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Revised
17 May
1999

Troubador Tech

Delays & Loops

A solo performance by Steve Morse in the mid-1980s turned me on to the power of sampling one's playing, delaying it, and combining it with later playing. My own attempts, described on this page, have utilized some unlikely tools; see the Looping Links to see how others do it.

More useful tips:
-MIDI synth tricks
-MIDI guitar solo

On this page:


Casio VZ Synthesizers

Hear me play
Besides the brief song excerpts here and on the Sounds page, you can hear my MIDI guitar playing on complete songs at my Sensory Syrynx page.
Like many synthesizers, the Casio VZ-1, VZ-8M and VZ-10M permit voices to be layered. The VZs do not incorporate any built-in effects, as many tone generators do, but (like several other designs of the late 1980s) the VZ architecture permits delaying one or more layered voices, for flanging, chorusing and echo effects.

The VZ delay parameter is adjustable over a range of zero to 99. "At a value of '0', the patch is sounded immediately after Note On message received," says the manual, "while at a value of '99', there is a long delay before the patch sounds."

These words had the effect upon me that a red flag is popularly supposed to have upon a bull. "What do you mean, 'long delay'?" I asked the manual, which still has not replied. I set the delay parameter for a voice to 99, triggered a note, and-- not having a stopwatch handy-- started counting, "One, one thousand; two..."

Twelve seconds? Twelve seconds? Repeated tests with more sophisticated timing equipment indicated that it wasn't a fluke. I immediately set to work to determine how to exploit this feature. I quickly discovered that it would not be easy.


The incentive was strong: Up to three echoes of a synthesizer sound, each with a totally different timbre, and potentially four multitimbral echoes of my MIDI guitar...
One difficulty is that the change in delay time for different value settings is extremely nonlinear, with delay time increasing in tiny increments for small values, but large jumps at the high end of the value range. This makes sense; any normal musician (to coin an oxymoron) will use the feature for flanging, chorusing, and short echo much more frequently than for long delays.

Another problem is that the delay time is not absolute. It is noticeably affected by how many notes are being played at the same time. Forget pitch bend; not only does the huge data stream drastically slow down the processor, but the bend tracking is destroyed at long delay times as well.

Having made these discoveries, I forgave the author(s) of the manual for their lack of specificity regarding long delays.

Where do I find one?
See the FAQ Page.

I persevered in my efforts to exploit the long delay feature. The incentive was strong: Up to three echoes of a synthesizer sound, each with a totally different timbre, and potentially four multitimbral echoes of my MIDI guitar. Each echo can be detuned to any interval, to the nearest 1.6 cents... Each can respond differently to the same MIDI Continuous Controller message... Velocity response of any sound within a patch can be inverted... The mind boggles.

After much experimentation, I found a pair of delay intervals which showed promise of musical utility: Delay parameter settings of 83 and 93 yielded delay times of about 4 1/4 and 8 1/2 seconds. (See what I mean about nonlinearity?) This configuration produced echoes at two- measure intervals at a tempo of 113 bpm. This proved a comfortable tempo for a medley of children's rounds.

RealAudio Examples
Playing A Round
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Noodle
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More on the Sounds page

At the time I made these discoveries, my primary interest in a long delay was in creating a rhythm part to support a solo. Since the VZ proved so difficult to use for this purpose, I largely abandoned my efforts. With my newly rekindled interest in looping, and in music with other rules than those which constrained me when I was playing for a living, I'm taking a second look at the VZ's long delay possibilities. The biggest problem, of course, is synchronization, especially since I've given up the use of a drum machine.

For Noodle, I used a hornlike synthesizer sound with a single delay set at maximum. Before starting, I listened to a metronome for a few bars, and tapped in the tempo on my Lexicon Vortex, set to provide quarternote echoes. This proved sufficient to keep me fairly close to on time, though it's not a satisfactory longterm solution to the sync problem.


Lexicon Vortex

Vortex features: The Lexicon Vortex is a stereo-capable signal processor which includes a pair of delays, a pair of modulators, and an envelope follower, which can be configured in a variety of ways. It stores 16 pairs of factory patches and 16 user-programmable patch pairs.

One of the Vortex's strongest features is that it allows the user to "morph" between the two patches in each pair, either with an expression pedal or by programming a morph duration (which can be up to ten seconds) and using a footswitch. Some seriously twisted things can happen during the morph, which is much more complex than simply panning between two conventional effects. The envelope follower can make things even stranger.


