Here's what I get in client logs regarding audio:
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.387: ../../src/channel-playback.c:346 playback-5:0: playback_handle_mode: time 66944572 mode 3 data 0000000006EB1E56 size 0
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.388: ../../src/spice-gstaudio.c:370 playback volume changed to 65535 (100.00)
(remote-viewer.exe:14404): GLib-GObject-CRITICAL **: 01:18:06.388: g_object_set: assertion 'G_IS_OBJECT (object)' failed
(remote-viewer.exe:14404): GLib-GObject-CRITICAL **: 01:18:06.388: g_object_unref: assertion 'G_IS_OBJECT (object)' failed
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.389: ../../src/spice-gstaudio.c:396 playback mute changed to 0
(remote-viewer.exe:14404): GLib-GObject-CRITICAL **: 01:18:06.389: g_object_unref: assertion 'G_IS_OBJECT (object)' failed
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.394: ../../src/spice-channel.c:1296 display-2:0: channel up, state 3
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.394: ../../src/channel-display.c:1040 display-2:0: spice_display_channel_up: cache_size 83886080, glz_window_size 67108864 (bytes)
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.396: ../../src/spice-channel.c:2693 inputs-3:0: Open coroutine starting 00000000051572A0
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.397: ../../src/spice-channel.c:2534 inputs-3:0: Started background coroutine 0000000005157148
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.398: ../../src/spice-session.c:2202 Missing port value, not attempting unencrypted connection.
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.398: ../../src/spice-channel.c:2560 inputs-3:0: trying with TLS port
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.399: ../../src/spice-session.c:2214 inputs-3:0: Using TLS, port 61000
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.399: ../../src/spice-channel.c:2693 cursor-4:0: Open coroutine starting 0000000005154120
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.399: ../../src/spice-channel.c:2534 cursor-4:0: Started background coroutine 0000000005153FC8
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.400: ../../src/spice-session.c:2202 Missing port value, not attempting unencrypted connection.
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.400: ../../src/spice-channel.c:2560 cursor-4:0: trying with TLS port
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.400: ../../src/spice-session.c:2214 cursor-4:0: Using TLS, port 61000
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.401: ../../src/spice-session.c:2162 (with proxy
http://192.168.1.11:3128)
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.401: ../../src/spice-session.c:2162 (with proxy
http://192.168.1.11:3128)
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.401: ../../src/spice-channel.c:1296 record-6:0: channel up, state 3
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.401: ../../src/spice-session.c:2086 proxy lookup ready
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.402: ../../src/spice-session.c:2069 inputs-3:0: connecting 0000000009A1FE10...
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.402: ../../src/spice-session.c:2086 proxy lookup ready
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.402: ../../src/spice-session.c:2069 cursor-4:0: connecting 0000000009C1FE10...
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.403: ../../src/spice-gstaudio.c:429 record volume changed to 0 (0.00)
(remote-viewer.exe:14404): GSpice-WARNING **: 01:18:06.403: gst lacks volume capabilities on src
(remote-viewer.exe:14404): GLib-GObject-CRITICAL **: 01:18:06.404: g_object_unref: assertion 'G_IS_OBJECT (object)' failed
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.404: ../../src/spice-gstaudio.c:455 record mute changed to 0
(remote-viewer.exe:14404): GSpice-WARNING **: 01:18:06.406: gst lacks mute capabilities on src: 0
(remote-viewer.exe:14404): GLib-GObject-CRITICAL **: 01:18:06.407: g_object_unref: assertion 'G_IS_OBJECT (object)' failed
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.407: ../../src/spice-session.c:2053 inputs-3:0: connect ready
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.408: ../../src/spice-channel.c:2456 inputs-3:0: Load CA, file: (NULL), data: 0000000004D5E780
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.408: ../../src/spice-session.c:2053 cursor-4:0: connect ready
(remote-viewer.exe:14404): GSpice-DEBUG: 01:18:06.408: ../../src/spice-channel.c:2456 cursor-4:0: Load CA, file: (NULL), data: 0000000004D5E780
(remote-viewer.exe:14404): Spice-DEBUG: 01:18:06.411: ../../../spice-common/common/ssl_verify.c:407:verify_subject: subjects match
(remote-viewer.exe:14404): Spice-DEBUG: 01:18:06.412: ../../../spice-common/common/ssl_verify.c:407:verify_subject: subjects match