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Rockbox mail archiveSubject: Re: dB volumeRe: dB volume
From: BlueChip <cs_bluechip_at_webtribe.net>
Date: Fri, 19 Mar 2004 21:04:15 +0000 >>I would also prefer a dB display going from -something dB to 0dB. > >So are you recommending that Rockbox report the +12dB point as 0dB? Or >did you want Rockbox changed so that the highest value of 0dB is what we >call 93% now? These are all the same: # Archos 100% # Rockbox 92% # MAS 0dB Archos puts the max vol at "0dB" so that digital distortion is not a risk. Rockbox puts the max vol at "12dB" so that quiet tracks/poor recordings can be cranked up to an audible level. >I'm confused about all of this. A decibel is a logarithmic expression of >the ratio between two signal power, voltage, or current levels. Assuming >that P2 and P1 are power in watts, the decibel rating can be calculated as: > >dB = 10 log10 (P2 / P1) > >I understand that the wattage can be measured at the headphone output, but >how is it measured internally? > >Note: Decibels can be calculated in terms of the effective voltage if the >load impedance remains constant: dB = 20 log10 (V2 / V1). Since the >headphones vary wildly in impedence, that calculation is out the window. > > > I don't think this is so unusual - all the modern amplifiers / > > receivers (including mine) show volume in dB. > >While typical mid-fi consumer products do that, high-end audio components >and professional products generally do not: > >http://www.adcom.com/preamplifiers/gfp750.htm >http://www.atma-sphere.com/products/mp3.html >http://www.legendaudio.com/prod02.htm >http://www.ys-audio.com/symphonies.htm >www.metaxas.com/pages/products/ opulence.html >http://www.tascam.com/images/popups/TASCAM_AV452Front_Rear.jpg > >Regards, > Fred Maxwell > >_______________________________________________ >http://cool.haxx.se/mailman/listinfo/rockbox _______________________________________________ http://cool.haxx.se/mailman/listinfo/rockbox Received on 2004-03-19 Page template was last modified "Tue Sep 7 00:00:02 2021" The Rockbox Crew -- Privacy Policy |