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IVL Steelrider

MIDI Interface

Famed for playing its part in the MIDI Chapman Stick, IVL's pitch-to-MIDI system is now opening the world of MIDI to the pedal steel player. Vic Lennard picks his words.

The Country & Western favourite pedal steel guitar might seem an unlikely convert to the world of MIDI, but IVL's Steelrider makes it an able MIDI controller.

Although midi was originally designed with electronic keyboards in mind, it's since been adapted - with varying degrees of success - to work with other instruments. MIDI is a logical extension of the guitar synth (although most suffer from the delays attributable to pitch-to-voltage conversion and any not using such a system are usually prohibitively expensive). MIDI wind controllers have enjoyed a degree of success through the Yamaha WX range (although slurring notes without retriggering or using pitchbend is still a problem). Drum pads have probably been the most successful of any non-keyboard MIDI instrument. Simmons and Roland, in particular, have capitalised on MIDI, but now even cheap drum machines offer touch-sensitive pads capable of transmitting MIDI information to the outside world. IVL, a Canadian company, brought out a system they called Pitchrider some time ago - in fact, it's at the heart of the MIDI versions of the Chapman Stick. The 7000 series Pitchrider is a guitar unit, while the 4000 is triggered by microphone, giving MIDI to "traditional" acoustic instrument players. IVL have now turned their thoughts to one instrument which has never been successfully adapted to MIDI - the pedal steel guitar - and have adapted the 7000 series accordingly.


STEELRIDER IS NOT a new MIDI interface but has recently benefitted from various updates. The rackmounted "brain" comes in a 2U-high black case whose front panel is divided into three areas: String, which has 12 numbered LEDs for monitoring which strings are currently being triggered, and a string select push button for choosing a particular string whose parameters need to be edited; Setting, which has a two-digit display and individual increment and decrement buttons for altering the values of parameters (this also shows the tuning of a string while playing); and Mode, allowing 11 different operational parameters to be edited. The Mode section has six LEDs and a Mode Select button for moving between parameters. On the left-hand side is the power switch.

The rear panel of the Steelrider is a relatively sparse affair with an input socket for the external, 7-10v AC power supply unit, a stereo footswitch socket for connection to the MFS40 foot unit and a single MIDI Out.

There are three aspects of the pedal steel guitar which make it a prime candidate to succeed with a pitch-to-voltage system. Tolerances in the manufacture of the instrument, for example, are so fine that the height between the pickup and strings is guaranteed to remain constant. Also, string lengths remain absolutely constant due to being locked at each end - there are none of the problems associated with guitars, where strings can move across the nut when a string is bent. Then there's the speed of note attacks - notes played with fingerpicks have a slower attack than on a fretted guitar. Consequently, delays are not likely to be as audibly apparent.

There are two basic varieties of pedal steel - these differ in having either ten or 12 strings. Curiously, then, there are three types of pickup provided by IVL: ten-string, 12-string standard size (0.343" gap between poles) and 12-string special (0.32" gap). The pickup is bolted directly to the bridge assembly and may need a new block in order to give it the rigidity necessary for accurate triggering. Indeed, the setup is the kind of task which should only be undertaken by an experienced technician. The leads from the pickup pass through carefully routed holes in the pedal steel body to a small box mounted underneath which contains two pre-amps; one deals with even-numbered strings, the other with odds. A pair of eight-pin cables then connects the preamps to the front panel of the Steelrider's brain.


WITH A FRETTED guitar, specific kinds of MIDI events have to be generated - for example, notes on and off, and pitchbend for string bending. Most guitar synths will also give access to MIDI modulation and aftertouch. Fortunately for its players, a steel guitar is far more simplistic in its MIDI needs. At the moment the strings are plucked, MIDI notes on for each string have to be sent. Any change in pitch is then carried out by the movement of a steel bottleneck (called a steel) over the strings - there is no need to retrigger. Consequently, once a MIDI note on has been generated, all other movements are translated into MIDI pitchbend. Modulation is achieved by a gentle movement of the steel, so doing away with the need for MIDI modulation. This makes the MIDI implementation of Steelrider relatively simple.

