03-18-2014 03:18 PM
I have already PMed NINE about the RMA number of my previous T440s which sent back to Lenovo due to the noise. I don't think the noise is only noticeble in a deadly queit room. If you use it at night in bedroom, you can clearly notice it.
Every T440S has this problem, but if you test it in a workplace, you may not notice it.
At this point, I don't think Lenovo is able to fix it. It's a hardware problem.
03-18-2014 11:49 PM - edited 03-18-2014 11:59 PM
in my opinion, this sound is near-ultrasound range noise, that's why younger people hear it very loud, and adults, or people about of after 30 years old don't hear it at all.
I know this from a documentary movie, and this is a fact.
As people get older, they hearing range spectrum lowers significantly in higher frequencies, and fully drops in the near-ultrasound frequencies.
Maybe this could be the case.
BTW, I'm exactly 30 years old and I don't hear the noise, or better said, hear it, but very quiet.
Just my opinion.
Can anybody confirm this?
This problem is also discussed here
EDIT: Mark, what I would do is to connect professional spectrum analyzer / oscilloscope to the output of the sound card and look at what frequencies does the sound chipset output.
I'm pretty sure I'm right at this.
03-19-2014 12:06 AM - edited 03-19-2014 12:08 AM
I'll be glad to post a video of it later, but multiple people have already done so in the previous pages and it's pretty much spot on.
I'll summarize the points here so its absolutely clear to the staff of Lenovo
1. Stick your ear right next to the speaker to diagnose! On the W540, that would be the slit, about an inch away from the palmrest Thinkpad logo. The hissing is not really noticeable if you have a lot of ambient noise. However, everyone works in a different environment and when your surroundings are quiet, the noise is irritating.
2. It's easiest to notice when you flip between Mute and Unmute. Make sure the volume is not "0" when unmuted (when volume is "0" hiss is less audible, but still there).
3. The sound is best described as a constant "shhhhhhhhhhhhhhhhh". It's similar to cranking up the volume on a stereo system without attaching a source.
4. Diagnose in a quiet room and get feedback from multiple people. If one person can't hear it, it doesn't necessarily mean another person won't.
5. This also happens on the W540.
Mark, let me know if you need any additional info.
03-19-2014 01:56 AM
03-19-2014 04:25 AM - edited 03-19-2014 04:41 AM
Are you one of those people who are testing it in Lenovo labs?
One can hear the shhh noise being switched on and off when using a pair of headphones. It's quite subtle but it is definitely NOT a normal noise by any means for any laptop's speakers!
P.S: A pro-tip on how to make the noise more reproducible: uninstalling realtek drivers and using default windows drivers instead makes the noise permanent, unless the speakers are muted.
P. P. S: might it be a grounding issue?
03-19-2014 05:02 AM