TCM MASTERING: HOME MUSIC STUDIO PART 28 – SIGNAL PROCESSING

TCM Mastering: Home Music Studio Tips and Information

Part 28 Signal Processing – Effects Processors

We’ve been looking at Signal Processing over the last few weeks. Starting with EQ then Dynamics and finally Effects.

Last week we looked at Reverb, probably the most used Effects processor in music. This week, we’ll continue looking at more Effects processors – specifically Delay, Chorus, Flange and Pitch Shift.

Before we get into it, I’d just like to mention that TCM Music Group have some great recording packages on offer at the moment. So if you would like some professional session musicians on your track or need help with production, mixing or mastering those tracks – get in touch by clicking here to contact TCM. We’re here to help with a professional, fast and affordable service for today’s musician.

The Massey TD5 Plug-In, Sounds And Acts Like A Vintage Tape Delay, With Up To 2 Seconds Delay Time.

Delay – If you’ve ever shouted out at the top of a canyon and heard your voice come back a second or so later – that’s echo or delay in acoustic terms. It’s a series of distinct repeats at regular intervals. The interior of a church sounds reverberant, where there are thousands of sound reflections much closer together and shorter.

Size Matters? Is Your Living Room More Like The Room On The Left Or The Right?

In most normal sized rooms at home, it’s difficult to hear a distinct delay because the room is too small, although you might hear a slight reverb, especially if you’re singing in the bathroom. Rooms with hard, tiled surfaces like bathrooms and kitchens will be more reverberant than carpeted living rooms with fluffy sofas.

Left: Sound Reflections Reaching The Ear After 30-40 m/s Are Perceived As Echo (Distinct Delays). Right: Reflections Shorter Than 30-40 m/s Are Perceived As Reverb.

The speed of sound is approximately 340 metres/second in air. Sound reflections which reach the ear more than 30-40 m/s (milliseconds) after the original sound are interpreted as echo…..less than 30-40 m/s, the ear perceives them as reverb.

A Lot Of Recordings From The 1950s Used A Slapback Echo Effect On The Vocals.

There are different types of delay effects available from straightforward delay (short, medium and long) to slap, multi-tap and ping-pong delays. The main parameters are gain, delay time, depth, rate, feedback and mix/effect level.

The Gain controls the amount of input signal to the delay unit.

The Delay Time is the difference in time between the original signal and the repeated sound. This can vary from a few milliseconds (m/s) to several seconds.

If you listen to recordings from the 1950s eg. Elvis Presley, a lot of them use a slapback echo (75-250 m/s) effect on the vocals. John Lennon also used this type of echo to great effect on some of his recordings.

The use of delay on specific words or phrases can prove very effective, often with a little reverb added too.

An Example Of Pro Tools’ Slap Delay Setting.

The Depth parameter allows you to add modulation to the delay. This can produce a chorus type effect.

The Rate control determines the length of time it takes the modulation to go through one cycle. The combination of rate and feedback can produce a huge variety of echo delays. Like the 1950s short, slapback effect to the lengthier more ‘spacey’ effects used by guitarist John Martyn.

Guitarist John Martyn (Top) Developed A Signature Sound By Running His Guitar Through A Fuzzbox, Phase Shifter And Echoplex (Bottom).

By matching the rate of echo to a multiple of the music’s tempo you can often add depth to the track without cluttering it up.

The Feedback parameter sets the number of times the echo repeats. If you want a single echo repeat use the lowest setting to get the result. A higher setting produces more repeats. By setting the feedback very high you can make the echo feedback on itself.

The Mix/Effect parameter controls the effect’s output level. A higher setting gives more of the delayed signal compared to the original.

One Of The Many Delay Plug-Ins Offered By Pro Tools – Used On Rihanna’s Vocals By Engineer Gimel Keaton.

Some plug-in delays can produce stereo outputs from mono signals. These outputs can be panned left and right.

The ping-pong delay by using two delay lines (one fed to each output) takes this a step further. The feedback from the left delay line is returned to the right input and vice versa. This results in the echoes appearing to bounce from one side to the other.

Pro Tools D-fx Bundle Of Audiosuite Plug-Ins Includes Chorus, Ping-Pong And Multi-Tap Delays.

The multi-tap delay emulates the old tape delay machines. The tape delays had multiple playback heads (often 3 or 4) which provided multiple echoes that could then be fed back to create complex delay patterns.

If you make a copy of a sound and slightly vary the pitch of that copy over time, when played against the original sound you will get a Chorus effect…..think, the guitar sound of Andy Summers of The Police!

