I notice you're using Asio for all and/or VB Audio Virtual Cable to connect JRiver to Ekio. Is that necessary? Couldn't Wasapi Exclusive mode be employed instead? What are the advantages of using your approach vs. Wasapi?
Well, I have "historical" and "practical" reasons for sticking to "all in ASIO I/O" in my PC based multichannel audio system.
I started to use 192kHz 24bit USB DAC in 2009, the first one was RATOC RAL-24192UT1 on Windows 7 Pro 64 bit PC. After that I purchased ONKYO DAC-1000, KORG DS-DAC-10, OPPO SONICA DAC and finally OKTO DAC8PRO, with Windows 7, Windows Vista, Windows XP and Windows 10.
Throughout the usage of these DACs with Windows PC, I have been always sticking to ASIO I/O fully independent from Windows OS audio services including Kernel Streaming, Direct Sound and WASAPI; as you may know, there have been several confusions, change of policies and inconsistency problems with Windows audio services especially associated with the major version-up of the OS,
i.e. 7 to Vista, Vista to XP and also XP to 10.
Even though current WASAPI Exclusive mode on Windows 10 maybe be quite OK, I experienced uncomfortable and sometimes nearly harmful (to my speakers) kernel sound intrusion incidents when I used Kernel Streaming, Direct sound or WASAPI (non-exclusive), and therefore, I still do not fully trust Windows OS oriented sound I/O services including WASAPI Exclusive. I also heard in Japanese audio enthu forums that several recent major update of Windows 10 caused unexpected initialization(?) and/or inconsistency problems with WASAPI service.
As far as we use full USB ASIO I/O with using each of the specific DAC dedicated ASIO driver, we can avoid any problems/issues associated with Windows updates. In other words, I always would like to eliminate (or minimize) Microsoft's direct involvement in audio I/O.
As for ASIO4ALL....
ASIO4ALL is a quite unique "software/driver", and looking from music player software including JRiver and Roon, it also behaves as if one (virtual) USB hardware audio "device".
ASIO4ALL sits/dominates in front of all the available other ASIO drivers, and together with VB Audio Hi-Fi Cable and ASIO Bridge, we can establish very flexible unlimited number of I/O routings with "independent" crossover software EKIO which has simple intuitive GUI capabilities. Almost all of the EKIO's DSP features, including the XO filter configurations, can be changed while listening to the music.
Especially I like the flexible EKIO-ASIO4ALL output capabilities; with ASIO4ALL, we can assign any of the available USB ASIO drivers for output channel of EKIO, and with EKIO's unlimited number of I/O settings, if needed, we can assign multiple channels into one single DAC, or one output channel into multiple DACs, and the mixture of these. Of course, if we like (even the synchronization issue exists), we may simultaneously assign outputs into multiple DACs,
e.g. 8 channels of DAC8PRO plus OPPO SONICA DAC plus DS-DAC1000 plus DS-DAC-10. Or we may very easily inter-change these multiple DACs.
Since this is "DAC8PRO review" thread, I feel, if needed, we may better to continue this discussion in
my multichannel multi-amplifier thread.