In previous columns, various Waves plugins that I use on vocals, horns, violins, electric guitars, bass guitars and drums have been discussed. By now it should be apparent that I like to use a lot of compressors. This current entry will focus on my compressor of choice for the acoustic grand piano: the Waves CLA-2A Classic Compressor.
The task of live mixing has many recurring challenges, and one of the most difficult to accomplish successfully is maintaining control over the dynamics of each instrument without sacrificing the natural energy and expression of the musicians. An engineer simply doesn’t have enough hands, fingers or the multitasking mentality to exercise constant vigilance over the all the instruments in a 60-plus input show. It becomes necessary to employ electronic hands to exert that control.
One Size Doesn’t Fit All
By definition, correct application of compression makes softer parts louder and louder parts softer, with the goal of making it easier to hear and appreciate the characteristics of that particular instrument or vocal in the mix. However, it’s never enough to just “sit” on the dynamics of an instrument. That’s the minimum asked of a compressor plugin. I also choose plugins that enhance the differing musical properties of each instrument. I have yet to encounter a “one size fits all” compressor, so I always go through a trial and error process for each input until I find the plugin that properly marries itself to the timbre and dynamics of an instrument.
On the James Taylor tour, we carry a beautiful Yamaha C7 MIDI grand piano that is expertly maintained and tuned by Mark Konrad, our keyboard tech. For obvious isolation reasons, the lid is closed during performances. However, closing the lid creates a very different sound and produces a radically different audio environment for the transducers inside the piano. Mics must be placed close to the strings, and this predictably results in hot spots. Furthermore, reflections are coming from everywhere in a closed box. The instrument’s inputs become harsher and less connected.
The magic is to then reintegrate the whole and somehow create the auditory illusion of listening to a raised lid piano in a normal performance environment. Several tools can be used to attack this audio conundrum. One invaluable tool has been the Earthworks PM40 piano mic system. These remarkable small diaphragm omni mics have revolutionized closed-lid miking techniques. The engineers at Earthworks have created a flexible system that produces astounding results within that less-than-optimum environment.
As noted, mic placement is critical and varies with each piano. The two PM40 transducers are mounted on a telescoping carbon graphite tube allowing variable horizontal placement, both mounted on 6-inch goosenecks for vertical adjustment. One can choose to orient the capsules toward the hammer or toward the nose of the piano. Placement choices become myriad, and the only right way is the one that sounds best right out of the box.
Wherever the mics end up being placed, proper application of equalization will be necessary to smooth out the hot spots created by proximity to the strings. It’s simply a necessary evil dictated by the closed-lid condition. High-pass filters, low-pass filters and parametric EQ must all work in concert to massage the sound back to a more natural, even distribution across its 88 keys.
Subtle is Good
Larry Goldings, our pianist on the James Taylor tour, is an incredibly gifted and expressive musician, and it is never my intention to impose needless dynamic restrictions on his playing. To that end, I chose a compressor that exerts very subtle dynamic control and also enhances the closed lid piano sound by its inclusion in the signal path.
The Waves CLA-2A Classic Compressor plugin was modeled from a legendary unit in the enviable collection owned by Chris Lord-Alge. The overview from the user guide is helpful:
The CLA-2A is modeled on a hand-wired, tube-based compressor originally produced by Teletronix in the early 1960s. Intended for use in broadcast, the original employed an electro-luminescent optical attenuator for gain reduction called “T4.” Unlike other designs, electro-luminescent circuitry doesn’t add distortion when it modulates the sound. (Tubes, however, do, and Waves made sure to model that distortion.) Additionally, the inspiration for the CLA-2A’s frequency-dependent response made it an instant favorite of audio engineers. However, many consider its most unique feature to be its program dependent, multi-stage release, which was achieved using a 2-stage photo-electric cell. With a Frequency Response of 30Hz to 15kHz (+/- 1dB) and < 0.5% THD, the original provided up to 40dB of gain limiting.
The “tubes” do exactly what one expects in the Waves CLA-2A emulation. The audio result is a warmer, richer and denser sound that more closely resembles the output of an open lid piano. I set the compression threshold to just nip 2 to 3 dB off the loudest passages Larry plays. As I said, I want Larry to create his own dynamics and weave his parts in and out of the mix because of the way James and the band have layer arrangements. Instruments speak, then pull back and let another voice be heard. There’s much movement and texture woven into the tapestry created by the mature, gifted players in James’ band.
The screen shot shows the setting on the piano low mic on the PM40 system. There are simply four user variable parameters. Begin with unity gain and no compression, and then turn up the gain reduction until you hear the desired result. Add makeup gain to compensate for compression and “Viola!” One caveat I must give to those who have used old Teletronix units in the past: Don’t get fooled by the metering. Old units still in use often have a tired T4 unit inside them, so 6 to 8 dB on its meter may translate to just 1 or 2 dB of actual compression. On Waves software, however, what you see is what you get.
And what you get is a remarkably accurate emulation of the classic original. It’s not overly noisy, operation is smooth, output is velvety, and the compression characteristics lay gently on the dynamics but leave the musical quality pristine. Adding in the two other parameters allow the user to further enhance the audio result.
The Hum circuit is common to most of Waves’ classic emulations and is included to more accurately recreate the actual operating conditions in which the original units were employed. It’s a simple push button control that lets you decide if the signal is enhanced by adding 50 Hz (Europe) or 60 Hz (USA) line hum to the signal. Don’t like it? Switch it to off. You’re the chef.
The fourth parameter controls how the compression circuitry responds to HF information. Again quoting from the user guide:
HiFreq increases voltage amplifier gain in the peak reduction circuit, for frequencies above 1 kHz, leaving lower frequencies less affected. When set to Flat, the CLA-2A provides equal reduction to all frequencies. The more you move away from Flat, the less sensitive the compressor is to lower frequencies, resulting in less low-end compression.
I dial this control down to increase the HF crossover effect on the low mic. Greater compression on the HF component of the signal lets the left hand come through a little better with more push at the bottom. It also allows me to back off on some of its HF EQ bands.
I’ve also employed this plugin on an acoustic guitar that didn’t produce enough bottom end output. The CLA-2A produced equally pleasing results. This is a good product and carries the venerable LA-2A into the digital age with very little compromise. The CLA-3A is also great addition to the Waves lineup and I will discuss this solid-state brother to the CLA-2A next month.
Happy New Year!
