Wouldn't it be better to use values other then 0 - 100 for the volume slider? Maybe 10 - 110 would be better. Lowering the volume by 10% makes only 1 dB change. The algorith I use is dB = (100-sliderValue)^2/83, where the slider return 0 for silence and 100 fo full volume, the result value is 120 - 0 dB.Īlso at the upper side, the change is quite small. A Bode plot showing the gain in dB versus frequency. An example application could be expressing the gain of a linear system as a function of frequency in a Bode plot (Figure 1). I set it to -120dB, I'll try to figure out if other values (possibly lower) aren't better. This can be useful to express gains on a logarithmic scale and can also make arithmetic easier, as decibels can be added instead of multiplied. I'll have to figure out what is the best value for "silence". The glossary within the same document does not even list this supposed term, even though weighted decibel terms are defined. What youre measuring is dBFS (decibels full-scale, I think). If youre trying to measure the actual Sound Pressure Level or SPL, you would need to calibrate. This seems to be the best solution so far. The formula for converting a linear amplitude to decibels when you want to use 1.0 as your reference (for 0db), is. The reference added to the decibel article ends up being a document that merely includes 'dB SPL' in a list of terms. I think Yann means that Decibels are a relative scale. It has the best perceptual friendliness: % = sliderpos ^ 2. Recommendation: don't use linear, don't use dB - use power scale. Background The deciBel or dB scale is a convenient way to represent both large and small numbers. If you use a decibel scale, you'll have to constrain the scale to -x dB, cannot achieve 0 volume - fail. To avoid confusion, simply refer to the definition expressed in Equation 3.8.1 3.8.1. A common point of confusion is the proper use of the decibel scale to represent voltage or current ratios. Linear to dB Formula If the ratio represents power. I do not want to calculate exact dBA, I just want to see a linear relationship after my calculations. This tool converts from dB (deciBel) to a linear value. I want to calculate dB from these graphs (they are long arrays). I found some equations in the web: dBVal 20 log (linVal) linVal 10 (dBVal/20) But it’s obvious, that these equations don’t work, because linear 0 is -51.0 dB for Master Volume and -40.5 dB for. This works because the common units of m 2 2 in the numerator and denominator cancel, leaving a power ratio. Ive a Python code which performs FFT on a wav file and plot the amplitude vs time / amplitude vs freq graphs. The C-weighting filter is often applied when representing peak levels. As acoustic sound level measurements are often motivated by the effect of sounds on humans, the A-weighting filter is commonly applied. I hope you’ve learned something from this article.Quote from: Alexey Lukin on 21:53:08 If you use a linear scale for mapping slider position to %, the dB steps near 0% are too big - fail. A’m not using decibels in my app, so I need to convert decibels to linear 0-100 scale and back. The A and C weightings are thus most meaningful for describing the frequency response of the human ear toward real world sounds. Let’s start with this simple math that you’ve learned in the middle school: So we need to discuss logarithm before talking about dB. Using decibels involves working with logarithms, and this is the very minimum math knowledge you should have. This brief tutorial will help you clarify the difference between working with decibels and working with linear values. We can use the decibel gain to compare and calculate the levels of change of two power quantities. I saw a lot of young RF fellows who ignored the importance of understanding dB, eventually realized that they need to learn this simple term well if they want to go further in the RF field. In this post I’ll do the best to explain the basics in plain words and hopefully you’ll not have any more confusion after reading it.ĭealing with numbers for gain, voltage, and power that mix dB, dBm, dBc, dBW, dBmW, watts, milliwatts, volts, millivolts, etc., often requires converting back and forth between linear values and decibel values. Unfortunately, if you can’t thoroughly understand this important scale, then you will have tremendous difficulty to get your RF expedition moved on. It will take a lot of work to keep track of the 14 numbers that change in front of you. The decibel range and resolution of a sound meter display may be similar to the dynamic range of the human ear but usually only in the louder range. Visit ABOUT to see what you can learn from this blog.’ĭB (Decibel) is the most important and often used scale in the RF field, but it’s also understandably difficult and confusing for someone just being introduced to it. The decibel scale (dB) measures a sound’s loudness. ‘Note: This is an article written by an RF engineer who has worked in this field for over 40 years.
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