Case Study: Recording with Networked Audio
Moving recording, streaming and live sound of one of the largest publicly enrolled music colleges in the nation to the Dante network.
You’ve seen articles about concert tours and live system installs that use mostly static Dante routing and a few devices. This is not that kind of article. This is a 1700 channel, 70 devices, in multiple locations install.
About UNT
The University of North Texas College of Music presents about 1,000 events a year; more than half of those are recorded. They range from multi-camera video shoots, live streaming, classical recitals, and jazz combos, to big name performers with large technical riders. Many know UNT as a jazz school and it does have a large jazz program with just under 20 ensembles, part of the 70 in the college. We had to find a solution that was easy enough for student workers to repeatedly operate, but could provide the needs for high quality recording sessions to more complex broadcasts.
Disclaimer, I am no longer at UNT, and this archived article may have outdated or inaccurate information.
About Recording Services & Murchison Performing Arts Center
I oversee the College of Music Recording Services department, that records audio and video of concerts and the live streaming project. It operates in two of the buildings that have concert spaces, the Main Music Building and the Murchison Performing Arts Center (MPAC). The MPAC has its own dedicated staff including an audio technical director.
You can also see our post production web-based workflow here: article.
The FOH engineer, Derek Miller of the MPAC and I put in the 1700 channel system over approximately two weeks.
Our Requirements:
- Simplify by moving to a single transport and routing system.
- Shared remote preamp control with FOH/Recording.
- Access to every channel in all locations.
- Quick and easy to operate with student workers.
- Expandable.
The Process
No to Dante First Time Around
I had a lengthly conversation with Focusrite around 2013 on Dante after being recommended the solution from our dealer, and FOH staff member at the time. I remember thinking down on it, almost like it was a hack or glitchy work-around for situations where funding or physical limitations prevented running more stable dedicated copper and fiber lines. After all, we were awesome enough to have our own fiber optic lines most places, why would we step down to a shared system? Why choose to deal with IT and all their silly overburdened policies and restrictions?
“So make your own network then.”
At the time I remember considering that option, and at the time mistakenly assuming that running a dedicated AV network with quality of service and business-class switches would be a considerable amount of learning and work that only I would understand how to operate. Should I get hit by a bus there would be no one else able to operate it, and that would not be a good solution for the college.
Looking back, I think the sales approach of IP workflows hasn’t been as good as it can be. Looking into IP for video production we are running into the same problem. Give it time.
Exploring MADI
We explored MADI solutions for quite some time and it seemed like the next progression in moving audio. The MADI router became the most important part of the chain and the equipment choice we had to get right. We needed a unit that had buttons on the front for easy student operation to change routing, a website interface for remote control, and inter-channel routing for each MADI line. We found none that fit. There seemed to always be a workflow or situation that was made more complicated by using these routers.
Back to Dante
With the encouragement from the new FOH staff member Derek I looked at Dante again, though this time a larger number of vendors were supporting the spec. Overnight we roughly redesigned the system using Dante instead of MADI. The process was easy, and solved every problematic situation we had with MADI. Initially nothing drastic changed in the layout, but after realizing how much more we could do with less the designs simplified and then expanded.
So I admitted my huge mistake to Focusrite, we hugged it out, and the planning started.
Both the FOH engineer and I met the heads of IT early on to discuss a plan where we had overlap between their network and ours. They were fantastic and agreed to support it, though still setting support expectations around their work schedules, access, and network load priorities. With so many other services moving to the network it made sense that if we had another option that reduced their load we should take it. So for the first implementation it made more sense to run our own network, and the learning began.
Dante Planning Strategy
After watching every possible Dante video we realized we could run our own internal, dedicated, isolated network very easily. It gave us control that we would not have had with a shared network. Yamaha had a great guide on the Cisco router that calmed configuration worries by only needing about 4 setting changes. Cisco switches were less than half the cost of a MADI router, and with more splitting ability, inter-channel routing, and easy to find fiber modules for our building and hall connectivity. Now we have a solid network to build Dante on.
We did a demo of the MP8R Rednet mic preamp since there was no video demo. It also gave us a chance to demo Dante. I would highly recommend trying to demo a Dante unit if this is your first time with it as it answered a number of questions we had. Half way through the design process we attended a short Audinate conference that also helped with the specifics of Dante networking in a more complex environment, and showed some amazing examples of what was possible.
