Wily WILLY T explains everything DELAY & MODULATION. Mmm Delay.

Delay, originally called echo, is one of the oldest artificial effects used live or in the studio. Often used on guitar or vocal sounds, delays are used to produce discrete repeats of the input signal, at regularly spaced intervals. Old school analogue delays – and echoes that occur in nature – get duller every time they reflect from a new surface. If the delay is quieter and duller-sounding than the original sound, we accept it as an echo, but if it’s equally loud and just as bright sounding, our brains interpret it as a note in the wrong place! In a great irony for the gear slutz, the technically bad specs of the early gear made their echoes and delays seem more ‘organic’ than the perfect clones that are spat out by today’s pristine sounding digital delay units!

When used with a Low Frequency Oscillator (LFO), a delay can be a very creative tool. The LFO is used to ‘modulate’ the signal by continuously varying the delay time by a slight but noticeable amount. The recombining of the varying delay time signal with the original dry sound produces a form of phase cancellation or ‘Comb Filtering’, which creates the illusion of movement and depth. By adding an LFO to a delay unit we can create a ‘whooshing’ or ‘liquid sky’ type of effect, as well as the more common Chorus, Flanging and Phasing FX.

Ask any axe-warrior guitarist about modulation FX. They may not know it but they all know the effects … or at least what pedal to stomp on to get the sound of them! But, if they had an old delay unit lying about, one with a broad range of delay times, and a modulator on-board – not too much to ask for – they could set it up to produce Chorus, Flanging, Phasing and Vibrato effects straight out of the box. Of course, this will rarely happen. For, as we know, musos are not sound engineers. They follow the KISS principle – Keep It Simple Stupid.

The amount the signal is delayed – plus the depth and speed of modulation – determines the type of effect produced. Delays shorter than 10 milli-seconds (mS) create flanging and phasing effects in which certain frequencies cancel out, changing the tone. Shorter delays – 10-20mS – produce chorusing effects, making it sound like two or more instruments playing together, with vocals thickening up to around 50mS. Delays longer than about 75mS create ‘separate echoes’ or ‘slap-back’ effects.

The modulation speed control sets the speed at which the oscillator continuously varies the delay time. When the delayed sound is recombined with the original signal, the frequency of the phase cancellation is determined by the length of the delay time. By continuously varying the delay time, the ‘swishing & swooshing’ of phase cancellation moves up and down the frequency range, giving the impression of movement. The faster the speed, the more pronounced the movement.

This sets the ‘depth’ of the phase-cancellation that produces comb filtering. The depth is varied by changing the balance between the levels of the direct sound versus the delayed sound.

The better delay units allow the user to control the modulating frequency of the LFO. This control is expressed in cycles/sec or Hertz (Hz) and allows the operator to fine-tune the modulation FX to the music.

Delays are an effect, relying on an electronically treated version of the sound being added to the original source. When using a mixing desk, we send the sound out of the desk to the delay unit using the channel auxiliary-sends and feed the delay from the desk’s auxiliary master send. In this way, adjusting the master-send level will adjust the overall level sent to the delay unit. With the delay’s Mix control set at 100%, the output of the delay is then ‘returned’ to the mixing desk and blended with the original dry signal, and mixed with the rest of the band/music/instruments. Voila – a kick-arse mix!

When using a delay over one instrument, or if the mixing desk has channel inserts, the balance must be adjusted on-board the unit before being returned back into the channel. Use the effect gear’s on-board Mix control to set the balance of the wet and dry signal.

Finally, there are no set rules for delay times and their use. Use your ears and be alert for any ‘muddying-up’ of the original sound – particularly across the vocals. Use FX sparingly … a little goes a long way. The music – not the effect itself – should be what the punters remember, with the effect there to spice-up or accent the piece. Even though an effect may initially sound cool, it can also quickly sound tacky. Have a good listen to the way the pros use FX in your sub-genre of choice. Then try to do the same. It’s often surprising just how little they use.

"But you know FX and all that stuff’s nice, it embellishes and that’s great," says FOH sound engineer Jonboyrock (Reguritator, Jet, Wolfmother, Screamfeeder). "I Sometimes it really adds something but what the guys are doing on stage is the most important thing. The people aren’t there to hear you, they’re there to hear the band and you’re just the medium between them. Don’t be the star, let the band be the performers."

WILLY T runs Giraffe Media. Providing Words, Pics and Live-Audio Recording Services to the entertainment industry. Email  for more information.

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