Similar to bug #72511 I get this message for a ZOOM H2n USB audio interface in 24bit multichannel mode (new in firmware 3.0): Sep 25 20:42:50 i7 kernel: usb 3-14: new high-speed USB device number 11 using xhci_hcd Sep 25 20:42:51 i7 mtp-probe[5188]: checking bus 3, device 11: "/sys/devices/pci0000:00/0000:00:14.0/usb3/3-14" Sep 25 20:42:51 i7 kernel: usb 3-14: New USB device found, idVendor=1686, idProduct=01c5 Sep 25 20:42:51 i7 kernel: usb 3-14: New USB device strings: Mfr=1, Product=2, SerialNumber=3 Sep 25 20:42:51 i7 kernel: usb 3-14: Product: H2n Sep 25 20:42:51 i7 kernel: usb 3-14: Manufacturer: ZOOM Corporation Sep 25 20:42:51 i7 kernel: usb 3-14: SerialNumber: 000000000000 Sep 25 20:42:51 i7 mtp-probe[5188]: bus: 3, device: 11 was not an MTP device Sep 25 20:42:51 i7 kernel: usb 3-14: Warning! Unlikely big volume range (=32767), cval->res is probably wrong. Sep 25 20:42:51 i7 kernel: usb 3-14: [5] FU [Mic Capture Volume] ch = 4, val = -32767/0/1 Sep 25 20:42:51 i7 kernel: usbcore: registered new interface driver snd-usb-audio Some details from alsa-info: Card: ZOOM Corporation H2n at usb-0000:00:14.0-10.2, high speed Unit: 5 Control: name="Mic Capture Volume", index=0 Info: id=5, control=2, cmask=0xf, channels=4, type="S16" Volume: min=-32767, max=0, dBmin=-12799, dBmax=0 Unit: 5 Control: name="Mic Capture Switch", index=0 Info: id=5, control=1, cmask=0x0, channels=1, type="INV_BOOLEAN" Volume: min=0, max=1, dBmin=0, dBmax=0 Card hw:2 'H2n'/'ZOOM Corporation H2n at usb-0000:00:14.0-10.2, high speed' Mixer name : 'USB Mixer' Components : 'USB1686:01c5' Controls : 4 Simple ctrls : 1 Simple mixer control 'Mic',0 Capabilities: cvolume cswitch cswitch-joined Capture channels: Front Left - Front Right - Rear Left - Rear Right Limits: Capture 0 - 32767 Front Left: Capture 32767 [100%] [0.00dB] [on] Front Right: Capture 32767 [100%] [0.00dB] [on] Rear Left: Capture 32767 [100%] [0.00dB] [on] Rear Right: Capture 32767 [100%] [0.00dB] [on]