I had a nifty, bluesy little lick whirling in the Vortex... I stomped on the Tube Screamer... and sighed, the way you do when you can finally scratch a really deep, persistent itch.

Flanging, chorusing, tremolo, ring modulation, and rotary speaker effects can be combined with delays in a multitude of configurations. The two delays can be cascaded for a total maximum delay time of 1.846 seconds; tempo can be tapped in with a footswitch, and each delay can be subdivided to produce rhythmic or polyrhythmic echoes.

And it can be configured as a looping sampler.

My first loops: Electric and acoustic guitar sounds, from the same instrument, playing different parts, heard at the same time? This was a long-imagined, never-realized objective for me-- until I got the Vortex.

While I primarily play an electric MIDI guitar, I'm privileged to own some wonderful acoustic guitars. Most are equipped with original Bill Lawrence FT-145 magnetic soundhole pickups, but a couple also have piezo pickups in the bridges. My first test of the Vortex was with one of these guitars.

I routed the piezo pickup through an Ibanez PQ-9 (quasi-) parametric equalizer, into a volume pedal, and into the Vortex, whose output fed one channel on a mixer. The magnetic pickup's output went to an Ibanez TS-5 Tube Screamer (which I like much better than the original TS-9 I traded away), feeding a second mixer channel.

What's mine worth?
See the FAQ Page.

Then I set the Vortex to Deja Vu B, a factory looping sampler patch. Whatever comes into the input is delayed, then added to whatever may already be in the loop. The loop is then mixed with the input signal and sent to the output.

A few minutes later, I had a nifty, bluesy little lick whirling in the Vortex. I backed off the volume pedal, to avoid further additions to the loop. Then I stomped on the Tube Screamer...

...and sighed, the way you do when you can finally scratch a really deep, persistent itch.

I'm pursuing this contrasting-sound concept, and hope to offer one or more examples here, once I get better at...

RealAudio Example
That Thing I Do
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More on the Sounds page

Looping on the fly: I constructed my first Vortex loops deliberately, and somewhat laboriously, before I started playing along with them. There's nothing wrong with that-- in fact, this was my first real awareness of the possibility of making the loop itself the focus of the music, rather than an accompaniment only, as I'd been hearing in my head.

I still craved the ability to use loops to accompany my other playing, though. Clearly, conventional rhythm guitar parts were out of the question, because of the Vortex's limited delay time. I soon realized I needed to develop the ability to create accompaniment loops on the fly, without doing violence to the music in progress. That Thing I Do was one of my first efforts using this technique.

Looping
"That Thing I Do"
[(a) Standard notation - 515 bytes]
(a) The three notes I played just after stepping on the Vortex's A/B switch to create the loop. X is a forceful slap of the muted strings.
[(b) Standard notation - 955 bytes]
(b) The most prominent elements of the much more complex pattern which emerged from the Vortex. The size of the X crudely shows the relative volume of the percussive sounds.

A pair of factory Vortex patches-- Deja Vu A and B-- offered the technical means to meet this goal. Deja Vu A, which is primarily an echo patch, cascades the Vortex's two delay lines, offering the maximum possible delay time. Deja Vu B, as noted above, is a looping sampler.

I made only one change to the factory patch pair: I set the Envelope parameter of Deja Vu B to a value of 1 (the factory patch's value is 9). Since Deja Vu B accepts no input signal with Envelope set to 1, what goes into the loop can only be what goes into the Vortex during the morph, plus what's carried over as echoes from notes played right before the morph. This establishes the loop as a fixed entity, instead of the constantly changing loop created while playing through Deja Vu B unaltered.

For this recording, I reduced Deja Vu B's Mix parameter from 64 to 48, to keep the loop volume from overwhelming the "live" guitar sound.

Vortex Links: Though discontinued by Lexicon, the company makes strong assurances for its support of the Vortex (and any other company product) for at least five years after discontinuation.

The Looper's Delight site has two Vortex pages. One has just about all the technical information one could want; the other is an early mailing list discussion of the Vortex's capabilities. (This discussion is what reawakened my own Gear Acquisition Syndrome, leading inevitably to my purchase of the Vortex and creation of this page.)


Looping Links

In a very short time, Kim Flint's Looper's Delight Web site and mailing list have become the nerve center of the looping world. In addition to pages devoted to looping tools, techniques, and philosophy, there's a World Wide Index of Loop Artists.

More useful tips:
-MIDI synth tricks
-MIDI guitar solo

Chuck Zwicky's Solo Looping Rig is remarkable for its compactness and flexibility.

Do you have a Web site that should be included here? If so, please let me know!


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