Optical-in audio occasionally pauses

[Asterra]

Not really sure where else to ask about this. I already know there's probably little real hope of fixing the problem because of the probable uniqueness of my situation.

I'm using an Asus Xonar Essence ST soundcard for audio output (to headphones). This card lacks any sort of input, which means I have to retain the services of my motherboard's onboard audio for that. In fact, the audio input I am using is the optical-in (on a Gigabyte EX58-UD5). This input is almost a hidden feature of the motherboard, requiring the acquisition and installation of a simple optical-in card which feeds the audio to the input on the motherboard. The input is then handled by the Realtek audio drivers.

Here is my problem. The audio coming from the optical-in will occasionally pause for a split second. Call it a tenth of a second, at a rate of about once every two to five minutes (it varies). The audible effect, apart from a minute pause in the flow of the music or whatever, is a somewhat jarring audio pop, like a bad edit in an audio waveform editor. When I say it pauses, I mean literally that; no input is actually lost. Instead it's as though the drivers handling the input are doing this in order to re-sync the input with the Windows mixer, which suggests that the audio is being mixed in at a rate that is very, very slightly too fast, and so needs the occasional tiny pause.

Even though this is clearly not a problem with bad cables, I switched it out regardless, to no effect. No, the problem is either with the drivers (Windows, Realtek, who knows) or, somehow, with the settings I have chosen. By settings, I mean the input and output frequencies and bit-depths, all of which I have set to their maximum (192Khz, 24-bit, I believe). I've fiddled with these at some length but never found any solution to this issue.

Anyway, just thought I'd see if anyone had any suggestions or had heard of this problem before.

[johns0]

I checked on your card specs and it says it has analog input jack shared with the mic.

[Asterra]

Ah, yes. You are correct. Still, the optical-in is my primary source of audio, and obviously it eliminates a couple of unneeded DA/AD conversions. Just need it to not come packaged with this audio pop problem. ;p