I know this is a stupid question, but what exactly is the sample and hold most useful for? Can someone show me some classic examples of a sample and hold in action? Is it just a random LFO generator of some sorts? Also, are there any good bits of literature about it that I can look up on the internet? I just haven't had any experience using this feature of the Nord.

The best place to start is in the modular help, which says -quote- This module takes samples of the values of an incoming signal. The sampling occurs every time a signal shifting from 0 units or below to anything above 0 units appears at the yellow logic input. Inbetween these trig signals, the module transmits the value of the latest sample to the output.

To create the traditional Sample & Hold or random LFO synthesizer effect, connect the output of a white noise generator module to the input of the Sample & Hold module and trig the Sample & Hold module with an LFO. Connect the output of the Sample & Hold module to a Pitch modulation input of an oscillator and route the oscillator's output to an Output module. -unquote-

The traditional lfo driven white noise sampling illustrated in the above example will create regular stepwise random changes of pitch, and give a sequency sound to the patch. When i used to use it on old analog synths though i preffered to use it as a modifier of amplitude (whitch i'd trigger off drum machine sync pulse, but these days midi clock works better), and that could provide a pleasing random rhythmic pulsing for pad like sounds with long sustain, locking them into the rhythm.

Creatice uses of sample and hold abound. For instance, in a two oscillator patch you could triger the sample function off key trigger and route the output to modulate oscillator 2 pitch. Turn the modulation down to a small value and now every note you hit will have a different random oscillator detuning, cereating a lively patch where no two notes sound exactly the same.

Run at very high trigger speeds the sample and hold function can be used to give you a function similar to the digitiser module. Being slightly less specialised however you might view it as an even lower resolution version of that module and so capable of greater evil.

Remember also that you don't always have to process audio with it. You could sample an adsr output and thus make a jumpy adsr that moves in regular timedsteps rather than smoothly - perhaps an idea if you wanted to make a low-fi digital or computery sounding synth patch. Some early digital synths used to actualy do this, so if you introduced radical modulations from slow adsr envelopes you could actualy hear the adsr clicking through it's values in the sound. If you're very naughty and unmusical with your nord lead you can actually get this as well, though it requres playing around far outside the paramaters of good taste in sound design. (SID chip emulators take note - digital aliasing in the sid chip was a strong component of the commodore 64's warmth, and provided a richer sound input to it's analog filtering section. Even the modern waldorf va synths allow you to dial up aliasing to get a retro sound.)

Speaking of the nord lead - i've got a NL2, and one of the most charming modulators in it is the smooth random lfo. You can get one of these by driving the sample and hold module with a regular pulse (such as a traditional lfo) and using a noise input as the signal source, just like the clavia sample above. Rather than using it directly as a control source however, run it through a portamento or envelope follower module first. This gives you a regularly moving random control source which works beautifully as a filter cutoff frequency modulator. You can get your filter to sweep smothly randomly without the repeating character of traditional lfo filter sweeps, the filter randomly wandering hither and thither picking out harmonics as it may. The result is a much more organic sound, and often far more pleasing than the predictable pumping wah-wah action of lfo modulation.

In addition to what Pavig said, I would like to add that the importance of the S&H module is that it is actually a memorycell. It is the only module capable of 'remembering' something. And there are actually a lot of things one would like to remeber. E.g. not only the value a LFO or noise generator has when the S&H is triggered, but the S&H is an important syncronizing module. Imagine that you would like to syncronize your keyboardplay exactly to the clockpulse of a 16th beat. Inserting a S&H between the keyboard module's note output and another between the keyboard module's gate output and clocking these with the 16th clockpulse will 'delay' your keypress exactly to the beat.

The S&H is a real 'jack of all trades' module, one you will discover more and more. Whenever you feel that you can't solve a timing problem in a patch in a straightforward way the first module to think about is always the S&H. Here is an example where the keypress is synced to the clockbeat. A total of three S&H's are used to keep everything in perfect beat. If you want to know what happens to the keyboard signals, just slow down the clock to 24 BPM and remove the S&H modules.

One thing to keep in mind about the S&H is that it does not behave correctly when cascaded, that is several S&H's in a row.

> One thing to keep in mind about the S&H is that it does not behave correctly when cascaded, that is several S&H's in a row.

Why is that? A NM bug?

Here is an example, the left cascade doesn't work at all. You should hear the last three pitches played, but you hear the same pitch. It should work like the right cascade, where an old analog trick is used to make it working. There you do hear the last three pitches.

It has to do with the calculation order of the modules and how the calculations for the yellow and blue signals are 'interwoven' between the calculations for the red and grey signals. Its not really a bug, Clavia explained me there is some logic to it as calculated outputs will become immediately available for the next module to be calculated. However, with a S&H it would be better if the output would only become available at the next calculation round. Clavia said they will have a look if they can come up with a solution.

S&H cascades are ideally suited to make melodylines that have neither start nor end and seem to wander aimlessly into oblivion. Still they can be a source for interesting samples.