Resources

CTA Classroom - Phantom of the Power

AddThis Social Bookmark Button

by Mike Sessler, ChurchTechArts.org

Today we're going to continue our series on the electrical side of sound. Last time, we tackled ground loops; their cause and a few solutions. This time around, it's phantom power. Phantom power is one of those often misunderstood aspects of sound. It's one of those things that's really not that complicated once you get it, but up to that point it's a bit of a mystery. So today we take the mystery out of phantom power.

Why Use It?
The first question we need to ask is why use phantom power at all? Strictly speaking, we don't need to, as the only reason we need phantom power is to power condenser microphones. Take all the condensers off stage and you can shut off phantom power forever. But most of us like to use the occasional condenser mic or active DI, so phantom power is necessary. Some condenser mics and active DIs will run on a battery, but if you don't have to power something from a battery, you shouldn't (you know it's going to die at the most inopportune time). It should be noted that it is only condenser mics and active DIs that require phantom power; for all other sources, it's best to turn it off if you have the option to do so on a channel by channel basis.

Phantom power moving from the console to the mic, audio goes the other way. In basic concept, anyway.

What is it?

Read more: CTA Classroom - Phantom of the Power

 

CTA Classroom - Ground Loops

AddThis Social Bookmark Button

by Mike Sessler, ChurchTechArts.org

The topic for today's post comes from a reader, Jonathan Mould. He wanted to know more about the electrical side of sound. This is an interesting topic because sound is both electrical and physical. Sound systems turn physical movement of air into electrical signals, then process and amplify those signals (sometimes changing them into streams of 1s and 0s and back), and finally turn those amplified signals back into physical air movement. It's all kind of crazy when you think of it that way.

I started this post thinking I could tackle three topics and realized that even a cursory explanation of ground loops would take a whole post. So, you're witnessing the beginning of a series here. First up, Ground Loops.

Ground Loops

To understand ground loops, one must first understand electricity. A full explanation is beyond the scope of this article, but here's a brief description. Standard 120 volt circuits consist of three leads; a hot (current carrying) lead, a neutral (the return) and a ground. To vastly over-simplify, the electricity leaves the panel on the hot lead, travels to the appliance, does some work and returns to the panel on the neutral. The ground is properly called a safety ground and serves one basic function—to send any electricity right back to a safe place (the earth) if anything goes wrong inside the appliance. This is a preferred outcome (as opposed to sending said accidental electricity through your body to the earth).

Electrons go from the panel, to the appliance, do some work and then back to the panel on the neutral leg. This is vastly simplified, OK?

Electricity always wants to get back to ground, or earth, and will always take the path of least resistance. Should there be a short inside an appliance, the chassis of said appliance could become energized. If you touched it and happened to be providing a good path to ground, that current will flow through you. Since it only takes about 20 milliamps to stop your heart, it's very possible that a short like that could kill you. This is why we never...

Read more: CTA Classroom - Ground Loops

   

CTA Classroom - Set Auxes to Post

AddThis Social Bookmark Button

by Mike Sessler, ChurchTechArts.org

Last week, Chris Huff had a great post over at Behind the Mixer that explained the differences between pre- and post-fader aux mixes. He said, quite correctly, that you generally want monitor mixes to be pre-fader, and FX sends to be post-fader. I totally agree with that, and run my auxes that way almost all the time.

This post is going to be about when it makes sense to break those rules. Keep in mind that this is a compliment to, not a criticism of Chris's post. But first let's review. You generally want monitor mixes to be pre-fader because you don't want changes made to the house mix affecting the monitor mix; most of the time. Every once in a while, however, that's exactly what you want. Let's look at some examples.

Read more: CTA Classroom - Set Auxes to Post

   

Environmental Projection

AddThis Social Bookmark Button

by Mike Sessler, ChurchTechArts.org

I was about to start this article off with the phrase, "A few weeks ago..." but then I realized it was actually a few months ago now. Anyway, a few months ago, we had the privilege of hosting Camron Ware at Coast Hills as he did a hands-on demonstration of Environmental Projection (EP). Camron is a great guy; very knowledgeable and very humble. He will say he didn't invent EP, but he certainly has been a driving force in helping churches all over the world get up and running with EP systems and media. 

When I was approached about hosting this event, I was a little concerned that our room would not be conducive to EP as the front of our auditorium is a mishmash of curtains, walls, screens, angles and the stage. It didn't take long to find I was wrong. The first thing Camron did was to set up three projectors. Two were supplied by a local vendor (a pair of Chrisite 5Ks). The other one arrive with Camron in a suitcase. No kidding. He walked in with a rolling suitcase in tow, and pulled out a projector the size of two pizza boxes. Made by Hitachi, it spits out 4000 lumens and costs about $2,000. I believe this is the one: Hitachi CP-X4021N LCD Video Projector

After connecting all three projectors to his MacBook Pro using a TripleHead2Go from Matrox, he threw up this very cool grid in Photoshop. He created this to help him create the mask he uses in ProPresenter to mask out the areas he doesn't want to project on. He spent about 10 minutes creating the mask, though he conceded that in a real installation or bigger show, he might spend quite a bit more time getting it dialed in perfectly.

Read more: Environmental Projection

   

The Final 10 Percent

AddThis Social Bookmark Button

The first factor was that we’ve radically overhauled and upgraded our infrastructure since last year. This made set up and rehearsal go very smoothly. I also had a great team in place, which meant that I could really focus almost all my energy on being the audio director for the week. That, combined with our relatively new SD8 and virtual soundcheck system meant I could spend two entire mornings refining our mixes.

Normally, we don’t do a mid-week rehearsal for our weekend services. So even though we record one service a week in multi-track, it’s really more for training than anything else. But this week, we had a Tuesday night rehearsal for Easter, and a Thursday rehearsal for Good Friday. I tracked both rehearsals, then spent the morning after tweaking. I have to say, it was a lot of fun.

Now, it should be noted that the mixes didn’t get radically better as I tweaked.

Read more: The Final 10 Percent

   

Page 13 of 20