The quest for the best case

Finding a suitable case for the IDR32 is important. The case should house the IDR32, the PL10, the wireless router and a 5m-8way XLR snake for connecting to the house system. For the case, we have some requirements:

• Size is a big issue for us, the smaller it is the better. We want to really push the limits on keeping this as small as possible. Not only for transportation, but also for the space it consumes on stage. Often, there is not all too much space since we are already with 10-12 people on stage. For easy of transportation, a pull-out handle and 2 wheels would be really nice. Also, the IDR32 is only 25 cm deep, so shallow cases are best.
• Setup-time is the second requirement. The system should be set up within seconds. Most festival-like gigs we do, there is sound-check time in the afternoon and in the evening we have change-overs of 15 minutes. Sometimes, we'll be able to leave this case on stage and sometimes we'll have to remove it from stage. A short setup-time is therefor important.
• Safety is the third requirement. The equipment is expensive (for us) and it is basically a computer. This means that should handle it with care. If it is possible to buy a case that provides better protection, this would be nice.

The first question to answer is: do we want 6U or 8U? Using a 6U system is certainly good with regard to the size, but having an 8U system allows us to include a power conditioner and move all connectors to the front using an 8 hole 1U plate. The front could then include: powercon in, powercon out, some ethernet ports, 3 antenna's and 1 XLR for a light. The power cable and the XLR snake could be stored in the front lid, the PL10 in the back lid. Setting up the system would consist of removing the front and back lids, connecting the power cable, connecting the XLR snake and connecting the PL10. For the 6U system, this means that the router (attached to the back) will also need to be connected to the front and we lose the power conditioner and the light. We can mount a power strip to the back rail, with a 5m power cord. This means we have 1 extra thing to do: connect the ethernet cable from the router in the back to the front of the IDR32. Also, we'll need access to the back of the rack when we connect a laptop.

We have found the following products that could work:

Picture	Brand	Model	Rack height	Rack depth	LxWxH	Weight
	SKB	Standard 6U Effects Rack	6U	40cm	55.88 54.61 33.02	6.67kg
	SKB	6U Ultimate Strength Series Roto Rack	6U	43.18cm		6.76kg
	SKB	6U Roto Rolling Rack	6U	47.63cm	62.23 60.96 35.56	8.89kg
	SKB	6U Roll-X Rack Case	6U	44.45cm	55.25 62.87 35.56	7.33kg
	SKB	Standard 8U Effects Rack	8U	40cm	55.88 54.61 41.91	7.51kg
	SKB	8U Ultimate Strength Series Roto Rack	8U	43.18cm		6.78kg
	SKB	8U Roto Rolling Rack	8U	47.63cm	62.23 62.23 45.72	12.49kg
	Gator	G-PRO-6U-19	6U	48.26	54.61 53.72 34.29	15.00 pounds
	Gator	G-PROR-6U-19	6U	48.26	55.88 53.72 34.29	18.00 pounds
	Gator	G-PRO-8U-19	8U	48.26	54.61 53.72 43.18	18.00 pounds
	Gator	G-PROR-8U-19	8U	48.26	55.88 53.72 43.18	21.00 pounds
	Gator	GR-6S	6U	37.47	44.45 54.61 33.02	13.00 pounds
	Gator	GR-6L	6U	48.90	57.79 54.61 33.02	14.00 pounds
	Gator	GRR-6L	6U	48.90	58.42 56.49 33.02	18.00 pounds
	Gator	GR-8L	8U	48.90	57.79 54.61 41.91	17.00 pounds
	Gator	GRR-8L	8U	48.90	58.42 57.78 41.91	20.00 pounds
	Gator	GTOUR EFX6	6U	38.10	57.79 58.42 33.02	28.67 pounds
	Gator	GTOUR EFX8	8U	38.10	57.79 58.42 15.25"	32.37 pounds
	Boschma	6U HE Rack	6U	45cm	53.5 62.0 37.5	7kg
	Boschma	8U HE Rack	8U	45cm	53.5 62.0 46.5	8.3kg
	Bespoke	6U Rack Case	6U	30cm
	Bespoke	8U Rack Case	8U	30cm

(sorry for the bad layout)

Network bandwidth

Before deciding on the wireless access point to buy, it is useful to have some idea of required the network bandwidth. The IDR32 and ilive editor communicate using TCP/IP, and I installed ntop to get some information about the data thoughput.