Each string can be set to any MIDI channel, so you can end up with many strings sharing the same MIDI channel. When you bend a string on a normal guitar, you change the length of the string and the pitchbend information being transmitted will be directly proportional to this change in length. Bending more than one string will entail sending out different amounts of pitchbend per string. This necessitates the use of MIDI mode 4 - where a separate MIDI channel is allocated to each string - with guitar synths, to be able to send out multiple string pitchbends. A pedal steel is entirely different in operation - moving the steel does not change the length of the string and the steel always moves at right-angles to the strings, so the pitchbend value sent out is the same for all strings. All Steelrider has to do is to ignore identical values of pitchbend on the same MIDI channel when received consecutively.


PRESSING THE STEELRIDER'S Mode select button cycles you around the 11 available functions, showing the current value of each parameter in the two-digit "setting" display. Some functions can be different for each string, in which case the relevant string has to be first selected via the string select button. Other parameters are global, that is for all strings. Sixty-four groups of settings are allowed, each termed a Preset. The available functions are:

MIDI Channel: each string can have its MIDI channel set independently. So you can set up, perhaps, three or four strings with the same MIDI channel to create a chord with the same sound.

Pitch Bend: a global setting of up to one octave in semitone steps.

Transpose: ± octaves per string in semitone steps.

Volume Dynamics: this is equivalent to touch sensitivity. At a value of zero, all notes have a velocity of 64. The higher the value, up to a maximum of nine, the wider the velocity range.

Input Sensitivity: a value is set between zero and seven which dictates the input threshold to ensure that mis-triggers don't occur with different playing styles.

Tuning: the tuning reference has a value between zero and 60. Add this on to 400 to give the tuning in hertz. Standard is 440Hz but due to the fact that many pedal steel guitars use a tempered flat tuning on several strings the master tune needs to be around 437Hz. Otherwise many of the open strings will be sending pitchbend to compensate. This setting has to be a compromise and needs a good pair of ears coupled with the display in tuning mode - see the end of this section.

Program Change: each string can have a MIDI patch change assigned to it. Whenever a preset is selected, those patch changes will be sent out on the MIDI channel for that string. A zero setting is available for no patch change transmission.

Sustain Limit: any of the 12 strings can be set to be sustained while the non-latching Sustain switch on the MFS40 foot unit is held down. The MIDI note off is suppressed until the switch is released, allowing a player to play other notes over the top of those being held.

Hold Select: this is controlled via a latching Hold switch on the floor unit and offers a choice of three modes. Mode zero allows non-selected strings under Sustain Limit to transmit over their set MIDI channels while Mode one suppresses all MIDI transmission. Mode two again gives MIDI transmission but on a selected MIDI channel so that a solo can be played on a specific sound. Unfortunately all pitchbend is suppressed while either of the foot switches is on. This is because, should one of the sustaining strings be on the same MIDI channel as one being used for solo, its pitch would change with the pitchbend information being sent out. This makes mode one the most useful in practice.

"Pitchrider 4000 is used by many professional wind and brass players, and I fully expect Steelrider to attain a similar standing among pedal steel guitarists."

Preset Save: having gone through the settings and selected the relevant values, they can be saved in one of the preset slots. This is achieved via the MFS40 foot unit again.

Preset Delete: a preset has to be deleted before another can be saved in its place (you can't update them). This is inconvenient as you can only move in one direction round the settings - which means that you select your values, go to preset delete and then hack back round again. Still, it deters you from making rash decisions.

Having a two-digit display does have its shortcomings. For instance, if you set a negative transpose of greater than -9, you lose the negative sign, which can be confusing. On the other hand, IVL have a neat method for being able to check the tuning of a string. When playing, the display acts as a tuning guide for the string currently being played; using small vertical and horizontal lines the display shows seven degrees of tuning from severely flat through in-tune to severely sharp. Due to the non-fretted nature of the pedal steel, this lets you play microtonal tunes with the display as a guide.


THE OPTIONAL FOOT controller gives you control over various of the Steelrider's functions from the floor. It consists of five pedals; Chain, Step, Hold, Sustain and Bypass.

Chain and Step work in conjunction - you can regard Chain as a collection of Presets in a specific order and Step as allowing you to move through these Presets one at a time. A maximum of 32 Chains can exist with up to 16 Steps per Chain, but subject to the maximum number of Presets, which is 64. In fact, Presets cannot be saved or accessed without the MFS40 which makes it a little more than "optional". More to the point, a pedal steel has various pedals and knee levers - the model demonstrated to me had six of each - and an additional foot unit is difficult to operate. Perhaps IVL should consider a small hand-operated unit as an alternative.

