An Introduction to Live Audio Production

September 29, 2017

1~4 class

At Kittredge Theater on the Warren Wilson College Campus

The class is being hosted by WWC student and Theater Crew member Caroline Daniels
with Weogo directing the teaching.

Free

We will cover the basics of:
Safety, AC Power
Listening, Acoustics, Live Recording
Audio Equipment, from Microphone to Speaker
Decibels, Audio Measurement
Feedback, Troubleshooting
And More!

This class is for:
) Aspiring Live Audio techs, whether in the concert, wedding, theater, church, dance or corporate world
) Anybody interested in how Live Audio production happens
) Musicians who want to better communicate with mix techs

Bring a notepad

Seeya soon! Weogo

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Analog or Digital???

Analog came first.
> All audio equipment used basic electrical principles to convert sound waves to electrical signals, make those signals bigger, and then convert them back to sound waves.

Then came digital audio equipment.
> First were digital effects processors – various flavors of reverb and delay, etc.

> Next were digital recording systems.

> Then came stand alone EQs, dynamics processors, crossovers, delays, or routing devices.

> Eventually many of these processes were combined in to one box, commonly called a DSP, or Digital Speaker Processor, as these commonly go after a mixer, and before amplifiers.

> About the time DSPs were coming out, Digital MIXERS started showing up.
Smaller ones were around $50,000, larger, more complex ones could easily go over $100,000.
Digital mixer prices came down.
The larger digital mixer here on the stage, a Yamaha 01V96 from 2003, cost $2000 new, and pretty much did more than that older $50,000 mixer.
The smaller Mackie DL1608 from 2012 is quite a capable mixer and currently costs $600.
The larger DL32R from 2015 is fairly full featured and costs $1500.

> Digital processing started showing up all over the place.
Amplifiers and self-powered speakers got much of the processing that was in the DSP boxes.

> Digital wireless mics started showing up.

So, is Analog better, or is Digital better?
1.) With Analog, from when a sound wave enters a microphone, goes through all cabling to a mixer, processing, amplifier, and speaker, and is converted back to a sound wave, is essentially instantaneous.

> With Digital, in every device, a digital microphone, mixer, DSP and/or digitally processed amplifier or speaker, there is always a certain amount of computing time, called latency.
Early digital units had lots of latency, newer units much lower. But they will always have some.
How much latency in a system?
3.5ms, digital wireless mic
2.5ms, digital mixer
2.5ms, digital speaker processor
= 8.5ms 9.6′

OR 1.ms for just digital mixer

> Compare to air time for monitor to ear transmission.

> Where this is likely critical is when using IEMS, In Ear Monitors.

+) So, Analog has no latency, Digital does.
Plus 1 for Analog.

2.) Digital devices use converters. Analog to Digital at inputs, Digital to Analog at outputs.
Every time you run a signal through a converter you degrade the signal.
Early converters noticeably degraded signal quality.
Current converters commonly have a measurable, but tiny effect.
But if you add lots of conversions, the changes to the signal do add up.

+) Analog has no converter degradation.
Plus 2 for Analog.

3.) When patching Analog equipment you go from a real, physical connector to
another connector.
Finding patch errors is fairly straight-forward – just follow the cable.
With Digital, patching is done on one or more patch screens.
Finding a patching error means knowing the program/app pretty well.
+) Plus 3 for Analog.

Analog is repairable at a fairly basic tech level. This could be very useful in a lower-tech future.

So why use Digital?
Look at these processors. Imagine having multiple racks of processors like this.
1.) All this extra Analog EQ and dynamics processing requires patch cabling to connect.
Connectors get dirty and can have intermittent, hard to find issues, or can have a continuous buzz, or not work at all. Lots of connections, means lots of points of failure.
With analog mixers, dirty linear faders and rotary potentiometers can have issues similar to those noted for connectors above.

Digital allows you to do some things that you can’t do in the analog world, for instance remote control of preamp gain. This allows for placing a mixer on stage and mixing remotely, without running a snake or power to an analog mixer.
Digital allows you to mix not just where the mixer is, but where the audience is. Very useful for dances, where you can’t have a mixer on the dance floor.

