Members rasputin1963 Posted September 16, 2015 Members Share Posted September 16, 2015 Just a real basic dumb n00B question here: In digital, why is 0.0dB your "brickwall" number, and why do all other dB readings plunge into the negative digits? (I realize, this is like a small child's "Why is the sky blue" kind of question, but all info appreciated). Of course, I fully use this system every single day, but when I was first getting into digital audio, it was momentarily counter-intuitive to me. Link to comment Share on other sites More sharing options...
Phil O'Keefe Posted September 16, 2015 Share Posted September 16, 2015 Decibels are a ratio unit of measure that has to reference something - a level or voltage... in the case of digital audio, that reference is full-scale; "0" on your meters. Anything lower than full-scale has a negative number because it's below that point, not above it. So -3 dBFS is 3 decibels below maxing out. In the analog days, we also referenced 0 dB on our meters (usually that corresponded to +4 dBu, or 1.228 volts RMS across a 600 ohm load), but if you look at old-school VU meters, you'll notice that the numbers are negative below 0 (-20, -10, etc.) but also positive above 0 (+1, +3, etc.) - unlike digital, you could often actually exceed 0 without suffering any negative consequences. And you're right - if you're coming from an analog background, it can seem counter-intuitive, and it threw a lot of people off when the transition from analog to digital recording systems was occurring. Link to comment Share on other sites More sharing options...
Members rasputin1963 Posted September 17, 2015 Author Members Share Posted September 17, 2015 Thanks very much, Phil! Link to comment Share on other sites More sharing options...
CMS Author MikeRivers Posted September 17, 2015 CMS Author Share Posted September 17, 2015 http://www.recordingmag.com/resources/resourceDetail/246.html Link to comment Share on other sites More sharing options...
Phil O'Keefe Posted September 21, 2015 Share Posted September 21, 2015 Coincidentally I ran into an article from Presonus today that you might find interesting Ras... http://support.presonus.com/entries/22234380-StudioLive-metering-dbFS-vs-dbu Link to comment Share on other sites More sharing options...
Members Notes_Norton Posted September 21, 2015 Members Share Posted September 21, 2015 <...> but if you look at old-school VU meters' date=' you'll notice that the numbers are negative below 0 (-20, -10, etc.) but also positive above 0 (+1, +3, etc.) - unlike digital, you could often actually exceed 0 without suffering any negative consequences.<...>[/quote'] I remember trying to max out at +3 on analog VU meters. It was the spot with the most energy and undetectable distortion. I tried it with digital when I was new at that and got a wake up call for the difference between the two. In the analog days, low recording levels seem to make the end product sound duller, that doesn't seem to be the case with digital -- at least to my ears. So I record a little low, and then boost the volume a little to get it closer to zero. I don't know if that's proper procedure or not, I'm a player, not an engineer, but it seems to work for me. Insights and incites by Notes Link to comment Share on other sites More sharing options...
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