Hi Alan,
Thank you very much for quick response and the patch. The patch fixed the mic on both cameras.
I have also added the following patch (see https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=3...) for avoiding the kernel warning.
--- linux-3.10.5-orig/sound/usb/mixer.c 2013-08-04 12:51:49.000000000 +0400 +++ linux-3.10.5/sound/usb/mixer.c 2013-08-06 21:12:42.274197287 +0400 @@ -888,6 +888,7 @@ case USB_ID(0x046d, 0x081b): /* HD Webcam c310 */ case USB_ID(0x046d, 0x081d): /* HD Webcam c510 */ case USB_ID(0x046d, 0x0825): /* HD Webcam c270 */ + case USB_ID(0x046d, 0x0826): /* HD Webcam c525 */ case USB_ID(0x046d, 0x0991): /* Most audio usb devices lie about volume resolution. * Most Logitech webcams have res = 384.
-- Maksim Boyko