Significant audio delay

[Clanman]

Hi. I'm a new user of both OBS and this forum. I'm setting up streaming of services from our church. I have a problem with major time lag (up to 15 seconds!) on the audio. This is not consistent - I have streamed three days with no problem then the fourth day gets the time lag problem. This is present on the recording as well as the stream so it must be something to do with the set up in church rather than the streaming server. Any help greatly appreciated.

 

[Clanman]

Sorry for delayed response to this. My set up is :
Intel Core i5-M520 Processor, 2.40GHz
120GB Solid State Drive
8GB DDR3 RAM
I have a papalook Webcam 1080P, AF925, Behringer U-PHORIA UMC202HD mixer taking a line out feed from our church PA system. Camera & mixer are both USB connected.
In addition to the intermittent time delay problem, this morning OBS crashed as the streaming/recording was started. I'm attaching a log file from last Wednesday when we had about 17 seconds delay and the crash log from this morning. Hope someone is able to help.

 

[Clanman]

Cpubusage shows 35 - 50% when streaming and recording.