Many of you were caught out by our 1995 April Fool preview of a fictitious piece of software that could modify the musical style of a MIDI file to create specific emotions in the listener. Now, however, it seems that fact may have caught up with fiction. Martin Walker tries out Ntonyx's innovative Style Morpher.
Have you ever been asked to create music 'in the style of' another musician? Whether the end result is intended as a pastiche for radio and TV, or a copycat soundtrack for a computer game, many of us have faced this challenge at some point in our musical careers. Trying to emulate someone else's music is also a great way to learn more about song structure and arrangement, and a potential starting point if you're stuck for original ideas and fancy taking your own music in a different direction.
Ntonyx have already gained much praise for their MIDI Style Enhancer, which I reviewed in SOS November 1999. This cleverly distills the nuances of various musicians' performances on different instruments into a number of 'styles', which can then be imposed upon a bland MIDI file to make it sound as though expert performers had played it. Now Htonyx have turned their expertise from performances to songs themselves, and the result is Style Morpher, a real‑time tool for morphing the harmony, rhythm, meter and voicing of a song into something totally different, while retaining the essence of the original. You can change a waltz into four‑on‑the‑floor dance music, rock into ethnic polyrhythms, happy songs into sad, or make hundreds of other equally startling transformations.
Style Morpher will run on a PC with Windows 95, 98, NT 4.0, or 2000, and has very modest system requirements — any PC bought in the last four or five years will be more than adequate. It's a stand‑alone MIDI tool that can work its magic on any section or the entirety of a Standard MIDI File in either format 0 or 1. The main Style Morpher screen display is divided into several panes (see screenshot above). The main portion is similar to the arrange page of many sequencer applications, with Track settings on the left‑hand side and Measures — a graphic display of note and controller information — on the right. Toolbar buttons are ranged across the top of these panes, and a status bar across the bottom.
The Tracks pane has columns displaying track numbers (up to 64 can be accommodated), their Names, Mute and Solo status, the Patch name along with its associated GM number, and the current settings for MIDI Volume and Pan. As with many other Windows applications, you can resize any column by dragging its divider sideways, and you can also double‑click and then drag columns into a different order.
The Measures pane shows MIDI information in a similar way to a 'piano roll' editor, with each track's note pitch in the vertical direction and duration in the horizontal. Above the instrumental tracks is a separate Tempo track with the current tempo displayed as a horizontal line, along with any copyright, marker, and text information included in the MIDI file. At the top of the measures pane is the Time Ruler showing the song structure in bars, while the current song position is displayed by a cursor which scrolls during playback. Apart from a useful display of the current information in the song, the Measures pane is primarily used to select fragments of a song for morphing, by dragging from left to right from the desired start to end position. Dragging from right to left anywhere in the Measures pane de‑selects the fragment.
There are five menus: File, Edit, Playback, View, and Help. File contains the normal Open, Save, Save As, Close, and Exit commands, along with Save As Clips. The latter is a useful option to save the entire song as a series of shorter clips: a small dialogue box lets you choose the starting bar and the number of beats in each clip, whereupon a whole set of MIDI files of this length is saved, starting at the selected starting bar and with the bar numbers appended to the filename, along with the current transform settings (more on these later).
The View menu contains entries to disable/enable the Toolbar and Status Bar displays and move the horizontal Split position between the Tracks and Measures panes, as well allowing you to hide or view Controller information. When this is set to 'view', any existing MIDI Controller information in the file is superimposed on the note display in the Measures pane. Pitch‑bend data is shown, as well as modulation, volume, panning, and expression (MIDI Controllers 1, 7, 10, and 11 respectively). Each has its own display colour, which can be changed along with the text and background colours from within the Options dialogue box. This is also where you choose a suitable MIDI Out device for the entire song; in most cases, a GM‑compatible synth will be the preferred option.
Like most of the frequently used functions in the menus, the Playback menu entries are all duplicated as icons on the Toolbar, and give you standard Rewind, Stop, Play, and Fast Forward buttons, along with Loop on/off during playback and a handy Tempo Ratio control with nine settings ranging from half speed through normal to double speed. These can be used while editing to hear the morphs more clearly, and files are saved with the current setting, so you can also use this as an editing tool.
The Edit menu contains multi‑level Undo and Redo options to retrace your steps should things go wrong, along with Copy and Paste As New Document commands to extract a section of the current song and use it as the basis of a new one. You can also navigate through the song manually using the Go To Measure function, and mark your song for morphing with the Select and Select All functions.
