joist sound insulation

[The Natural Philosopher]

That's *highly* subjective.

I'd say more like 40dB is a 'halving of the noise'

[Dave Plowman (News)]

10dB has long been established as a *subjective* halving or doubling. 40dB is more like the difference between a whisper and shout. It's approximately the dynamic range of FM radio - so if you can imagine the quietest passage on a symphony being broadcast on R3 against the loudest part, you'll get the idea.

[tony sayer]

dB scaling looks like its been re written;!...

[geraldthehamster]

Which is why heat insulation and acoustic insulation batts are different products ;-)

Cheers Richard

[Huge]

Well, you can always rely on TNP to be wrong.

[RobertL]

That's also what I was taught many decades ago.

Robert

[The Natural Philosopher]

Odd. My radios turned in > 60dB S/N.

[tony sayer]

You can with some equipment get better than that!. Not that its a lot of practical use these days...

[The Natural Philosopher]

Subjective cant be right, d*****ad.

Lets see. 10dB is one tenth the noise POWER so it cant be half as loud by any OBJECTIVE measurement.

It isn' one half the amplitude, either. Its about one third.

It cant be one half the log power or log amplitude either because thats nonsense.

Ergo its an entirely subjective assessment which is merely what some people decided 'felt right'

Is the city (80dB) twice as loud as the country (40dB). And a rock band at 120dB twice as loud again?I would say so, personally. I am entitled to my subjective assessment like anyone else is.

I mean if I only kick your head in half as much as your opinions deserve, how much less damage, is that?

Entirely subjective I would say.

[Dave Plowman (News)]

If you take 100 people and get them to turn down a radio so it is half as loud, it averages at 10 dB. That's why I said subjective. Nothing whatsoever to do with power or voltage ratios.

[Dave Plowman (News)]

Not by very much. ;-)

[The Natural Philosopher]

which 100 people would that be, then?

[Dave Plowman (News)]

Any normal people. Which excludes you, obviously.