Sampler is Ableton Lives newest Instrument, brand new as part of the Live 6 upgrade.  Like Operator with version 5, sampler is not a free instrument, and must be purchased for $199 US before you can use it outside of demo mode in Live 6.  Sampler is only available in Live 6, it cannot be used in previous versions of Live or in other DAWs.  However, like Operator, all of Sampler's parameters are controllable via Clip Envelopes and Arrange page automation, which really expands on what the instrument is capable of.  Very loosely, it means you can modulate ANY parameter in the synth via clip envelopes, you're not constrained by the number of LFO's or envelopes the instrument itself has.  And on that note, lets take a look at some of the key aspects that make up Sampler.Sampler is organized into 6 main pages of parameters, each of which is accessed via tabs at the top of the unit.  The first Tab is the "Zone" tab, and it's here you assign the key and velocity splits for the samples you want to use.  Sampler is capable of loading hundreds of samples, all of which are located in the Zone window pane that pops up above Sampler when the Zone tab is first selected.  Just drag and drop samples from either the Browser, Session view, or the Arrange page here, and they show up as new Zones.  It’s also possible to drag samples directly into the waveform view in Sampler if you only want to load one sample.  This makes it especially easy to use in a live setting, as you don’t need to dive into the Zone editor each time you load a new sample.Those familiar with Live 6's Racks features will be right at home, as Zone mapping working on the exact same concepts.  Zones can be key or velocity split, and it's possible to set up key and velocity crossfades as well.  One of my few complaints about Sampler, is that the handles you use to change the key and velocity crossfades are very small. On a higher resolution monitor they can be downright hard to grab.  Right-clicking on the Zone map window does offer you 3 different zoom settings (small, medium, and… you guessed it, large), though I find the crossfade handles are still sometimes kind of close to the velocity or key range handles. It's a minor complaint, and hopefully something Ableton can address in the future.
Once you've assigned you samples to separate Zones, you can modify each one via the "Sample" tab.  Here you can set which portion of the sample plays back, snap the start and end points to zero crossings, detune, modify the sustain and release modes (three different modes each), set your loops points and cross-fade said loops, and reverse the sample among other things.  More or less the standard controls you find on any recent sampler.

 
The "Pitch/Osc" tab is interesting, in that it allows you to frequency or amplitude modulate the sample with a dedicated oscillator for just this purpose. You can choose from 21 OSC shapes to use as a modulation source, and even control the depth of modulation with a dedicated ADSR envelope on this page as well.  The dedicated pitch envelope is also located on this page, as well as a Spread control that widens the stereo imagining.

The “Filter/Global” tab features a lowpass, bandpass, or highpass filter, which can also be a 12dB or 24dB morphable filter.  This morphing filter is continuously variable between multiple filter types, thus it's possible to smoothly morph through all the filter types with one control.  This is one of the nicest parts of Sampler for me, and can provide hours of fun and sonic mayhem.  In general I think the filter is very nice sounding.  It's not as warm or fat sounding as some other software synths/samplers on the market, but it strikes a good balance between clean and unobtrusive, and warm and rich sounding.  The Filter and Amplitude (volume) envelopes are also here, as well as panning controls (including random panning), and user definable voice count for Sampler.

 
The “Modulation” tab contains an Aux envelope that's assignable to two difference Sampler parameters with varying depths.  There's also three LFOs you can use on this page, with LFO1 hard wired to either Volume, Pan, Filter Cutoff, or Pitch.  LFO's 2 and 3 (6 Osc shapes  each) offer two assignable destinations each, as well as tempo-syncing, fade-in controls, assignable phase shift, and stereo/mono switches.  I do wish there was a more freely assignable mod matrix here, as I could see wanting more than two destinations for the LFO's.  Still, as there are three on hand, its not that big of a point, and there’s always Clip Envelopes to achieve more or less the same thing.

The “MIDI” Tab allow you to set the pitch bend range for Sampler, and two destinations (and amounts) for the following MIDI messages; Key (note), Velocity, Release Velocity, Channel Pressure (aftertouch), the Mod Wheel and Pitch Bend.  Nothing fancy, but certainly enough to allow you to make any patches as responsive and dynamic as your keyboard playing skills allow.  While it might not seem like many midi messages are catered for, specifically MIDI Continuous Controller’s) remember that all Sampler parameters can be directly controlled by Clip Envelopes, MIDI Assignable Macros, and Live’s Automation as well.

