If I take a Performance like "Saw Lead" and take both elements 1 and 2 and set the attack to 127 - then this is the start of a sound that could benefit from Legato Slope. Now turn on portamento and set the Part to Mono(phonic). Hold down a key and play other keys. This will ensure everything you play is legato. You'll hear "pop" or "click" kind of sounds. More like "woosh" sounds as you hit a key. I think if you focus on each note you play during the attack you'll get a feel for the sound. Now rank up legato slope to 7. This will get rid of that artifact. And that's what it's there for. The "unnatural attack" sound.

I can't tell you exactly what it does or what exactly 7 means vs. other values. I can say that, in practice, this is what it's for and why you may want to use it.

I can say that the "time" settings means it takes a certain amount of time to go between any two notes. So if you play the lowest note and then the highest note it will take the same amount of time to go between these two notes as if you played the next chromatic note up. So pitch would change faster the further apart the notes are. And then rate says the speed of pitch change will always be the same so if you played notes far apart - it would take longer to reach the second note than if you played an adjacent note.

BM already covered the difference between the "1" and "2" time/rate options here:

https://yamahasynth.com/forum/portamento-time-mode

Regards Portamento Time Mode

Using an Analogy:-

Airplane Flying time:-

London to Paris = Short Distance/Short Time
London to Berlin = Long Distance/Longer Time

"Rate"

The set Rate Value governs the speed of the airplane.

In this case, the speed of the plane is fixed. You will reach Paris in a shorter time than you will reach Berlin.

In the case of Pitch, it will take less time to raise pitch by 4 semitones (major 3rd), than it would to raise pitch by 7 semitones (Perfect 5th). Importantly, the sense of pitch rise is steady or constant.

Why would you use this musically?

If the intended effect is just as a "Riser", where the destination pitch is not important, only the "crescendo" like contribution, over time, matters. The user can release the destination key, in time and sympathy with the musical composition... for example at the end of a drum beat Crescendo.
In this case you would probably set a low Rate Value.

"Time"
The set Time Value governs the Time between destinations, and makes it constant.

In the Paris/Berlin scenario, if two planes departed London at the same time, then each plane would arrive at its destination (Paris or Berlin) at the same time. This means the Berlin plane would be flying around 4x faster than the Paris plane.

In terms of Pitch, the sense of rise in pitch would be slower for short intervals (e.g. 2 semitones, major 2nd) but extremely fast for higher intervals (e.g. 24 semitones, 2 Octaves).

Why would you use this musically?

This mode would allow you to stay in Tempo, whilst hitting the desired pitch. In this case the destination pitch is presumed to be important and relevant. The Time Value should be set in such a way as to allow you to play in Tempo, without notes being skipped or never attaining pitch.

It's a feel thing, and you would need to adjust the Time Value accordingly, but it would be typically short.

This mode allows you to play "normally".

Regards Legato Slope.

In my opinion, you need to distinguish between "Real Instrument" simulations, and "Traditional Mono Synth" sounds.

In the case of the former (e.g. real piano samples, rhodes samples, trumpet samples, violin samples etc) the XA Legato feature best handles Legato behaviour, and I'm not going to get into that. Best advice... choose and learn from Factory Presets on how best to set this up.

In the case of Mono Synths (most examples found in Cat Search, Main = SynLd) then you will find that only the EGs (ADSR) of the first note in the legato phrase activate. All subsequent "Legato" notes adopt the Sustain portion of the ADSR's of the first note. Looking at it from a different perspective, each new Legato Key On, does not re-trigger an ADSR.

So in effect, only the first note has an Attack & Decay portion, all subsequent notes just melt into one continuous sound. This may be the desired effect. But there may be cases where you want each subsequent "key on" to have at least some definition (i.e. percussion, punctutation, attack etc) to distinguish it, rhythmically, from the previous note. Take for example a case that is using a Low Level Sustain value in a Filter EG. Each subsequent legato key on will produce a "very dull" note, even to the point of it not being audible.

This is where you would likely employ the Legato Slope feature.

The Legato Slope adds a faux Attack/Decay to each new legato Key On. As far as I can tell, the shape of this Attack/Decay is not related to the actual ADSR of the Part, but is sufficient enough to provide a differentiation between one note and the next.

In my limited experience with this, I tend to avoid running into such issues by setting my ADSR Sustain Levels (Decay 2 Level) such that the legato notes do not "disappear" (i.e. a ground up approach). Equally, if I want avoid the issue all together, I set the Part to "Poly", adjust the ADSRs for a softer attack, and just play single notes. I find you have more "design control" doing it this way.

All that said... the MODX provides a thousand ways to skin the same rabbit. You can choose whichever way suits your needs best. You are not locked in to a single method.

Also, sometimes I look back in history to see how past keyboards document the same parameter.

Before MODX, there was MOXF, then going back there was MOX, then going back there was MO. MO is associated with the Motif ES (released in 2003). And the Motif ES documentation shows the following for legato slope:

Determines the speed of the attack of legato notes, when Portamento Switch above is set to on and Mono/
Poly is set to mono. (Legato notes “overlap” each other, the next being played before the previous is
released.) The higher the value, the slower the attack rate.
Settings: 0 ~ 7

The benefit of this description is that it tells you how it operates. The latest documentation focuses more on the why.

Thanks Jason and Antony (The airplane analogy was perfect! lol) for the great clarifications and examples, that was very helpful. 3 things to add from my end (not asking more questions, just sharing some observations):

1. "Pop" Sound

You'll hear "pop" or "click" kind of sounds. More like "woosh" sounds as you hit a key. I think if you focus on each note you play during the attack you'll get a feel for the sound. Now rank up legato slope to 7. This will get rid of that artifact. And that's what it's there for. The "unnatural attack" sound.

