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Vocal Harmony Made Easy


Introduction
The DigiTech® Vocalist line of vocal/guitar pedals are the first products to feature the revolutionary new musIQ™ technology. This discussion highlights the problems with the current generation of harmony processors, and explains how musIQ technology addresses these problems to bring harmony processing to new levels of quality and ease of use.


Before musIQ: It sometimes works, but…
Let’s say you’re a singer/guitar player and you want to add some harmony vocal sounds to your performance. Perhaps your version of Lyin’ Eyes by the Eagles needs a little more impact during the chorus.

Before musIQ, you might do the following: First, get a harmony processor, plug in your mic, and maybe find a preset that has a harmony based on 3rds above the melody. You’d then need to play around with the user interface a bit so that you can enter the key of the song you’re playing. It’s actually surprising how many amazingly talented players don’t know what to do at this step, but let’s assume you know that the key is G, so you set that. You then start playing the song, and when you hit the chorus, you engage the harmonies. Things actually sound pretty good until you sing “I thought by now, you’d realize”. Suddenly you stop. The last two notes of the word “realize” are totally wrong. First, a B is harmonized with the melody G over a C major chord (instead of C), and then a C is harmonized with the melody A over the A major chord (instead of C#). These are not just passing tones – they are very important notes, and so the result sounds terrible.

You might then go back to the quick start guide (in one existing harmony product this consists of 6 pages of small print!) and find out that you can play around with some harmony scale modes (like maj1, maj2, maj3, or min1, min2, min3), but you’ll find that you’ll end up playing “whack-a-mole”. Fixing one note will invariably cause another harmony note to be wrong.

So now you start to look for a work-around, because you really like the harmonies when the notes are right. You might try to create some presets, and then try jumping ahead to the special note-fixing preset at just the right moment, and then jumping back to the first preset, but doing these kinds of gymnastics isn’t fun, and the resulting sound is often not very good.

If your harmony processor supports “song-mode”, you might scour the manual so that you can learn how to enter every single chord in the chorus and then try stepping through them with your foot as you change the chords on your guitar. Even if you can do this without losing concentration for a moment and getting your guitar out of sync with your foot, you’ll find that the harmonies generated, while not being wrong, are very static as they remain on chordal notes the entire time. This isn’t what people expect when they hear Lyin’ Eyes!

And if you’re thinking that Lyin’ Eyes is a special case, you might be surprised to find that a huge number of songs just don’t work with a single key/scale setting in current harmonizers. In fact, all you need to look for is a song that has the same note sung over two different chords (for example a C sung in the melody over a C maj / F maj chord sequence).


With musIQ: Forget about the technology – just sing and play!
Now let’s try Lyin’ Eyes using the Vocalist Live 4 with musIQ technology activated:

  1. Plug in your mic and guitar
  2. Find a 3rds up harmony preset
  3. Sing and play – when you want harmony, just step on the harmony pedal!
That’s really all there is to it. With musIQ technology, you don’t have to learn anything new because the harmonies are created from the two things you already know how to do: singing and playing. For example, when you’re singing an A over the chords that are generally found in the key of G, we’d probably harmonize with the C. But if you then played an A major, we would move to the C# because, like any good harmony singer, we listen to the guitar. Simply stated, musIQ technology brings musical intelligence to harmony processing.


How it Works
The patent pending musIQ technology is built around two components: note detection and harmony generation. The note detection component analyzes the complex guitar waveform and determines the important notes that are present in the signal. We don’t need special MIDI guitars or hex-outputs for this – we look directly at the standard output signal from any electric or pre-amplified acoustic guitar.

This information is then fed to the harmony generation engine in order to create harmonies that are consistent with both the singer’s melody as well as the underlying guitar accompaniment notes. This means staying true to both the overall key and scale of the song, as well as any localized variations due to chords which are not part of the global key. Our harmony generation can be thought of as a musically intelligent hybrid of the two well-known harmony modes: chordal (produces static but “safe” harmony notes), and scalic (produces active, but often incorrect notes).


Summary
Forget complex user-interfaces, music theory, and hit-and-miss results. With musIQ technology, you can create vocal harmonies with the interface you know best: your guitar and your voice.

musIQ is a registered trademark of 3dB Research Ltd.
DigiTech is a registered trademark of Harman International Industries Inc.

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