Tuesday, April 14, 2009

Pseudo Reverb With a Very Long Delay

I have definitely waited too long to put together a Sunday-in-Review post. Three Sundays have flown by, one being Easter, and only now am I getting around to a more in-depth evaluation of the effectiveness of the production elements.

Meanwhile, we are in the big push for our annual youth drama. This year we are putting on an original show based on the best-selling book, Pilgrim's Progress. As a result, I am going to abbreviate my review once again this week, and simply share some very random bullets on what has been swirling in my mind.
  • People don't make church happen. They are the church. I've said this before, but the Sovereign Grace Pastor's Conference always brings it back to the forefront. And I often need the reminder.
  • Covenant Life Church is made up of my favorite people on the planet. Our volunteer teams, as the church, strive effortfully to create contexts for gospel opportunities. They are joyfully supporting all our normal activities, even with a conference and a major production in the same month as Easter.
  • I no longer believe in the 3-to-1 micing rule. OK, I do believe in it. But I've decided it's a rule I'm willing to break. Sometimes, down-to-earth gain before feedback is much more important than pie-in-the-sky "phase coherence." Overmicing seems to ever-increasingly be my style, and I haven't found the problem in it yet. (Purists may rant here.)
  • Lyrics lead. Like it or not, where the song lyrics go, there goes the congregation. In our case, there goes the worship team as well, since our vocalists are following the lyrics on confidence monitors instead of song sheets. The importance of this role can hardly be overstated.
  • If I ask for feedback, I must be ready to listen carefully and respond quickly. I have learned a lot from our team members these last few weeks. They has sent me some truly excellent, excellence-forming ideas. Hopefully, I've done all I can to implement their suggestions.
  • When in doubt, make a phone call. Often, emails stink. Especially when I write them. Enough said.
What are you learning about ministry and technology these days?


Nick Fitzkee said...

What are the situations where you find the 3:1 rule not to apply? Could it be the pick up pattern of the mics? Could it be a sound source that's not well-represented by a single point? Could it be that the combing only happens for irrelevant frequencies? Could the effect be masked by the loudness of everything else? I hate to write off physics (being a scientist), but I can imagine several scenarios where the 3:1 rule may not hold.

If I were a betting man, though, I'd wager that, in a quiet room, you could notice the combing effect from the extra mics.

Dave Wilcox said...


I would definitely agree that, in a quiet room, you might notice the comb filter effects. However, with a drum set on stage, we rarely have a quiet room.

I also think that you've very accurately identified the weaknesses of the 3:1 rule. It assumes an omni microphone. It assumes a point source. When is that really the case? Never, exactly.

It also assumes a mono sound system where all the sources end up in the same speaker output. In our case, where we have three different clusters, we can easily add more mics without getting any comb filtering, simply by using careful panning.

Unknown said...

I know this forum is primarily for CLC, but those of us lurking from the north also find it very informative!

We've also been debating choir mic strategy recently. How close are you setting the mics to the group? Do you use a mix of mic models or all the same? We found better success with an array of SM58 and KSM27 (2 each in our instance) to pick up the different vocal sections.

Fred Baumert
Covenant Fellowship
Glen Mills, PA

Dave Wilcox said...

Hey, Fred.

We have been trying a bunch of different mics for choir. We are still experimenting. This Sunday we used 2 AKG C414s (stereo pair, cardiod), 2 Neumann KM184s (stereo pair), 2 AKG 535EBs on the outer edges.

At this point, I'm almost convinced to scrap the 414s. They just don't get the gain before feedback of the others, and they were barely in the mix.

Please let us know what you all land on as the best option, and I'll try to keep stuff up here as well. Hopefully, we can learn from each other.


Bryan Kirby said...

We just have to remember that the 3:1 rule is only a means to make the sound source 9-10dB softer in the second microphone. Because comb filtering is dramatically reduced when the out-of-phase source is 9-10dB or more softer in level than the original source.

My point (like you said in your reply comment): in a situation with multiple sound sources spaced differently from the microphones (like the individual voices in the choir, or pieces of a drum set) there is always going to be phasing. Always. I beleive this can actually help the choir sound more blended.

Not to mention that hard-panning would negate a lot of the phase problems (but the digital processor might be mixing the busses anyway, and then there's the acoustic interaction in the room. so...).

I like using 3 C414's: one dead center and the other two equally spaced from center at the back-row height, tilted down slightly. But the C414's are suceptible to a lot of bleed (and therefore feedback). We use 12 Nuemann KM84's on our unusually large 80-100 voice choir every sunday. Those are hung from the ceiling in our choir loft in two rows of six. I've also used AKG C100S, and the AT U853 and the AT 4051 with some success.

Thanks for the posts, your blog is an encouragement and admonishment to any of use that have care over technical ministries in the Lord's church.