Pro percentages should
be read on the assumption that 400 percent
is the theoretical maximum performance
achievable, while 200 percent is the
maximum for the Macbook Pro (100 percent
represents the theoretical maximum of one
processing core).
With the Mac Pro, Logic usage was 13
percent when the tracks were record
enabled and 20 percent during recording.
On the Macbook Pro, Logic usage was 26
percent when the tracks were enabled and
29 percent when recording. I repeated the
same test with larger buffer sizes (and thus
greater latencies), but I ve put these figures
in a separate chart, so as not to fill up
a paragraph with tedious numbers.
By way of a comparison, I tried the same
test with a Fireface 800, to see how Logic s
CPU load compared. Admittedly, this isn t
a technically fair comparison on the Mac
Pro, since one system is PCI-based and the
other Firewire, but at the time of writing
I didn t have access to any other PCIe audio
cards (except for Pro Tools) to make the
test more fair. The other caveat in the
comparison is that the Fireface has
a maximum of 28 inputs at 44.1kHz, so the
four-channel difference should also be
considered.
Using the Fireface
800 with a 32-sample
buffer on the Mac Pro,
Logic reported a 15
percent usage when idle
and a 22 percent usage
when recording 28
mono tracks. It s
a subtle difference, of
course, but shows that
the Symphony card
(perhaps aided by the
fact that it s PCI-based)
is working slightly more
efficiently. I expected
a more dramatic
difference on the
Macbook Pro, but Logic s
usage was almost
identical.
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APOGEE SYMPHONY
Here you can see the output of an
Audio Instrument track being
recorded by an Audio Track using
Symphony’s VBus channels. The
window in the background shows
that a recording made via a VBus
is sample accurate. The upper
window shows the original audio
file, while the lower window
shows the file that has been
recorded via the VBus.