In this graph, I started the ilive editor around 17:00. You will see a small peak of 1.4 Mbit/s while the editor receives the configuration and all other information from the IDR32. After this, there is a steady stream of 1.2Mbit/s. This steady stream does not depend on the number of channels actually receiving input, as I started with feeding 10 channels into the IDR and I stopped this from 17:07.

This information tells me that any network connection that we use must be able to sustain 1.4 Mbit/s. Hopefully, this will help us in making a decision on the wireless networking technology to use.

Latency of the system

A digital system always has some latency. On a forum, someone questioned the use of digital mixing desks because of the latency that is added by the system. Although my experience tells me that the latency is really small, it is always a good idea to measure it.

For this test, I downloaded the 'test tone generator' software an ran this from the tablet. The headphone-output of the tablet is split to two XLRs: one going in the IDR32, the other going in a two channel USB pre-amp. Then, a cable is connected between output 1 of the IDR32 and the second input of the USB pre-amp. Using Audacity, it is possible to capture the exact delay added by the IDR32.


The latency turns out to be 1.2 ms (or 53 samples at 44100 samples a second). This is equivalent to time it takes sound to travel 41 cm through the air. I think this latency is very acceptable for live sound, but things might be different when using in ear monitoring.


(BTW, the gain of the pre-amp was not matched, this is only a test on timing).

PL10 working

I tested the PL10 device, and it works brilliantly. Using the 8 rotary knobs, you can control the levels of your channels, the aux sends for each channel etc. The 16 push knobs at the top allow you to select different scenes. For now, just a picture showing the levels for the first 8 channels on the tablet and on the PL10.

One problem I found was that when the tablet is unplugged, the PL10 stops responding for almost a minute. This is a problem since I planned to use the PL10 as backup in case the tablet has some problem. I've been told that A&H is aware of this problem and is working really hard on fixing it.

Soon, I'll do some digging around on the network protocols to see what is actually happening on the cables.

Poor man's multitrack

A while ago, I wanted the ability to practice mixing without a band present. Normally you would buy a nice multi-output for your computer (or go digitally, for example with MADI) and connect that to your mixing desk. There are many expensive solutions for this, and I settled for a very cheap one.

Buying two cheap USB 5.1 channel sound devices, I now have 12 outputs (14 including the outputs of my macbook pro). These outputs are minijack, so using minijack to 2x XLR I can connect to the mixing desk.

Very cheap USB 5.1 Audio Devices

Minijack to 2x XLR

Combining the two usb devices in one aggregated device

In Mac OS X, there is a nice feature called aggregate devices (in Audio MIDI setup). An aggregate devices allows you to tie multiple sound devices together. Using this, I create a virtual sound device with 4 inputs and 12 outputs.




Next I installed Ardour and Jackpilot. This open source 'digital audio workstation' allows me to load my tracks and play them to the different outputs I have. With this, I have my poor man's multitrack output for less than 100 euro's. Such a system is unsuitable for real use, but allows me to play around with the IDR32 without a band present.

Jack Pilot

Ardour

The complete setup

It works!

IDR32 and PL10 arrived

Today the IDR32 and PL10 arrived!

The tablet and IDR32 work!

First test is connecting the tablet to the IDR32 with a network cable. The process is fairly simple: connect the tablet to the IDR32 with the network cable, set the IP address of the tablet to 192.168.1.10 (netmask 255.255.255.0) and run the ilive editor.

Some problems did occur. First, I had to update the firmware of the IDR32 to match the editor (V1.70). Second, when I connected the system said something about a connection error. There were no problems at the next try, but this is something to keep an eye on in the future. Finally, it seems that the pad is turned on default for the input channels. When connecting my SM58, I had to turn up the gain significantly to get any signal and the resulting background-noise was terrible. Of course, when I figured out the pad was turned on the problem was solved.

Now we have a nice system and can start playing with wireless, the PL10, multitrack, etc!

The firmware needs updating

Updating the firmware is simple

First connection attempt failed

Second attempt succeeded

Don't forget to turn of the PAD!

IDR32 and PL10 are on its way

We have ordered the IDR32 and PL10 @ TMaudio, and they will arrive tomorrow or the day after! We are really looking forward to testing this system, the tablet is already in place and we also have some poor-mans multi-track playback system.