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what a load of waffle, all im talking about is an upgrade from some thing inferior to some thing better, its not meant to prove any thing to any body and i don't have to. like i have said before, if i was that serious about wanting to prove the upgrade was better i would have already built an anechoic chamber to test and listen to my music in, with all the relevant diagnostic equipment built in, which i haven't.If 'better' requires a human assessment, it suffers from bias. If > > "better" can be reduced to merely the absolute measurement against > > a universally accepted scale, then the comparison can be objective. > > Therefore, 1 decibel can be objectively compared with 4 decibels.> > "Too loud" is entirely subjective and cannot be assessed without > > bias. So you could compare the results objectively by measuring > > signal:noise ratios or some other absolute measurement but whether > > that measurement means that the equipment is "better" is not > > necessarily objective unless everyone agrees on what type of> > measurement result IS better. > surely the reference point would be the object that is being replaced.No, the reference point depends on the parameter being measured. You have to be able to calculate absolute parameters for the two objects *AND* agree ranges for those parameters that are universallyaccepted as comparable.Merely comparing two values without reference to an accepted range is meaningless. If both values are within "normal limits", any difference is without merit. Therefore the reference point itself is not a single point but a range with an error range as well, depending on how it was measured. DeviceA could give 24 decibels and DeviceB could give 25 decibels but if the measurement itself has an error margin of ± 2 decibels, the comparison is meaningless. The reference has to be a range, beyond which you can statistically show that the difference could not have arisen from pure chance. Hopefully you'd use a measurement device that is more accurate than ± 2 decibels but the point is that a range must still exist, even if it is ± 0.05 decibels. That also then mandates repeated measurements in multiple circumstances. -- Neil Williams
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