In previous installs we had to allocate a certain amount for the install company to do physical wiring, plus overhead. Realizing we could deploy almost the entire system without crimping or soldering massive snakes we dropped labor all together and nearly doubled the gear purchase. We ordered about 120 bulk network cable of pre-made lengths and color for under a thousand dollars, along with pre-made DB25 to XLR fanouts. Fiber optic lines between major locations were already in place. The university internal data communications install team pulled 5 CAT6 network lines for about $1,000.
To keep latency and complexity low we avoided going switch-crazy. The preamps were one switch away from the front of house console. One of those 5 newly pulled lines were dedicated for that purpose. The most used connections were 3 switch jumps or less.
With two music buildings to support we decided on two solutions to connect them together. The first solution was to use the network and make one large Dante network, but that can have complexity problems. So the second solution was to use MADI between the buildings to keep networks independent but connected. These can be switched by simply reconnecting fiber on both ends from the MADI box to a optical to copper network box, about $500.
Everything had to be on Dante. We connected lobby sound, analog tie lines, wireless mics, pre-show playback, stage wedges, projector playback, talkback, video editors and recorders, broadcast sends, outboard gear, studio monitoring…
Concerning workflow we tried to avoid needing to use Dante Controller routing for every task, and instead rely on presets. That means limited patching by having plenty of I/O both in units and channel counts.
For stability we went to the fully redundant secondary Dante network. You can disconnect a line, even a fiber trunk, without any sonic change. The cost for this was about 1.5% in doubling the switches and extra network cable. For new fiber optic cable installations adding additional lines is about +5%.
This moved signal flow from traditional inline paths to a star/tree topology making any device directly accessible to any other device.
For example, routing wireless microphones took around 7 device patches to reach the entire system. These were a mix of analog and digital that we had to always be aware of. Dante took this down to a single route, actually a single mouse click. While in reality there are still three network switch jumps, Dante handles it.
In the diagram above you can see in red the before layout has multiple analog and digital paths, but in below these are simplified to just one. The gray line in the after diagram is the actual path that Dante takes.
Training students and staff on this one improvement alone has become much easier.
Here are the connectivity layouts for the two music buildings. This shows how units are physically connected, but not how audio is routed.
Murchison Performing Arts Center & Annex.
Implementation:
- 1754 total channels of Dante I/O.
- About 80 Dante-enabled devices.
- Two 64* channel recording/broadcast/reinforcement systems.
- One portable 24 channel jazz small group recording system.
- Multiple small stations for concert recording.
- 128ch of Focusrite preamps + Dante.
- 40ch of Upgraded Grace Design with Dante.
- 8ch of Millennia Media with dante.
- 16ch of pretentious 500 series preamps with Rednet A/D.
- 18ch of Forssell, 4ch of Hardy mic pre with Rednet A/D.
*Keep in mind the 64 limit is from the mixing consoles, and certain recording units, but Dante does not have that limit, and even the Yamaha PCI cards hit 128ch. Using the other input types like analog and AES, along with Dante, the Soundcraft can get to 96ch.
Network Setup
At the Audinate conference they said the most common mistake was due to over-configuration. So network switches were setup with the fewest amount of configuration changes. We did packet priority, turned off port power saving, named the units, removed the password, and gave each its own IP address. We did not create a VLAN, or enabled DHCP. There was no reason to. Network device use Link Local for addressing, and the network is audio-only, plus EuCon, so additional VLANs aren’t necessary. Each switch had a set of LC multimode fiber modules to connect switches in other rooms together.
The 24 channel Focusrite MP8R system rides in a cart that can connect to one of six locations with dedicated fiber to a central control room. Other less used rooms continue to use analog mic cable to preamps in a single control room while the two larger halls have installed microphone rigs and larger channel counts.
The jazz division purchased a Yamaha QL1 and Shure wireless both with Dante, so during a jazz singers concerts we are able to get a split with just a network cable. The room also has a small audio system so providing splits is simply an analog output from a Rednet unit. Until I can convince them to move to Dante that is!