When the sound is amplified by an effect (EQ or Amp Sim), that "Pop" sounds like someone is blowing into a Mic and it is very very hard to get rid of it.

2.

In my opinion, you need to distinguish between "Real Instrument" simulations, and "Traditional Mono Synth" sounds.

I understand and agree. Not sure if I can explain it, but the music I play the most is oriental music which uses maybe ~3 pluck instruments, ~2 bowed, ~3 winds, ~1 "mono synth" (lets say tons of mono synth sounds, all almost with same characteristics, but just different tone/pitch), and of course when needed we do use western instruments (piano, guitars, brass, etc...). Most of the sounds we use, are played in Mono Legato (except the plucks maybe), not because it is like that in real life, but because the keyboard style requires it, especially in Live (one man band). So while I agree with you, XA does not work for our Live Gigs for Dance Music (it may work in a studio though to replicate the real instrument for Production Music), so we have to use the unnatural legato for the Real Instruments as well.

3. Other Keyboards:

Also, sometimes I look back in history to see how past keyboards document the same parameter.

I loved how Yamaha did it in their PSR A5000 Arranger, have a look at the screenshot and it will show how straight forward it is:

Cheers

Re: Pops and Clicks

This usually arises due to a vertical slope in the Amp EG (Amplitude ADSR).

The vertical slope arises when the transition time between two different volume levels is 0.

This can happen, for example if Attack Time = 0, or Release Time = 0 (most common, but Decay1/Decay2 = 0 will also cause it)

You can test this with an AWM2 INIT + Saw Wave with Amp Attack & Release set to 0.

Similarly, if any offsets cause the transition time to reduce to 0, you will get the Pop/Click... such as Legato Slope. But there are other factors than can cause it e.g. Time/Vel etc.

Recognising the "Zero Transition" Click, can help you debug issues in your sound.

I remember having looked at Legato Slope in the past, and mentally ticked it off as "tried and understood". But I don't remember which Preset I used to gain this understanding.

Now, this thread has sparked my interest again. However, now I can't seem to get Legato Slope value to make any difference at all.

My recollection of Legato Slope was as I described above. Although reading the description in the Parameter Manual, the actual intention seems to be the reverse... i.e. remove/soften Attack on notes played legato.

It could have more relevance to the XA Control (Real Instruments) version of Legato, although I haven't tested this just now.

So, it's probably best to ignore my earlier comments, and experiment to make your own conclusions.

You will often find with the MODX, the only real way to understand what a Parameter or Function is doing is to experiment with all options... most of the time you will find the answer.

Depending on the properties of the sample, attack, etc - legato slope may not make a difference. Even when it's working where you can hear it doing its job - it's not as "in your face" as other parameters. The experiment I gave before starting with the preset "Saw Lead" (or similar starting point) might be the best way to walk through hearing the "problem" and the "solution" involving legato slope. The artifacts of the non-legato-slope sound may be desirable or "cool" - so it's a judgement call if you would want to employ this or not. And even still, the conditions won't always be there to need any change in legato slope. I think this is generally what some run into. There's an old motifator forum post that has someone confused because they tried all values without hearing anything.

At least running through the experiment with "Saw Lead": changing the attack to a slow attack then listening to legato slope = 0 (artifacts) and = 7 (artifacts gone or smoothed out) will help provide some idea of what it can do.

I also think as you layer other sounds - these artifacts may get buried in the mix.

Because my keyboard is often in transit - I'm using headphones at the moment rather than the studio monitors. This may help listen for detail.

[quotePost id=116173]
So, it's probably best to ignore my earlier comments, and experiment to make your own conclusions.
[/quotePost]

Truer words have never been spoken...

[quotePost id=116173]
You will often find with the MODX, the only real way to understand what a Parameter or Function is doing is to experiment with all options... most of the time you will find the answer. [/quotePost]

And it's probably also true that most everyone that's come to the forums to ask specific questions in search of actual values (and their relationships and impacts) has already done as much of this as they're able, asked people they know in the real world for any and all help they can be, and are now in here asking for help that extends into the realm of previously tried, tested, proven and real insight, into real values that reveal really real truths about what's actually happening.

I don't mean this insight into what folks have done before coming here to ask questions just for you, @Antony. It's also for everyone else that repeats the tired trope of "try and it and see/hear" mantra, to folks who've (much more than likely) already tried doing that, and now want something more concrete and less subjective so they can extrapolate, experiment and iterate more precisely and purposefully, with more predictability.

There are some cases where the ONLY insight and full extent of insight is limited to what can be perceived. In those cases, that should be explained first, foremost and always, as it's a huge insight, in and of itself.

@Andrew...

FWIW... there are dozens of daily threads I do not respond to, simply because, I have no experience and no idea of the solution. So I stand back, watch, and hopefully learn.

However, in cases where I have had some limited experience, possibly even having suffered the same problem, I offer help. Usually with the caveat that I am not a guru super user. Being an altruistic guy, I don't mind spelling out the detail, rather than leaving a question answered with more questions, vagueries or irrelevancies.

Equally, if I realise any advice I have given turns out to be incorrect, I feel no shame in subsequently announcing my error... to err is human. I would prefer to do this, than see somebody walk away with my bad advice and waste their precious time.

What I don't do however, is just pounce on every thread, venting my spleen because I have nothing better to do.

@Jason... thanks for your solution and relevant example.