The final six Edit options are where the real power of Style Morpher lies. The Filter option is fairly straightforward, providing a dialogue box with a series of tick boxes that let you delete specific types of MIDI event, as well as assigning a constant Tempo value from 10bpm to 250bpm. The available event types are Pitch Wheel, Aftertouch, Modulation, Breath, Volume, Expression, Pedal, and Brightness, and buttons marked All and None jump to the two extreme settings to save you time. These different filter settings help you initialise the song for best results when morphing (see the Suitable Source Material box on page 118).
Transpose provides basic up/down note shifting by up to 32 steps in either direction. Transform To Single Tonality lets you transform a fragment or an entire song to a selected scale (rather like the Scale Transform function in Cubase). There are 30 options in all, including all major and minor scales arranged by the number of sharps or flats contained in their key signatures. These include duplicates such as A flat and G sharp, A sharp and B flat, and so on, although I suspect that many musicians unschooled in traditional notation might prefer them sorted into note order. A 'Set Key Signature Event' tick box adds the appropriate MIDI event into your song if required.
Single Tonality is useful for changing key and from major into minor scales and vice versa, but the Transform To Single Chord option is rather more clever, since it identifies and strips out key changes as well, leaving the selected fragment or song all in the selected key. This time, two drop‑down selection boxes are provided in the dialogue box — one for the 12 root notes in an octave, and the second to select either a major or minor scale.
The main Transform option launches the most complex dialogue box of all, and it's here that most of the fun is to be had. It contains six main transformation types — Music Figure, Meter, Rhythm, Harmony, Voice, and RND Influences — which allow you to make radical changes to the initial song. Each transformation has eight modes, selected using numbered buttons. To apply a transformation you click on the desired type button to activate it, choose one of the eight transformation mode buttons, and then click on the Apply button. A small green activity indicator temporarily turns yellow during the short time it takes to perform the transform. If you tick the Auto tick‑box, each transform will be carried out as soon as you alter any transform setting, for even quicker changes.
A further button labelled Quantizing, along with a 0 to 100 percent strength slider, optionally pulls note start times towards their 'perfect' positions by the selected amount, since although nuances in timing add feel to a human performance, the algorithms employed in Style Morpher work better when notes are closer to their 'ideal' positions.
Music Figure analyses the melody, chords, arpeggios, or drum figures, and may then change the length of existing notes or add extra ones, to provide new phrasing or extra expression in a variety of ways depending on the source material. This, I suspect is a simplified form of Ntonyx's existing style‑enhancement algorithm. Meter changes the time signature by shifting the note timings within each bar, so for instance 4/4 could morph into 6/8, 3/4, 5/4, or even 7/4, while 3/4 could morph into 4/4, 5/4, or 7/4.
Rhythm also shifts note timing, but this time leaving the number of beats in each bar unaltered, so that you can add syncopation or swing, rather like the groove quantising provided in many sequencers. It's capable of more radical modifications than groove quantising, however, and can also be used to reduce complex rhythms to simpler structures.
The Harmony transform analyses the 'changes in musical modes' within a song, and while leaving the timing of each note unaltered creates new phrases in a similar style but with a different set of notes. Sometimes the scale type alters from major to minor, but although the actual melodies have completely changed, they are mostly still recognisable as variations on the original.
Voice changes the initial GM patch values into new ones, both for instruments and drum and percussion sounds. It does this in an intelligent fashion, by selecting sounds with a similar function within an ensemble: for instance, Fretless Bass might change to Synth Bass or Bassoon, while Acoustic Guitar might alter to Viola or Tenor Sax. In drum tracks, a new set of sounds is chosen by altering the notes themselves in the drum map.
The final Transform is RND Influences, which adds some random elements to the start time and velocity of notes, as well as to the Tempo, to compensate for any rigid quantising. The Edit menu also contains an option called Batch Processing, which lets you choose multiple MIDI files using a standard browser dialogue window, and then create from them a user‑selectable number of randomly transformed variants, all of which are saved as new files with the mode number of the transformations used appended to the original filename.
I began my trials with the six MIDI file examples supplied by Ntonyx (if you want to get a quick idea of the possibilities, these files are also available from the Ntonyx web site, each with six transformed versions to show you the possibilities). I then went on to morph dozens of MIDI files in styles ranging from dance, pop, rock, and jazz, to film and classical orchestral music, to put the transforms through their paces.
After a few random crashes, which were eventually cured by lowering the Hardware Acceleration of my graphics card a notch, I found the easiest way to work was to highlight a musical section, switch on loop playback, and then open the Transform dialogue box. You can then hear each change you make in real time while the track carries on playing, either by clicking on the Apply button or using the Auto option to do this automatically. It would have been useful to have a Bypass button available as well, to instantly hear 'before and after' versions.