Selecting a Step sends out all of the information for the Preset assigned to that Step. This includes the MIDI patch changes per string.

The really interesting part about the MFS40 is the hold/sustain. Pressing the Sustain switch lets you set how many strings are going to be sustained (between 0-12). The idea of this is to be able to play a chord whose notes then sustain and to follow with a second chord which will then cut out the notes from the first chord. This is particularly effective when playing an arpeggio of, say, four notes with the sustain set to the same number. Each new note played beyond the fourth will cut out the first and give a rolling note effect.

The Hold switch selects one of the above three modes, and can be set to a number independent of the Sustain switch. So if it is set to, say, three, the Hold switch will ensure that a three-note chord is held while other notes are played over the top. The only restriction is the maximum of 12 for the combination of numbers set for the Hold and Sustain switches together.

The purpose of setting the master tune to around 437Hz was mentioned above, but it is really brought home when using Sustain or Hold. Not only is pitchbend suppressed, but values are sent out on the relevant MIDI channels to re-centre the pitchbend. Consequently any strings which require a small amount of pitchbend to give their true pitch when open will now sound out of tune.


THE MAIN PROBLEM with a pitch-to-voltage system is the delay between the note and the MIDI equivalent. IVL claim a speed of 1.5 cycles or 12 milliseconds, whichever is greater. This means that any string with a frequency of greater than 125Hz should have the same response time, and on a 12-string pedal steel that would encompass all but the four lowest strings. The lowest string has a response time of about 24 milliseconds. Steelrider will also track to two harmonics beyond the natural notes of the strings, but draws the line at anything below 60Hz. This only rules out tracking the bottom B string when detuned by the pedal steel.

Steelrider scans incoming pitchbend in a rather novel way. Given an octave range, the steel playing slowly through an octave on four strings gives about 60 changes in pitchbend per string - the equivalent of around seven-bit resolution. Play the same sweep at high speed and only about 30 changes occur - around six bits of resolution. But you don't hear any stepping - this shows a very intelligent approach on IVL's part as most pitchbend systems have a fixed resolution which can give delays at high resolution and a lot of pitchbend information, or an audible step through the pitch at low resolution.

The system was demonstrated by BJ Cole, one of the world's foremost pedal steel guitarists (credits span the Sensational Alex Harvey Band and a recent spot on Tonight With Jonathan Ross). Using an Evolution EVS1 as the MIDI sound source, Steelrider's tracking proved to be no problem with only very occasional glitching. More subjectively, the response was quite incredible, especially when using a choral sound and altering chord voicing via levers and pedals. The result was what you would expect from a real choir where only some of the different vocal parts change at any one time - a result difficult to achieve on a keyboard and nigh on impossible on a guitar. Vibrato is imparted as marginal pitchbend by subtle movement of the steel, and the result is uncanny. With careful setting of instruments for each string, a complete string section could be played quite authentically.

The technology of using pitchbend to move between notes effectively rules out any serious use of samplers with Steelrider. Samples would be played outside their useful range when sliding the steel more than a couple of semitones, resulting in "munchkinisation" (the "Mickey Mouse effect" associated with severe pitch shifts on voices). Any vibrato recorded with the sample would make the situation that much worse.


THE WAY IN which IVL have implemented MIDI within Steelrider is most impressive - just notes on/off and pitchbend without any MIDI controllers. The response of the Steelrider interface is excellent, and has to be one of the most usable MIDI systems on an instrument which can still retain its original integrity. Pitchrider 4000 is used by many of the professional wind and brass players, especially saxophonists, and I fully expect Steelrider to attain a similar standing among pedal steel guitarists.

Price Series 7000 unit, pickup and MFS40 foot controller, £835 (approximate only, due to fluctuation of the Canadian dollar exchange rate).

More from Don Mackrill Musical Instruments, (Contact Details).

Special thanks to BJ Cole for his time and demonstrating prowess.

Previous Article in this issue

En Routing

Next article in this issue

Postcards From The Edge

Music Technology - Copyright: Music Maker Publications (UK), Future Publishing.


Music Technology - Apr 1991

Gear in this article:

Pitch->MIDI Convertor > IVL > Steelrider 4000

Review by Vic Lennard

Previous article in this issue:

> En Routing

Next article in this issue:

> Postcards From The Edge

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