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NI Session Strings Pro

String Sample Library
Published December 2011
By Nick Magnus

Huge, elaborate orchestral sample libraries are all the rage right now, but for more modest requirements and lower budgets, Session Strings Pro could be just the ticket.

The Main tab controls level balance between sections 1 and 2, bow-noise amount, stereo width and AR envelope controls. When release samples are active, the release envelope control is disabled.The Main tab controls level balance between sections 1 and 2, bow-noise amount, stereo width and AR envelope controls. When release samples are active, the release envelope control is disabled.

When it comes to mocking up large-scale orchestral strings, there are plenty of sample libraries that address the subject, often brandishing buzz-words such as 'Hollywood', 'Cinematic' and 'Epic' amongst their USPs. The price tag and system requirements for such libraries can be equally epic, requiring a substantial financial outlay; not just for the software, but also for a system capable of realising their full potential. What isn't so commonly addressed is the need for a smaller string section suitable for pop productions, where a grandiose 64-piece string section is frequently inappropriate. Session Strings Pro (SSPro) aims to provide just that, at a relatively affordable cost.

The Story So Far

To get an idea of what SSPro is all about, let's quickly take a look at its predecessor, Session Strings (released early in 2010). This featured four violins, three violas, two celli and two double basses, playable as an ensemble across the keyboard. Fourteen articulations were provided as individual instrument patches; with several of these loaded at once and assigned to separate MIDI channels, this allowed for articulation changes if your arrangement was split across multiple MIDI tracks. Articulations comprised between one and three velocity layers, depending on type; the lowest two adjacent layers could optionally be crossfaded using the mod wheel, for more naturalistic dynamic expression, instead of the default key-velocity switching method. Ten Performance patches provided a predetermined selection of velocity-switched articulation pairs, plus scoops and falls activated by the pitch-bend lever. In addition to this was the Animator, a built-in sequencer that played chords in a rhythmical pattern using a staccato, spiccato or pizzicato articulation. This was restricted to using 48 preset patterns, with no option to customise them. Despite the limitations, it was fun, but begged a more flexible implementation. Lastly, all instruments and Performances were provided in two flavours, 'Standard' and 'Motown'. The former had a natural, uncoloured tone, while the latter benefited from a convolution impulse, imparting a mid-range presence and ambience reminiscent of string sections from the Motown era. All the instruments sampled were made in the 18th and 19th centuries by Italian craftsmen, lending the library an unarguably 'vintage' provenance — an interesting contrast, considering the intended modern applications.

Supersize Me

Five articulations, a default plus four performance-dependent alternatives, can be set. The knob below Expression Control sets key signature, so SSPro can 'intelligently' select half-tone or whole-tone trills.Five articulations, a default plus four performance-dependent alternatives, can be set. The knob below Expression Control sets key signature, so SSPro can 'intelligently' select half-tone or whole-tone trills.

Whereas the SS core library came in at 1.63GB when installed, SSPro raises the bar considerably, coming in at 29.4GB — just over 18 times more sample data. As you'd expect, this gives SSPro plenty of scope for extra articulations, and a generally more detailed and comprehensive coverage of the string section than its predecessor. Compared to the 14 articulations of SS, SSPro provides 29. Further sampling details include up to four velocity layers (depending on the articulation), 4x 'round robins' and release samples. The round robins and release samples can be disabled if required, but as they add to the realism of SSPro, and use no less RAM when disabled, I suspect that most users will choose to leave them on.

