User manual

grouping, phase, muting, phantom power and Soft Limit). The
leftmost QuickTouch pads are numbered one to four for input
selection. Two more buttons select speaker or headphone
level adjustment and there’s simultaneous metering for all
four inputs and the output levels. The single controller knob,
with its integral push-switch, is used to adjust all the variable
functions and is suitably large to use as a main volume control.
Apogee make a big deal about the low latency that can
be achieved with the Quartet: at 96kHz and at a buffer size
of 32 samples, latency is just 3.6ms — a full millisecond less
than the equivalent Firewire 400 setup. I used a buffer size of
64 samples at 44.1kHz for most of my tests and still couldn’t
perceive any delay. Also of note is Soft Limit, Apogee’s
proprietary circuitry for subtly squashing the peaks of loud
signals to produce a more analogue-like saturation when the
maximum signal level is approached. This can be enabled or
disabled on an individual channel basis via the included (via
download) Maestro 2 software.
The Maestro 2 control software is an integral part of the
package. It has a straightforward, single-window interface and
is compatible with current Mac operating systems, as well as
Snow Leopard. Here you can configure the system, select the
input type, enable or disable Soft Limit on the inputs, and use
Maestro’s mixer section for low-latency monitoring. Assigning
speakers to touch pads and configuring the front-panel A, B
and C buttons is also done here.
Connectivity
The Quartet has six balanced output jacks that can be used in
pairs as three stereo speaker feeds, as a 5.1 feed, or as sends
to external equipment. There’s also a separate headphone
output located on the right-hand side of the case, which has
full level control via the front panel, and that can be fed from
its own monitor mix if required.
A-D/D-A conversion is courtesy of Apogee’s respected
conversion technology, and the designers have paid a lot of
attention to providing really good quality mic preamps to do
their converters justice. These digitally controlled analogue
preamps, each fitted with a ‘combi’ XLR/jack input socket,
offer a very wide gain range of 0 to 75dB and have click-free
transitions as the gain is adjusted. Phantom power at the full
48 Volts is available for capacitor mics as you’d expect, and is
independently switchable for each input.
The USB port marked MIDI is configured only for Core
MIDI devices, not for general USB functions, presumably to
conserve bandwidth. While you could plug directly into your
computer for MIDI over USB, this approach saves using up
a port on your Mac. There’s a separate mini-USB socket for
connection to the host computer using the included cable.
Apogee have settled on the USB 2 protocol for connection
to the host computer, as in its current incarnation it is actually
faster than Firewire 400, and although USB 3 offers more
bandwidth, the designers tell me this wouldn’t result in any
performance benefits. USB also seems likely to have a longer
life-span than Firewire now that Thunderbolt is on the scene.
Other rear-panel connections include an input for the
included power supply and a word clock output on a standard
BNC connector. A separate ground terminal (useful for
laptop-based systems) also includes a cable clip for the power
lead. The two ADAT ports allow S/MUX operation to double
up the sample rate to a maximum of 96kHz and are inputs
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