On Sun, Jun 25, 2017 at 02:34:07AM +0300, Sampo Syreeni wrote: > Could it be that you're just talking about different perceptual > weightings? I mean, if we talk about noise, there we shouldn't ever > go with A-weighting, or even C-weighting, but the ITU 468 curve.
Electrical noise from active mics and mic preamps is normally white and Gaussian, except at low frequencies where you will typically find some 1/f noise. If that is not the case there is something seriously wrong (but see remark about A/B conversion below). If the noise is white then it doesn't matter much which weighting filter is used, as long as it is specified. Compared to a flat 20 kHz bandwidth, the A-filter will typically show around 2 dB less, and ITU-468 will give around 11 dB more. Most manufacturers provide A-weighted measurements, these are more or less the de-facto standard. Very few will give ITU-468 figures. > The one which peaks as fuck between 2-6kHz, and explains how things like > Dolby B and C sliding band companders work so well; the one which > also fails to explain the loudness of impulsive, nonstationary, > nonlinear noise, yet. Not sure what you mean by the latter. The ITU-468 method is quite sensitive to impulsive noise - it was designed to be. That is mainly not the result of the filter but of the very peculiar pseudo-peak detector specified by the standard. In the case the issue is complicated by the EQ which is part of the A/B conversion. The W signal normally requires some boost in the high frequency range, how much depends on capsule directivity and the array radius. My original post was triggered by one of the various "this can perhaps be explained by" remarks in the web article - none of them make much sense IMHO. Another thing which triggered my scepticism neurons is this 'timbre' evaluation of the various mics. Small differences of the 'dull vs bright' and 'thin vs full' kind can usually be corrected by some gentle EQ, so I really doubt if any of this is relevant in practice. More after I've read the AES papers. Ciao, -- FA A world of exhaustive, reliable metadata would be an utopia. It's also a pipe-dream, founded on self-delusion, nerd hubris and hysterically inflated market opportunities. (Cory Doctorow) _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on.
