[dylan604]

Maybe? It doesn't have a scale on the vertical, so you don't know how loud it is. It only shows that the horizontal bars are about 10dB. It's not a good chart. Essentially, somewhere just below 220Hz, it appear that there is a 10db dampening of the noise. We still don't know what that dampened level is though which makes this a meh chart at best

[bgoated01]

Since sound levels differ with distance and environment, absolute levels are not all that meaningful without a detailed explanation of their measurement setup. A 10dB reduction roughly corresponds to something sounding about half as loud to human perception.

[dylan604]

I can see this point, but a 10db reduction from 90db to 80db is still really loud. A 10db reduction from 40db is even more impressive.

So having some baseline would still be helpful just to get some sort of reference. For science, you'd put the dampened wheels on a car and get readings from inside the car as that's the only thing relevant. You'd then replace the wheels with non-dampened versions on the exact same car, and then take your measurements from inside the car again.

This isn't rocket science. It doesn't need to be any more complicated than taking readings where your target audience will be sitting. The fact that this even needs to be stated explicitly just makes me sad for common sense

[bgoated01]

I mean, we’re talking half as loud. I would have thought to a layman it would be a lot more impressive to remove half of a loud sound than half of a quiet one. But I’m wrong on that one judging by your comment, which is fine. To a noise control engineer whether the sound is loud or quiet makes no difference to how impressive it is because these are linear systems (unless we are talking extremely loud e.g. >140dB). Good point on the obvious measurement location.

[dylan604]

If I offer you half of a pie, you might think I'm being generous. If I then tell you the pie is actually only 5cm in diameter, you'd be disappointed. Receiving half of a pie that is 30cm would be much more impressive.

Telling me you removed half of something with out telling me the size of the something isn't compelling.

[brokenmachine]

You do have a general idea how loud an undampened car is, though.

Taking half of that noise away is pretty good, although a bit less good because it's only at certain frequencies.

[bgoated01]

Yeah, I guess the reason we're talking past each other here is I'm thinking of the tool; if I gave you a coin that would purchase half of any pie then the pie size is irrelevant. Put this tire on a different road and the absolute sound levels will change, but the sound difference with and without the treatment will not.