User Manual

Configuring Multiple AES16e’s
9 Configuring Multiple AES16e’s
More than one AES16e card can be installed in a computer for additional audio channels. It is also possible
to mix AES16e and AES16 or LynxTWO/L22 cards in systems that have both PCIe and standard PCI slots.
If required, all AES16e’s in a computer can be configured to maintain sample accurate synchronization
during digital audio recording and playback.
9.1 Clock Synchchronicity
In multi-card configurations it is essential to good performance that a coherent clocking scheme is utilized.
As in any digital audio system, all devices must utilize a single clock source to prevent audible digital
errors. Additionally, audio software programs can behave erratically if each card in a multi-card system has
a unique clock reference.
An acceptable clock scheme can consist of either:
A. Establishing one of the Lynx audio cards as a clock master, and the other card(s) as clock slaves.
B. Configuring all of the Lynx audio cards as slaves to some external clock reference, either through
word-clock or digital input connections.
Which arrangement is appropriate will generally depend on the equipment included in the system, the
context of use, and user preferences. Details for correctly setting up both types of clocking scenarios are as
follows.
9.1.1 Configuring one Lynx card as clock master and others as slaves
In this case, cards are synchronized in a master-slave arrangement with one card selected as the clock
master, which provides the word-clock source for the other slave card(s) in the system. From the master,
the word-clock signal is daisy-chained from one slave to the next.
Word-clock signals can be connected internally using the CBL-ICC Internal Clock Cable, which is
available from Lynx. The CLOCK OUT header of one card is connected to the CLOCK IN header of the
next card. A separate cable is required for each slave card in the system. See Section 9.1.3 - Clocking
multiple cards with the CBL-ICC Internal Clock Cable. Alternatively, the CLOCK connectors on the CBL-
AES1604 cables can be connected externally with a standard 75 ohm BNC patch cable.
In order to select master and slave AES16e’s in a system, each adapter ID must be first physically
associated with an AES16e installed in a computer slot. The procedure is as follows:
 Connect at least OUT1 of each AES16e to your AES/EBU monitoring equipment.
 Choose an audio application that allows selection of audio devices for audio playback.
 Select “AES16e 1 Play 1” as the playback device.
 Listen to the playback of any audio file and note which AES16e card is generating the audio signal. In
this case, the card generating audio is adapter 1.
 Repeat steps 3 and 4, for “AES16e 2 Play 1”, “AES16e 3 Play 1”, and so on until all AES16e’s in your
system have been identified.
We strongly suggest making the first adapter be the clock master. This is preferable because applications
that are capable of sending sample rate change requests to the audio hardware, will only be able to
communicate a sample rate request to the first card available. This way, when you choose a project with a
different sample rate, or specifically change sample rates for an open project, all of the cards will
automatically switch to the new rate.
After the cable connections have been established, the clock sources for each card must be set correctly in
the Lynx Mixer.
AES16e User Manual
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