2.) Some of this equipment is expensive, some comes with only a modest price tag.
But even with the modest cost items, when you start adding up ten or twenty units, it can get pricey.
3.) All these processors require power. More AC draw might mean you need a larger AC service to run your system.
4.) All electronics create heat. If you are outdoors in the sun, you may need rack fans to keep equipment cool.
5.) All these processor take up space. Four racks this size would not hold all the processing in this little DL1608 mixer. Since they take up so much space, in the past we just made do with less, and had to really think, which channels are ok without a compressor, which ones really would benefit from having one?
6.) Big analog mixers and racks can take up a lot of venue space. They definitely take a lot of truck space and added weight carrying capacity. Equipment storage space is large.

Mixing speed is a TIE:
Analog mixers and processors have all possible controls at your finger tips.
Digital mixers use various layers on hardware and software.
The fact is, some adjustments are faster on an analog mixer, others on digital.
The real factor here is knowing really well what you are working with.

In reality, a competent tech can walk up to a good analog or digital system and do a good mix.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Hi Folks,

Audio for a new dance, from the beginning:

The Asheville Monday Night Dance has moved to a new location at:
The Center for Art and Spirit at St. George’s Parish Hall
One School Road, Asheville, NC 28806
http://www.centerartspirit.org/map–contact-info.html

The first dance in the new location will be January 2nd, 2017.
Come on out and dance!

LiveEdge Audio is managing audio for this series.

With a nice, hardwood dance floor, and mostly hard surfaces for the walls and ceiling,
venue acoustics are lively, and Caller intelligibility may be a bit of a challenge.

Overall, the maximum dance floor space is 35′ wide x 43′ long.
The stage area is a nice 16″ above the dance floor.

First things first:
On a recent afternoon a crew met and carried in audio test equipment.
This was for some VERY basic testing. (Yay crew!)

Two speakers were used for initial testing.
Speech intelligibility metering was done at:
a front corner, front-center, center, and back/center of hall.

A) The first test was with a speaker in both of the front corners.
Fair intelligibility overall, except poor at the front center of the hall.

B) The second test was with speakers spaced about 20′ apart.
Poor intelligibility overall, except fair at front corner and center.
The picture above is this test scenario.

C) Single speaker in center.
Best intelligibility overall, though only fair at front corners.

(A fourth scenario will be tested:
The EV ELX15 boxes in the corners will be used to cover most of the hall,
with a small center-fill speaker at the front/center of the hall.)

For the first dance, A Danley SM60F will be in the center of the hall,
on the stage, covering most of the venue.
The SM60F is a pretty high intelligibility speaker, with
pattern control that goes a couple octaves lower than
many common speakers used at Contra dances.
It will be mounted in a yoke, allowing the speaker to be
optimally tilted for dance floor coverage, while minimizing spill to the ceiling.
http://www.danleysoundlabs.com

An EV ELX15 will cover each front corner, running at fairly low volume.
These will be mounted on customized tilters that maintain the
speaker’s weight center over the center of the speaker stand,
while aiming sound down on the dancers.
For one of these speakers, the low frequencies
will be boosted to give a little bit of low end oomph.

The dance floor will accommodate a little over 100 dancers, so
a small blessing is that the noise of the dancers on the floor
will be less than a large hall that can fit over 250 dancers!

For now, David Hayes and LiveEdge are providing audio equipment.

Long-term, the Asheville Monday Night Dance Management
would like to help the Church install a useful audio system.

If you have a donation, even a mic cable or SM58 microphone,
we would be happy to have them!

Updates to this post will come as we test various speaker configurations with actual dances.

Thanks to Beth Molaro, Manager of the Asheville Monday Night Dance,
and all the volunteers making this dance happen!

Good health, Weogo

Some microphone cables I bought used around 1991 from the old Greenville, SC Memorial Auditorium, are still in very good shape.
Take care of your cables and they will serve you well for a long time.


Cable cleaning:
) Check that the outer cable jacket is in good condition.
) Dip the rubber part of the cable in a tub filled with soapy water. Scrub with a sponge/scrubber. Keep connectors dry.
) Rinse, dry with old towels. Lay out in sun to make sure cable is completely dry.

Cable storage:
) Learn how to over-and-under cables. This is a cable coiling method that minimizes twisting of cables.
Good video showing over/under: https://www.youtube.com/watch?v=0yPcJD7RVuY
) Put velco ties on the male end, or use black cotton trickline.
) At a venue you can store cables on pegs.
) Or store cables on a reel. My issue with reels is I have 5′, 10′, 15′, 20′, 25′, etc. cables. Using a reel means I may have to pull every cable off the reel, even though I might only need half the cables on the reel for a particular gig.
) Do not wrap cables around your elbow. Do not wrap cables around your elbow. Do not wrap cables around your elbow.

