Measurement difference OSX vs Windows 10 home

[MartF]

I'm a REW newbie, but have had some success measuring my system using a mac mini. Recently I wanted to change to a windows laptop and cannot get the measure to show the sub 100Hz output as did the OSX system. My set up is simple - U-MIC and a USB out to my DAC. The two measures are shown below - I simply changed USB feeds into each computer, mic in same position, pre amp vol the same, note I have no av system components implementing a low pass crossover yet the Windows 10 output appears to be subjected to a steep roll off. I'm sure the answer is extremely obvious... but any advice or tips gratefully accepted.

 

[John Mulcahy]

Make sure the Windows laptop isn't set up for a sub, see this link for related info, you may need to configure your device as Stereo if it is somehow set as a 2.1 or surround device.

 

[MartF]

John, thanks for the quick response. I have gone through all the available settings and the problem persists. Here is a shot of the setup - as you see, the soundcard has no sub / other speaker options and I have set the output to 'full range'. I take it many users are able to use Windows 10 with the Realtek soundcard option? I could try reloading the Realtek software

 

[John Mulcahy]

Strange stuff. If the laptop has a line input you could try looping the DAC output back to the line input to see how that measures, could also make a loopback measurement of the laptop's headphone output back to the laptop's line input. If you post the mdat file for the measurements I can see if anything else looks odd.

 

[MartF]

No line inputs only usb, hdmi and a headphone jack. Thought it might be worthwhile posting the info tags for the mac osx - which works (noting its an older version of REW) and the corresponding Windows measurement. It may well be something is very obviously wrong in my setting up of REW Preferences.

 

[John Mulcahy]

Post mdat files rather than images.

 

[MartF]

Here are the mdat files for the mac system then the Windows 10.

 

[John Mulcahy]

The output is set to L+R, are you playing both speakers when measuring? If so, try measuring with one only. The Windows measurement shows the effect of quite a steep high pass filter, for comparison here is the Mac response after applying a 100 Hz LR6 high pass overlaid with the Windows measurement. If both speakers were playing I wonder if there is a polarity issue on one channel with the Windows setup.

 

[MartF]

Thank you for that work! I think it indicates clearly some imposed low pass filter operation. As the laptop was 2 weeks old the retailer agreed to change it! The Dell I did have had an app called Waves Maxxaudio which seems to be slated on the Dell forum - the HP laptop I now have does not have that so fingers crossed - better results when I re try.