Impressions of Yarra 3DX surround capabilities:
- Multichannel PCM doesn’t work at all for surround whether via usb or HDMI.
- At near field distances, the far field surround mode is more noticable and convincing and for me closer to the experience of a true setup.
- In terms of surround effect (rear cues in particular), although good, it still feels and to some extent sounds more like processed virtual surround than it does a true setup.
- Pre-binauralised content fed to the Yarra in 2.0 stereo requires the Yarra’s surround mode to be in effect (i.e. double HRTF) in order to be convincingly enveloping and cues to be accurate. Unfortunately doing this also destroys the sound quality / fidelity.
Dolby Digital 5.1
When DD5.1 works on the Yarra, the Surround Effect can be very good but works in a similar way to headphone VSS and as such will be limited by the mixing of the source content and the limitations of VSS. Rear channel sounds will be appreciable but feel somewhat artificial/processed, particularly in videogames where rear cues are often boosted in comparison to front cues. In terms of rear and side cues, it is not noticably better than the best headphone / virtual surround combos. The advantage it does have over headphones however is its installation position as physical source of the sound either beneath or close to the TV / monitor screen, thereby avoiding the perceived “in your head” disconnect you can get with headphones clamped to your ears in comparison to the physical distance between you and the speakers and the Tv or monitor. So I guess in that sense cues from the front/center tend to feel like they have more depth and distance (but then again that would likely be the case with any physical speaker setup).
Near field vs Far field Surround modes
While I am not familiar with the exact mechanics behind Yarra’s surround field processing and output, I was under the impression that the bundle of sound beams would be output in a wider, more diffuse pattern in near field mode in order to create an enveloping surround effect for the close range user while the far field bundle of beams would be narrower and more focused at point of origin in order to preserve equivalent separation and surround effect at farther distances where the effect created by the near field mode would have otherwise dissipated due to being much wider and more diffuse to begin with.
Regardless, in practice (at least to my ears and no matter what ambient preset or HRTF model I use), at near field range the surround effect is much more apparent, enveloping and convincing if using the far field mode instead. . .!?
I have yet to try in a different room which would allow me to test both near and far field modes at a far field listening distance. Will update if I get a chance.
Binaural Content and Pre-binauralised surround mixes using pre-existing virtual Virtual Surround sound solutions.
In the few instances I have seen this previously discussed by commenters on forums, the big concern appeared to be ensuring that Yarra’s surround mode could be turned off to avoid double HRTF or the re-binauralisation of already binauralised content.
Well, in my testing of specifically binaural tracks like “virtual barbershop” and also discrete multichannel content binauralised into headphone virtual surround (via Dolby Atmos for Headphone, DTS Virtual X and Creative SBX surround) then fed to the Yarra, the Yarra’s surround effect needs to be set to “ON”, presumably to detect and exploit the various cues in the pre-binauralised 2.0 stereo. While the mechanics behind it may well be different, in terms of results, it reminds me of using Dolby Pro Logic or DTS Neo on surround content that has been downsampled into 2.0 stereo. You won’t get much in the way of surround effect from it unless you use something to intelligently upmix back into some semblance of the original surround.
In every instance and sample content I tried, setting the Yarra to stereo just meant the cues and depth were all over the place, with rear and sides totally off, whether in near or far field modes. Setting the Yarra to surround on the other hand, positioned the cues exactly where they were supposed to be.
If you want to try this out, just go to the “virtual barber shop” binaural demo on YouTube. Listen to it a couple of times using the best pair of headphones you have, familiarising yourself with the positional cues. Now try that same content with the Yarra. In stereo mode, the bits where the barber is behind you and cutting the hair around your ears sounded markedly in front of me with no illusion of rear placement. Setting the Yarra to surround mode fixed this and the cues were back to where they should be. Unfortunately, however it also wrecked the sound quality.