HDMI input/passthrough would probably be more future-proof and more widely comparable than Optical. Most consoles and PCs have HDMI outputs these days. The upside of optical, of course, is you don't need to pass the video through. Copying my post from MLE's thread too...
You mention that the Recon3D USB works on console, PC and Mac. I can see it presenting itself to the latter two as a USB soundcard. On the other hand, it receives signals from consoles via optical? This would be a Dolby Digital or DTS signal right? Where does Dolby Headphone or GenAudio Astoundsound come into this? As far as I know these are handled by the computer / console and output a processed stereo output that would only need to be amplified or decoded in the case of a digital output (insofar as all digital output need to be decoded by a DAC like the E18)?
The short version, what the Creative's Sound Blaster Recon3D USB does is provide a connection for headphones, an amp, a DAC, and a processor.
On computers, the Recon3D USB connects via USB like your FiiO DACs, but it has drivers to enable settings and identify it's available resources (surround decoding) to the computer and games. For consoles, it has an optical input that takes the Dolby Digital Live 5.1 signal that would be normally sent to a home theater speaker system. It would be nice to have two inputs, but that's a secondary goal. Here's basically what we, as consumers, have figured out about these surround processors, with Recon3D USB as an example:
- Computer or console sends sounds already split into positional channels corresponding to where 5.1 or 7.1 speakers would be placed in a typical home theater setup. Consoles send a Dolby Digital Live (or in some cases a DTS Connect) signal out, digitally, that would need to be decoded by the Recon3D USB to understand the different channels of sound.
- The Recon3D receives that "home theater" mixed sound, and uses a licensed decoder to understand the DDL or DTS signal
- the Recon3D applies a Head Transfer Related Function (HRTF) encoder to create a stereo virtual surround mix for headphones, the Recon3D's HRTF is called THX TrueStudio Pro (perhaps available for licensing from THX?) but other processors use Dolby Headphone to do the same thing.
- At this point the audio is a common 2 channel stereo mix, so that is transferred to a DAC, and then an Amp.
So basically, the external device needs a processor and some licensed software to convert home theater surround into headphone virtual surround, after that is just basically the hardware which is FiiO's strength and where the current products are weak. OpenAL and TrueAudio are kinda special cases, may be beyond FiiO's scope to implement those (and games have to have been created with support built-in), so I'd suggest just looking at HRTF's that can convert the common home-theater surround. Microphone input with a computer is easy, unfortunately each console is different (I believe the PS3 uses USB? Can anyone confirm?). It might be best for FiiO to start out with a more simple device, like an improved
Turtle Beach DSS. Some HRTFs that FiiO may be able to use could be:
- Dolby Headphone (mode 2, or DH2, is used by the Astro Mixamp, Asus Xonar products, Turtle Beach DSS (the first one), Tritton's AX720+ processor, and others)
- Cirrus Logic (headphone surround? Name of the processing isn't clear, Cirrus Logic is the company)
- AstoundSound (by GenAudio, I don't have enough info for you to say it can process any 5.1 or 7.1 mix)
- THX TrueStudio Pro (may be a Creative exclusive, but maybe THX could license it to you?)
FiiO probably could NOT use CMSS-3D or SBX ProStudio, I doubt Creative would license this to a competitor... But who knows? DH isn't my personal 1st place favourite, but I do like it and use it, pretty much everyone here would be happy with DH2 processing. A few of us here thought FiiO was already doing this when your company announced the D5 DAC, but it wasn't what we had hoped (5.1 to 2.0 headphone virtual surround processor and DAC).
Thanks for checking this idea out! Headphones + gaming still has untapped potential, we gamers realize this would be a bit of an expansion to your current target market, but it's awesome to get your attention and we'll try to help if you need it.