KnowHOW: Ones and zeroes – Going fully digital (part one)
KnowHOW: Ones and zeroes – Going fully digital (part one)
Gordon Moore explains the planning involved in a full digital upgrade
When I first joined my church, over 20 years ago, the sanctuary was an acoustical nightmare coupled with a sound system disaster. The room itself was very nearly a perfect echo chamber with no acoustical treatment and the sound system was a very simple consumer-level mixer/amplifier hooked up to low-cost music system speakers with a very low-end wireless microphone. Intelligibility was impossibly poor, and the overall sound was a severe distraction from the worship experience.
As discussed in my last column, we treated the acoustical problems and replaced the system with an engineered automatic mixer solution. We selected an automatic mixer because, at the time, the church was strictly liturgical with no band, just a strong choir that needed no amplification. Four professional wireless microphones were installed, three body packs and one handheld.
About six years later, a band and more contemporary style service was introduced, which called for another upgrade – this time to a manual mixing console. We kept the same speaker cluster (which was designed for the eventuality of a band). A sound booth in the acoustical field was built. This required training technicians to mix live, developing a projections team and adding more professional wireless microphones. The automatic mixer was replaced with an analogue Yamaha MG series and floor monitors were brought in for the band. Nearly three miles of audio cabling was installed to lead the sound booth from the stage area.
In 2012, we upgraded a third time. This upgrade brought in-ear monitors, more channels of wireless and multiple floor pockets leading to a 56-in x 20-out matrixing mixer system under the stage that routed the stage audio back to the sound booth via Dante. The Yamaha mixer was replaced with a PreSonus mixer using a Dante breakout box to allow it to receive Dante signals. The Aviom in-ears, however, were still tied to the PreSonus via analogue cables and the booth was still mostly analogue for all support gear.
Seven years later – summer 2019 – after zero failures on the Dante network in spite of lightning strikes and power outages, we upgraded for the fourth time to a full-on Dante installation. We upgraded the mixer to a Yamaha TF3 with the Dante NY-64 card installed. We upgraded the Avion in-ear system to their Dante-based headend. We added eight channels of Lectrosonics DSQD digital wireless microphones, plus two M2T Duet transmitters for wireless IEM – all Dante enabled. The existing six channels of digital hybrid wireless were put on the Dante network with an 8-in, 8-out line level Dante breakout box. We re-wired every rack and the sound booth.
The under-stage headend features 56 channels of input and 20 channels of output using Lectrosonics Aspen mixers that are all placed on the Dante network via a 32X32 Lectrosonics Dante SPNDNT automixer. This stack services seven floor pockets around the stage.
This last upgrade allowed us to pull 56 analogue cables out of the sound booth and replace them with just four Cat-6 cables. We eliminated multiple stages of A/D or D/A conversions and reduced the latency in the entire system dramatically.
Another positive: we did this last upgrade in just three days and never lifted a soldering iron!
Planning a system upgrade
If you are planning a major upgrade such as this, the devil is in the details. We planned for six months prior to ordering any gear. How do you go about doing this?
Step one: Document your existing system in great detail. Your existing system must be drawn up in a complete document showing all cabling as it currently stands. This critical step is important because you want to make sure your new system offers the capabilities you already have, plus any new capabilities you want to add. You can’t do this if you don’t write it all down and double check everything. If you haven’t documented your cabling, you will miss the chance to clean it up (make it better and neater in the rack), to refine and improve your signal paths, and to have the necessary documentation you will need when you rebuild it all. So, your planning starts with drawing your system as it is today.
After documenting your cabling routes, you need to document your signal routes. What is the difference? Signal routes will take into account which signal goes from what source to what destination and how. Is it being routing through the matrix in your mixer? Or is it being routed via a patch bay (analogue or digital).
Cable routing is the actual cable diagram. In an analogue system, the cables will typically match the signal routing (one or two signals per cable). In a digital system, one cable may carry thousands of signals routing to many different destinations.
