Recent content by MRC01

  1. MRC01

    How to best explain dB to non-audio experts?

    Except when 10 dB is "times 3.16"...
  2. MRC01

    How to best explain dB to non-audio experts?

    Well, she understands that an ounce is actually two different things. It can measure weight (1/16 of a pound), or it can measure volume (30 milliliters). They're the same only when you're measuring water, and they're different for anything else. So how hard is it really to understand dB? In...
  3. MRC01

    How to best explain dB to non-audio experts?

    :facepalm: Nope, she didn't say that. She did say, "So there are two different sizes of dB?" I said, "Yes, there are 2 different dB units and you use one or the other depending on what you're measuring."
  4. MRC01

    How to best explain dB to non-audio experts?

    When I explained this to my Mom, I told her a dB is a ratio from comparing 2 values. If A is 26% bigger than B, that is 1 dB (power). If A is 12% bigger than B, that's about 1 dBV.
  5. MRC01

    Emerson Quartet plays Mendelssohn Octet

    I'm listening to the recording on Primephonic and find the sound quality to be excellent. Very well recorded. Mendelssohn in general has never been one of my favorites, and I've heard all these pieces before. But the way Emerson plays them, I'm hearing new dimensions to this music.
  6. MRC01

    Emerson Quartet plays Mendelssohn Octet

    It's unusual for classical music to overdub like this. Neat stuff about the recording method, the instruments used, etc. And just general goofing off for fun. Part 1: Part 2:
  7. MRC01

    How to best explain dB to non-audio experts?

    0 dB is not total silence. It is a reference point of loudness or amplitude. Total silence is not possible, since air molecules are always moving and bumping into each other. There is always some non-zero level of thermal activity or noise, no matter how small. That's not only true of air, but...
  8. MRC01

    How to best explain dB to non-audio experts?

    Ah, loudness versus amplitude. Two different things, and another common point of confusion.
  9. MRC01

    How to best explain dB to non-audio experts?

    Where is halving 13 times coming from? -130 dBV is halving 21 times. Halving 13 times is only -78 dBV. In the pizza example I think each person's piece would be slightly bigger than 1/8" x 1/8". A 16" diameter pizza has 201 square inches of pizza. Divided equally by 8192 people is 0.0245 square...
  10. MRC01

    How to best explain dB to non-audio experts?

    How many times you halve it is not intuitive; it shrinks much faster than most people's intuition predicts. That said, -130 dBV is a ratio of 3.16 Million to 1, or a ratio of 3.16e-7. That's halving it just over 21 times. Put differently, log base 2 of 3.16e-7 is -21.6. PS: to assess how...
  11. MRC01

    How to best explain dB to non-audio experts?

    For 10 dBV, 20*log(R) = 10, so R = 10^(10/20) = sqrt(10) = 3.16. So 10 dBV is 3.16 times more voltage than 0 dBV. Example 1: suppose someone analyzes an analog audio waveform (which has Volts on Y axis, time on X axis) and says, "The signal is 10 dB louder at time T1, than it is at time T2"...
  12. MRC01

    How to best explain dB to non-audio experts?

    Speaking of bases, I've always thought we should express the frequency axis in log base 2, since that matches our perception. However, using log base 10 doesn't distort it much, it's still way better than linear.
  13. MRC01

    How to best explain dB to non-audio experts?

    The take-away is simple: use 20*log(R) for most of the specs that Amir publishes for DACs & preamps (SINAD, THD, IMD, etc.). Every factor of 10 is 20 dB, e.g. -40 dB is 1% or 100:1. Exception: when measuring power output use 10*log(R). This is important to note cuz some people might look up the...
  14. MRC01

    How to best explain dB to non-audio experts?

    That is incorrect. A dB for measuring voltage is different from a dB for measuring power. This is often confused. Correct. If there were only 1 dB unit as @Cbdb2 suggests, then a 6 dB increase in voltage would create a 12 dB increase in power. Since doubling the voltage doubles the current...
  15. MRC01

    How to best explain dB to non-audio experts?

    That's true for a dbP, but not for a dbV. Most of the specs that Amir measures here are voltage, where every 10x change is 20 dB. For example, if someone says SINAD is 100 dB, that's 10^5 or 100,000:1, or 0.001%. It's not 10^10, or 0.00000001%. This is another common confusion about dB: when to...
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