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FAQ - How to play a keyboard in alternate tunings

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I've made this page in reply to Steve Grainger's forum post - this is something of a FAQ with users of my programs. Please visit the forum to comment on it - or you can join the wiki and edit this page.

This is a bit complicated, sorry.


The different tuning methods

You have tuning tables, or pitch bend retuning.

Tuning Tables

This is the most flexible and would be brilliant if there only could be a single standard that worked with all synths. But unfortunately there isn't so it is tricky to use.

The nearest to a standard for retuning in MIDI is the MTS sysex - but though it is a good standard, unfortunately few synths support it, they nearly all have their own custom tuning methods. Then a newer standard is the .TUN table which some synths support.

Pitch bend retuning

Most synths and soft synths let you do the pitch bend retuning. If done properly you can get good quality sounds with no pitch glitches at all for quite demanding microtonal music.

Not all synths work though. Some don't let you bend the pitch of a note at all. Some do let you retune but use non standard pitch bend ranges such as two octaves or one semitone instead of the standard of +- a twelve equal whole tone - these can be used you just need to set up Tune Smithy to work with the desired pitch bend range.

Also some will only let you use one pitch bend at a time while others let you have up to sixteeen different pitch bends, one for each channel. The ones that only let you use one pitch bend at a time can only be used to play monophonic microtonal music - though they become more flexible if you are able to run several of them at once simultaneously and route a different midi channel to each one.

To help with the pitch bend retuning, I added the various Wizards you find in the Out menu in Tune Smithy and the Play menu in Bounce Metronome Pro - to test the capabilities of your synth to see what it can do.

How to do the retuning

The quickest way to get started with it may be to use the PC Keyboard player.

If you have a midi controller keyboard or synth you can also hook that up to the computer to play soft synths or put Tune Smithy into the loop to retune a hardware synth. music keyboard retuning

I've done a web page with help about how to work with some particular soft synths here:

FAQ - Soft_synths

This is all for the pitch bend retuning method (mainly anyway, that and the MTS sysex retuning).

For the tuning tables, I only have support for the MTS sysexes so far but may later add other types of tuning table when I return to work on Tune Smithy.

I'll be returning to this hopefully some time next spring, to work on the midi keyboard retuning and pc keyboard player in FTS amongst other things. At the moment I'm still working on Bounce Metronome Pro but the various improvements I've done there will help with Tune Smithy when I return to it.

Anyway meanwhile if you have a synth that needs tuning tables then your best bet may be to use the Scala software to retune it. It can retune nearly all hardware synths, so I've heard.

You get it here: Scala home page

Sound Quality

What counts as "good quality" is something that depends very much on the individual. Amongst users of my software, I find that some want a "pure sound" for instance, and either want pure tones like sine wave, triangle wave etc, or are interested in the various types of synthesizer sound. Others are more interested in sounds that are as close as possible to the sound of the "real instruments" - these tend to be not quite so steady and pure in pitch as the synthesized type sounds - they often have a small amount of vibrato in string sounds for instance even with the modulation set to 0 - but they sound very nice indeed.

But anyway whatever your taste, there's no doubt that with a modest laptop you can make good quality recordings of microtonal music. If you want sounds like real orchestral instruments, then you would want to investigate the various "virtual orchestras" and sample players such as GPO and Giga.

For synthesizer type sounds then you may want to look into the FM synths, and VST plug ins. You need a VST host to use the VST plug ins. If you haven't got one, then a good free one is Cantabile lite.

For pure sine waves, triangle waves, and other interesting waveform based instruments, you can use the Waveform Player that comes with Bounce Metronome Pro and Tune Smithy. These are particularly useful if what you want to do is to hear the fine nuances of just intonation chords clearly, or count beats etc.

The various contributions to the sound quality

Laptop speed - any laptop made in the last ten years or so is fast enough to do a fair amount of polyphony on most soft synths and samplers.

Laptop noise - you may find the laptop makes a bit of sound, seldom completely silent, so it is a matter of taste there, whether the sound of the laptop is something that bothers you. If it is then the only real solution is to get a laptop that is quieter - or you can do things like put the laptop next door and listen to it over a long cable, or cover it up and sound proof it in various ways (obviously taking care that it is cooled efficiently). As far as making recordings is concerned, then there are two ways to do it - either play the sounds over loudspeakers and then record on a microphone - or more commonly, you do the recording entirely within the computer.

When recording within the computer again, one way is to make a midi clip and then render it to audio e.g. with Audacity or the Roland Sound Canvas or similar software that lets you convert a midi file to a wav file. With this then it doesn't matter what the soundcard is like except for listening to the result. The audio file you make is of perfect quality as it is rendered directly to a file and never needs to be "recorded" as such.

Another way is to record in real time as the sound is played. For this, the quality of the soundcard does matter, the better the soundcard then the less noise and the more faithfully the waveform is reproduced.

The speed of the laptop doesn't affect the quality of the recording unless it is so slow that you get drop outs. Drop outs are very noticeable if you get them, they make the recording "unusable", it's not just a bit of noise. You may get clicks, or gaps of silence or white noise. Or the audio may repeat like a stuck groove on an LP. Or the synth may cope with CPU overload by skipping some of the notes in faster passages or passages with lots of polphony so that some notes don't sound at all because there wasn't enough computer speed to play all the notes.

Anyway on any computer in the last few years, you are unlikely you get those issues unless there are many notes played simultaneously, or you try to play it in real time with the latency set very low.

Latency issues

These used to be a big deal over ten years ago but nowadays they aren't really much of a problem. Latency means that there is a delay between pressing a key and hearing the sound. You can still play fast passages, it is just that the notes sound after a delay (a bit like the delay you get between a sound and its echo) so you play a fast passage and if there is a big latency delay, you may be able to play several notes before the first one actually sounds, so then keep playing ahead of the sound - which you can get used to but can be a bit disconcerting especially if you are new to it.

So anyway, when you play notes in real time from a keyboard you may still get a bit of latency on a slower computer, like a few milliseconds or tens of milliseconds. That's because you need a sound buffer which gets regularly filled before it is sent to the audio output - and on a slower computer if the buffer is too small then the computer may not manage to fill it before the next buffer needs to be sent.

Anyway, the latency it is usually reasonably tolerable, and you can get used to it, after all organists regularly play with latency much higher than that on their instruments.

If you get a large amount of latency like say 100 ms, then that is probably to do with the design of the synth rather than a limitation of the computer. For some reason the Microsoft S/W synth has huge amounts of latency on some computers, with some tweaks available to get it down to more normal levels that may or may not work but are worth a try. See my tips for the FAQ_-_Soft_synths#Microsoft_GS_Wavetable_Synth Microsoft GS Wavetable Synth

So, anyway, you are likely to find that your laptop is plenty fast enough at least to start with until you get to really demanding pieces.

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