one of the first features being explained is the ability to store up to 128 "programs" (let them be either voices, performances, etc) and recall them with a single button press: but what are the buttons designated for this? How do I move from one stored "program" to another during a live concert?

You can move between MASTER programs by pressing the [INC] button or by setting a Foot Switch to advance programs when you press it.

I see the synth has input for two (continuous, right?) foot controllers, can I use one of them to control a parameter different from the volume, i.e. the attack speed of a string voice / sound?

The two continuous Foot Controller (FC7s) are both assignable. They can be assigned to any control change number 1-95 (except 32 which is reserved for Bank Select)... the FC1 jack defaults to cc011 Expression and the FC2 jack defaults to cc004 Foot Control which can be assigned to any of 101 parameters per Voice.

given that the previous has an affirmative answer, will I be able to store that setting along with the voice / performace / master I'm configuring? So that when I recall a stored program, the pedal settings will be recalled too?

The assignment of the pedals is global. If the FC1 jack is set to do Expression it will do that on every program. If the FC2 jack is set to Foot Control what it can be doing a different thing in each Voice - Foot Control can be assigned to any of 101 destination parameters per Voice - so it can be Filter Cutoff in one Voice, and Rotary Speaker Speed Control in another, and LFO Speed in yet another.

I read that there's the possibility to record or reference (or similar, I didn't get it all) a wav file on the synth and set it up so that it is part of the performance being played: it that right? will I be able to, e.g., play a portion of a song with a piano voice, then start the wav file reproduction, then stop it and continue with the piano portion?

Not exactly. The S70 XS can record a .wav file either to its internal 192MB of Flashor directly to a connected USB drive. The .wav can be accessed to playback same as .MID files in the SEQ PLAY function. and yes you can play along with it but you do not place it as Part of a Performance.

You would have it available to start playback whenever you desire. So you could call up whatever program you want to play on the S70 XS, and when you needed the .wav press the SEQ PLAY button to start playback of the .wav - you can continue to play the pre-selected program. But the wav cannot be placed in a Performance as one of the PARTS, no.

The S70 XS does not have a sampler, nor can it load user samples... it will basically stream playback from its internal memory or direct from a USB drive. The Internal memory will hold about 18-19 minutes of stereo audio, a USB drive can steam up to 74 minutes from a single stereo .wav File.

Thank you for your thorough explanations, Bad Mister, you're really helping me making a good idea about the board capabilities.

Not exactly. The S70 XS can record a .wav file either to its internal 192MB of Flashor directly to a connected USB drive [...]

I've probably mixed together a couple of meanings for the same words (performance, part, ...) here. My apologies.

What I meant was if I could, play my song for, say, a minute, then start the playback of a WAV or MIDI file, and then go on with playing my song, with the optional possibility to play along with the file playback.
If I understand you that can be done.

But, I can't e.g. use a generic WAV file (say an MP3-converted-to-WAV or an excerpt from a Youtube video) on a USB stick and reproduce it on the keyboard, can I? Is that what you mean when you talk about the board not having a sampler? I can only playback music produced by the same keyboard?

Next, some more questions arise 🙂
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But, I can't e.g. use a generic WAV file (say an MP3-converted-to-WAV or an excerpt from a Youtube video) on a USB stick and reproduce it on the keyboard, can I? Is that what you mean when you talk about the board not having a sampler? I can only playback music produced by the same keyboard?

You can playback any .wav file that is 16-bit/44.1kHz and stereo. MP3 are not wav - if you have converted it and it is 16bit/44.1kHz stereo it should playback just fine

When you used the "performance" that is a technical term in the S70 XS - our synthesizers that feature a Sampler (like the Motif XS/XF) you can actually use your .wav as a OSCILLATOR (tone source) inside one of the Programs - so that it can be played back like any other audio sample. Like when you press a key and trigger a Piano note, you could place your sample in a program and trigger it manually or have the sequencer send a NOTE-ON to trigger playback - that you CANNOT do on an S70 XS because it does not have the built in ability to manage samples as OSCILLATORS.

The S70 XS deals with .wav files the same way it deals with .MID files - it simply plays them back - streaming the data directly from the internal 192MB of FLASH ROM or from a connected USB drive. It plays them back as if they were a SEQUENCE.

when I change program with the buttons you mentioned, will the already playing sound (i.e. due to a sustain pedal) be cut? Not a big deal, but worth asking

Yes, if you change programs while in VOICE mode, or PERFORMANCE mode, or MASTER mode using the buttons or a FOOT SWITCH, (called a PROGRAM CHANGE) yes, sound will be cutoff - this is because a PROGRAM CHANGE message includes an ALL SOUND OFF message.

if you need to change sounds seamlessly the way to do that on your S70 XS is to build a MULTI containing the sounds you wish to change between in PARTS 1-16. You can seamlessly switch between any of the 16 PARTS by simply pressing the corresponding number [1]-[16] - you can continue to sustain a sound with the sustain pedal and change PARTs and play with the full keyboard while still holding the first PART with the sustain pedal... and finally when you release the pedal that first sound will stop.

The reason this works is because you are not sending a PROGRAM CHANGE and no ALL SOUND OFF messages is ever sent, you are basically changing TRANSMIT CHANNELS and playing on a different MIDI channel. The only mode where you can access 16 internal MIDI Channels is MULTI (thus the name).

when a foot controller changes the volume, can it do that for just one of the parts when in performance or master mode, like just controlling the volume of an organ voice while the piano voice volume isn't affected?

