Recording levels

Discussion in 'Microphones (live or studio)' started by alexfree, Sep 1, 2004.

  1. alexfree

    alexfree Guest

    Hi! :)

    I'm new hear at RO (hey to everyone from sweden) and have some questions about recording levels. 24 bit recording gives me a big dynamic range to record my analog stuff.

    Question is what is cubase (or other sw) showing with the peak meter, is it the headroom/clipping of the soundcard if its 0dB? WHy is the soundcard mixer showing different signal level than the one in the sequencer software and the 1 million dollar question ....are there some guidelines of where in the db scale I need to be to make clear recording (Bob Kats wrote in his book that -3dBFS or even down to -10dBFS in 24bit) is perfect as recording level....then I realised that I don't have a meter that can give that information....not the sequencer mixer, not the soundcard mixer....????

  2. soundlevelz

    soundlevelz Guest

    This answer is going to be horribly technical but I hope it helps answer your question...

    The level meters on your soundcard will not read the same values as the level meters in Cubase SX, and do not even change on a comparitive basis, because they are measuring different things.

    dBV stands for Deceibel Volts and is and compares and analog voltage Reference level is 1V Formula is 20xlog(voltage/1). 1 was taken as a rounded number to the original reference 0.775V which was based on the voltage needed to generat 1mW of power across a 600 Ohm load. This harked back to the days when most recording equipment had a 600 Ohm impedance. All other voltages were compared against this reference to give a dbV value. Since an analog signl is essentially voltage varying with time you can hopefully see how dbV is used to measure signal levels in a sound card.

    “dBFS,” stands for “decibels full scale” which was created specially for digital epuipment. Unlike dBV, the reference level isn’t somewhere near the middle, but at the very top possible measurement. This means that “0 dBFS” designates the highest possible level. So all other measurements expressed in terms of dBFS will always be less than 0 dB, in other words, a negative number.

    So - dBfs compares sample levels Reference level is 2^(n-1) where n=no of bits Formula is 20xlog (sample level/2^(n-1)). The dynamic range of a 16-bit digital system will be much lower than for a 24bit (or in the case of Cubase) a 32-bit system.

    You're therefore not going to be able to measure like for like between your Cubase mixer and you sound card. Optimal levels for digital recording (use your Cubase meters) are between -3dBfs and -10dBfs. If you start to push a digital signal beyond this it will sound very bad indeed!

    Just ensure that neither is clipping and you should be fine. Don't rely overly on meter levels either you're best reference points are your EARS!
  3. Roey

    Roey Guest

    Hello Sweden,

    I'm 99% sure that your meters in Cubase are PPM dBFS. If so, you should use them to record at the highest levels possible WITHOUT CLIPPING (which is kinda the rule for digital recording).

    If you don't know what PPM or dBFS means - you should undertake some research, cause dBs and meters are such a vital part of the recording process.

    Here is what, in my opinion, is the best explanation of dBs:

    As for PPM/Vu meters, there are so many resources on the web, so just google...
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