This is contents of '/proc/interrupts' - any guesses as to which line is the sound card?
CPU0 CPU1 CPU2 CPU3 CPU4 CPU5
10: 0 0 0 0 0 0 GIC-0 29 Level arch_timer
11: 102373 41736 36628 22308 111462 18627 GIC-0 30 Level arch_timer
14: 0 0 0 0 0 0 GIC-0 92 Edge Meson TimerF
15: 3 0 0 0 0 0 GIC-0 192 Level ffe40000.bifrost
16: 0 0 0 0 0 0 GIC-0 193 Level ffe40000.bifrost
17: 0 0 0 0 0 0 GIC-0 194 Level ffe40000.bifrost
20: 3 0 0 0 0 0 GIC-0 241 Edge
21: 1 0 0 0 0 0 GIC-0 242 Edge
22: 54 0 0 0 0 17913 GIC-0 40 Edge eth0
23: 126 0 0 0 18256 0 GIC-0 62 Level xhci-hcd:usb1
24: 1 0 0 0 0 0 GIC-0 48 Level amlogic_botg_detect
25: 0 0 0 0 0 0 GIC-0 63 Level dwc_otg, dwc_otg_pcd
26: 0 0 0 0 0 0 GIC-0 232 Edge meson-g12a-saradc
27: 0 0 0 0 0 0 GIC-0 67 Edge ff634800.p_tsensor
28: 0 0 0 0 0 0 GIC-0 68 Edge ff634c00.d_tsensor
29: 0 0 0 0 0 0 GIC-0 247 Edge ffd1d000.i2c
31: 59 0 0 0 0 0 GIC-0 71 Edge ffd1c000.i2c
33: 0 0 0 0 0 0 GIC-0 113 Level ffd13000.spi
34: 472 0 0 0 0 0 GIC-0 225 Edge meson_uart
38: 38 0 0 0 0 0 GIC-0 184 Edge
39: 9 0 0 0 0 0 GIC-0 185 Edge
40: 9 0 0 0 0 0 GIC-0 186 Edge
42: 0 0 0 0 0 0 GIC-0 212 Edge aml-aes, aml-tdes, aml-sha
44: 0 0 0 0 0 0 GIC-0 58 Edge meson_uart
45: 1 0 0 0 0 0 GIC-0 89 Edge hdmitx
46: 0 0 0 0 0 0 GIC-0 235 Edge hdmi_aocecb
48: 0 0 0 0 0 0 GIC-0 178 Edge ge2d
49: 54155 0 0 0 0 0 GIC-0 35 Edge vsync, osd-vsync
50: 0 0 0 0 0 0 GIC-0 176 Edge gdc
53: 0 0 0 0 0 0 GIC-0 75 Edge vdec-0
54: 0 0 0 0 0 0 GIC-0 76 Edge vdec-1
57: 54154 0 0 0 0 0 GIC-0 121 Edge rdma
58: 0 0 0 0 0 0 GIC-0 88 Edge osd-vsync-viu2
59: 23028 0 0 0 0 0 GIC-0 223 Edge meson-aml-mmc
60: 0 0 0 0 0 0 GIC-0 222 Edge meson-aml-mmc
62: 0 0 0 0 0 0 GIC-0 83 Edge dmc_monitor
72: 0 0 0 0 0 0 GIC-0 78 Edge pre_di
73: 0 0 0 0 0 0 GIC-0 72 Edge post_di
74: 0 0 0 0 0 0 GIC-0 33 Edge audiolocker
IPI0: 155005 80979 70658 64124 80714 83240 Rescheduling interrupts
IPI1: 1961 12771 2012 2758 485 406 Function call interrupts
IPI2: 0 0 0 0 0 0 CPU stop interrupts
IPI3: 0 0 0 0 0 0 Timer broadcast interrupts
IPI4: 0 0 0 0 0 0 IRQ work interrupts
IPI5: 0 0 0 0 0 0 CPU wake-up interrupts
Err: 0