Strange audio Ads.

For starters, I run Zone Alarm and Spybot Search and Destroy on a regular basis.

Within the last 10 days, after I sign on, I'm getting strange 'Audio ads' when I'm on line. They sound 'scratchy' as in low quality AM radio signals and also sound as if they're 'bleeding over' one another. Nothing is obvious in task manager.

The only way to 'quiet' them is to mute my audio. Not desirable.

Thanks in advance.