All the locations have various Rednet, Yamaha and Studio Technologies units for connecting non-Dante analog and digital sources like monitor returns, talkback, external preamps, and lobby for an additional 22 units or about 260 channels. A Rednet D16 and Rednet 2 are used for sending control room monitor feeds to editors around the room for speakers and headphones. Another set is used to do a send/return to a matrix processor and multiple send/returns through video systems. One Rednet 2 is used for outboard analog gear inserts, and another for sourcing a 500 series rack of analog preamps.
Both building studios have video systems for recording and streaming with the option for three ways to handle audio. A Soundcraft Vi3000 mixer, ProTools with the Focusrite HD32R interface with Avid S3 for live mixing with automation recording, and a Yamaha Dante Accelerator cards used with Logic or channel-reduced ProTools.
The advantage here is being able to use one DAW for recording, and one to insert plugins, but with no extra cabling, equipment, or loss of channels. For the live concert streaming one computer runs Logic and ProTools at the same time, one for tracking the other for inserts (plugins) for loudness and EQ control.
Control Room 149
In the other building there is a centralized control room connected to multiple halls that was outfitted with three iMacs with the Yamaha Dante Accelerator card stations plus one Mac Pro with the PCI card and adding ProTools. With the 128ch count, each recording station gets all the channels from all the halls all the time. A Logic/ProTools template for each hall simply changes the input to that hall. This gives enormous flexibility in the need for different configurations each night without physical patching or loss of audio quality. A student simply picks the most convenient workstation.
Since ProTools and Logic use different cards, both can run at the same time making a single Mac able to process 192 channels.
Where RedNet fit:
Not every piece of audio equipment has Dante, and that’s where the RedNet interfaces come in.
RedNet 1 & 2, D16
These are the analog and AES to and from Dante units. For example the Grace 900-series monitors that connect with AES and analog, AES program audio for video, and inserts for outboard analog gear.
HD32R & D64R
These are more specific units. The HD32R is a ProTools HD hardware alternative that is less expensive and direct to Dante. The D64R is for communicating between Dante networks we want separated using MADI in-between.
PCIe Problem
At the time Focusrite made a single port PCIe card, but lacked redundancy, so we chose the almost identical Yamaha card that had the second redundant port. If we had a primary network failure we could lose the multitrack recording.
MP8R
We had to define the musical needs and find preamps to match. The MP8R solved the remote control problem with an app and mixer control and the product was on its second generation hardware.
We use Grace Design preamps in a number of halls, and had Dante cards installed in all of them. However the m802 pre does not have shared gain control over the network like the MP8R, a feature needed for live reinforcement. So they are used more in recording sessions, stereo recitals, specific client requests, or in smaller channel counts where non-remote preamps are easier to manage. There is also one Millennia mic pre.
Results
There was no other technology, no other way, that this size of a system could come together so easily and be easy to use, reliable, and sound completely transparent.
Using less expensive network switches that support copper and fiber means more connectivity on each node. Rednet provides each kind of input and output needed in a typical studio, so it was simply dropping in those units where we needed conversion to digital or analog. Each device got its own set of channels into or out of a Rednet box, and into Dante. Anything can route to anything without channel restrictions. It is quite incredible and relieving to not have to worry about channel counts, even considering we had been using multiplexed “single cable” solution for several years. Most case studies focus on transitioning from copper cable snakes to Dante, but that wasn’t our case. We had been using fiber solutions for over 10 years.
The difference here was the direct connectivity to devices. With other digital snake solutions we still would need an analog patchbay or an AES router. That still means multiple route points for what should be simple and quick changes. It didn’t feel simple. It was still going from one signal type to another, with lots of conversion. With Dante those conversion points have vanished. While a device that doesn’t support Dante may still have its last connection on AES or analog, you’ll never notice since routing is all Dante.
The First Event
Our first event was the yearly university president’s address, followed by the first symphony concert a few hours later. The system was put in just weeks before this event. Nothing like the most high profile event of the year to try a brand new system, but we weren’t worried at all.
Reduced Training.
Having all devices routed the same way cuts down on training considerably since you only explain it once. Before I would have to overload people’s brains on all the subsystems of patching for all types of cases.
Difficult to Break.
Using unicast, we were able to send about 350 channels of audio from multiple devices to multiple devices, but all through a single network line. Switching to multicast, we have still been unable to route enough channels to see bandwidth issues. In fact Dante professionals says most problems are from over-configuration.