Music Figure transforms proved happiest with tracks containing few notes, since they often add extra ones of their own, and I produced excellent results with sparse ambient music and slow church‑organ tracks, where they added a lot more movement and interest. With traditional rock and roll material, using the different Music Figure modes sounded rather like auditioning new musicians playing the same tune but with a different phrasing and feel, and I was particularly impressed with the phrasing that Style Morpher generated from electric guitar and drum tracks. With songs already containing lots of notes, the results were less successful.
As you might expect, the Meter and Rhythm transforms make some pretty fundamental changes, so only one or the other can be enabled at a time while working in the Transform window. I found that they worked well enough for straightforward transformations such as turning a straight 4/4 feel into a chugging 6/8 shuffle and a waltz back into 4/4, and occasionally with other material, but it proved very easy to end up with a stilted feel when more unusual time signatures were used. Many of the possibilities produce results that are a little too radical for practical use.
The Harmony transforms will probably be the first port of call for most musicians, and once again, these seemed to work better with the simpler chords used in dance, rock, and pop songs than the more complex structures of jazz and orchestral works. Music in these styles is better transformed in shorter fragments of, say, eight or 16 bars. I found that Harmony transformations left the root notes largely unchanged, while the harmonies ended up moving in differing ways, providing 'variations on a theme' rather like the results that often emerge during a long jam. Usually, they still bore a recognisable resemblance to the original song, but not always.
The Voice transforms were rather more effective than I expected, largely due to the intelligent choices made, and I found the process capable of a wide range from subtle right through to extreme. At the latter end, I managed to turn the Pink Panther theme into an Eastern boogie with wailing pipes and funky bass. RND Influence was effective in adding random timing and velocity changes, ranging from subtle alterations, using low‑numbered modes, through to the 'after‑effects of 10 pints at the local' at the other extreme.
At first I found choosing the various modes a little hit‑and‑miss in the absence of any further documentation on what each was doing to the song, but Ntonyx explained that it was impossible to provide this, since the transformations are dependent on the original data. For instance, Meter mode 4 would change 4/4 into 6/8, but 3/4 into 4/4, and the note movements might also be different in different parts of the song. However, the result of each Transform mode is fixed so that you do get totally repeatable results, and these are often impressive. I managed to create a wide variety of new songs ranging from heavy metal to film scores.
Style Morpher is an extremely clever utility that can manipulate existing songs in a huge number of ways, although it certainly doesn't guarantee pleasing results every time. It should prove valuable to many different types of musician, such as those searching for fresh sources of inspiration from other people's material, film composers looking to stretch existing themes in new directions, and even those doing advertising work where novelty versions of well‑known songs are needed. In fact, the use of morphed music in a commercial context raises some interesting copyright issues.
Ntonyx are to be congratulated on this first release of Style Morpher. More complex, 'pro' versions are likely to appear in due course, including additional functions such as scale transform and the ability to treat individual tracks, but the current version is already capable of some complex and quite unique results, while still being extremely easy to use. At the price of $49 (about £34) Style Morpher 2.4 is also excellent value for money — a must for MIDI musicians everywhere.
You can load any Standard MIDI File of format 0 or 1 into Style Morpher, but it helps if they are General MIDI‑ or XG‑compatible, since you can only use the Voice transform when GM patches have already been specified. Drums should also be on MIDI channel 10 if possible.
However, it's perfectly possible to load in any MIDI file and use another synth editor to download suitable sounds. I loaded in various Yamaha SW1000XG songs and downloaded the appropriate soundbanks using XGedit, along with all the original effect settings, and found that all the transforms except Voice could then be used. If you want to use the Voice transforms you could choose suitable temporary GM patches by hand in Style Morpher. This is also a useful workaround for those with complex multi‑output MIDI setups, to overcome the limitations of the single MIDI output option.
The Music Figure, Meter and Rhythm algorithms rely on being able to analyse note positions relative to beats and bars. For this reason Style Morpher may provide better results if you use its Quantize function to pull all of the notes more 'into line', but this won't work with songs recorded free‑form without a metronome. Apparently, some commercial MIDI files are also doctored by changing the tempo slightly and altering the note positions relative to the bar divisions, to make them harder to edit, and these won't be suitable candidates either.
For the best results using the Harmony transform you should avoid songs containing notes with heavy pitch‑bend information, since only the original note is sensed, and not the final one once the bend has finished. With complex music it's often best to morph in shorter sections, to make analysis easier, since like Style Enhancer, Style Morpher often produces better results from simpler initial files.
- Can generate a vast number of new songs, patterns, or riffs.
- Allows experimentation in real time during playback.
- Capable of both subtle variations and radical alterations.
- A Transform bypass button would be useful.
- You can only choose a single global MIDI output.
A fascinating and extremely useful utility for any MIDI musician who wants to generate new songs from old ones.