Gain Staging and Why You Should Care

 In TSM Studio Blog
  • When we question what adjectives best describe some of the greatest mixes in history, we often use terms such as “dynamic”, “wide”, “punchy”, “musical”, “balanced”, and so on and so forth. At the root of all timeless mixes lays proper gain staging structure that enhances the musical content and allows for those descriptive terms to fit that specific program of music. To further this discussion, we would first need to understand what exactly is gain staging? 
  • The simplest definition of gain staging can be described as the process of passing a signal from one stage of processing to the next. Whether you were aware of it or not, you’ve engaged in the process of gain staging if you’ve ever leveled out a production, affected a signal with a preamp or DI box, controlled the output of a guitar pickup, or manipulated a signal in transit to another location. At every point along the way, how you manipulate your signal will affect the end result of your mix.
  • Let’s say, for example, that you would like to record an electric guitar. Your gain structure begins at the source and would look something like this:
  • Beginning with the level at which the musician plays -> guitar output level -> cable used to transmit the signal from the guitar to the amplifier -> the amplifier’s make, model and construction -> gain/volume settings dialed into the amplifier -> which microphone is used -> which cable is used to transmit the recorded signal to your preamplifier, ad nauseam.
  • As you can see, gain staging begins with the source recording and often continues beyond the final master file print. With modern day DSP’s (Digital Streaming Platforms, not to be confused with Digital Signal Processors) and broadcast compression affecting finalized masters, it’s essential to understand these principles to assure the final result will translate across a variety of mediums. If your intention is to achieve the sonic impact of records engineered for artists such as The Beatles, Michael Jackson, Pink Floyd, and others, you will benefit by keeping your signal healthy as early on in the chain as possible while maintaining that signal’s strength until the very end.
  • How do we assure our gain staging is proper depending on if we’re working in analogue or digital domains? We will begin to discuss this by first addressing the analogue domain. Analogue signals are measured by dBu and dBV, which are two decibel units that specifically measure voltage. In the analogue domain, if your signal is measuring 0VU on an analogue VU meter, then, assuming your working with a professional-standard device where 0VU is equal to +4dBu, you will have at least 20 dB of headroom, likely more. This is typically a ton of room to work with and rarely poses an issue. Each channel strip would need to be driven extremely high into the stereo mix buss in order to overload. On top of that, even at the point of overload, engineers oftentimes seek to obtain the added warmth generated from harmonics as a result of analogue clipping.
  • On the other hand, in the digital domain, signal values are measured in dBFS (decibels full scale). These digital signals act as a flow of information in discrete form with two numerical values: 0 or 1, with 0 being low level and 1 being high level.  Unlike the pleasing sound of analog clipping, when a digital signal is driven beyond 0 dB, the clipping occurs as a result of a system running out of 1’s and 0’s to accurately convert our signal into digital information. Any information that approaches the 0 dB ceiling will be entirely disregarded. Although the digital domain offers what seems like nearly infinite headroom when operated at 24-bit, a greater dynamic range than most users need, driving a signal beyond its -0.1 dBFS ceiling will result in a less musical style of clipping that is essentially an inherent loss of information and fidelity.
  • Having discussed the technicalities behind gain structure within the digital and analogue domains, we can now go about ways to properly structure a mix while keeping our signal’s strength in mind. 
  • First, you’ll want to begin by bringing your signal to line level as early as possible in the signal chain. Ideally, you would want to assure that your signal is recorded with a substantial amount of headroom. When working with 24-bit depth in a DAW (Digital Audio Workstation), an ideal recording signal range should be between -10 dbFS and -20 dbFS on input, however as with everything, there are no rules, trust your ears. If a signal is recorded too low, the added gain necessary to raise its level can induce more noise and bring out artifacts and low-level passages that weren’t initially noticed at the time of recording.
  • You’ll then want to continue your processing by bearing in mind that every component adds noise. Whether working with plug-ins that model analogue hardware or a real-deal FET compressor with circuits hand-built in the 80’s, they will raise your noise floor. On a side note, most hardware-based plug-ins are designed to optimally function at -18 dBFS, so understand that the input level to your plug-ins does matter.
  • As you continue to work on a mix, be sure that you understand the tools at your disposal. Generally, if you have to boost or attenuate, it’s advised to do so with the earlier component in the signal chain, but if you’re aware that the output gain from one piece of gear differs to another in tonality, then accommodate for that. 
  • Next, you’ll want to be mindful of your output faders. I typically recommend keeping them at unity gain as often as possible throughout a mix, forcing you to control most of the leveling within the signal chain. This will allow for the signal path’s true colors to show prior to reaching the output fader. Keeping this method in practice will allow your levelling to become easier as the signal chain progresses, ultimately resulting in the output faders creating a uniform blend across instruments.
  • This next piece of advice goes hand-in-hand with the previous bit about keeping the output fader at unity gain. When processing a signal, adjust for the changes in the output level. In short, this means that if your signal enters a compressor at -8 dBFS and is brought down to -12 dBFS post-compression, correct the output by adding 4 dB of make-up gain in order to maintain your leveling. If you have the ability to prioritize your output fader as the final point in your signal chain prior to it feeding any sub groups or mix busses, do it.
  • Always use your ears and don’t rely on meters all the time. If your mix sounds better with more dynamic range as opposed to meeting an unrealistic loudness standard that differs across genres, then don’t feel like you’ve made a mistake. Whether the gain structure results in a bombastic rock mix with incredible dynamic range and blazing drum sounds or a flat-lined waveform that’s a signature characteristic for EDM, service the music you work on as opposed to serving engineers’ judgment
  • If you’ve read through this entire article, I hope that you picked up on the “shades of grey” associated with the application of these methods. Now that you have a basic understanding of these principles, begin experimenting and focus on how you can break the rules to create something unique and defining. Prioritize your discovery along the way rather than following these rules to a T.