You have what are called RECEIVE SWITCHES (RCV SW) which allow you to activate or deactivate any controller on a per PART basis.
From your PERFORMANCE
Press [EDIT]
Select PART 1 to view PART parameters
You will find RCV SW among the parameters.
When you want to just control one sound and not the others clear the box for the PARTS you want to ignore the VOL/EXP changes

(please consider that I'm totally new to synths) what sound creation capabilities does the S70/S90 XS support? You said there's no sampler onboard, and from the manual I get that I can change the existing sounds, modifying their various parameters; but I see on the web that there are sound packages compatible with this board and I've read a bit about "additive and subtractive synthesis" - consider that it would be perfectly fine if I could do all the editing on the computer. Am I limited to modifying the existing onboard sounds, or could I access the oscillators, filters and all those things mentioned in synthesis tutorials?

The S-series is basically the sister product to the Motif-series (without the Sampler and the recording Sequencer)... It can be fully edited. However, unlike the Motif XS/XF where deep editing can take place using the Motif's large screen, the S-series was designed as a Motif-series for the STAGE performer (S -for Stage Synthesizer) and it is assumed you want to edit deeply but NOT while you are on stage - but when you are in the comfort of your home studio. So you can edit using your computer screen and store your edits in the product and then go to the gig, where you recall your customized edited sounds!

So with the sampler, the sequencer and the on-board deep editing - you save more than $1000 over the full Motif-series series (that works for many, many people) - Truly you can see it was streamlined for stage players!

So download the Yamaha S70 XS/S90 XS Editor Standalone/VST Editor for your computer type and you will have every edit parameter you find on the Motif XS/XF. This means you can deeply edit everything about on-board VOICES.

The Editor is FREE and available from the Official Yamaha Download site:
http://download.yamaha.com

You will need the Yamaha USB-MIDI Driver for your computer type. The Editor can be run as a Standalone or as a VSTi Plugin within Cubase.

Thank you very much, now you made me willing to try out one! 😉

Yesterday I got another one, but I don't know if it really makes sense, was just a quick thought:
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You need to be concerned with matching input level (not just the jack). The input is clearly marked MIC, so it is not anticipating a LINE level input. Microphone signals are typically very weak signals -55dB ~ -45dB; most direct boxes output must stronger levels on the order of +4dB so, in general, no a direct box is NOT necessary.
Electric guitars are usually in between (approx. -35dB). That still qualifies as a relatively weak signal.

When I say weak, it is in comparison to items like CD players, handheld play back devices which can be -10db, +0dB, +4dB or more, all of these are considered Line level. Dynamic microphones and guitar/bass pickups are both based on tiny magnets and coils of copper wire to induce signal flow. They therefore generate very small amounts of electrical signal.

Unlike the Motif XF or MOXF which feature two 1/4" inputs (that accommodate any single device, be it mono or stereo) and they feature a Mic/Line switch (input pad) to prepare the internal engine for signals from weak/strong (mic/line). The jack on the back of the S-series is combi-jack. It accommodates an XLR or 1/4" connector. Do not just match the jack - recognize the input is looking for a specific level input, as well - in this case a relatively weak signal. You can plug your electric guitar directly in without a Direct Box! In fact, we recommend NOT using a DI box.

While you can try it (we know our recommendation will not stop you if you are curious) but do so with the knowledge you are going to potentially overload that input if you output LINE level signal. So keep the gain at minimum!!!! Now if your DI Box has a lower level output as well, you can use it, but typically DI boxes boost level to balanced LINE level as principally they are used for long cable runs. But since you can use a regular guitar cable, no extraordinary adjustment to the connector or the level need be made. The S90 XS and 70 XS can put Insertion, System and Master effects on any incoming signal.

The AD input has its own "Part" within the internal engine with output level, pan, access to a pair of Insertion Effects, a Send to the Reverb and a Send to the Chorus Effect. It can also be routed as a source to the Vocoder.

Hope that helps.

That helps for sure 🙂 and thank you for the explanations about input levels, I wasn't aware of them.

In fact, I thought that the combo input was anyway expecting a balanced input, that's the primary reason why I thought about a DI.

There's one thing I didn't understand: is there any (even remote) risk to damage the keyboard when doing these experiments? Or when you talk about keeping the gain very low is just because I could get distorted / clipped / etc sounds?

You will know immediately about distorting the input with too much signal. Unlikely that a brief test would hurt anything, but just recognize that nothing is labeled "Line" level... So just use common sense when connecting Line level devices. I wished they published the specifications (not that everyone would know, but at least the info would be available). The circuits and build quality are built rugged enough for musicians so it should not be major issue, testing out different sources as connections.

Common sense means starting with volumes all the way down before ever turning ON the signal flow. This way you protect your hearing - and your gear. Never press a button that could potentially make the connection with the Volume already up! The first time you hear signal from the AD Input should be by fading up its GAIN - not by parting your hair!!!

If you cannot set the gain low enough without distorting, this is a clear indication you should not use that device as a source. A Mic/Line option "pads" the input to prepare it for a "hotter" signal. The S-series is labeled for "mic" which translates to lower level signals - that's all. Eyes wide open. Guitar (unboosted) should be able to be plugged in and the S-series preamp should give you enough signal to drive the signal though the system.

Sorry, I've never plugged a Line level device into the S90 XS/S70 XS to see what happens. Guitars, directly in, that I've done.

Thank you for the advices 🙂 , I will be very very careful.