I built myself a new mobile webcast in a road rack case. It has been a bit of a learning process, so I wanted to share my experiences and also ask for some help with my last outstanding issue - ground hum.

Here is a bit of background on the computer that built. The link is to an article that I wrote for Streaming Media Magazine:
http://www.streamingmedia.com/Producer/Articles/Editorial/Featured-Articles/How-to-Assemble-a-4K-Switching-and-Webcasting-Solution-for-Less-Than-%245K-116685.aspx


Here are the final specs of the computer

Core i7 7700K
Gigabyte GA-Z270X Gaming 7 motherboard
Corsair Vengeance 2x16GB DDR4-3200 memory
Asus GeForce GTX1070 8GB video card
Silverstone GP09B HTPC case
EVGA SuperNOVA NEX 650W 80+ Gold modular PSU
Icy Dock
Noctua NH-U9S CPU cooler

Samsung 850 EVO 250GB SSD (OS)
Sandisk Ultra II 960GB SSD x2 media drives

Blackmagic Design Decklink Mini Recorder 4K
Blackmagic Design Decklink Quad 2

Furman power conditioner

1 RU Keystone Patchbay

Gator G-TOUR12UCA-24D - 12U, 24" Deep Audio Road Rack Case w/ Casters

Lesson 1

I went to my local custom case builder with some designs to build a custom case with a lid that would turn into a table and a monitor that attached to the lid. I didn't really know how deep of a case I would need as I didn't already have my computer case and I neglected to factor-in the DIN to HD-SDI break-out cables from the Blackmagic Quad 2 capture card. The case maker had a case that they made a mistake-on and they offered to configure it for my needs for a really big discount. The biggest difference between my original design and this case was that this one was much taller and we considered it a tip-in design for loading into my van, as it was too tall to stand up-right. In the end this proved a bit of an issue because it was still very heavy.

I then bought an HTPC case that I thought would fit my mobile webcast studio case but it turned-out that I needed a deeper case, because of the extra space needed for the DIN break-out cables.

I decided I didn't want to hurt myself lifting the case constantly (it weighed over 200Lbs and I wasn't even done putting all the gear in it yet) and I didn't like that I had to disconnect the DIN cables to close the back of the case. So I looked for a replacement case that would better fit my needs.

I decided on the Gator G-TOUR12UCA-24D - 12U case, especially seeing Amazon had it for only $351 USD with free shipping and its usual prices is $550. I actually bought the last two at that price, although I have no immediate plans for the second case. This case isn't as tall so I can roll it into my van using two 2"x8" wood ramps. I cut the bottom of the ramp at an angle to match the ramp angle (and so there was no longer a 2" step at the bottom of the ramp) and bought a metal ramp plate so it rested nicely on the bumper of my van. I then attached 1"x3" wood rails on the outside of the ramp to prevent my case from sliding-off the side of the ramp. Then I lined the bottom of my van with a sheet of wood so the cart wasn't directly on my stow-n-go seats in my Dodge Grand Caravan.

Now I have to off-load my custom case as I have no use for it.

Lesson 2

The computer build itself was a bit frustrating because my local computer supplier did not have all my parts in stock and they kept selling my parts that were in stock (even though I paid for them in advance). So once an OOS part came in, something else became OOS. Eventually I told them off and they started holding parts for me. This was very important because there was very little I was willing to accept substitutes on. Mostly this was because of space restriction in the small HTPC case. The MoBo was critical for me because I wanted Thunderbolt 3 for future use and not many MoBo's offer TB3. RAM became a bit of an issue because nothing was in stock when I ordered. Overall the case is very tight and there is no wasted space. The Icy Dock that goes in the typical space for a optical drive is where my media drives are mounted (2x SSDs). I left the spot below it open for airflow but could also throw another HDD or SSD in that space. If I needed to add more SSD space, I only have room to put in one of those NVMe drives or connect to something in an external enclosure.

I used-up all the available x16, x8, and x4 PCIe slots but I still have 3x PCIe 1x slots, although some might not have enough clearance due to the GPU. I am glad my MoBo has dual Ethernet for when I need to connect it to a Blackmagic ATEM switcher for live IMAG workflows that require less latency than I get with vMix.

Lesson 3
Audio and MIDI
I have two audio options. One is the Behringer UMC202HD USB Audio Interface and the other is a Mackie Pro FX12 v2. Both have USB outputs and the Behringer is for when I get a sound board feed, while the Mackie is for when I run all the microphones through my own sound board.

The Mackie will live in an SKB 1SKB-R104 Audio and DJ Rack Case, along with a pair of rack-mount Sennheiser G3 receivers, while the Behringer will live in the Gator webcast studio case.

For MIDI I am using the APC Mini

Lesson 4
I still need a solution to this. I am experiencing ground loop hum with my new webcast studio. At first I thought it was the signals from various the sound boards that I connect to that were the issue. On one occasion getting a more direct XLR run from the sound board did the trick, but more recently, on two different sites, I was able to isolate it to the SDI from my camera. SDI from cameras connect to the SDI patch bay, that connects to the DIN to SDI cables, that connect to the Blackmagic Quad2.

These are the connectors I am using:BNC connector


So I started to do a bit of reading about insulated SDI connectors. I have no idea if these are insulated or not.

My patch bay has a ground cable but I have no idea what to connect it to.

Any ideas on how I remove the ground hum coming from my SDI cables?

I saw this video hum eliminator for $310 that could do the trick. But before I go that route, I wanted to see if there was something I am missing or if my SDI connectors in my patch bay should be swapped-out for something different.

I do own a Radial ProAV2 Multimedia DI (RCA, 3.5mm, and 1/4" to XLR) that I use as a DI for computer audio. But rather that converting the typical XLR feed that I receive from a sound board to XLR, I think I should just buy a ProAV1 that accepts a line level XLR and outputs an XLR mic output It also has RCA, 3.5mm, and 1/4" to XLR inputs.


On the subject of audio, I ran into an issue that I have never experienced before. Sometimes instead of a DI, I send my audio through my Sennheiser G3 transmitters, using a 3.5mm to XLR cable on both the Tx and Rx sides. At my last site the DJ could only give me a pass-through from the subwoofer. When I ran an 1/4" to XLR converter to XLR cable to my video camera, I got a proper line level signal. But when I connected my G3 using a 3.5mm to XLR cable with an XLR to 1/4" converter, I could not get a signal. Even though it was the subwoofer, it had the whole frequency range and not just the low frequencies, btw. Any ideas as to why I could not get an input signal on my G3? I have done this many times before with a straight XLR connection and with the same adapter I was able to get a direct connection, so I thought it should work.

Thanks.

Well I started the process with a DIY plan. Then when I went to buy the parts locally, I decided to buy a modified custom case. Eventually I found an off-the-shelf one that worked for me and was a fraction of the cost (and none of my time).

I posted this thread on the Streaming Idiots FB page

What I decided to do was to buy a Radial AV1 XLR direct box and see if that will solve my problem. It is much less expensive than an SDI hum eliminator and I don't think that the SDI is the "source" and the ground issue is coming through the audio lines.

I am attaching a photo of the original case that I no longer use.