[LAU] Trying to get 8 channel sound from Linux Mint and an Intel NUC

I am trying to get software control of 8 channels of audio over HDMI. I don't know very much about linux audio software and naively assumed I'd plug an HDMI into an audio converter/splitter and get 8 working outputs. What I get is silence. Someone here must understand this and I'd appreciate help! Here's everything I know about collecting. Sorry for the length or if it's insufficient. Code: wget -O alsa-info.shhttp://www.alsa-project.org/alsa-info.sh && chmod +x ./alsa-info.sh && ./alsa-info.sh http://alsa-project.org/db/?f=9a8a1a...a1d071064900d5 <http://alsa-project.org/db/?f=9a8a1a8f97c09f05356c327bc8a1d071064900d5> Code: uname -r 4.15.0-64-generic #I'm guessing this is what should work, but doesn't: speaker-test -D surround71:CARD=PCH,DEV=0 -c 8 Code: speaker-test 1.1.3 Playback device is surround71:CARD=PCH,DEV=0 Stream parameters are 48000Hz, S16_LE, 8 channels Using 16 octaves of pink noise Channels count (8) not available for playbacks: Invalid argument Setting of hwparams failed: Invalid argument But trying speaker-test -D surround71:CARD=PCH,DEV=0 -c 2 doesn't return errors, but gives silence (even with the SKSL converter set to stereo) pavucontrol Unable to init server: Could not connect: Connection refused (But do I need it?) alsamixer shows Auto-Mute Disabled, Loopback Enabled. Master, Headphones, Speaker and PCM all have columns in the white (but a green 00 at the bottom). There's no line, front, center, side, rear, etc. There are 5 S/PDIF columns, all blank and showing 00, and I can't get them to change (but presumably I don't care.) inxi -Fxz System: Host: lachesis Kernel: 4.15.0-64-generic x86_64 bits: 64 compiler: gcc v: 7.4.0 Console: tty 0 Distro: Linux Mint 19.1 Tessa base: Ubuntu 18.04 bionic Machine: Type: Desktop System: Azulle product: Inspire v: N/A serial: <filter> Mobo: INTEL model: SKYBAY serial: <filter> UEFI: American Megatrends v: 5.12 date: 10/10/2017 CPU: Topology: Dual Core model: Intel Core i5-7200U bits: 64 type: MT MCP arch: Kaby Lake rev: 9 L2 cache: 3072 KiB flags: lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx bogomips: 21696 Speed: 619 MHz min/max: 400/3100 MHz Core speeds (MHz): 1: 600 2: 600 3: 601 4: 600 Graphics: Device-1: Intel HD Graphics 620 driver: i915 v: kernel bus ID: 00:02.0 Display: server: X.org 1.19.6 driver: modesetting unloaded: fbdev,vesa tty: 154x34 Message: Advanced graphics data unavailable in console. Try -G --display Audio: Device-1: Intel Sunrise Point-LP HD Audio driver: snd_hda_intel v: kernel bus ID: 00:1f.3 Device-2: C-Media type: USB driver: hid-generic,snd-usb-audio,usbhid bus ID: 1-7.3:10 Device-3: C-Media type: USB driver: hid-generic,snd-usb-audio,usbhid Sound Server: ALSA v: k4.15.0-64-generic Network: Device-1: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet driver: r8169 v: 2.3LK-NAPI port: e000 bus ID: 01:00.0 IF: enp1s0 state: up speed: 1000 Mbps duplex: full mac: <filter> Device-2: Intel Wireless 3165 driver: iwlwifi v: kernel port: e000 bus ID: 02:00.0 IF: wlp2s0 state: up mac: <filter> Drives: Local Storage: total: 960.82 GiB used: 187.73 GiB (19.5%) ID-1: /dev/sda vendor: Samsung model: SSD 860 EVO M.2 500GB size: 465.76 GiB ID-2: /dev/sdb type: USB vendor: Samsung model: Portable SSD T5 size: 465.76 GiB ID-3: /dev/sdc type: USB model: SMI USB size: 29.30 GiB Partition: ID-1: / size: 456.96 GiB used: 102.94 GiB (22.5%) fs: ext4 dev: /dev/sda2 Sensors: System Temperatures: cpu: 48.0 C mobo: 29.8 C Fan Speeds (RPM): N/A Info: Processes: 208 Uptime: 17m Memory: 15.59 GiB used: 828.9 MiB (5.2%) Init: systemd runlevel: 5 Compilers: gcc: 7.4.0 Shell: bash v: 4.4.20 inxi: 3.0.27 cat /proc/asound/car*/co* | grep Codec Codec: Realtek ALC269VC Codec: Intel Kabylake HDMI lspci -nn Code: 00:00.0 Host bridge [0600]: Intel Corporation Xeon E3-1200 v6/7th Gen Core Processor Host Bridge/DRAM Registers [8086:5904] (rev 02) 00:02.0 VGA compatible controller [0300]: Intel Corporation HD Graphics 620 [8086:5916] (rev 02) 00:08.0 System peripheral [0880]: Intel Corporation Xeon E3-1200 v5/v6 / E3-1500 v5 / 6th/7th Gen Core Processor Gaussian Mixture Model [8086:1911] 00:14.0 USB controller [0c03]: Intel Corporation Sunrise Point-LP USB 3.0 xHCI Controller [8086:9d2f] (rev 21) 00:14.2 Signal processing controller [1180]: Intel Corporation Sunrise Point-LP Thermal subsystem [8086:9d31] (rev 21) 00:16.0 Communication controller [0780]: Intel Corporation Sunrise Point-LP CSME HECI #1 [8086:9d3a] (rev 21) 00:17.0 SATA controller [0106]: Intel Corporation Sunrise Point-LP SATA Controller [AHCI mode] [8086:9d03] (rev 21) 00:1c.0 PCI bridge [0604]: Intel Corporation Device [8086:9d13] (rev f1) 00:1c.4 PCI bridge [0604]: Intel Corporation Sunrise Point-LP PCI Express Root Port #5 [8086:9d14] (rev f1) 00:1f.0 ISA bridge [0601]: Intel Corporation Sunrise Point-LP LPC Controller [8086:9d58] (rev 21) 00:1f.2 Memory controller [0580]: Intel Corporation Sunrise Point-LP PMC [8086:9d21] (rev 21) 00:1f.3 Audio device [0403]: Intel Corporation Sunrise Point-LP HD Audio [8086:9d71] (rev 21) 00:1f.4 SMBus [0c05]: Intel Corporation Sunrise Point-LP SMBus [8086:9d23] (rev 21) 01:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller [10ec:8168] (rev 0c) 02:00.0 Network controller [0280]: Intel Corporation Wireless 3165 [8086:3165] (rev 81)