How to measure noise by ears?

Vidicio · Post by **Vidicio** » Mon Apr 23, 2007 12:46 am

Are there any guys having some computer always on and trying to make it practically silent? As the tolerance for noise and ambient noise varies a lot, is there a better way to measure the noise levels but using own ears?

When trying to listen to differences in noise levels, I found it quite challenging. When I really want to hear something, I hear it fine and when not concentrating to it, it is easily covered by ambient noise. Then how do I know if the noise is fully covered by ambient noise or contributing to it?

I finally found some ways to measure (extremely low level) noise just by using my own ears. This is the best method I invented for measuring if the computer increases ambient noise:
- Ensure that there is no exceptional noise around, just plain ambient
- Run in the computer some O/S that can shutdown using a command
- Set an alarm (using e.g. mobile phone timer) to start after 1 minute
- Start a script, which:
1. Sleeps 15 seconds
2. Sleeps randomly 0 - 30 seconds
3. Initiates a system shutdown
- Move to position in the room at where you might spend time
- Close your eyes
- Concentrate to listen the ambient noise
- You may try to separate different noise frequencies
- Do you hear some notable change in the ambient noise?
- Is that change the alarm you set in the beginning?

If you hear a clear decrease in the ambient noise when the computer shuts down, it tells you exactly how much it contributes to ambient noise. It doesn't tell how much that may bother you. Anyway, after this test a computer which wasn't supposed to be audible can suddently appear noisy, or at least way more audible than before the test. You hear it now, don't ya?

Bluefront · Post by **Bluefront** » Mon Apr 23, 2007 2:28 am

Sound is a difficult thing to judge using your own hearing, particularly in your own home with a quiet computer. And it becomes increasingly harder as your computer becomes quieter, using SPCR techniques. If you just sit there quietly with your eyes closed trying to tell just when your computer turns off, I suspect you will always be able to do so, if your hearing is normal and your computer has moving parts.

The other day I was sitting there with nothing turned on except my latest computer project. I kept hearing a strange noise which I could not identify. Turned out it was the small fan in my DVD recorder, on the far side of the room. I had accidently left the DVD turned on, and it got hot enough to start the fan. I guess my computer is quiet enough.......

Vidicio · Post by **Vidicio** » Mon Apr 23, 2007 3:53 am

Bluefront wrote:Turned out it was the small fan in my DVD recorder, on the far side of the room.

It is a bit annoying that audio/video devices are internally more and more like a computers and the cooling is resolved using small fans. Those are found even in many receivers.

When byuing A/V devices, I first check that there are no fans. I don't know if that's always better because now I have a receiver and a DVD player without fans but I can't stack the player on top of the (much bigger) receiver because the heat from the receiver then makes the player go haywire within one hour.

Bluefront wrote:I guess my computer is quiet enough.......

No doubt about that.

s_xero · Post by **s_xero** » Mon Apr 23, 2007 3:56 am

Remember that placebo's can play some interference with your own judging.

That's why hard numbers are the finest!

Post by **NeilBlanchard** » Mon Apr 23, 2007 4:19 am

Hello,

Qualitative comparisons are useful. Numbers without subjective comparisons are almost useless.