When the Problem is Staring You in the Face

I had an interesting experience over the last couple of weeks, with a mixing problem that should have have been obvious and easy to fix, but because I was too focused on details, I missed the bigger picture and let the problem persist for way longer than it should have.

I’m still in the finishing off stage of a track which has ended up becoming the most drawn out and time consuming piece I’ve worked on so far. I just looked back to previous posts and realised I said I was on the ‘home straight’ with it more than 2 months ago.

Part of the reason this track took longer than others was that it was the first where I’d used an acoustic instrument for one of the main themes… an acoustic piano riff (from NI’s ‘New York Grand’). As with acoustic percussion samples I’ve discussed in a previous post, any recorded acoustic instrument is inherently going to have a much greater dynamic range than synthetic sound. And to fit this into the generally very narrow dynamic of club music, considerable but careful application of compression is required.

The piano riff I came up with, I thought, had a nice dynamic… getting thicker in texture and a bit louder/stronger towards the end of the riff… I felt this gave it a bit greater feeling of tension. Although a fair amount of compression would be required to make the riff fit well in the mix, I was keen to try and preserve as much of that dynamic as possible. Hence when mixing I was too focused on trying to preserve dynamic of the riff that I’d liked in the soloed part. This unfortunately led me to being too cautious in applying compression, and ended up pushing the piano part way too high in the mix (in order to get it to stand out properly). Added to this was the mistake of not following my own advice and regularly checking back against reference tracks, so when I finally did do a side-by-side comparison with my usual reference material I’d created a kind of ‘inverted smile’ in terms of frequency spread… with piano and mid-range way too dominant, and not nearly enough bassline nor cymbals.

Once I figured out my mistake, it was pretty easily corrected with a simple application of Waves’ Renaissance Axx compressor (after having spent at least a week going in the wrong direction)… sure I had to sacrifice some of the nice dynamic I had originally wanted to highlight, but looking back, I think that original desire was misguided. The track I’m writing is in a minimal-techno style… where narrow dynamic and very loud overall track levels are commonplace… the expectation to keep a main acoustic instrument part fairly dynamic, and achieve a competitive level in the overall track was a bit unrealistic.

So 3 important lessons I learned for going forward…

  1. Audition parts in the context of a mix. Things that sound good on a soloed part may no longer sound so good, or even be completely lost in the context of a whole mix. I was too swayed by trying to work towards a soloed piano sound which I thought sounded good… it would have been better to have always auditioned it in the context of the mix right from the start.
  2. Be realistic about how much dynamic range you can achieve in styles which are innately highly compressed.
  3. Listen to and compare to your reference tracks regularly!
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Cleaning Up a Mix

there’s usually not one magic fix in order to realise a fairly abstract goal like ‘make the mix clearer’

Over the last week I’ve been finalizing the mix of a new track (Summer Wave).  In terms of sound texture, it’s the ‘thickest’ track I’ve written this year, with quite a lot of instrument and percussion layers mixed together.  The thicker the texture of a track gets, the more challenging the mixing process becomes, as you’ve got more layers of sound, and more frequencies competing to be heard in a limited space.  Hence, early in the process when I started with a rough sequenced mix, one of the first things I wanted to do was clean up the mix… to remove ‘mud’ and make the individual layers more distinct and audible.  Generally I find that in removing ‘mud’ from a mix, there’s usually no one ‘silver bullet’ solution, and the improvement comes from repeated iterations of small fixes.  That was the case here, but there were 2 changes which both made a significant improvement to cleaning up the mix.

The rough mix sounded like this…

…not too bad for a first cut, but i wanted the individual elements to be clearer.  While doing some cleanup work on some of the individual layers, I soloed this ‘glass bottle’ track (so named because it came from a sample of a glass bottle being tapped on a tiled floor)…

I was surprised at how much low frequency content there was in this part… especially because i usually high pass filter the raw samples of sounds like this long before I get to the mixing stage.  The sample had a loud transient ‘thud’ sound at the start at approx 135Hz.  This sat right in the frequency range of both the bass line and the ‘meat’ of the bass drum, and given the ‘glass bottle’ sound had been included for its high frequency, bell-like rhythmic pattern, this sound down around 135 Hz was redundant, and was probably just ‘muddying’ the sound of the bass drum and bass line.  I initially applied a high pass filter at ~300Hz, but after a few more iterations of review decided I could set it at 518Hz without detracting in any way from the part of the glass bottle sound I wanted to hear.  The soloed glass bottle sounded like this with 518Hz high pass filter applied…

The full mix after this change, sounded like this….

Granted its subtle, but to me there’s a definite improvement in the ‘smoothness’ of the bass line (because the rhythmic pulsing at around 135 Hz caused by the glass bottle pattern has been removed).  And importantly, as discussed at the start of the post, it’s an important step in the iterative process of cleaning up the overall sound.  (Note – to more clearly hear the ‘smoothing’ in the final full mix, download the before and after mix clips and A/B them with a low pass filter at about 200Hz).

More towards the end of the mix process, i was reasonably happy with the overall sound of the mix on my monitors, but i felt that the synth ‘stab’ sound was not clear enough in the mix when auditioned through my tablet and earbuds.  The mix at this point sounded like this…

After soloing some of the parts, i realised that one of the background percussion parts (sourced from a sample of an aluminium coke can) had a note which played at the same time as the synth stab…

Coke can…

Synth stab…

The problem was that the fundamental of that first coke can note was at 221Hz (the A below middle C), and that same A was one of the notes in the synth stab chord.  Basically the 2 sounds were competing for the same frequency space.  Give that first note of the coke can was really just a grace note to the second higher and more prominent note, I made a 3.3dB cut at 221Hz on the coke can track, which resulted in…

And sounded like this in the context of the whole mix…

To me this made a pretty significant contribution to allowing the stab sound to sit more clearly in the mix.

Again, my experience is that there’s usually not one magic fix in order to realise a fairly abstract goal like ‘make the mix clearer’.  But through iterative and successive iterations of fixes like those above, high-level overall improvements can be achieved.