SOLVED - With Step-by-Step and Images - HELP! Sonar X3 and Lexicon MX400

So I have the MX 400 also except that I use it via the quarter inch inputs and outputs.  With that said... Just to reiterate .. outputs five and six from the interface feed the inputs to the lexicon.. The output (return) of the lexicon is going to SPdif of the interface.. The lexicon has routing that needs to be aware of this setup. Also...what in Mix control is taking the SPdif output? This would generally go to a channel(s) for the effect signal... So in my setup.. the output of the daw is sent to a physical output on the interface which feeds the input into the MX and the "output" signal of the MX is "returned" to a channel(s) on the interface and then those channels are captured in the DAW setup. I don't thing that SPdif setup in theory should be much different.
 
Once that is mapped out the external insert follows that mapping for latency free effects. IHTH

Hi WillieWonka,
 
Below is an excerpt about the SPdif routing for the MX 400.. IHTH..
 
 S/PDIF Digital In/Out
Digital input accepts 44.1kHz / 48kHz signals. When the S/PDIF digital input is selected
and active, the S/PDIF LED on the front panel lights.
Important: It is recommended that you do not connect any digital device to the
MX400’s S/PDIF inputs that transmits at sample rates other than 44.1 kHz or 48 kHz
(such as 96kHz). Doing so can cause unpredictable performance. Make sure the device
you are connecting to the MX400’s S/PDIF In is set as the Clock Master (if that option
is available) and transmitting at a sample rate of 44.1kHz or 48kHz only. As with any
other connection, if you need to unplug the S/PDIF cable, it is recommended that you
switch to the analog inputs (see Input Source in the System menus) or bypass both
processors before disconnecting the cable.
 
The MX400 and Digital I/O
The MX400 is equipped with two digital inputs and outputs (S/PDIF A and B). Each
S/PDIF pair is the digital equivalent of analog input/output pairs A and B. The digital
outputs on the MX400 are always active and will always mirror their analog output
counterparts. This allows you to plug in an analog input source and have it be output
as a digital stream.
 
The MX400 has three options for input sources which are configurable in the System
Menu: Analog Mono Left, Analog Stereo and Digital. (Press the System
button to access the System Menu; turn the Page/Select knob to scroll up and down
the menu.) Each input pair (A and B) can have different audio sources selected depending on your
needs. While in the System Menu, use Knobs A, B, and C to change values. As with
all equipment that receives digital audio streams, when setting either Input Source A or
B to Digital, the MX400 can no longer use its own internal clock source for the audio
stream, and it is necessary to change the clock source from the MX400’s internal clock
to Digital. Furthermore, the MX400 only receives external clock sync on the S/PDIF A input.
This means when using both Digital inputs (A and B), the devices that are connected
must be synced to a common clock source to work properly with the MX400.
If the Clock Source isn’t changed to Digital when digital input sources are selected,
there will be synchronization problems between the incoming digital audio stream
and the MX400’s processing, and the System Input Source menu will display DIG NO
LOCK. When the MX400 is properly synchronized with the incoming digital audio,
the System’s Input Source menu will display DIGITAL.

The MX400 only runs at 44.1 kHz or 48 kHz sample rate (using internal or external
clock sources). Do not connect external digital outputs to the MX400 that run at higher
sample rates (88.2 - 192 kHz) as the MX400 cannot accept them.
 

All,
With tons of trial and error as well as help from LunaTech (thank you) I have solved my issue.  I wanted to try and give back to the forum so I included details of how my setup works. Please understand that I will give as much detail as I can in hopes of helping someone else.
 
Step 1.
 
In the image below, I am using the Focusrite Saffire Pro 24 DSP and I have 2 SPDIF cables coming out and into the
Lexicon MX400 SPDIF inputs.  See Step 2 for image.  Please notice in this image the 2 white analog cables coming out of outputs 5 and 6 on the Saffire Pro.
 

 
Step 2.
 
This image is the back of the Lexicon MX400 (the middle device).  As you can see, I am using the SPDIF input (Channel A only) coming out of the Saffire Pro 24 (see image above). Also notice the "Analog Input" on the Lexicon MX400. Both left and right channels are coming out of channels 5 and 6 (see image above) from the Saffire Pro and into the Lexicon MX400 Analog Inputs A left and right.

 
Step 3.
 
In the Saffire MixControl, open the "Router" section and choose the following inputs.

 
What this is doing is routing anything that coming out of the Saffire Pro channels 5 and 6 and route them to the SPDIF outputs 1 and 2. (Remember the analog cables coming out of the Saffire Pro coming out of channels 5 and 6?)
 
 
Step 4.
 
On the front Lexicon MX400, press the "system" button.  You have to change the following settings:
 
"Input Source A"  - Digital     - This is set because the SPDIF (digital) is connected on the "A" section (see step 2 image).  If both A and B were used, they would both be set to digital.
 
"Clock Source" - Dig 44.1. kHz  (Digital and what I am using out of Sonar X3 Producer for my sample rate.  They have to match). Also, make sure that your sample rate in the Saffire MixControl matched what you have in Sonar.
 
MIDI Clock SYNC - SYNC  (This should be SYNC NOT "OFF")
 
 
Step 5.
 
Open Sonar X3 Producer (if you have it) and create a Bus and name it something like "Lexicon" or "external reverb" something you can remember.  It really doesn't matter.  Once the is created, go to the FX bin and insert the "External Insert" plug-in.  You should be able to right-click and find it.  On the left, choose the "Saffire Pro Line 5" as the SEND and the Saffire Pro SPDIF L or R or Stereo as the Return.  Mine is set for "Saffire Pro SPDIF stereo".
 

 
After this is complete, create a new audio track in Sonar.  For this example, I am using the Saffire Pro L Channel 1 (where my mic is currently plugged in.  You can change this based on the device you have plugged in).  In the output section, choose whatever you named the Lexicon MX400 bus.  Since you routed the BUS with the External Insert, it should route the source from Output of Line 5 from the Saffire Pro to the Input of the SPDIF channel. (In my case the Saffire Pro Stereo SPDIF input. 
 
Test the audio on the new audio track and if everything is working correctly, you should be able to hear the sound from the device with the Lexcion.
 
I hope this helps and I want to thank this forum for all the past help as well as LunaTech for their assistance.
 
Thanks All!!
 
Take care,
 
WillyWonka71 (Dave in Memphis)

Dave,
 
One final comment.. No need for thanks.  That's what (for the most part ) we are here for. I have gained so much from users on this forum ... FBB, Danny, Panu, Bapu, John .. many others.  It is my pleasure to contribute and give back as you have.  We help one another to create what we feel.. How cool is that?