AES16e LStream Loopback

What is loopback?
Loopback is simply routing an output channel back to an input channel so you can record what is being played. This can be used for recording a soft-synth performance, capturing audio that is being played from a web browser, creating a sub-mix of multiple input channels to record to a single stereo pair, or any situation where it is not practical or possible to capture what is being output from the audio card any other way. Both the input and output loopback channels must run at the same sample rate.

Internal LStream expansion port loopback
The internal LStream expansion port on the AES16e is intended to connect LStream expansion modules such as the LS-ADAT or LS-AES to the main audio card for Digital I/O expansion. The LStream port accommodates up to 16 channels (depending on sample rate) of external I/O. If you do not have an LStream expansion module connected to your main audio card, you may use the LStream port for up to 16 channels of loopback.

Physical Connection
To use the internal LStream expansion port for loopback, you must connect a 0.100" jumper between pins 2 & 4 on the internal LStream expansion port on your Lynx audio card.

It is not necessary to use a jumper that looks exactly like the example in the photograph. Any 0.100" jumper will do. Many older hard disk drives have 0.100" jumpers on them for master/slave selection. You might be able to harvest a jumper from a discarded hard disk drive.

How to install the Jumper

1. Turn off the power to your computer and unplug the power cord.
2. Open the computer chassis. Refer to your computer documentation for precautions and instructions on how to do this. Be sure to touch metal inside the computer case to ground yourself and discharge any static charge you may be carrying.
3. Locate your Lynx audio card and place the 0.100" jumper between pins 2 & 4 of the internal LStream expansion port. Use the example photograph above as a guide. Please note the photograph is of an AES16e so the components below the three connectors may look slightly different on your card, but the LStream connector and two clock connectors are the same on all AES16e cards. This photograph has the card with the D connectors to the right, component side up.
4. Replace the cover to the computer and plug the power cord back in.

Software Settings
The LStream expansion port will carry all 16 output channels that are displayed in the Lynx Mixer's output pane.  When the driver is in 16-channel mode, the LStream outputs will mirror the AES/EBU outputs.  When in 32-channel mode, outputs 1-16 are the AES/EBU channels, and outputs 17-32 are the LStream outputs.

Selecting LStream In 1 through 16 on the Record Device channels will route the audio from the LStream Inputs (fed from the LStream Outputs due to the jumper installed above) to the selected Record Device channel.