/proc/asound/HELIX/stream0:

LINE 6 HELIX at usb-0000:07:00.0-2, high speed : USB Audio

Playback:
  Status: Running
    Interface = 2
    Altset = 1
    Packet Size = 224
    Momentary freq = 48005 Hz (0x6.0029)
  Interface 2
    Altset 1
    Format: S32_LE
    Channels: 8
    Endpoint: 3 OUT (ASYNC)
    Rates: 48000
    Data packet interval: 125 us

Capture:
  Status: Running
    Interface = 3
    Altset = 1
    Packet Size = 224
    Momentary freq = 48005 Hz (0x6.0029)
  Interface 3
    Altset 1
    Format: S32_LE
    Channels: 8
    Endpoint: 3 IN (ASYNC)
    Rates: 48000
    Data packet interval: 125 us