The single ensemble of Session Strings is multiplied fourfold in SSPro. Once again, each of the four 'sections' comprises four violins, three violas, two celli and two double basses, organised into two preset groups for Sections 1 & 2 and Sections 3 & 4. A Section 1 & 2 preset, for example, will load those two sections together, the balance between the two being adjustable from the 'Main' tab. As well as providing all-in-one 'ensemble' presets, SSPro includes separate presets for violins, violas, celli and basses. Not only does this afford each instrument its full playable range, but it allows for different articulations and custom dynamic control over each part, greatly enhancing an arrangement's realism. The four sections differ in the following ways: Section 1 (closely equivalent to that of Session Strings) has a close, dry sound, with the basses placed centrally. The celli are panned equally to each side of centre, with the violas spread wider still, giving the violins the widest stereo panorama. Section 2 employs the same orchestral seating, but with the mics placed further from the players. Although the Section 1 and 2 samples sound like the same sampled performances (ie. not double the number of players), a mix of both sections provides a warmer and fuller tone than either section on its own. Section 3 and 4 presets follow a similar close/far mic placement pairing, but with traditional orchestral seating (basses to the right, progressing to violins on the left) for the closer-miked section 3, and the opposite stereo placement for the distant-miked section 4. Of course, you can layer Section 1 & 2 presets together with Section 3 & 4 equivalents on the same MIDI channel, for an even fuller sound. However, what isn't clear is whether Sections 1 & 2 are actually separately sampled performances to those of Sections 3 & 4. All four sections layered together certainly doesn't sound like a 44-piece ensemble, but I found that detuning Sections 1 & 2 against Sections 3 & 4 (about 10 cents seemed a good amount) gave a reasonable impression of larger resources.

Preset Types

Up to six keyswitchable articulations are available in Production presets. Keyswitches can be user assigned.Up to six keyswitchable articulations are available in Production presets. Keyswitches can be user assigned.

Every instrument category contains three different preset types — Performance, Production and Animator — each focusing on different ways of working with SSPro. Performance presets are optimised for live performance, offering up to five immediately accessible articulations, triggered by predetermined conditions. The main articulation (user selectable) is the one that plays by default, but is replaceable either by exceeding a specified key velocity, using the sustain pedal (CC64) or the expression pedal (CC11), or by operating the pitch wheel. The 'replacement' articulations for each condition are assigned from a drop-down menu containing all those available, with the exception of pitch wheel, which offers a choice of 'normal' pitch-bending or the scoop/fall articulations (down triggers falls, up triggers scoops.)

Production presets are optimised for recording, and provide up to six possible articulation choices, selectable via latching keyswitches. There is no default articulation here; the one that plays is the last one you selected. No two keyswitches can share the same articulation, but you can leave as many as you like empty, so only the articulations you need are loaded. The default keyswitch assignments can be fully customised if you wish, with the caveat that if a keyswitch is placed within the sounding range of an instrument, the keyswitch function presides, and that note makes no sound.

SSPro's Animator presets see a very welcome development of the concept that first appeared in Session Strings. Animator transforms chords into tempo-sync'ed, chugging, rhythmical patterns or arpeggios using staccato, spiccato or pizzicato short note articulations, and comes stocked with a list of 36 preset patterns. Similarities to SS end there, because now the patterns can be fully customised to your wishes, and saved to any of 10 user slots. These user patterns are selectable on the fly using keyswitches, meaning that you're not stuck with just one repetitive pattern; you can create a collection of motifs that change and develop throughout a song. Editing patterns is easy and intuitive, using graphical faders that represent each step of a pattern. The faders control the velocity of each step — so if you want a 'rest' note, just pull that step's fader to zero. The four velocity layers and 4x round robins provide sufficient sonic variation to give a pretty good impression of a lively, chugging ensemble in full Michael Nyman mode. Additional knobs control the overall dynamic response of the patterns to key velocity, add variable amounts of swing feel, and multiply/divide the tempo scale. You're not restricted to compound time, either: patterns can easily be made to cycle around odd numbers of steps. This could inspire a new wave of Prog Baroque concept albums...

The Sound

Words that come to mind when describing the overall sound of SSPro are clear, precise and intimate. Some may feel it's a little too precise, considering that SSPro is primarily aimed at pop productions, which often benefit from a few rough edges. This could well be due to the extremely accurate tuning. A little laxity here, especially with regard to the very close unison tuning between instruments in the same group, might help SSPro sound a little less 'genteel' for some applications. The individual instrument types have very distinct characters; the basses are very focused, packing low-end weight without sounding muddy. The celli are warm and expressive, benefiting from occasional touches of the portamento and glissando articulations. The Violas are quite possibly the star of the show; rich, warm and authoritative, with a lovely resonance, they carry a melody particularly well. The violins sound best in their lowest octave, but above that the sustaining articulations feel like they lose momentum. My personal feeling is that their loudest dynamic is underplayed, and a smidgeon more vibrato wouldn't have gone amiss to impart a more energetic feel.

