G'day,

Welcome to the Live Audio Workshop.

Out of the swags of emails that I’ve received since doing this column there are three questions that rear their head many, many times. So lets get them out of the way.

Q.. “How come my recordings sound dull and lifeless, even after I put lots of ‘Hi EQ’ on it?”

The answer to getting recordings that sound great is to record great sounds…doh!! Get the sound right at the recording stage. Not everything can be ‘fixed in the mix!’ In other words…’you can’t polish a turd!!’ LOL.

A mistake often made by newcomers to recording or live-sound is to try to brighten up an inherently dull sound. Their first reaction is to reach out and grab the channel EQ and feed in large amounts of boost to the top-end frequencies. This rarely achieves anything more than an increase in background noise, hum and hiss and a general grittiness or harsh quality to the sound. For example, a synth sound played through a dull-sounding amp and miked-up, will not respond well to high-frequency boost, because there’s none there!! All that is in those frequency bands is mainly noise and interference. It’s not the gears fault, it’s a basic lack of understanding…operator error.

EQ CAN ONLY BOOST FREQUENCIES THAT EXIST!

Q.. “I’ve just scored a 200 Watt amp, will it blow my 100W speakers?”

Amp ratings can get fairly complicated as there are lots of variables to consider. (Things like Impedance, Continuos versus Peak Levels etc.) Many people think their amps are always putting out their max rating, but this isn’t the case. The power output of an amp varies with volume level. When there is no sound the amp is producing zero watts. When the volume is low the amp is putting out only part of its potential. As the volume is increased, the amplifier power output increases.

Your 200 Watt amp will safely drive your 100 w speakers – or even smaller ones - UNLESS you crank up the volume to the full power-output capability of the amp.

Q.. “Why do the roadies go ‘Check, One-Two’ over and over at Soundcheck? Can’t they count to three?”

For those who came in late…
Every venue has it’s own 'Room Sound' or acoustic properties. Such variables as the shape of the room, height of the ceiling and the materials used in construction for wall and floor coverings determine whether it will reflect or absorb different frequencies of sound. This will either artificially boost or cut frequencies.

Polished floors, mirrors, tiles and any hard surface are reflective and help make a ‘Live room’, sometimes with ‘discrete echoes’. Carpets, curtains and soft furniture are absorbent and help make a dull sounding or ‘Dead room.’

Tuning or EQing the Room.
We use a ‘31-Band Graphic Equaliser’ patched-in across the stereo outs of the Desk to boost those frequencies that have been absorbed, and to cut those that have been boosted. Thus the room sound is taken out of the equation and the soundie can concentrate on getting a vibing mix rather than fighting the effects of room-sound. (Technically, the room is ‘equalised to a Flat Response'.)

Q.. Why “Check, One - Two” at Soundcheck ?

When used for Room Tunning, “Check One-Two” shows us the interaction between the effects of Room Sound and the different energy levels generated from the various types of sounds produced by the vocals. It contains a representative range of not only the different frequencies of sounds, but also all the types of sounds the human voice can make.

The human voice can make many types of sound, with the different types varying in strength according to the manner in which they are generated. Of most interest to Soundies are the sounds of ‘Plosives’ and ‘Sibilance’, as they release a lot of mechanical (breath) energy.

The ‘Plosives’ - like their name hints at - are formed by a mini-explosion when air comes out with a rush from behind the lips. The “POP” in ‘p’s. - also found in “cha” and “sha” type sounds - or any sound of an ‘explosive’ type of nature.

‘Sibilance or Sibilant Sounds’ - also like the name hints at - are the ‘hissing’ type sounds that are formed when air is forced by the tongue between the teeth, lips or a combination of the two.
The ‘hissss’ found in “ss”, “ts” and “tw” type of sounds.
The Low, Mid and High frequency sounds are represented in different words and combinations, within the phrase. For example,

When saying ‘One-Two, Tswooooooo’, let the end of the ‘two’ drop down in Frequency - to almost ‘gravely’ - ; to identify the Low Frequency Vocal Resonances.

When saying ‘Check - One, wa, wa One ; Check Wa Wa One.’ the ‘problem mids’ around 800 Hz. give the characteristic “HONK or HORN” sound.

When saying ‘One - One Tsoo, Ts Ts Tsoo, Two’, the frequencies around 6 kHz. and their associated Upper-Harmonics which cause the High Frequency ‘ Ringing’ are identified.

Well that's about it for this week, next week I’ll catch up on some more emails I’ve received lately.

Until next then….have a good one!!

Willy T.

Email - giraffemedia@optusnet.com.au

[Willy T lectures in audio and A-V at the Entertainment & Technical Events Training College. (ETETC)]

This is extracted from the book:
"LIVE-AUDIO WORKSHOP: A Hands-on Guide to Rigging and Operating PA Systems." ISBN 0 646 36408 1.
© Giraffe Communications 1998.
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