Preamps are a topic we’re talked about extensively in the recent year, but we love them so much we wanted to revisit them again! This week, one of our lovely clients asked a great question - ‘Can you tell me please, if you know of a good tutorial that can explain to me how to properly set up mic preamps?
I generally understand the premise, but I'm not sure if I'm setting the levels correctly, as I connect it to other preamps that are installed into my interface. Things like which preamp levels should be set higher than the other. Or maybe that has to do with some other factor like the track itself. Or nothing at all (It's flip a coin and take your pick).’
Let's dive in, and talk about this.
Depending on the source and the makeup of your preamp, running them hot can be the best way to use your preamps. By running hot, this applies to tubes and transformers. To achieve this, you increase the input of the signal into the preamp which in turn, increases the voltage into the component (tube or transformer).
By doing this, you’re adding more harmonic distortion to the signal giving a thick and warm sound to the timbre/tone of your instrument or voice. The output of the preamp however, needs to be compensated for the increase level on the way in (I’ll explain why in a second). Harmonic distortion is a topic we’ve talked about alot in recent months so I won’t go into too much detail, but if you’d like to understand it in more detail you can find the previous posts here.
But a brief understanding would be that it fills in the gaps of the audio and adds more depth to your tracks. This is why tubes and transformers are great to run hot as they impart a certain flavor respectively that you can’t recreate by using an EQ or compression.
Running cold is of course, the opposite of the above. This is for hen you’re looking to achieve a more transparent sound and can be a great tool for hen you’re not looking to drive the signal and add distortion to the signal.
As opposed to a warm sound, using the preamps in this way will retain your source tone a lot more and you’re be far more reliant on the sound of the microphone and instrument you use. This technique is a great tool for say a soft vocal, or violins/orchestral elements. You’ll also find you have much less noise and hiss when you’re monitoring tracking or listening back.
Another benefit of recording in this way is that when you compress later on during the mix you’ll find you can compress more without raising the noise floor/bringing up more hiss - but you can also add distortion later should you need it.
Adding harmonic distortion during the tracking process means you are committing to it. There's no way to remove harmonic distortion once imparted onto the signal, so make sure you think ahead during recording and always keep the big picture of the entire track in your mind's eye so you can make the best choice for the source you’re recording.
Lastly, Gain-staging your preamps is an absolute must. If you’re pushing the level into the preamp, you need to compensate on the output of the device. The same applies for running cold and backing off the input of the preamp, you’d need to push the output of the unit.
The reason for this is you’ll find it very hard to process the audio and limit noise if you don't have a correct amount of level from the source. Your DAW should ideally show around -12 to -8db of headroom when recording.
The opposite of the problem of too much noise is digital clipping. This happens when gain-staging has been done incorrectly but you’ve left no headroom and either not compensated for pushing the input of the preamp, or you’ve compensated far too much.
There's a clipping light on all tracks in a DAW or on a desk if you’re an analog user. When this is illuminated it signals your level is far too much and will add artefacts and unwanted, very nasty sounding distortion (not like our much loved harmonic distortion!)
Always make sure you gain-stage with any part of the mix process as digital unwanted clipping can happen at any stage of the process. A/B’ing before and after any changes whether EQ, compression or saturation, etc. is imperative to preserve the quality of your original source recording.
After all, the last thing you’d want is to ruin your newfound knowledge of how to best utilise your preamps, by carelessly gain-staging now, would you!