Using Sonar since it's first iteration.  Have upgraded multiple times - currently running X3 producer, windows 7 Ultra - M-Audio Delta 1010 interface.  Audible pop and crackle 3-4 seconds into any new recordings on record and playback.  Began about a month ago. Does not affect any older files recorded prior to the issue nor on the MP3 player, Windows audio player etc.   Hoping someone has some advice on what may be the cause and some resolution.  Thanks.

Hi, and welcome to this forum. Which driver mode do you use with your 1010?  
Are you using 32 bit or 64 bit Windows? 
I used ASIO drivers when I had mine in Vista and Win 7.
If you are not using them, I suggest that you switch to ASIO drivers.
They are found here: http://m-audio.com/support/download/drivers/delta-6.0.8
Have you tried to increase the (ASIO) latency buffer?
That is all I had for now.
Best of luck.

 64 bit Windows.  I will try the download you posted - thanks for the response.
 

You have Win 7 SP1 installed?

Hello and welcome,
without knowing your system specs it´s 
hard to help, but I remember having similar problems during the
time I was recording  with the Audio Delta 1010 le, which is the economy 
version of your audio interface. The non-symmetric ports didn´t shield
the voltage network connection.
 
Are you using symmetric  cables and do you switch off your network  etc during mixing aso ?
 
regards
Pragi
 

Thank you will look into that