On 19/08/2010, at 1:30 PM, Rob Danielson wrote:
> So we don't confuse anyone, recorders have input noise, mics have self-no=
ise.
Hi Rob,
Sorry to cause confusion. In reality we are looking at combined mic/pream=
p noise output rather than mic self-noise and preamp equivalent input noise=
in isolation.
> Many level references and measurements can
> be incorporated but it doesn't solve the predicament that the pres
> have different frequency response under 80 Hz.
It's not a predicament unless you are setting out to prove all preamps soun=
d the same. ;) It's simple enough to use an alignment tone that is above t=
he problematic frequencies.
> If the perceptual tests we've been making over the last 6+ years
> proved to conflict with results in the field or with each other, I
> would have stopped making them.
I agree the tests have generally been useful. In cases like this compariso=
n of Emil's test recordings those who relied purely on the level matching =
in the posting got the wrong answer, simply because the two preamp/mic syst=
ems are so close that a 1-2dB is enough to change the ordering of noise lev=
els for a casual listener. Of the four who got it "right", Raimund, Mike a=
nd myself all used analysis tools in addition to listening tests while Emil=
conducted the original tests. John and Tom who just listened to the file g=
ot the order wrong. I have to admit if I hadn't spent some time investigat=
ing after noticing that clip 4 was quieter than the previous clips, I would=
have picked Recorder A as having lower self noise.
cheers
Paul
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