300 days later none of the network switches have needed to be restarted, and there has been no problem with Dante. The more used ports report about 800TB of audio data transmitted.
Virtual Sound Check.
Can’t make it to the rehearsal? Have someone record it, and playback into the system later for mixing. This is such a breeze that I’ve been able to drastically cut the amount of time at rehearsals.
Monitoring.
I can sit at my desk and monitor any channel from any hall. Some nights there are five to six events going on at the same time.
In theory I could record all the events and never need to hire staff, but lets pretended I didn’t write that.
Routing to lobby, video, talkback.
Being able to change our lobby feeds from simple hanging microphones to broadcast mixes or from different halls used to involve digging through cable spaghetti and only done at the last minute, if at all. Now it is a simple click I can do from anywhere.
Video Feeds
Routing our video suite used to be complicated. Only the main program feed had embedded audio, so camera iso-recorders needed manually synced audio, or to be reconfigured to accept program audio from another input. Playback for intermission features needed a dedicated line back to the mixing desk. By connecting the video recorders to Rednet Dante units we can push playback or isolated audio feeds to any recorder by clicking. That could be sourced directly from the mics, live mix, a DAW mix or even the FOH mix.
Talkback
Talkback was also a patching problem, but now we can talk to any the halls at one time with just a click. In fact it is so easy we have to be careful not to talk to all the halls at the same time.
Routing inserts to a DAW for plugins.
By using inserts over Dante I have access to all the plugins I’m familiar with including measurement and loudness meters in real time.
I’m able to easily route the Soundcraft’s mix output back to the computer for recording. Before this would have taken precious channels, but with 128 on the Yamaha card, and 64 in ProTools, there’s plenty to work with.
All the classic analog outboard gear is connected through Rednet, so accessing them for inserts follows the same path as the DAW and accessible to any editing station in either building.
Computer Feeds are Super Simple
The days of noisy, problematic, uneven feeds from computers is completely gone. Dante Virtual Soundcard or Dante Via solve those problems by putting the computer’s output and input on the network.
For example, in one click I can route Spotify to a stage wedge, lobby, studio speakers, or headphone amp from any connected location on the network. My office computer is tied into the network and I am able to stream music to another building.
If a presenter wanted audio playback from their on-stage computer to both FOH and on a live broadcast we can either de-embed HDMI audio to the Rednet D16 in one route click, or install Virtual Sound Card, put the computer on the network with a CAT6 and get a direct feed in one click to both FOH, broadcast, and recording. Before this would have been some kind of 1/8th inch cable to a line-level DI box, that is analog split after the FOH console as a mic channel. Ick.
Standardizing Systems
The biggest adjustment is the idea that each system is the same. There is no hard-wired system for specific halls or tasks. No cables stretching across the room during complex evenings. Clocking issues have disappeared. A high channel count system doesn’t need racks of gear. Even the FOH position doesn’t need the recording department to record a multitrack rehearsal.
Feature Request: RedNet SDI & HDMI
While it does not exist, this was the one unit missing I would like to see. Right now we use the Rednet D16 for AES to SDI embedding through AJA and Blackmagic embedders.
Cost Breakdown:
This is completely out of your price range, right? Considering the size and scale this was relatively inexpensive. A significant savings was made by not needing to install patchbays, custom cable pulls/terminations, and splitters. Analog installation are labor intensive and parts are still expensive.
20%-30% of an install can be labor, and for us that went to more gear.
Missing from this graph is about 15% in existing fiber optic connectivity.
At the time of this writing ProTools requires an HD card and I/O interface that pushes the cost to six times more than Logic with a PCI card, and only handles 64ch instead of 128.
A 3-slot bay full of Dante cards could record 384 channels of audio for about $3,000. To me that makes Dante the most cost-effective way to split and send large numbers of audio channels.
In the graph below is the breakdown of channels. The PCI cards handle 128ch. The 41% of DAW channels cost only 3% of the total budget.
The photo above shows how deep the integration can go. While some digital snake solutions replace large analog or low-capacity digital snakes, they only replace connecting hubs. Stage to mix pit, stage to recording, stage to monitor world…etc. Dante is usable within the studio, replacing numerous smaller patches like backup recorders, speaker and headphone feeds, outboard gear, lobby sends…etc.
