What are decibels fullscale (dBFS) and clipping

[@baghdadiabdellatif1581]

Thank you

[@66DX7]

You avoid talking about the digital dB values of peak and rms, and that there are two different ways of defining them. This is making it difficult to handle crest factors when going from analog to digital domain. A sine wave with 0dBFS peak should logically have an rms value of -3dBFS rms.. However some companies and also some standards say that a sine wave of 0dBFS peak also has an rms level of 0dBFSrms, which is making everything complicated. For instance, you get different crest factor calculations in analog and digital domain. You also can create signals that have positive rms value, like a full scale square wave that would have +3dBFS rms. Life would be much easier if we consider a full scale sinusoidal as 0dBFS peak and -3dBFS rms.

[@AwesomeAcousticsEnglish]

Hello! Thanks for your comment. You will notice that this is just a highlight from a longer video. The full video is linked in the end screen and in the description (episode 2 of my main series). There I specificy that dB SPL are referenced to an rms value while dB FS are referenced to a peak value. I don't go as far as to compare the different situations where a sine wave can either be -3 dBFS rms or 0 dBFS as you mention, but I often have to limit the scope of each video at some point to avoid them becoming infinitely long 😅

[@66DX7]

@AwesomeAcoustics in English Yes, I understand. But we need to talk about the elephant in the room. Peak values and RMS values and the relationship in between (crest factor) have been measured and calculated for 100 years in the analog domain. I cannot understand why the dBFS unit should be any different than dBV peak and dBVrms. In analog domain a sine wave always has a 3dB difference from rms to peak. Logically we should actively choose to do so also with dBFS. Some audio softwares allows us to choose.

[@baghdadiabdellatif1581]

​@@66DX7I think the difference is due to reference. There is a reference for consumer instruments such as a sound card and professional instruments such as a guitar mixage panel ... so we find dbu dbv dbfs...

[@66DX7]

@baghdadiabdellatif1581 I am not sure what you mean. Are you sure you understand the differences between peak and rms levels?