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U3011 DisplayPort Audio Distortion
I own a U3011 monitor and I'm having issues with the audio quality from the line-out port. Audio played at maximum volume (0dB) is distorted and clipped.
The monitor is being driven via DisplayPort from two computers: A custom-built Windows machine with a NVidia GTX 670 and a MacBook Air running Mountain Lion. Both sources exhibit the problem. There is a DisplayPort KVM in-between the sources and the monitor, but the issue still remains if I connect the computers directly via DisplayPort to the monitor.
Under Windows, the volume for digital outputs can be adjusted. I can workaround the distortion by setting the system master volume to 50%. Windows seems to occasionally forget the master volume setting, resetting it back to 100%.
Under Mac OS X, digital outputs have no volume control so I cannot simply set the master volume to 50%. A complex workaround is to use a combination of Soundflower (a virtual audio device) and AULab (Apples audio developer test-bed and mixing utility). I set the system primary output to Soundflower to route the audio through AULab, which can adjust the volume of input & outputs, and then set AULab to output the audio over DisplayPort. This workaround is clunky.
I've tried adjusting every setting available on Windows and Mac OS X with no avail: number of output channels (2 or 6), sample rate, bit depth.
I've also fiddled with the one option on the monitor OSD: Audio Settings -> Audio Configuration. Selection 2.0 or 5.1 makes no difference.
To rule out my speakers (Logitech Z-5500's) causing the clipping due to different input levels or something similar, I connected the audio out from the monitor to the line-in on my Windows machine..
Using Audacity I played a sine wave (amplitude 0.8) through the monitor and recorded the line-in input twice. Once with the Windows master volume set to 50% (top), and once with the master volume at 100% (bottom)....
You can clearly see the output is being clipped in the bottom recording.
I firmly believe this is an issue with the internal audio processing of this monitor. There are workarounds for both operating systems I use, but they are clunky.
Is there a solution?
- Adam
JoshSanders
1 Message
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January 30th, 2014 05:00
Bit of a long shot here, as this post is over a year old at this point, but nobody else on the whole wide internet seems to have had this problem.
Did you ever find a solution to this?
Airport1
1 Message
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October 5th, 2014 09:00
Better a late answer than no one. I have the same problem and fixed it like you with setting master volume to 50%, but if Displayport disconnects (which happens sometimes, then also the screen goes blank and sound is gone, and I have e.g. to reconnect the DP cable), often the sound is even worser after that.
So there are 3 issues IMHO for the Dell U3011 at all:
- the described sound distortion, which is even worser sometimes after you re-connect the DP cable
- sometimes while working (via DP) the screen goes blank, then you have to re-connect the cable, no solution found so far?
- no automatic scan for sources (I have two devices attached and always have to select the source myself, even if 1 device is turned on only)
darrankelinske
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January 8th, 2015 13:00
I'm also having audio distortion when using an HDMI Roku stick. The audio output is connected to a logitech speaker system. Has anyone found a fix/workaround for the distortion caused when using audio output port and an HDMI source?