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< Part 16 | Intro | Part 17E | Part 17G | Part 18 >

The Videomaker's Journey: part seventeen
Editing Principles for Beginners

Use the links in the text to move between sections.

Step 6: Adjust the dialogue audio volume

Audio level calibration

The audio level gauges in some editing software are not related to standard zero dB audio. [For audio recording purposes "zero decibels" is the upper limit before distortion is evident - so it means the loudest your soundtrack should ever normally be. Most of our soundtrack should be in the "minus" range.]

The audio level has to be set by ear - this seems to be typical of some of the computer systems in use in the club I attend. This is not good enough - I have calibrated the audio level in my iMac -so that I can read the audio volume on an external audio level gauge, as I adjust the volume to the required level on each clip.

Adjust the audio level so that most of the peaks touch zero dB. An occasional high level peak is OK - but no higher than about + 3dB.

I have made a DVD with zero dB sound recorded on it. I use this to calibrate my audio level gauges and other equipment:


Clip 10 Zero dB Audio Test (1 min)

A now superceded JVC, S-VHS VCR serves as my audio level gauge.

If you still have an old Panasonic FS 90, S-VHS VCR and the audio doesn't work - it may be OK -some of these failed regularly. Make sure the power cord is disconnected from the power point. Remove the top from the case. The fold down control panel is connected by multiple wires to the internal circuit. The connector plug corrodes - unplug it and re-connect it - if that was the fault - it will now work.

This is how I set up my equipment

Step (a) Make a DVD copy of the Clip 10 Zero dB Audio Test, or buy a CD of test tones. [Go to eBay and enter "Audio test tones CD" and you will find several CDs around £2.49+£4.98 p&p.]

You cannot do this by taking the audio from the headphone socket - you cannot regulate the volume, yet.

Now play this DVD or CD through your audio level gauge - note the reading that you get . The reading on my VCR is +2 db - that is my zero dB signal. [Ideally I would be able to adjust the meter itself so that it reads zero but that is not practical with most meters. So long as I keep in mind that for my system "+2" = "0".]

Step (b) I now connect my iMac computer to the S-VHS VCR by plugging the stereo cable into the headphone socket of the iMac computer. This will switch off the computer speakers, but the volume control on the keyboard still works.

The other end of the cable is connected to the microphone, mono left and mono right connections on my Vivitar VSM - 30 audio mixer. The cable I have has RCA fittings at this end - so I have to use plug adapters, it is impossible to buy the correct cable.

Step (c) Now connect the master line out on the audio mixer to the S-VHS VCR's, audio in.
Step (d) Now connect the VCR to the tv monitor - this is so you can hear the sound.
Step (e) Because we are feeding headphone audio into a line-in socket [If you connect the Cables the wrong way you might over-load the Input or damage your ears- refer to Part 12 Impedance of Line Level Audio and Microphone Level Audio and there read First a Warning.] - what we are about to do is not dangerous, but nevertheless only gradually increase the volume with the controls.

Set the TV volume to your normal setting, this can be varied at any time - this does not affect our calibrating process, but you need to hear properly.

Set the mixer controls to zero. Set the computer speaker volume to a low setting.

Switch on the audio mixer and the VCR. Play Clip 10.

Step (f) Gradually increase the computer speaker volume control - at the same time, gradually increase the volume controls on the audio mixer - until you get the calibrated reading on the audio level gauge - the one that corresponds to zero db. [In my case +2dB.]

The readings on my equipment are:

  • +2dB on the audio level gauge (the S-VCR audio level gauge cannot be reset on my S-VCR, the Panasonic S-VCR's audio level gauge could be reset by a technician)
  • Computer speaker volume at 45%
  • Audio mixer - microphone in at 27%
  • Audio mixer - master line out at 27%
Note your settings - they should not to be altered from now on.

I am now ready to adjust the volumes in the various movies.

Adjust the volumes for each clip to get most of the peaks at the calibrated zero dB level on your audio level gauge.

Refer  to Clip 6 extract from Dressed To Kill - this is an example of loud background noise that has been reduced to an acceptable level. The actors spoke very loudly - when the dialogue was reduced to zero dB in the edit - the background noise dropped to a low hum.


Clip 6 extract from Dressed To Kill

[Some editing programs include Vu meters - Premiere Pro for example. For PC users there are a number of software sound meters available free from here. For general advice on getting the best from your soundcard look here. I have not tracked down any free Vu Meter software for Macs yet - please email me if you know one. - asstweb@theiac.org.uk]

Getting rid of excessive background noise or unwanted music in the background

If this nuisance noise is of a lower volume - the special effects "noise reducer" may do the job.

The "noise reducer" removes the unwanted background music.

Another way to get rid of excessive background noise, is to replace the bad dialogue with fresh dialogue which is lip synced to the video clip.

Refer to Clip 11 (8 seconds) extract from New Beginnings.


(8 seconds) extract from New Beginnings.

The method

  1. Plug headphones into the computer - this will mute the computer speakers.
  2. The actor has to learn the words off by heart.
  3. Set up your video camera close to the actor's mouth - ready to record.
  4. Have the computer repeatedly replay the offending video clip - the actor watches his lips on the computer screen, listens to his voice in the headphones - and speaks the words.
    When the actor's voice is lip syncing in a good manner - start the video camera. Record this twice - I kept practising until I was getting it spot on, it took me about 20 rehearsals. It has since been pointed out to me, that if you have a consistent delay of say half a second, this will work just as well, this may make the job easier.
  5. Editing the new dialogue to the video clip is easy with a computer.


  < Part 16 | Intro | Part 17E | Part 17G | Part 18 >

© copyright Arthur Bullock, 2008


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