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Replacing an old analog mixer with software
Over the past few weeks we’ve been working on getting a new audio mixer up and running. After the last broadcast we did it became somewhat obvious that the Behringer X1622USB mixer that had served us well over the past 2 years was no longer enough. So it was finally time to Pound The Alarm and invest in a new solution. We looked at various mixers, analog and digital. The downsides of the lower end analog boards around this price range is the questionable quality on some of these boards (I’ll mention no names). The drawback to the more expensive digital mixers is the price, which ends up way more expensive than this set up. They also lack the flexibility gained here. For example - I can download a new compressor off the internet for free, rather than having to upgrade hardware. I’ve also got much expanded control options over a lot of other solutions. I can download the Logic Remote app on my iPad and control it from there, while also using my choice of MIDI controller.
The setup:
Host computer - Intel Core i7 2600K, 8GB 1866mhz RAM, VIA Firewire PCI card.
Audio interface - PreSonus Firestudio Project 10x10 Firewire audio interface.
Software - Mac OS X, Logic Pro X
Hardware controller surface - Korg NanoKontrol 2
Total cost for the rig is about £500. We could have saved money by using Studio One which is included with the interface, but I already owned a copy of Logic Pro X and know it much better.
The FireStudio was the choice of interface for a few reasons:
a) It’s cheap. £309 in GBP, $399 in USD. This includes a license for Studio One Artist.
b) It has spdif digital IO. I’m now getting audio in and out of the TriCaster digitally via AES.
c) It has a hardware DSP mixer on board, for zero latency monitor mixes (more on that later).
Logic Pro X has been great. In the attached screenshot you can see how I have it configured. I am running it with a 32 sample buffer to keep latency at it’s lowest. It’s running at extremely low CPU utilization, and thus far I have not heard one dropped sample (even while running the Cinebench render test @ 100% CPU load). In my Logic doc, I’ve got 8 inputs configured (6 mono, 2 stereo), 4 aux sends for Skype mix minus feeds, a studio bleed clean feed (no mics to avoid feedback) and a master program output. With this set up I can do up to 8 mix minus feeds if I choose, or if I had a bigger audio interface I could do up to 64 (!!). Logic Pro also natively supports MIDI, so I’m able to have tactile control over the mixer using a Korg NanoKontrol 2.
Initially one of the biggest concerns was the amount of latency it would take for the signal to be processed through the computer, but this turned out to be something of nothing. A few people have suggested because of the latency of a system like this, there will be AV sync issues. However this could not be further from the trut. Our TriCaster 8000 takes about a frame to process the video, and we take an additional hit on latency as non of our sources are genlocked, so the TriCaster has to frame sync all the inputs on the way in. So by that calculation (assuming at worst, 3 frames of latency on the video) our video takes 60ms to process. The new audio system takes only about 6 MS from input to output (round trip). The only place where the latency becomes a problem is when trying to listen to yourself through the mixer (It’s perfectly listenable, but you can tell it’s delayed). However, the Firestudio has a built in DSP mixer. This allows it to mix audio in hardware, for zero latency monitor mixes. We take a aux from the Logic Pro into this mix (that contains everything but microphones) and then mix in the microphones in hardware. Only downside is that this mix does not contain any processing that you do in Logic. It’s definitely advisable to listen to the processed version while setting something like this up.
Some might ask why we choose a Firewire interface, considering that Firewire is supposed to be dead and all that. Presonus does also make some USB interfaces, and while in 2013 USB audio interfaces are probably excellent, there are a few issues. The USB Audiobox line does not have the DSP, that we depend on to do the zero latency monitor mixes. A Google search for “PreSonus Audiobox Latency” says it all.
So to summarize, for significantly less than a digital mixer, we have way more flexibility, more routing options and we’re able to utilize existing hardware. So far the audio quality seems to be way better than what it was on the old analog board. One of the big contributing factors to this is probably that we can independently gate each channel as required. Only the test of time will prove or disprove the reliability of this setup. As mentioned earlier, I have not heard one dropped sample yet. This system is also greatly expandable, I can daisy chain up to 4 Firestudio Projects for up to 52 inputs and 52 outputs.
Joe de Max
http://i.imgur.com/ZV6w0wD.png
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