Beside 3D playback and Android feature 1186 chipset more faster and stable than 1073 in term of high bitrate mkv hd-audio.
One of mkv dts-hdma 6.1 playback on 1073 loud pop sound every 40secs so unbearable till upgrade to HD900B test no more loud pop and like dual subtitles display.

Thank you for your reply. Titanic 3D is one title that has audio drop out when played from a BMDV folder or a rip to M2TS, .ts or .mkv with DTS MA audio. All these files play perfect on my 5 year old Popcorn Hour B110 that has a 100mb network. The B110 will not play the BMDV folder directly, one reason I upgraded. Himedia need to fix this issue that many others report, but they dont seem willing to do so. I wont make a Chineese purchase again.

I wanted to ask again about people's experiences with sound between Realtek and Sigma Chip

I just got the iconBit player with Realtek 1186 chip and it plays everything and it is quick and can read and play files from 3TB and 4TB drive so I give it strong grades for that

BUT the sound quality is not as good as my Sigma 8642 chip in my HDX; there is a clear difference; the sound on Realtek is thinner; Bass not as strong
I noticed on 5.1 playback as well as 96/24 audio files

this is the exact same thing I noticed on Egreat R300 with Realtek 1186 chip when I compared that to my HDX

so the realtek chip is great when it comes to features and playing all files but there is no way it sounds as good. I am sure of what I heard; I compared a few times

Yup