Sound not coming out of my external speakers when plugged into my docking station


I have a Sony VAIO VGN-CR120E laptop running Windows 7. My Plugable docking station works great in every way except for one. When I plug my external speakers into the docking station’s headphone jack, the sound comes out of my laptop speakers, not my external speakers. But if I plug the external speakers into my laptop’s headphone jack, the sound comes out of the speakers as designed. But I don’t want to plug any more into my laptop than I have to (I already have the power and firewire).


Hi Ed,

Thanks for the question! The default on Windows 7 is to switch audio output to any new USB audio device that arrives. But perhaps Sony has changed that default in some way.

This post (from a user having the opposite problem) shows the audio control panels in Windows 7:…

So on your laptop, when the docking station is plugged in, does the “USB Multimedia Device” show up? And what audio device does the Sony laptop leave as default?

Thanks again for your purchase and for posting your question!


For the benefit of others, want to post what the problem and solution ended up being.

The apparent problem was Windows would not match any driver to the audio function on the dock. In Device Manager for the USB audio device, the status was “The drivers for this device are not installed (Code 28).” This is unusual, since the CM6300 chip in the dock uses the built-in Windows audio class drivers - there are no other drivers to install.

The problem turned out to be that somehow on this system, Windows 7’s built-in INF for USB audio, which should have been located at \windows\inf\wdma_usb.inf, was missing (either because the machine was upgraded from Vista to Win7, or because of some other audio work an IT helper had done months earlier).

So the solution turned out to be: copy wdma_usb.inf from another Windows 7 machine back to the \windows\inf directory, then go to device manager, “upgrade driver” on the audio device, and explicitly point it back at the \windows\inf directory to find the inf.

That resolved the problem - audio playback then worked as expected. We were glad this mystery got solved!


I am also having exactly the same problem - laptop speakers work with dock but external speakers plugged into dock don’t. External speakers work fine if plugged directly into the laptop but not the dock. My laptop (Toshiba Satellite 740) is brand new (only two weeks old). I’ve looked to ensure that \windows\inf\wdma_usb.inf is present and it appears to be. All drivers appear to be up to date. I don’t have access to another windows 7 machine to copy the file from. Do you have any other suggestions?


Hi Kristen,

Thanks for posting! I am sorry to know that you are having trouble getting the audio to play through speakers plugged into the audio port on the Plugable Docking Station UD-160-A.

Are you seeing ‘USB Multimedia Audio Device’ in the list of Playback devices? Here is how to check on Windows 7 -:

  1. Click on Start>Control panel and select ‘Hardware and Sound’

  2. Click on ‘Sound’. This will bring up the list of available audio devices, one of which should be your USB audio device. You should be seeing something like this-:


Do post back and let us know and we will figure out the next steps.