1. Audio / Video for
Slidecasts &
Podcasts
Giving Life to
Online Media
July 24, 2010

2. The Signal
Path

3. The Signal Path
The Signal Path (or Chain)
The steps the sound must pass
through to be played to your viewers
the sound source
the microphone
the connectors
the mixing and routing
the digital recorder
the digital compression
The Signal Path is only as strong as
its weakest link
photo credit: Paul Graham Raven on Flickr licensed CC-BY-NC-SA

4. Signal Path

5. The Sound
Source

6. The Sound Source
The Sound Source
Best place to avoid poor sound
quality
Often the easiest overlooked
The least expensive solution
Listen first!
photo credit: Maccio Capatonda on Flickr licensed CC-BY-NC-SA

7. The Sound Source
Ambient Noise
“The pervasive noise associated
with a given environment, being
usually a composite of sounds
from sources both near and
distant.”

8. The Sound Source
We have an amazing amount of
ability to mentally filter out
ambient noise
wind, traffic, refrigerator hum, light
ballast buzz, computer fans, etc.
As recording engineers we have
to learn how to stop our filters and
listen again
photo credit: Barking Tree Frog by Brian Gratwicke on Flickr licensed CC-BY-NC

9. The Sound Source
Ambient noise we can sometime
filter out in post-production
Typically when it is a consistent
frequency
It can be useful to record a few
seconds of “silence” with each shot
to capture a “reference sound level”
This can be used later to help
eliminate ambient noise, or to cover
up sounds
Professional recording engineers
also record a reference tone
photo credit: Barking Tree Frog by Brian Gratwicke on Flickr licensed CC-BY-NC

10. The Sound Source
Problem:
Excessive environmental ambient
noise
background, traffic, wind, flags
Solutions:
Different environment
Different time of day
Close curtains
Remove hard furniture
Soften walls or ceilings
Reposition microphones
photo credit: LakeWentworth on Flickr licensed CC-BY-NC

11. The Sound Source
Problem:
Excessive environmental transient
noise
dogs, sirens, aircraft, frogs
Solutions:
Be aware of transient changes
and re-record
Wait it out
Different time of day
Buy the landscaping crew an early
lunch
photo credit: Barking Tree Frog by Brian Gratwicke on Flickr licensed CC-BY-NC

12. The Sound Source
Problem:
Building and machinery noise
HVAC, refrigerator, elevators,
clocks, computer fans, light ballast
hum
Solutions:
Different time of day
Know where the HVAC controls are
Run HVAC hard then turn off
Muffle vents
Turn off & unplug equipment and lights
Signage “Quiet Please!”
photo credit: RomulusNR on Flickr licensed CC-BY

13. The Sound Source
Problem:
Talent & crew noise
fidgeting, clothing noise, mouth
sounds
Solutions:
Train crew to be quiet
Avoid walking to avoid both creaky
floors and creaky squeaky shoes
Avoid noisy cloth, in particular silk,
rayon, corduroy, especially on talent
Readily available water between takes
& green apple slices to avoid mouth
noise
photo credit: Diamond Geezer on Flickr licensed CC-BY-NC-ND

14. The Sound Source
Problem:
Sound & video gear
crackles, ground loops, camera noise,
microphone pops, wind noise, phones
Solutions:
Mark and discard bad cables
Use balanced gear (see upcoming
slides)
Don’t use camera microphone
Be aware of microphone placement
Use a zeppelin or windsock on mike
Turn off or Airplane mode phones
photo credit: RomulusNR on Flickr licensed CC-BY

15. The Sound Source
Problem:
Lost or bad sound
microphone or recorder batteries
dead, cable loose or unplugged, etc.
Solutions:
Double-check!
Tape everything down
Backup with Additional recorder
“Plant” a digital recorder as a backup
Use iPhone Movie★Slate to sync
photo credit: tjmasiakowski on Flickr licensed CC-BY

16. The Sound Source
Movie★Slate
This iPhone / iPad app is a bit
expensive ($19.95), but very useful
Sync multiple audio sources
If you keep volume of iPhone same,
good reference tone
Accurate time
Good for making sure you have
notes on all of your shots
But remember turn on Airplane
Mode!
photo credit: PureBlend Software Movie★Slate

17. The Sound Source
Reference Headphones
Use your headphones – many
problems you’ll not spot unless
you use them
Anything is better then nothing
But if you buy a good pair, you
want
“flat response”
photo credit: Dale Gibert Jarvis on Flickr licensed CC-BY-NC-SA

18. Questions?
Feedback?
ChristopherA@LifeWithAlacrity.com