So far, 2017 has been an interesting year. In just the first three months, my touring schedule has taken me to New Zealand, Australia, Singapore, Hong Kong, Brazil, Argentina and Chile. We’ve encountered a variety of P.A. systems and used three different console types at FOH. The Australian shows were mixed at FOH on a DiGiCo SD5; the shows in New Zealand, Singapore, Hong Kong and Brazil were mixed on DiGiCo SD7s; and the shows in Argentina and Chile mixed on Avid VENUE Profiles.
Making the Console Switch
DiGiCo provides file conversion software for easily transferring show files between models in the SD platform line. This software agility enables maintaining up-to-date files for both the SD5 and SD7 mixing platforms. Although I migrated away from Avid to DiGiCo a few years ago, there have been enough one-off shows with locally provided VENUE Profile consoles to keep my Avid files up to date as well.
At one point in South America, the schedule presented an opportunity to closely compare the way the show sounded when mixed on the SD7 to the sound of the same show with the same band mixed on the VENUE Profile just two days later. It was particularly notable that I heard far more similarity than difference in the overall result. But arrival at this point of similitude occurred only after the mixes followed vastly different pathways. When using the DiGiCo format, I rely heavily on the onboard capabilities of the console. The stock mic preamps, the AD converters, the tube emulators, the extensive dynamics section, and the versatile equalizer section carry much of the signal processing workload. When using the VENUE platform, I relied far more exclusively on my library of TDM plug-ins to do most of the heavy lifting.
I have tried to keep this comparison experience fresh in my mind because it provided the incentive for a new project. During this time off before summer touring begins, I am investing some time in re-examining the sound of one particular instrument. To my ears there was enough of a difference in the main acoustic guitar sound that I want to do some experimenting. In specific, I really liked the guitar’s high-end sparkle I was hearing while mixing on the VENUE. Conversely, the low-end resonance and the lower midrange body through the DiGiCo system were both especially memorable. However, I wouldn’t characterize either guitar sound as clearly superior, just discernibly different enough to merit further investigation. Because the artist for whom I work is an acoustic guitar virtuoso, I am always searching for new methods to better present that instrument.
The Acoustic Guitar Project
Each year, we try to make specific improvements to the overall audio product. Sometimes changes are big, as they were last year with a new touring P.A. system. Sometimes changes are as small, such as switching out a microphone. In every case, it’s imperative that any changes result in improvement and are initiated by a reasonable expectation of achieving a specific goal. My goal is to knit together my positive experiences from each mixing platform and discover a synthesis that more closely resembles the electronically unencumbered sound of an acoustic guitar.
Accurately reproducing the sound of an acoustic guitar through a large venue audio system has always been a challenge for live sound engineers. Carefully placed, studio-quality condenser mics are the best way to truly capture the full character of the instrument. But then there’s that huge amount of preamp gain needed to fill an arena plus the existence of the multiple, and often very loud, sound sources on the stage that make the microphone option unusable. The struggle to make acoustic guitars audible yet not sound like an electric guitar is similar to the difficulties engineers encounter while attempting to make an acoustic piano played live sound natural — and not sound more like an electric piano being played through very small speakers. Resonant wooden boxes just like to resonate and often do just that at very low frequencies.
It does seem that the particular combination of transducers, electronics technology and software that we have evolved for use in the Yamaha C7 acoustic grand has succeeded admirably in producing a realistic live piano sound from that closed lid instrument. Our present amalgamation requires blending the two microphones included with the Earthworks PM40 piano system, an AMT M40 microphone and a Barcus Berry 4000XL piano pickup. Each of transducers is used to reproduce/reinforce different frequency bands and the results have been extremely satisfying. Having four inputs to manipulate in terms of time, polarity, equalization, modification and dynamics control gives an engineer a lot of freedom to shape the sound without asking too much from any one transducer.
