Hi Vinark - I first limited my testing to mp3 files in winamp or vlc, yep, but I am also a long time user of Cubase 7.5 (which I haven't updated) and if I add the stereo outputs and allocate them to PhL and PhR, I should expect any sub bus that is routed to the main fader to recieve those signals and they do, but the same phenomenon exists where panning anywhere in cubase hard left or hard right actually phase aligns the centre image.

Hello!

It sounds like the Mid Channel of a Mid/Side configuration is muted, to me. So can you check if you have M/S Processing activated in any of the Software Playbacks Outputs?

Here's a quote from page 71 of the manual:

I don't have a MADI FX, but this is what I can figure from your post.
Hope it helps!

Thank you all for the replies - yes it is presenting like the mid channel in M/S processing is muted, however, I looked at all the relevant channels with this in mind, which helped me understand that the problem lies elsewhere despite sharing the same symptoms.

The matrix view looks exactly as I would expect it to after a submix reset and I couldn't see any routing I wasn't expecting. What would a loopback look like in the Matrix, just in case?

At this point, the only theory I haven't tested is a possible problem with the socket itself (I've ruled out the male jacks by testing those cables/devices in other systems.

The socket does have a little bit of play, but I wouldnt say it's "loose". I don't have any instruments to test the signal current physically though

I guess I can take the card out for a closer look at least. Any suggestions?

I dug up my physical user manual for the HDSPe and read through the whole thing again (I find it easier to maintain concentration when reading from paper). There are a couple of features that I admit I've never used or realised existed, but nothing that should cause what I've described.

I will double check everything, including wriggling the jack and report back as I'm sure the thread will help others in future.

By the way, I read that the Phones output is not inherently linked to any physical input thus rendering it incapable of loopback.

Another couple of observations - I connected an analogue stereo meter bridge to have visual inrormation to refer to after the main output and I noted that no matter how I route or pan things (and even when the meters in TMFX show activity ONLY on one channel), the meter shows the same signal on both channels simultaneously. - I'm not sure if this helps narrow down the possible causes, but in my mind it is pointing towards a hardware defect (as suggested, within the socket).

Hey Polym0rphed!
Did you figure out?

As MC has, allready, suggested, it must be ground connection missing!

So, have you tried with different pair of headphones?
Is the card firmly seated in the PCIe slot? (could loose ground, if a few pins are not seated all the way in)
Is your motherboard screwed in with every screw required?(Screws in motherboards provide grounding)
Is your PC's PSU and power cable in good condition?

These are a few things that comes to my mind, you could check, if you haven't allready!

The cable that you have (according to your first post) is a simple TRS (stereo) to 2 x XLR Male (Mono L/R), and will not have any resistors as they have no purpose here. It might be possible that the cable is doubling the TRS into 2 x XLR by connecting Tip and Ring to pin 2 and 3 respectively. That would be a very unusual, and for this application wrong cable.

We all lost overview meanwhile, this thread has become somehow useless. And now you even misread my last reply. You do NOT need resistors in a cable, forget that. And I am not aware of any such cable that has them inside. Also already in your first post you wrote that your phones show the same issue. So how can it be the cable? It seems the TRS socket on your card is broken. Get yourself a technician with a multimeter, he can quickly clear a missing ground issue - and check your cables as well. Just takes a minute...