Setup, Design & Observations
Inserting the STRIX RAID DLX into your system takes a little more work than what you would have to go through if you used an external solution, which basically means having to open up your case and find a free PCIe 1x lane, or greater, for it to be plugged into. Once installed you can then plug in the included control box and any speakers or headphones you with to use with this device. You will then need to head on over to ASUS' website to locate the driver download.
The control box is fairly easy to use, rotate dial for volume, turn on the RAID button to adjust whichever option you have selected in the Sonic Studio which is microphone volume by default. If you wish to toggle between headphones, speakers or SPDIF, just press the dial down and it will jump between them. When toggling between headphones and speakers there is an audible 'tick' noise, similar to what we have experienced with a few other soundcards and is nothing to be concerned about.
The orange glow from inside the case is rather dull and localised which is a shame because for the price and being part of the STRIX series it does little to add to the aesthetic of your system should one be going down the route of a complete STRIX setup.
Running with the Creative SoundBlasterX H5, which is a 32 ohm gaming headset. Instantly there was a low level background squeal/hiss which I had not experienced with this headset before which has since been used with the integrated ALC 1150 and Creative SB ZxR in my main system, a second system using a different integrated ALC 1150 solution, a friends system running with a Creative SB Z sound card, and this low level interference was not present anywhere else.
This interference could be the root of the strange graphs seen in our RMAA tests. It wasn't until later in the day after I was going about some daily things when I noticed that this noise dipped and altered patterns when I plugged/unplugged things into my USB ports on my system. This is rather interesting as we have already identified that the audio processor is actually one created for a USB 2.0 system and that the PCIe controller is actually a PCIe - USB 3.0 controller. This find suggests that the interference is caused by a ground loop. This interference was subtle, but very noticeable with no audio being played. Another potential source for this interference could also be due to the power. LME 49600 opamps are known for requiring a fair bit of juice compared to other solutions so any other devices plugged into your rig sapping power from the USB ports may cause similar interference.
To test these things I tried 3x other headsets I had at hand, including the Logitech G633 (39 ohm), the OZONE Blast 4HX (50 ohm) and finally with our Beyerdynamics DT770 PRO 250 ohm. The interference was present in the G633, less so in the Blast 4HX and non-existent with the DT770. So it would seem that there was a scaling decline which would suggest that it could be something to do with the power flow and how the STRIX RAID DLX drives headphones.
Despite this interference, our subjective music listening revealed that the ASUS STRIX RAID DLX sounded fantastic, giving excellent character and separation with the right amount of warmth at the low end, which the highs were crystal clear. The STRIX RAID DLX didn't drive the DT770 PRO 250 ohm as well as one would expect, offering a maximum volume at a level one would consider to be 'comfortable but could be louder'. Despite that, the STRIX RAID DLX revealed the character of the DT770 PRO to an extent that left the gaming headsets in the dust, proving that the STRIX RAID DLX certainly does have some very good audio wizardry behind it.
In games the virtual surround worked surprisingly well, giving a nice wide open soundstage, though this came at the cost of a slightly weaker bass.
The STRIX RAID DLX supports up to 7.1 surround and thus gave be the opportunity to test out my Microlab Solo 9C + Logitech X540 combo which I was particularly pleased with. Firstly I am happy to say that there was no background hiss or interference to be reported. The audio quality again sounded great, clarifying minute nuances and details that are often overlooked.
The microphone pick-up is incredibly loud with the STRIX RAID DLX and so you will need to reduce the microphone volume a fair bit to compensate. The perfect voice mode seemed to help a little, but created a slight echo which to some sounded strange. The noise gate function removed all background noise and clarified vocal pickup very well... with the exception that it also created a playback lag. This made subtle sounds, sound strange, specifically insinuating S sounds. With the noise gate feature turned on words like 'sausage' would not even be heard.