Transients versus bass, a common misconception

If you've ever had any form of audio engineering training, you will have almost certainly have come across the perceived wisdom that bass sounds take up the largest room in the mix. You will have been told to cut any sounds with presence below a certain point, unless they are bass instruments. You will likely then have gone home and tried this and wondered why your mix suddenly sounds like it has no life and no body to it and isn't really that much easier to master or mix. The truth is that bass is not always the culprit for db headroom. The largest eater of headroom is often transients.

Loud sounds often have a very pronounced spike in their soundwave, usually right at the start of the sound. This is called a transient. This can often be very loud in comparison to the nature of the rest of the sound, leading to it spiking out meters and limiters, while the rest of the mix is nowhere near that volume. So why aren't these just picked off by the limiter? The problem lies in the fact that all the parts of a mix intermingle at the same time and within the same frequency space. Limiting that snare drum's transient might end up taking down that hi hat with it if you just slap a limiter across the mix. Some win can be had from using a multiband limiter and isolating the frequency of the transient in question but i've found this to be a mixed results endeavour. Personally I find it more effective to limit or compress the part in question, prior to the final mixdown.

So how does this relate to bass? Well the nature of transients is that they are usually quite fast, hence the name transient, and as such are less likely to be made up of bass content. Bass takes time to develop (in the context of millisecond measurements) and is therefore not normally the cause of the problem. Bass instruments turned up abnormally loud can also cause issues with headroom, as the whole sound then becomes louder than other peaks, but generally speaking they are just more likely to muddy the mix and make the low end less defined.

The way I often go about detecting this transient issue is to slowly build up my mix, hitting it off a limiter with a readout of the gain reduction, and see what instruments lead to audible and visible dips in the meter. The most common culprit for me is the snare drum. That initial 'whack' of the snare can generate a transient that is so obnoxiously high above the rest of the music, it makes it impossible to master without ducking everything else at that point. The trick is not to even attempt to hit the whole mix with a compressor/limiter until we'v dealt with that snare separately, as discussed above.

So in conclusion i'm all for cutting bass in instruments if they are causing a build up or an unfocussed, muddy, low end. If, however, you just want to give yourself more headroom and more volume in mastering, i'd look to transients on individual instruments.

If you would like to see a worked example, I've done a video on it which you can see below

Joey Sturgis

So I've been reading a lot about the Joey Sturgis method lately and to me its very interesting. Particularly the idea that he does everything himself, including mastering. Conventional wisdom in the audio engineering field seems to be that you should always have someone else master your music if you want it to be of the absolute top quality. Sturgis' argument is that having control of the entire process, end to end, gives him more control over the sound of the production. He follows up by saying that often mastering issues are actually deferred mix decisions. This part of the argument i've heard from the same people who say its a terrible idea to master your own music but to me its much easier to fix the mix issues if you still have access to the mix. Sturgis also states that he works with his mastering chain largely in place and treats the entire process as moulding a piece of clay. The mix is less a series of process steps and more an unfinished production that works towards being complete. When its done, its done - mastered and all.

As with all things I feel there is a balance to be sought. There are different mindsets for different problems with audio production and the mental blurring can be a bit disruptive if you aren't careful with it. That being said, the idea of mixing and mastering at the same time is quite liberating as you avoid the jarring "My music doesn't sound loud enough" towards the end of the mix process. If you want to read more I recommend the sound on sound article below:

http://www.soundonsound.com/sos/sep14/articles/joey-sturgis.htm

Mastering with headphones.

Probably not the world's most popular idea but recently I've been mastering with headphones. Why? Well a number of reasons.

•  Familiarity

I listen to pretty much all my music on my headphones. That is a whole lot of mastered, finished, polished, professional music. As a result, I know my cans inside out. I know how much bass they should respond with, how much treble there should and generally I know what music should sound like through them.

• Perfect listening environment

People tend to complain that headphones dont give an accurate responce, certain frequencies are hyped, stereo placement isn't good etc etc. But the one advantage they have for most home studio owners is that they dont suffer from reflection issues or peaks and nulls in an inconsistent way. If your room is quiet, headphones sound the same wherever you are in the room. As for the disadvantages, i've usually sorted the vast majority of those issues already by the time I come to do my mastering. Im really just making a few final eq changes at this point and doing a little bit of mastering compression and limiting.

• The microscope effect

Because headphones typically put the sound right at your ear, you can generally hear tiny details in the music. This is generally what you are looking for when it comes to mastering, the details, the small things that polish a track. As such headphones really are perfect for this task.
   

On limiting and stereo depth

The main complaint that people have about heavy limiting in the mastering stage is that it reduces dynamic range. This a perfectly well founded complaint but this heavy limiting also has a detrimental effect on other factors in the mix. One of the more overlooked side effects is the way that it damages stereo imaging.

The main way that we perceive a stereo signal is differences in the left and right channels (or speakers). If a sound is identical in both channels and our listening setup is relatively sane, we hear that sound from a, ghost, central position (mono). As if there was only a single speaker centrally playing the sound. If we add changes to the two sources individually and with different values (time shifts, pitch shifts, different eq etc) we hear the signal as stereo. A well crafted mix will have many of these differences and will make use of all of the stereo field to put the sound across.

Now if we consider what a limiter does, it essentially chops off peaks in the signal when it reaches a certain threshold of volume. So lets say that the left side has a signal which fluxuates around -6db and the right side a signal which is simply just a single sine wave hit at -3db. For the period that they are both over a threshold of -7db, both signals will simply be a flat-line at -7db. Not only have we lost dynamic information from either side but we'v lost that important difference between the two, and as we discussed earlier, this is what triggers our perception of a stereo signal. This is why simply slapping a limiter over a mix at the mastering stage can often lead to a more mono sounding mix.

As a side note, this also applies when using a brick wall limiter, and even aggressive compression, on stereo sources within the mix as well as at the mastering stage.