Problems and Gotchas:
Too Simple
Overcomplicating Dante is easy to do. Less is more. Engineers including myself think there has to be more to it. There isn’t.
When channel counts are getting into the hundreds and the network is mixed with public Internet traffic and other congestion then that is when additional configuration becomes nessisary.
Redundant vs Switch modes
Dante gear can be configured in redundant mode where there’s two independent networks or in switched mode where units can be daisy chained together. By default they come in Switched mode and would bridge both primary and secondary networks causing the network to fail. It makes for interesting errors in Controller that can be tricky to diagnose. This error does not show up as a typical primary/secondary connection problem.
Lots of DB25.
Don’t fool yourself that cable is going away. Interfacing with non-Dante gear usually means several DB25 fanouts. Just in Rednet alone there were more than 50 DB25 fanouts.
Latency
Keeping the mic preamps within one jump of the FOH console reduces latency down to the 250 usec level. We have had to make some increases in latency to 500 usec due to the MP8Rs increased latency after firmware updates. For recording and broadcast, milliseconds of latency are not a concern.
PCI cards are not network devices.
PCI cards cannot be used for Dante Controller and so it will add another network connection. The Dante primary port can not be used for control. For an isolated network each computer will need 4 network cables:
- Primary Dante.
- Secondary Dante.
- Dante control.
- Public Internet (or wifi).
PCI cards are seen as audio interfaces, not network interfaces, so you still need a network interface to your Dante network for control. And do not enable Internet Sharing on the Mac.
Firmware
Dante cards have their own firmware that is updated separately from the device the chip is in. Though they don’t update too often.
Get Big Switches
Most of the 10 ports went to 20, and one 28 went to 52. However the Cisco SG-300 52 port has a loud fan.
Get 1310nm Fiber Modules
If using multimode fiber, get the higher frequency wavelength modules whenever possible. Single mode is still better if you can afford it.
EuCon and Dante
EuCon will work on a Dante network. We run a few control surfaces without additional switch configuration.
Things we did not do:
As Steve Jobs and Apple have said, saying no is just as important as saying yes.
AVB/Ravenna/…etc.
The other network systems out there lack the quantity of vendors that support the platform. There is less complexity and cost by having all your gear speaking the same language. Dante provides centralized control with Controller, and uses off-the-shelf networking switches. Since an upgrade goal was to reduce transport technologies it did not make sense to have multiple transports. Though it seems these will all be compatible with each other in the future.
Grace/Millennia remote preamps
Owning and testing both the Millennia HV-3R and Grace m802 remote preamps we found both to be functionally problematic for a live environment. They just didn’t get the job done quick and easy enough.
Since the original purchase Grace Design launch the m108, a fantastic web-controllable remote preamp that works over Dante.
ProTools as a Live Mixer
One day I would like this to work, but testing this idea proved too problematic. Flexibility in assigning plugins and routing once recording is very low, and would not work with how late we can get concert information.
Resources:
Focusrite’s Case Study on UNT.
Yamaha’s Network Training Videos and Switch Setup Guide
The Audio DAWg — Our local sales rep, integrator, and audio ninja.
2 Years Later
The Soundcraft mixers are being outfitted with an additional Dante card to allow 64 inserts into a DAW. This will allow 64ch of plugins from a DAW. This means we can recall plugin settings from a post-production mix right into a live show and be up and running in moments instead of starting from scratch each time.
We have had some issues with switches needing restarts due to ProTools throwing clocking error messages. It took some time to determine the switch to be the problem.
After Avid allowed ProTools to have channel counts above 32 without Avid hardware, there is no longer a need for the HD32R and HD Native hardware. It is also limited to 64 channels where as the PCI cards are 128ch. By simply adding another Dante PCI card to the computer, we can continue to run Logic and ProTools both at 128ch at the same time using two different cards.
We are preparing for a complete replacement of our multimode fiber optic A/V network to single mode in order to support video system upgrades (more on that coming soon). To keep the Dante network updated we simply need to changing the SFP modules in the network switches from 850nm to 1310nm a hundred dollars or so each, where needed.
Countless stories of solving problems by quickly plugging in a laptop anywhere on the network to playback or record multitrack audio.
At this point the most frustrating aspect is why video hasn’t caught up.
Any questions, blair.liikala@unt.edu
