> ## Content Index > Fetch the complete content index at: https://wishingtree.audio/llms.txt > Use this file to discover other available public pages before exploring further. # Signal Levels - URL: https://wishingtree.audio/signal-levels/ - Published: 2026-07-27T12:00:35.000Z - Updated: 2026-08-16T23:46:58.000Z - Author: Mark Rudolph This article is a quick summary about audio signal levels, and why it's important to know what they are. ## AD/DA Conversion We won't go into great detail into this process in this article, but thought it was important to call out the importance. To get our analog audio into our DAWs, we need to use an *Analog-to-Digital* converter - typically incorporated in our audio interface. The *Voltage-over-Time* signal is sampled at some frequency, and quantized to a digital reproduction; or the opposite *Digital-to-Analog* on the way back out from our computer to some external piece of music gear. The main takeaway here is the capabilities of your converter are the crux of the quality of your audio your every time it passes to/from your computer, and it relates to voltages. For a very thorough overview, check [Chapter 3: ADC and DAC](https://www.dspguide.com/ch3.htm?ref=wishingtree.audio) of *The Scientist and Engineer's Guide to Digital Signal Processing* By Steven W. Smith, Ph.D. The entire book is free to read/download online! ## Decibel Get ready for the math-y part! A **bel** correlates to a change of *power (think Watts)* by a factor of *10*. 2 bel of amplification is 10x10, or a signal that is *100 times* *more* than the original. That's an awful lot for the signal levels we typically work with, so we usually use **decibel (dB)**, which is a tenth of a **bel**. -10 dB, 0dB, 10 dB have the power ratios of 0.1, 1, 10, and so on. For a $P\_{in}$ and $P\_{out}$, we can write that as $$dB = 10 \\times log\_{10} \\frac{P\_{out}}{P\_{in}}$$ We are usually more interested in a signals amplitude **A** than its power, so we can use their relationship to also write it this way $$dB = 20 \\times log\_{10} \\frac{A\_{out}}{A\_{in}}$$ These equations show us that the decibel are a convenient way to think of a **ratio** between signals (a great example is **gain**). Some useful things drop out of this, like every **+3dB** correlates to a **doubling** of the *power* (or **halving**, in the negative direction). If we compare the ratio of a signal against some standard, then we have something that allows us to speak to each other in a common understanding. But, in typical *human* fashion, we take common understanding and make it complicated. When something is given in **dBV**, it's references to a 1 volt rms signal. **dBm** is a signal that produces 1mW of *power* into a $600\\Omega$ load, but **dBu** is referenced to an unloaded rms *voltage* of 0.775V. $$dBm = 10 \\times log\_{10} \\frac{P\_{out}} {1mW}$$ $$dBu = 20 \\times log\_{10} \\frac{P\_{out}}{0.775V}$$ We'll talk about **dBVU** *(Volume Unit -* think of ananalog audio meter) in the [**Line Level**](#line-level) section. ## Mic Level Microphones typically output in the mV to tens of mV range, depending if they have a small amplifier already built in. Using our equations above, that correlates to roughly -60 to -40 dBV. We can see from these numbers that we could end up needing quite a bit of gain for a low-output mic. We can use this knowledge to make sure we have an appropriate mic preamp to pair with the microphone intended to be used. ## Line Level There are two line-levels to be aware of: *Pro Audio,* and *Consumer Audio*. In *Pro Audio*, **0 dBVU** is defined as **+4 dBu** or **1.228 V** rms (roughly **2 dBV**). In *Consumer Audio*, **0 dBVU** is defined as **\-10 dBV** or **0.316 V** rms. So if we try to use a lint out on our personal CD player into our pro mixer, we would find the signal is about 12 dB too low (or 12 dB too high the other way around!). Knowing all these operating voltage levels/ranges is important for different devices to work well with each other, so that the output of one is in the sweet spot on the input of another. Nobody wants an unexpected +12 dB blast to their headphones. This is the cornerstone of[ gain staging](#gain-staging). ## Digital Level **dBFS** (dB Full Scale), which is used in digital systems like DAWS, where 0 dBFS is the hard limit, and harsh clipping will occur with no wiggle room. There isn't an exact conversion from dBFS to dBVU, but it is typically *calibrated* somewhere around -16 to -20 dBFS to equal 0 dbVU - which will probably depend on what your AD/DA converters are capable of! If you don't have a VU meter handy, you can use a trusty multimeter to measure the AC voltage across pins 2 and 3 (hot and cold respectively, with pin 1 being ground) of an XLR output from your converters. You can use a tool such [Room EQ Wizard](https://www.roomeqwizard.com/?ref=wishingtree.audio) to send a 1 kHz sine wave at a particular dBFS level, and figure out which level gives you 1.228 V. Knowing this level will get you in a great spot to know what volumes to target for sending from your DAW to outboard analog audio gear, and how much headroom you have at your disposal. ## Gain Staging The key takeaway so far has been that it's important to know what signal levels different pieces of gear expect as input, and produce as output, so that we can effectively chain them together while they operate in there designed sweet spot. This is especially true for analog gear, which is usually made to operate nominally around 0 dBVU, and can be *musically* driven with slightly more gain. It is just as important in the digital-only world, as plugins can clip - or may even be made to emulate driving analog hardware. By keeping our audio levels in check between each piece of gear, or VST, (aka gain staging) we can avoid unwanted distortion and noise.