The Police Guitarist, Andy Summers With His GR300 Guitar Synthesiser And GR303 Guitar Controller.

Let’s take for example, a string or voice ensemble. The slight differences in pitch and tuning between the various string instruments or voices creates a full, rich, almost shimmering sound. The chorus effect simulates this.

Of course, if tuning or pitch is too different from the original it just sounds out of tune. We’re talking about very small pitch variations here.

Sanford Super Chorus Provides Four Independent Chorus Effects, Available For Windows As A VST Plug-In.

As with all effects units, parameters can vary between manufacturers. Chorus parameters usually include predelay, depth, rate, feedback and effect level.

The Predelay measures in milliseconds, how close or far the effected sound is from the original sound.

The Depth determines how much pitch modulation is produced by the chorus effect.

The Rate parameter, normally described as a frequency, controls the speed of modulation. It could be between 0.1 to 10 Hz. This does not refer to the pitch but the number of times per second the oscillation occurs.

A Selection Of Chorus Foot Pedals.

Feedback controls how much of the chorused signal is returned to the input. This parameter is sometimes referred to as Staging in some units.

Effect Level (or Mix) allows control over how much effect is sent to the aux return bus. Ultimately, determining how effected the signal sounds.

Chorus is very effective on vocals, both lead and backing. And as mentioned above, Andy Summers of The Police made good use of it in his guitar sound, as have many guitarists since from Kurt Cobain to David Gilmour.

Panning the clean signal to one side and the chorused signal to the other can prove interesting on guitars and some synth patches.

Jimi Hendrix Used Many Effects On His Classic Electric Ladyland Album – An Innovator Of Studio Techniques.

The Flanger effect is similar to the chorus, except that it alters the original sound signal in time and tends to use shorter delay times.

Two signal paths are employed, one clean and the other effected. The latter being delayed by several milliseconds and modulated. The distinctive whoosh effect of flanging is created by feeding back some of the delayed output signal to the input.

Because it is a very distinct sound it can come across very clichéd whenever it’s used, so use it wisely and sparingly.

For early examples, take a listen to The Beatles’ Revolver album, The Small Faces’ Itchycoo Park (1967), Hendrix’s Electric Ladyland (1968) or more recently, the lead vocals on SCARECROW by Chemical Romance (2010) which was supposedly inspired by the Beatles’ Lucy In The Sky With Diamonds.

My Chemical Romance Used Flange Effect On Their SCARECROW  Track.

The other problem with flanging is the background noise. With all the feedback that is being used it can sound really noisy, especially when there’s no useful signal present. So again, use carefully.

Note: Originally, flanging was achieved by feeding a signal to two tape decks running simultaneously. The outputs from these two machines were then mixed and fed to a third tape deck and recorded. Because the running speeds of the two machines were ever so slightly different, a phasing effect was produced when the two signals were mixed together.

The flange effect was born when an engineer placed a finger on the flange or rim of one of the tape reels which slowed the tape speed compared to the other machine…..causing a sweeping effect, produced by shifting sum and difference harmonics. When the finger was removed the reel would speed up, causing more sweeping effects.

Digidesign’s Pitch Shift Provides Coarse And Fine Adjustments.

The last effect we’ll look at this week is Pitch Shift. This effect allows you to raise or lower the pitch of a recorded signal. When mixing your tracks you can run background vocals, for example, through a pitch shifter to thicken them and make them sound fuller. Modern digital technology now allows the user to pitch shift in real-time.

Don’t confuse this process with Pitch Correction, which uses software like Auto-tune to correct a singer’s performance.

Depending on how much pitch shift you use, you can create a subtle effect of two voices almost singing in unison (like double tracking) or produce harmonies with bigger pitch shifts.

As an experiment, try sending a kick drum or snare through a pitch shifter and lower the pitch by intervals up to an octave.

Aphex Vintage Aural Exciter.

There are many more effects available eg. Wah-wah, Fuzz box, all kinds of Distortion, Aural Exciters and Tremolo to name just a few. And remember if you’re using plug-in effects or other signal processors, they can usually be automated within your music software programme. Pro-Tools can automate a whole bunch of plug-ins with even the most basic LE version.

Suffice it to say, if you want to play around with a sound there are enough effects on the market to keep you busy for a lifetime. Just go easy…..more music tracks have been ruined by adding too many effects than not adding enough!

Over the next few weeks we’ll take a look at the ‘multitrack’ process in detail…..from setup, recording, overdubbing, editing, mixing and mastering.

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