The points above only cover the highlights, there are many more function in Sampler that would just take too much space to cover in this review.  Everything is in the Ableton Live manual though, which is part of the free Live 6 demo available on the Ableton website if you want more information:

http://www.ableton.com/pages/downloads/demo

So, what do I think of Sampler?  First of all, I think it’s important to note some of the limitations in Sampler, especially as Ableton seem to be marketing it some what as a competitor to the likes of Kontakt, Halion, and Emu’s X2.  While sampler CAN load multi-samples, and even import patches from other sampler formats (AKAI S1000, S3000, GigaStudio, EXS, SoundFont and non-encrypted Kontakt patches), it’s filter, envelopes and modulation page are all global.  They do not operate on the Zone level like most of it’s competitors.  Additionally, Sampler does not offer multiple outputs or choke groups either, which are especially useful for drum kits. 

You can use multiple Samplers in instrument racks to get around some of these limitations, though it’s a slightly less intuitive way of working, and not as easy to use as the competitors mentioned above.  For someone just getting into software samplers, the above points might not be a big deal, and there’s certainly enough there to keep most people happy regardless.  For those coming from more established software samplers though, the omissions might be more important.  I have to admit I was initially pretty disappointed in these limitations coming from a Kontakt2 background, until…

…I began to look at Sampler in a different way.

Where Sampler really excels is as a quick and easy, ‘playable’ sound design tool.  It really opens up the possibilities of how you can warp even the simplest and most basic audio samples into something very unique sounding.  Here’s a couple of videos on YouTube where Robert Henke demonstrates some of these possibilities:
 

http://www.youtube.com/watch?v=s7Wityxkkjs

http://www.youtube.com/watch?v=e0Rk0nKWo2Y

For twisting and tweaking single samples or loops, it’s really one of the most intuitive software samplers I’ve ever used.  Especially as it’s dead easy to just drag and drop a sample from the session view directly into Sampler, and start tweaking it.  You could have an empty Sampler in your live sets or DJ sets, and just drop clips in there as needed.  Using a midi controller with the new automap and macros available, you’ll always know what you’re tweaking too.  It’s very simple to use on the fly like this, and almost feels more like a synth than a sampler. When you start using clip envelopes to modify parameters, you begin to see how endless the possibilities are. 

One thing I wish Sampler did however, was retain the global tempo of a clip when you drag it into Sampler.  IE, imagine you want to use Sampler in your DJ sets.  You’ve got some clips playing locked to the global tempo, and you drag one into Sampler.  The clip you drag into Sampler reverts to it’s default tempo, and not the tempo it was playing at in the project.  If this feature was added, I could really see this opening up HUGE possibilities for DJs.  Still, if you’re cueing up the Sampler in your headphones, it’s easy enough to adjust the playback speed via the pitch control on the “Pitch/OSC” tab to match the rest of your project.  No different than normal beat-matching, with some practice of course.  You could also take an acappella and really do some unique things to the vocal in real-time, especially with the morphable filters and FM/AM capabilities.

All in all I must say that my opinion of Sampler really changed after spending more time with the instrument.  At first, the lack of multi-sample features when compared with the competition really had me questioning whether I would want it.  If you’re thinking about switching from a more established software sampler to Ableton’s Sampler, and you create a lot of multi-layered instruments, be sure to spend some time with the demo to see how this will affect the way you work.  There are some important differences, and only you will know if they affect the way you like to work.

But, after spending more time playing around with Sampler, I began to realize how much it really suits Live.  Like everything else in the program, Ableton designed it to be about quick set-up, ease of use, while still offering tons of flexibility and hands on control.  It’s this area where it really shines, and stands apart from the crowd. The morphable filter and modulation oscillator are probably my two favorite features, as they are things you don’t see on very many synths or samplers. Sampler is one of those tools where very quickly you’ll find yourself coming up with new sounds and ideas all the time.  The direct integration with Live’s Clip Envelopes and automation is a major bonus, especially without a fully assignable modulation matrix onboard. 

Overall I think how well you get on with Sampler will really depend on what you use it for.  For sound design and as a live sample mangling tool, it’s a no-brainer in my opinion.  Even I was surprised at how much fun I had in this respect, and I can’t recommend it enough for this purpose.  As a multi-layered sampler, more time will need to be spent with it, to see how well it works for you.  Either way, I’d suggest spending some time with the demo before coming to any conclusions based on specs alone.  I imagine it’s one of those things that you will very quickly either like or dislike, and it all comes down to how you like to work.  I for one, am glad I have it now as it’s something I can see myself using a lot more than I would have thought!

More info available at:

http://www.ableton.com/sampler