Input – the first step
We get technical again for this weeks tip, and this is a good one. It’s just something you can keep in mind to make sure you’re getting the best out of your DAW, it’s mixer and all your plug-ins.
First up, let’s look at the differences between an old analogue mixer and a modern digital system. On the analogue mixer 0 or unity gain was not the top of the channel and pushing past it was possible and in some cases pleasing on the ear and as you drive up and things get fuzzy it can really benefit your music. Whilst in a digital system 0 is the rock solid top, there is nothing above 0, nothing, and if you push up into it you will only get missing data, which will manifest itself in harsh digital distortion…but there are a few confusing differences and misconceptions which I will endeavour to clear up now for you.
On the individual track channels and buss channels in a modern DAW such as Cubase, they use what’s called a 32-bit Float internal mixer. This has the effect of allowing you to push those channels without any of the horrible digital distortion you would associate with hitting 0 on a digital mixer – great right? As long as you bring the master fader back down so you are under 0 before your output you don’t have to worry, right?
Wrong! …well not completely, but there are a few things you need to know about before you do this, and a few very compelling reasons why you shouldn’t mix that high up.
If you look at a big desk, or a small one for that matter, you will find that the 0 or unity gain on a hardware mixer isn’t at the top, and there are positive figures above it. The zero equates to the point where you are neither reducing the voltage nor pushing it up. When mixing digitally, that unity point of 0 has an equivalent in the digital realm, and although there is no voltage in a digital mixer and it should be completely transparent at any level & there is much less need to consider the noise floor and the dynamic range available, it’s still good to aim to mix around there for many reasons which I’ll go into shortly. Due to differences in design and function, the magic figure you should be aiming for in your digital DAW varies, but to be on the safe side -18 is the best place to start. So think of going above -18 as beginning to push it a little, and you can imagine if you are up near 0 you’re pushing it a lot – right? Well you’re not, in a digital system there isn’t the inherent distortion and drive..but
Now here comes one of the “issues” to take into account: when many plug-in designers write their code these days they often, quite rightly, and desirably, copy and follow the function and specification of older hardware. Also copying its calibration and the way it operates. This calibration denotes how it responds to different input levels. So what you get when using your analogue emulating plug-in in your mix, (with your mix set up at levels higher up the mixer than what you would expect if you were mixing on a desk) is that in some cases you will get what would be the equivalent of a heavily driven mix. It can be quite subtle but this, along with other issues, can add up to a less open and dynamic mix.
Some plug-ins may clip internally, some may continue to respond well and as I mentioned some may be written to have input drive and distortion that is pleasing. But it is only in mixing at a good reference level of around -18, that you can make sure you use these effects on your terms when you want to. Making sure that they’re not forced onto your mix in a heavy-handed manner is important. A better option is to boost the gain into the plug-in to get that drive if you need or want it. So you’re not losing any flexibility or choices by doing this, rather gaining them.
There is also the issue of overheads as your audio combines as it goes through to your master buss, and you can end up with some digital distortion if you’re not peaking below 0. I would recommend making sure your master buss meter doesn’t peak much above -6 or even lower just to be safe. In doing this you can make sure you also avoid inter-sample peaks, which is where you can experience clipping and distortion even though there are no peaks above 0…if you have two or more consecutive sampling points next to each other near 0 the “line” (for want of a better word) the D/A convertor in your sound-card will draw between the two will go over. (see pic)
Now so far I’ve been talking about avoiding clipping, but sometimes that could be the desired sound you are going for. Clipping has become quite popular in some musical scenes. The best results often come when clipping into expensive equipment with high quality A/D convertors. It is also sometimes emulated in plug-ins in soft and hard clipping options and they’re well worth having a mess with. My point is mess on your terms, mess when you decide to. If you mix too hot you will have all sorts of distortion and clipping going on you didn’t choose to put in your mix.
Use distortion in its best form
Distortion is one of the most wonderful things! In its very best form it’s gorgeously musical and can add a truly amazing tone to your music. In its worst form, it can destroy your tone and dynamics and leave your music distracting and cold, even annoying.
By following the simple rule of making sure that on the input of every track, you are around -18 on the digital mixer, you will make sure you are not just getting the best out of your plug-ins but you will also be set at a prime level if you use any external fx or hardware.
Careful gain-staging = great sounding records = FACT.