Pickups and Post-Pickup
In the case of the acoustic guitar, one often has only a single sound source from which to attempt building a complex sound. That source is most commonly an under-saddle piezoelectric pickup mounted in the bridge of the guitar. Over the years, there have been many other attempts to create alternatives, but most of these well-intentioned solutions have instead turned the entire guitar into a microphone that feeds back constantly. The various sound hole magnetic pickups can be strong and punchy but may not exhibit their strongest articulation/definition in higher frequencies.
And so it always seems we return to using the saddle pickup as the most reliable sound source. This device provides the greatest gain before feedback without being forced to put a plug in the sound hole. A pickup that is well matched to the guitar should produce an output that can be shaped into a balanced sound. A high quality preamp with input circuitry optimized for a piezo pickup is the best place to start the signal chain to the consoles. Adding a second sound source that can be treated separately from the preamp signal is always a good option. We have had great success in blending the output of a Radial preamp with the output of a Fishman Aura unit. Early on, we learned to add a small amount of delay to the preamp output to compensate for the latency through the Aura system and things took off from there.
During my years on the Avid platform, I was particularly fond of the Smack! compressor. It was an important part of the acoustic guitar sound. Smack! operates with a very light footprint and the compressed signal does not exhibit an easily detectable high frequency loss. Smack! also holds the lower midrange together beautifully and the available operational options make it a versatile tool. Since moving to the DiGiCo SD5, my acoustic guitar compressor of choice has been the Waves V-Comp. As one would expect from a circuit emulation derived from Neve consoles in the 1073 era, the V-Comp is extremely warm sounding and produces a signal that has depth, texture and substance. We also gain substantial warmth by engaging the tube emulation section available in the input stage of the SD5.
We have been using the SD5 onboard 4-band parametric equalizers on both Aura and the Radial inputs. On the Aura side, the lower mid band and the upper mid bands have been switched into dynamic equalization mode for greater control of frequencies that often jump out when the guitar is hit harder. On the Radial output, the top two parametric bands have been switched over to dynamic equalization, as those frequencies seem to become more accentuated at greater amplitudes. The meat of the guitars is now so strong that I was not aware that I had traded some away some of the previous sparkle and shimmer until I heard the show mixed mix through the VENUE console. Creatively addressing this situation has now become the subject of my homework. I don’t want to remove any of the tools that are currently being used. I am very pleased with the direction we have taken. But I am hoping to add subtle touches to further improve what is already a very good presentation of the acoustic guitar.
In the (Home) Laboratory
To that end, I am now engaged in the process of recording my very old Taylor 815 acoustic guitar in order to make some reference tracks. The Taylor has no pickup so it must be miked in order to be recorded. I have initially chosen to use a combination of a Shure KSM44 and a Neumann KM-185. Once I am satisfied with the mic choices and their placement, I will play a couple of my employer’s songs and record to Pro Tools 12 using my new Apogee Element 24 Thunderbolt recording interface. The mixed down tracks will be exported to use in comparison to artist-played tracks that were recorded on tour last year. My intention is to capture the openness, the delicacy and balanced frequency response that my beautiful old 815 exhibits in this room. I will then use these tracks as a control from which I can quickly refer while I am engaged in massaging the actual acoustic guitar sound in the intended direction. I will in no way attempt to mimic the sound of the Taylor but I do hope to successfully re-imagine some of the harmonic combinations that make a guitar sound uniquely complete.
My intuition tells me that the Waves Vitamin plug-in may provide the means to add a controllable harmonic boost to either guitar input. Another option I am considering is creating a small room reverb to use in conjunction with the longer gold plate reverb we currently employ. The TC 6000 algorithms have great room sound presets that I can use as a stating point. I believe I can build a space that mainly consists of early reflections to add some tonal complexity to the guitar sound. I am also thinking about experimenting with replacing the Waves 2-tap delay I currently use with the Waves 6-tap delay. I may then be able to judiciously add a bit more sense of enclosed, reflective space to the guitar sound to enhance the shimmer.
So there is always much to do during my “time off.” Next month, I will report on the results of this particular process.
Safe Travels!
