Into The Danger Zone: Live Laptop Mixing – Blancer.com Tutorials and projects

The ability to walk into a venue armed with nothing more than mics, cables, stands, and a small road case is quite an alluring idea. Imagine being able to cut down your rig by half, and have even more flexibility. Sounds too good to be true? Well the ability to mix live shows on your laptop is a very real thing, but not without risk.

Today we are going to look deep into the pros, cons, and pitfalls of live mixing on a laptop. From saving our backs to risking our skins, the benefits must be very carefully weighed against shortcomings. We also will analyze just what makes a solid live computer rig, and how we can better prepare ourselves, and truly see if our gear is up to the task.

So if the thought of live laptop mixing has ever crossed your mind before, read on, and see if the plunge is worth it to you.

The Pros and Cons of Live Laptop Rigs

The Good News

The greatest problems we typically face when doing live sound is not having enough equipment, or having too much, and the investment cost. Thankfully a live laptop rig can remedy any and all of these problems very easily.

Let’s see just how:

Not Enough Equipment – Having gates, EQs, compressors, or whatever FX we might need is critical for live sound. The best way to cover ourselves is to have access to all of those FX on every channel, AUX, etc. By using a laptop rig and a DAW, we can add as many effects on as many channels as we want. Need to peak out a monitor? Put on a paragraphic EQ. Snare has too much bleed? Throw on a gate? Simple!
Too Much Equipment – So, what if you do have access to all the equipment you could ever want? How can a laptop help? It can save your back and time! One of the long-term problems for live sound engineers is the sheer weight of all their equipment, and constantly tearing it down and setting it up. More equipment takes more time. A laptop rig can significantly reduce the amount of physical equipment, and in turn reduce setup time and require less heavy lifting.
Investment Cost – It is no secret audio equipment costs a lot of money. A small but complete rig can cost thousands of dollars before you even buy a microphone! Since laptop rigs reduce the amount of physical equipment we need, they also reduce the cost of the system. One mammoth computer is nowhere near the cost of all those FX!

The Bad News

There is always a catch, isn’t there? While laptop rigs can provide us with a plethora of goodies, they also present a wide variety of potential issues as well. From latency, to stability, to having the right rig to begin with, setting up a laptop rig can be tricky and risky.

Let’s see what we’re working against with laptop rigs:

Latency – One of the biggest problems with live sound is that is has to be instantaneous, or it isn’t live anymore! While a little bit of delay into the audience is fine, the musicians need to be able to hear through their monitors without delay. Of course, there is always some small fraction of delay even in an analog rig, but a laptop rig can potentially introduce even greater problems. From buffers with the audio interfaces to plugin latency, it can be very easy to go from a solid sound to “something sounds weird”.
Stability – Generally speaking we want our audio systems to do one thing, and that of course is audio. However laptop rigs run on operating systems (Windows, OS X, Linux) that do other things as well: check the internet connection, update the clock, etc. This inherently makes laptop rigs less stable and more prone to audio dropouts and glitches. In the studio, this generally is less worrisome, since there is no audience. But live, the show must go on.
A Proper Computer – Unfortunately, not every computer is cut out to run live audio. When we drop our buffers to as low as 64 or 32 samples, we begin to really see how stable and tough our computers are. Only laptops and computers designed specifically for live audio are stable enough to do the job. This of course comes with a higher price tag than some would like. In fact, many would argue that you should just get a digital console and call it day.

The Laptop Rig

What You Need

So you decided you want to go ahead with a laptop rig, but what do you need? Thankfully a computer rig is fairly simple to setup.

So let’s take a look!

Computer – It should go without saying that you need a laptop or computer to run everything. While a laptop includes everything you need, a rack-mounted computer is also a viable option, and potentially more stable and powerful. It can also easily fit into a mobile case, and only needs a monitor to be usable.
Audio Interfaces – The next piece of the puzzle is having a set of audio interfaces for inputs. The more stable and powerful the interface the better. (Think better drivers.) You will also want to be able to expand your rig up to 32 channels to be safe, even if you do not need them now. ADAT, Firewire chaining, MADI, etc. are all very good features. Having additional features like individual pads, phantom power, multiple line outs, etc. is highly encouraged as well. If you think you need even more than 32 channels it might be time to look into ethernet-based systems.
Fast Plugins – Being one of the primary features of laptop rigs, the plugins we use have to be zero (or very minimal) latency. Generally speaking, if the plugin does not tell you the latency it induces, do not use it. You can, of course, check the pre-delay compensation if your DAW has that feature.
SSD – Having a solid state drive can significantly relieve the strain on your computer, especially if you are recording the show. Even if you do not have one, record the show on a separate drive, not the drive your programs are installed on!
Clean OS – The more junk you having going on in the OS, the more problems you will have. Turn off the internet unless you absolutely need it. Only do updates after the show, and otherwise keep them off. Disable any flashy graphics and other extraneous features. Keep it lean!

What to Look Out For

Before you ever do a show with a laptop rig, you will need to test the system to its absolute limits. Why? Because if it crashes in the middle of the show, it is your fault!

So how can we test the system? By setting up a little experiment:

After setting up your laptop rig from a hardware standpoint, create a new session in your DAW of choice.
Make sure your audio buffers are as low as possible, since you will need them low to run a show.
Add as many channels as you have microphone inputs, and set each channel to have its own unique input. Then create at least four to six AUX channels (more if you know you will use them).
Next, place a gate, compressor, and EQ on each input channel. On the AUX channels, place an EQ that allows for many bands (these will be used to peak out the monitors). If you think reverb is an FX, create a special reverb AUX channel as well.
Route every single input channel to all of the AUX channels, and make sure the set reverb channel to fully wet. On the AUX channels send the outputs to your various hardware outputs just like you would for monitors. At this point, your DAW should take on the character of a full board mixing desk.
Next proceed to record all of your channels, and let the system run. Why record and not just arm the channels? Because if you are running a laptop rig you at some point going to be asked to record the show as well!

While the system is running, you need to look out for a variety of things. If you encounter any of these problems you will need to tweak your system or upgrade to better interfaces/computer.

Do not walk away during this test! You need to keep an eye on the system for at least two hours, preferably four or more. Also, run the test more than once! Try it with a local band who needs to rehearse. You do not want to be caught with a glitchy system!

Buffer Drop Outs – If you start to hear clicks or pops, then your computer cannot handle the low buffers. These will be extremely annoying, and are warnings that a full-blown failure can occur. You can of course bump up the buffers, but at the cost of more latency. You will need to double check the latency if you do bump the buffers, to see if the delay is still acceptable.
CPU Usage – Just because you do not hear clicks and pops does not mean that your computer is not straining. Some DAWs have built-in monitoring, while other computers may need external software. Generally speaking, you need to keep your CPU below 25% minimum, and I would personally recommend less than that; 15% or less is much safer. Remember, more strain means more potential glitches during a three hour show!
Buzzing and Crashing – Even if the above are stable as can be, that does not mean that your drivers may not decide to give way after prolonged use. Usually this will sound like annoying buzzing, and may continue even if you hit “stop”. In this case, the only solution is to close the DAW.

Conclusion

As you can see, there is a lot to keep in mind with a laptop rig for live mixing. If you can make it past the setup and potential stability issues, then you can find yourself in a wonderful world of minimal equipment and greater flexibility.

However, do not fool yourself into thinking the rig works if you did not do the necessary testing. If everything goes swimmingly, then you can look into having MIDI control surfaces for mixing, local area WiFi for on-stage mixing via tablet computers, and a whole host of other goodies.

Just remember, live laptop mixing is a dangerous place if you do not prepare. Thanks for reading!