In this final instalment of the Mixing Drums in the Modern DAW series, we discuss
transients, ratios and other compression settings, EQ with compression and
ambiance.
Transients
Transients are the first few milliseconds of the waveform and drums are full of
them. In comparison with a flute, you will note that the flute’s transient
characteristic is slow and gradual, whilst a snare drum’s will be short and sharp. It
is largely in reaction to these transients that a compressor works. Generally, a
faster attack time will suppress the transient and a slower attack time will let more
of the transient through. Subsequently, a fast release will let more decay of the
note/instrument through, whilst a slow release will suppress it. It is by cleverly
utilizing these two controls that you can achieve the desired relationship between
transient information and sustain. Also please note that excessive [fast]
compression can greatly affect the top end and it is how a particular compressor
handles this problem that marks its quality.
Ratios and Settings
Generally the ratio is selected based on how much gain reduction you will need
when the audio extends over a given threshold. Typically, higher ratios for drums
are chosen from 4:1 all the way up to hard limiting, depending on the application.
For rock/pop drums I generally find myself using the UAD 1176LN between a 4:1 to
8:1 ratio with the attack set medium-slow around the “3’ mark and the release quite
fast, usually with the release dial cranked all the way to the right. This equates to a
release time of about 200ms but it is not uncommon for release times to approach
50ms, depending on the tempo of the music. These settings are not set in stone,
however, as I will adjust to the material for either less dramatic or more extreme
settings, whatever the need may be. As far as other compressors go, the DBX160
or the Empircal Labs Distressor will do equally well, pending the exploration into
their sounds. The DBX 160 is a VCA-based compressor and the Distressor is a
digitally controlled compressor that employs a harmonic distortion component. Both
have been used on many a hit record and will process drums in a very pleasing
manner. As far as plugins go, UAD makes emulations of both of them and they
sound very good.
A note on the 1176LN: The 1176 ratio buttons, when pushed in simultaneously, offer
what is called the “all button mode’. The result is a unique-sound that soon became
widely copied in rock music mixes and has been imitated by other compressor
manufacturers. The ratio goes to somewhere between 12:1 and 20:1, and the bias
points change all over the circuit. As a result, the attack and release times change.
This change in attack and release times creates a compression curve that results in
an “overdriven’ tone.
EQ with Compression
Naturally, because a compressor increases the average level of a given source, it
helps immensely to filter out the offending frequencies so that they are not
amplified along with the frequencies that you want. Cleverly isolating and
eliminating troublesome resonances and frequencies can aid in better sounding,
smoother compression. Just be aware that any erroneous boosts before the
compressor in any of the offending frequency ranges will result in those ranges
being amplified. Inversely, EQing after compression can help in gently tone shaping
the drums to the desired sound.
Ambience
Once I have got a good balance with my unprocessed drums, I focus on creating L
and R ambience tracks that can be blended into the master drum group to broaden
the spatial information of the drums and give them depth. It is also common to
have an additional snare reverb but often room ambience is sufficient so it is not
uncommon for the snare reverb to be omitted.
There are many ways to add ambience to drum tracks. The first and most obvious
is to record them in a good sounding room that has favourable acoustics and set up
a stereo pair of room mics. A single mic can also be used for this. Obviously this is
a luxury for most so knowing how to emulate ambience artificially using plug-ins is
essential.
In the interest of using only the highest quality artificial ambience, it is of my
opinion that convolution reverbs that employ impulse responses are the best option
for achieving this. I use SIR (Super Impulse Response processor) and Steinberg’s
Reverence, but there are many other (and expensive) alternatives out there such as
Altiverb, Waves IR-1, Wizooverb, Nebula, etc. The thing I like about SIR is that it
supports files up to 96kHz, is completely free, and is compatible with wave file
impulses which means that if you’re so inclined, you can make your own using
Voxengo Deconvolver or a similar de-convolving utility.
And it doesn’t just stop with reverbs. There are many websites on the web where
you can download all sorts of impulses made from various kinds of outboard units
such as preamps, compressors, famous outboard reverb units and also impulses
captured from real acoustic spaces.
The process of creating an ambience track is simple. What I do is I solo all the
drums and insert an instance of SIR on the master or drum bus (you may use your
favourite reverb plug-in) and set it to 100% wet. I usually turn the kick down quite
a bit as I don’t want it to cause the reverb to bottom out and because I am aiming
to recreate the sound of the drums in a real room as I would hear if it was actually
miked up. In fact, you can attenuate whatever you like as now the channel faders
essentially become FX sends. Just save your mixer level settings for the drum
channels so you can go back to where they were when you’re done.
Drums generally require short to medium room ambience so I scroll through my
impulses/reverbs until I find one that I like. What’s nice about SIR is that it has a
powerful filter section with infinite bands that can be used to pre-EQ the reverb and
eliminate mud and shape the reverb to taste. Once I’ve picked an impulse and
tweaked the filter I set my left and right locators to include the entire drum
arrangement (be careful to leave a bit of time at the end to capture the reverb
tails) and export/bounce the ambience down to split stereo mono tracks back into
the project / session. I then pan them left and right and bus them to their own
group, which is routed to the master drum group track. You now have a stereo
ambience that can either be mixed into the master drum group (for ambience
blending via the compressors’ release knob) or merely sent to the master bus as an
open, unprocessed ambience. It is also common to compress room mics quite
heavily and the UREI 1178 stereo compressor was a usual go-to compressor for this
duty. Also, the free SSL LMC-1 plugin was released for this purpose. It is a digital
emulation of an SSL reverse talkback microphone compressor that engineer Hugh
Padgham found worked great on drum ambience mics during a recording with Phil
Collins. It is now available in plugin format by SSL and it’s free.
When using a dedicated reverb for snare, the mono snare sub-group can be fed via
an FX send to an aux/FX channel where another instance of your favourite reverb
plug-in is inserted. High quality reverbs are a must here as they too are not all
created equal. The snare can be radically enhanced by a short roomverb, a gated
reverb or anything else that tickles your fancy and serves the mix. The options
really are endless and picking the right reverb for the song is just a matter of taste
and experience. The more you get to know your available reverbs the more you’ll
know what reverb to use for what purpose.
Final Considerations
The techniques outlined above are only guidelines and demonstrate only a few of
the countless techniques that are out there. These particular ones have worked for
me and the clients that I most encounter and should be viewed as techniques to be
used in a pop/rock production. I hope that some of you found helpful hints within
this guide and that they will help you along your way. I believe that audio engineers
should stick together, help one another and share experience so as to benefit the
industry as a whole so, happy production.