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Pitch artefacts

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Pitch artefacts at the start of the note

This happens with some soft synths. If you apply an "instant" pitch bend immediately before a note, the note doesn't respond to it instantly, instead it responds with a glide to the desired pitch from the usual equal tempered pitch. I can see no reason programmatically why a note shouldn't be able to start exactly at the pitch set by the most recent pitch bend, so perhaps this is intentional - maybe as a way to respond more smoothly to the pitch bend wheel? Anyone reading this know more about why it happens?

The solution that works best is to apply pitch bends to all the channels well in advance as soon as the scale changes. This completely eliminates the problem if you have enough channels available to send notes for each pitch bend on a different midi out channel.

The problem will still occur for large scales and non octave scales, or if several instruments are played simultaneously with varied pan position (left / right) or other effects. For instance if there are more than 15 pitch bends required for a scale, then as the music goes on, from time to time one of the existing channels will need to be retuned.

When this happens, the only solution is to add delays before the new pitch bends from time to time. There's an opton to add these delays - see Midi Out / Save Timing (Ctrl + 58) in FTS. If you need this just for Quicktime there is an opton to just switch on the option for QT in FTS.

With this option in place, then you will hear occasional pauses as you play in the more demanding tunings - also when you play some of the more demanding fractal tunes. But that may be preferrable to the pitch glides, and in many non demanding pieces they never happen.

Pitch artefacts at the end of a note

Gliding resonances after the end of a note played on harp or simliar instruments

This is something you may notice with instruments that continue to resonate for a fair while after the note is switched off. Many midi instruments will continue to resonate for just a moment or two when you release the key. But some like harp may resonate for several seconds.

Perhaps FTS needs to use the same channel for a new pitch bend immediately after the note is switched off. Although the note is switched off, instruments like harp may continue to resonate for a while after the note stops. These resonance type effects will get pitch bent by the next pitch bend in that channel.

This all happens after the note leaves FTS, in your output synth or soundcard. As far as FTS can tell, the instrument is already switched off.

Solution - first thing you can do is to configure FTS to stop sound abruptly as soon as it plays a pitch bend. Do that using More Pitch bend options - for rarer occasions (Ctrl + 164) If necessary switch on the option: Send All Sound Off Controller before same channel pitch bends. This will have the effect that the note stops abruptly, rather than fade away, if a new pitch bend is needed in the same channel. But that may be considered preferrable to the pitch bent resonances. If the output synth doesn't recognise the All Sound Off Controller - or uses it for something else - select the option to use the expression controller for all sound offs.

The other thing you can do is to minimise the number of pitch bends that need to be sent. Make sure you have plenty of output channels - in the Midi Output Channels for Parts & Polyphony (Ctrl + 60) window use the All for all option if possible.

Also run the Out Device Capabilities Wizard in the Out menu. In particular, you may be able to reduce the number of pitch bends by playing several instruments simultaneously on the same output channel if your output device supports that. Most soundcards support this feature.

Notes change pitch just before they fade to inaudibility

You may notice that long high pitched notes tend to go slightly flat they fade away at the very end of the note, and low pitched ones tend to go slightly sharp. Though you may notice it first for microtonal music, once your attention is drawn to it, you will find you get it in twelve equal as much as for any other tuning. It is nothing to do with the pitch bend retuning method. In fact it is to do with how we hear pitches.

The reason it happens is that we tend to hear high notes of constant frequency as sharper as they get louder, and flatter as they get quieter. If you play a high pitched note, e.g. a sine wave of constant pitch and raise the volume, it will seem to go higher in pitch - very slightly. This is especially noticeable if it starts very quiet.

Low notes work the other way. As you increase the volume at a steady pitch, a low pitched note will seem to go lower in pitch.

In real life, it seems that players compensate for this automatically by playing high pitched notes a little sharp as they fade out, and low pitched notes a little flat as they fade out. This is something you might do with no awareness of what is happening, just something you do automatically like the little movements you make all the time while riding a bicycle.

I did an FFT analysis of the samples for the 'cello arco / vibrato in the Dan Dean's solo strings and found that the pitch shifts made by the player were quite surprisingly large, considering. The player compensates by raising the c6 by about 27 cents as it fades almost to silence, and by lowering the c2 by about 20 cents. That is for the fade out right at the end when the note is nearly silent. The notes sound steady in pitch to the ear.

This is fine if you play the complete sample (especially if you play it at close to the original volume). But normally you will stop the note before the sample ends. Giga and other samplers have to fade out the note for a moment or two after the note off - as an abrupt cut off at the very millisecond you release the key would sound strange. But they just do that by reducing its volume. They are (currently anyway) unable to vary the pitch to compensate in the way a player of the instrument would do during the note off.

Though 20 cents seems like quite a large pitch change of nearly a fifth of a semitone - actually this is quite a subtle effect, because it only happens when the note is very very quiet. The note becomes almost inaudible before you need a pitch compensation of as much as 20 cents. It is most noticeable if the instrument fades out slowly, e.g. for plucked sounds. But you have to listen with a keen ear to hear it.

Pitch artefacts during legato transitions

If you get pitch artefacts during legato transitions go to [Window 98 | Portamento and Legato for parts (Ctrl + 98)]. Make sure you have it set to Retune for monomode trills - absolutely essential for legato and harmless otherwise. Also you may get better results if you choose Minimise changes in pitch bends instead of Minimise pitch bends

Pitch artefacts during portamento transitions

Portamento transitions are always by 12-et intervals ending at the desired pitch. So for instance if you do a portamento transtion from 6/5 to 5/4, then the glide will start 29 cents flat of the 6/5 and glide by a 12-et semitone to the 5/4. This is to do with the way portamento is implemented in Midi devices.

So if a portamento transition starts a bit flat or sharp of the expected pitch, this is just how it works. For some reason it seems to work reasonably well in practice - perhaps the end of the portamento transition as it slides to the new note is more noticeable than the start of it.

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