Cable testing:
) The ultimate test it to plug a condenser mic in a cable, talk on the mic, and wiggle the cable ends at the mic and mixer.
) Simpler is a basic cable tester.
) Another test is running a cable though your closed hand, feeling for insulation tears, kinks, leftover bits of tape, etc.
) For minor abrasion and tears, wrap with a bit of tape for a quick fix, or better, put a piece of shrink tubing over it. For bad damage, cut cable in half, add connectors and now you have a couple shorty cables.

Cable straightening:
) When a cable gets kinky from bad coiling, being jerked, wrapped oddly around a stand, etc., lay it out in the sun.
) When it is warm and soft, knead out kinks, and carefully re-coil, with no twists. The cable will (mostly)forget its bad ways.

Mice & Rats:
Over the years I have seen mic cables, snakes and other cables gnawed on by Mice or Rats.
Usually this is near the ends, where th cable is handled, and salt and oil transfer from skin to cable.
) Storing cables where rodents can’t get to them is advisable.

Cable paging:
Some singers spin the mic in their hand, or walk in little circles on the stage, while holding a mic. This puts twists in a cable.
I know one dance caller that will on average put a dozen twists in a cable per night.
) If you ask them to stop doing this, they might.
) If you regularly work with someone who does this, you can start the dance with some reverse twists in the cable.
) Or just know you will have to undo this at the end of the dance.
Cable labeling:

There are at least a couple reasons for labeling cables:

1) One being so you know who owns a cable:
If you label the male end, then the female end will look good for performers, and on camera.
<> These days my first choice is an ultra-fine paint pen. Depending on use, once-a-year touchup might be needed.

<> Adhesive labels are another option, or shrink tubing that has your name and contact info printed.

2) Another use for labeling is so you know what cable goes to what channel:

<> Put a small bit of tape on a cable end and mark the channel number.
Have a plan for the stage crew to keep track of what cable is where.

<> Use different color cables. In addition to black, blue is commonly available.
You can also get pretty much any color of the rainbow.
) Brown can sometimes be hard to tell from black.
) Red might be desired by some folks, but I try to use it only on the floor,
for going to a direct box, a foot switch, or maybe a shorty mic stand, etc.
) Orange is like red.
) Yellow definitely stays on the floor
) Green look ok on a stage to me, as long as it isn’t bright lime green.
) Blue is good, as long as it isn’t some neon blue.
) Violet works, but be careful, the less noticeable hues start looking pretty close to black.
) Gray, in the darker shades, can work, but again be careful how close you are going to black.
) White will look dirty very quickly.
) Some stage lighting makes colors hard to see.
) Short, bright colors can be handy for patching the back of a rack.
You may have very different color sensibilities than me!

<> If you are using Neutrik connectors, there are various colored sleeves available.

<> A couple inches of colored shrink tubing at each end can identify a cable.
But you have to remove a connector from the cable to install it, or have this figured out when building cables.
Or buy high-ratio shrink, that can go over a connector, and then shrink down to cable size. Can get kinda pricey.

<> Colored electrical tape.
Though I have done this in the past, it is my least favored solution.
If you go this route, don’t leave the tape on very long.
I recently removed some tape from some cables(not mine!). Adhesive was starting to come out around the edges of the tape.
GooGone got rid of most of the remaining residue, but some tape that had been on a LONG time left a hard crust that only yielded to steel wool.
Even then, the adhesive had permanently etched in to the connector.

What mic cable care advice do you have?

Thanks and good health, Weogo

ContraSF, Contra Sound Forum was started in 1998 as a simple e-mail forum for
folks who run sound for Contra dances.
Dance organizers, Callers, Musicians, Dancers, really just about
anybody interested in audio production for any form of Folk Music is welcome to participate.
We entertain questions from the most basic up to fairly sophisticated.
Posts are appropriate for all age groups.

Contra dance sound has some demanding aspects:
A clear caller and music need to be heard on the whole dance floor, at modest volume.
The music is live and there may be several microphones wanting to feedback.
Venue acoustis are often poor.
Budgets are generally limited.
Sound equipment is often hauled to a dance, set up, run, taken down and stored in a spare room.

The Forum is moderated, meaning all subscriptions are approved, so spam is not an issue.

SUBSCRIBING:
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Any issues, please see me contact page and get in touch.

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For contraSF,  Weogo Reed,  Asheville, NC