While you are doing this, take some time and label all your existing cables and terminations – it will be very helpful later.
Finally, document which devices will be used in the new setup and which will be eliminated.
Step two: Document your new system requirements. This is your chance to carefully assess what functions and capabilities you want to keep and what you would like to eliminate.
At first, your document will reflect only the signal routing requirements. How many inputs? How many outputs? What signals at each input and what signals at each output. Once you have the ins and outs decided, then you can determine the routing that happens internally in your new digital system and where (in which component).
Step three: Compare the before and after. This is the step where you must challenge every assumption in your system design. Do not get caught up in the ‘we always have done it this way’ mode of thinking. That might prevent you from making the right decision for future growth and improved workflow.
An example: in our old system, if the worship leader decided to move the band from the left side of the stage to the right, we would re-route our signals to the mixer by changing the Dante system routing using Dante controller. This would take some time, typically an afternoon, to re-route everything to the new configuration. We almost went that route in the new system, but then discovered we could route all our Dante sources into the Lectrosonics DSP Aspen stack via the Aspen software, then re-route/mix them to any other Dante bus without touching the Dante network at all. The software allowed for fast re-routing. With the new system, we can now re-route the entire stage to any input on the Yamaha mixer. If we move the drums from FP1-2 (floor pocket 1, input 2) to FP3-8 (floor pocket 3, input 8), we can still have the signal show up on the Yamaha’s input 2 and make the routing change in less than a minute.
Going full digital means rethinking your way of viewing the system. In the old system we had separate lines for the Aviom mixes from the mixer to the Aviom headend. In the new digital system, the direct outputs are simply the Lectrosonics preamps routed direct to the Aviom via Dante. We even pick off the house mix sent to the amplifiers for FOH for the last channel on the Aviom so the musicians can hear the house mix if they want.
Step four: Get rid of duplicate gear. When you go full digital, your mixer will come with signal processing, including limiting, compression, equalisation. I know many sound guys who love their preamps, their tube compressors and their old White EQs. If the new digital gear has those capabilities, use them. Retire the old gear. Let it go. Donate to a smaller church that needs help! But do not overly complicate your new system with redundant functions. We pulled a lot of gear with this upgrade and gave it all away. We kept the amplifiers, the speakers, the Aviom personal mixers, six channels of wireless and the computer audio interfaces. We eliminated the earlier mixer, the Aviom analogue head, two IFB transmitters, seven channels of old wireless, some old computer interfaces and a lot of cabling.
The document outlining your new system must be complete. In a full digital system, you will be dealing with matrices of inputs to outputs. Having these carefully documented in a spreadsheet – both electronic and hard copies, will help you avoid routing conflicts.
Step five: Tear down. Schedule your implementation carefully. Try to estimate the time it will take for each stage. For example, we used the first afternoon to tear down the sound booth. This involved removing everything from the booth with all the contents in four piles – Keep, Discard, Donate, Recycle. As the gear was removed, we placed it in its correct pile. Then we cleaned and vacuumed the entire booth so that we were starting out with a very clean work area. We had two computers, projectors and audio playback/control. The playback/control computer has our recording software for the Yamaha TF3, Dante Controller, Adobe Audition, and the library of manuals for the current equipment in pdf format. We threw out all paper manuals.
Day two was dedicated to the amplifier rack. Complete teardown, cable check, dust removal, cleaning and vacuuming. Then we reinstalled according to the new plan.
Day three was the under-stage rack (which required the fewest changes) for two hours and then two hours for programming and set up of the completed system.
A helpful tip: take your estimated time for each stage and add 33% more time. If you think it will take three hours for a particular stage, schedule four hours. This type of work rarely goes according to schedule. If you do complete within three hours, you have a spare hour for the next phase that doesn’t go smoothly. This helps avoid the late-at-night, 3am panic work the night before a critical service.
Until then, be blessed and mix well.
Gordon Moore is the director of technical ministries at Rio Rancho United Methodist Church in Rio Rancho, New Mexico and president of Lectrosonics Inc.