# Can Macbook Pro internal sound card be calibrated with digital out?



## wideopenvista (Dec 14, 2010)

I have already used the loopback method to calibrate the analog output and input using the right channels from each. What I'd like to know is whether this calibration is good when running sounds using the optical out (same port, oddly enough). Thanks!


----------



## JohnM (Apr 11, 2006)

There's no way of knowing for sure, typically the variations that the soundcard cal removes are more on the input side (anti alias filtering) than the output, but the low frequency roll off of the digital path through your system will likely be different than that of the analog output so at very low frequencies the cal would not be accurate.


----------



## laser188139 (Sep 19, 2009)

One way to test the difference is to take a measurement with each connection and compare the results. If your receiver has preouts for the front channels, you could measure one of these, with the front speakers set to Large/Full-range -- that would remove the microphone and mic calibration file from the system. Comparing the two measures would give you an idea of the combined difference of the digital output from the soundcard and digital input of the receiver vs. analog output and analog input. Then you can decide if it is negligible for your purposes. 

Bill


----------



## Martin_Andersen (Dec 4, 2012)

Hi are you using the digital out or have you bought a min jack to phono cable? I am asking because I also have a macbook and I am just starting with REW.


----------

