[LAU] Log F-scale for JAPA

Hello all, I've been asked (in a private mail) if I would provide 'upstream' support for the logarithmic F-scale patches for JAAA which have been discussed recently on this list. The answer is maybe, but certainly not in their current form. 1. As a first and sufficient reason, I don't want to develop the current codebase any further. It's a glorious mess, and in order to add some other features I want to add it needs to be redesigned from scratch or at least completely refac- tored. 2. The current log X-axis grid and annotations are a no-go. I pride myself on getting such things (including slider and meter scales etc.) right, even if that often takes more work than the actual DSP code. Very few tools get this right, even Gnuplot's log scale is useless in many cases (try zooming in). A decent log F-axis needs a lot of ad hoc code (which I mostly have, from other projects). It needs to support arbitrary zooming, and both a technical (i.e. based on a 1, 2, 5, 10 sequence) and a musical (based on octaves, as in JAPA) format. 3. JAAA's original purpose was to measure organ pipe spectra (it was presented at the same LAC as Aeolus IIRC). More generally it is a technical tool, meant for for electronic or acoustic engineers, not for sound engineers doing their normal job of recording or mixing music. As a technical tool it must provide results that are both as accurate as possible and well-defined. Well-defined means results that correspond to quantities, equations, etc. that are used in electronics, acoustic and DSP theory, not necessariy the most relevant ones in a musical context. For such technical uses the most convenient presentation is on a linear F-scale, for the simple reason that the analysis performed by JAAA (essentially a DFT with some extensions) is defined in terms of a linear frequency domain. 4. In those cases where a logaritmic frequency axis presentation would make sense (the classical 'marketing style' frequency response plots), JAAA is simply not the right tool. It does not provide enough resolution at LF, or tons of irrelevant and misleading detail at HF. And anyway, you can't measure speakers, mics, etc, with continuous signals (as expected by JAAA) unless you have a large anechoic room at your disposal. And if you really want to do such measurements, the tool the use ATM is JAPA with either a slow logarithmic sine sweep or pink noise. There *is* a lack of good Linux based tools for this sort of thing, but the cure is not a log F-scale for JAAA but some extra features in e.g. Aliki. But of course I'm looking at this from my perspective. If there are any people out there using JAAA _and_ wanting a log F-scale I'd like to know what exactly they are doing. It may not result in a log F-scale for JAAA, but maybe in something better. 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)