With Dell Support Assist microphone test -- earphone playback is good, on-board speaker is terribly scratchy. The sound card lists as "ATI high Definition Audio Device" and "IDT High Definition Audio CODEC."
The laptop is Dell Studio 15 (1555) running windows 7 Professional, 236GB used, 214GB free space, Intel P8700 2.53 GHz Processor, 64 bit OS, 4GB memory
The built-in speakers used to sound good but now they are too scratchy to understand. However the headset and external speakers (both 3.5 mm jack interface) sound good and a HDMI connected projector sounds good.
I will appreciate advice.
Hello. As a test, switch from the IDT audio driver to the Windows native audio driver.
1. Open the Device Manager (find it in the Control Panel, or type devmgmt.msc into the search box).
2. Expand the "Sound, video & game controllers" and right click on "IDT High Definition Audio Device".
3. Select to "Update Driver Software".
4. Click on "Browse my computer for driver software".
5. Click "Let me pick from a list of drivers on my computer".
6. Put a check in the box "Show compatible hardware" if not already checked.
7. In the list of devices, click "High Definition Audio" (the native driver).
8. Click "Next".
9. On the Update Driver Warning box, click "Yes" (install the driver).
10. Restart the laptop if prompted. If not prompted, then no need to restart.
[To get back to the IDT driver, do it again but reverse the names in steps 2 and 7.]
If you get the noise while using the native driver then it is not a driver issue, which would mean there is a strong chance of speaker failure, particularly since the noise is not in headphones. If you would like to replace the speakers I can point you to the service manual.