Gobuleberbu wrote: > I have been experiencing the same bug, although it was with the bruteFIR > plugin. Setting sound attenuation resulted in an increase in loudness. > It seems like a small bug [emoji218] > > I managed to enable attenuation through the squeezelite setting > directly.
IN C-3PO you have gain, that is linear like the one in squeezelite and Loudness. Loudness is not linear, it applies the Isophonic curve: 30657 The rationale is: 1. select the SPL where you 'perceive' your speakers as 'linear' (i.e. 60phon). 2. apply a gain variation i.e. -20db the resulting level is not a 'plain' reduction of 20db at all the frequencies, but some frequencies are reduced more than other, resulting in loudness, that is meant to 'preserve' the same perception (or EQ) you have when listening at 60db. In that example, at 60phon 200Hz are at 60db as 1000Hz are, but at 40phon (resulting from the attenuation of 20phon) they are 'louder', more or less 42db. The opposite for 500Hz, that is a bit 'louder' at 60phon than at 40. Posing the reference at 60, 40 or 80phon is arbitrary, you could select any of them, the result will change a little, being the differences form 100 and 80 different from the ones between 60 and 40, but, usually, an attenuation is resulting in more 'loud' where a positive gain will result in a flatter line. SOX has a caveat with loudness: the 'balance' of the two channels it often changes a bit, so you'll have to compensate using per channel volume controls. Loudness is not my 'preferred' way to EQ, the one I prefer is 'shelving EQ' (Treble and Bass command) that works like the good old' tone controls' in amplifiers, just remember to always use attenuation. I.e. Treble -3 160 results in a moderate boost of bass. Treble -2 160 Treble -2 630 Treble +2 10000 is a very little loudness Please note that the +2 is after two consecutive -2, so the resulting absolute correction at 10.000Hz and over is -2. Never be able to understand if the gain value is expressed in db or what. To me is smaller than db, but never measured. here some details: http://sox.sourceforge.net/sox.html about isophonic curves: https://en.wikipedia.org/wiki/Equal-loudness_contour +-------------------------------------------------------------------+ |Filename: Curve_isofoniche.svg.jpg | |Download: http://forums.slimdevices.com/attachment.php?attachmentid=30657| +-------------------------------------------------------------------+ ________________________________________________________________________ Author of C-3PO plugin, Squeezelite-R2, Falcon Web interface - See www.marcoc1712.it ------------------------------------------------------------------------ marcoc1712's Profile: http://forums.slimdevices.com/member.php?userid=34842 View this thread: http://forums.slimdevices.com/showthread.php?t=105309 _______________________________________________ Squeezecenter mailing list Squeezecenter@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/squeezecenter