One operational gripe concerns the use of the modulation wheel or expression pedal to control dynamics. When the wheel (or pedal) is stationary in the 'up' position and a new note is played, downward movement of the wheel causes an initial upward jump in volume. In order to maintain a consistent level, the wheel has to be constantly moving — if only just a little bit — whenever new notes are played. Every preset displays the same behaviour, so this is most likely a general problem within the KSP scripting.

When Polyphony Matters

Animator patterns can be customised easily by adjusting the graphical faders. Ten saved user patterns are selectable on the fly with keyswitches.Animator patterns can be customised easily by adjusting the graphical faders. Ten saved user patterns are selectable on the fly with keyswitches.

The Ensemble presets can be very demanding on polyphony when both sections are active and dynamics are controlled by the mod wheel rather than key velocity. In these circumstances, as many as 12 voices are playing at once for each note, and this can mount up to 24 when playing notes that fall within positional crossfade zones. It's not unusual for a three-note chord to gobble up 48 notes of polyphony, and the release samples can cause this to climb above 100 if you're playing legato, and reasonably quickly! If this becomes a problem in a busy sequence, you can halve the polyphony, at the expense of tone, by setting the level of section 2 (or 4) to 'off'. Alternatively, programme each part using the individual violin, viola, cello and bass patches. They don't make use of positional crossfades, so they consume marginally less polyphony, and make for a more natural-sounding result, with independent control over each part's dynamics and articulations.

Rosins To Be Cheerful

All SSPro presets are equipped with a trio of 'sweetening' effects: Equaliser, Compressor and Reverb. The Equaliser comprises Low, Mid and High bands, each with gain and variable centre frequency controls. The Compressor utilises Kontakt's 'Pro' compressor effect, and although there is only a single Amount control, delving into edit mode reveals this to adjust the threshold, ratio, attack and release parameters simultaneously. The range of settings suits SSPro well, with higher values adding extra bite to the Fortepiano, Attack and shorter articulations, and some additional 'oomph' to the higher violin range. The Reverb provides a choice of 10 convolution spaces and a Mix control. If you're running SSPro in the full version of Kontakt, you can extend these reverb options by dropping into edit mode and selecting any of Kontakt's own convolution presets, or even load your own impulses. The Main tab of every preset is home to two additional features: Bow Noise and Stereo Width. Bow Noise, to put it simply, adds more rosin to your bow — turn it way up, and you're right there at the player's elbow, as it were. It's a very intimate sound, and works especially well on the Celli and Violas. Variable Stereo Width uses pseudo-stereo processing to either collapse the image to mono at one extreme, or expand to a super-wide, out-of-speaker experience at the other. The default 12 o'clock position gives a 'normal' stereo image. As with Session Strings, all presets are available in a choice of Contemporary (named 'Standard' in Session Strings) or Motown flavours.


Given the current fashion for large-scale cinematic string libraries, it's interesting that Native Instruments have chosen not to follow the 'me too' path, opting instead to fill a gap in the market with this scaled-down ensemble. SSPro is actually more versatile than its suggested 'pop' applications, and is quite capable of handling baroque, classical and period styles. It's particularly good at evoking a wistfulness and nostalgia reminiscent of British movie soundtracks from the '60s and '70s. SSPro's tight, intimate sound undoubtedly works best matched with arrangements on a similar scale; anyone requiring rumbustious, larger resources will need to look elsewhere. Despite personal reservations — a lack of energy in the violins and the lumpy volume behaviour when using mod-wheel dynamic control — I like SSPro. Its simple operation makes for a fun sit-down-and-jam experience, but it can also sound quite impressive when sequencing a complex arrangement using the separate violin, viola, celli and bass instruments, carefully sculpted dynamics, and judicious use of the articulations on offer. Admittedly, larger mega-libraries offer more sophisticated and realistic implementations of certain features, but at the cost of higher hard drive footprint and a bigger hit on system resources and finances. And when the mega-libraries are sonically just too mega, SSPro might just provide a welcome calm in the storm.  


String libraries offering similar weight and function to SSPro appear to be scarce, and the following three examples were the closest candidates. Miroslav String Ensembles: Composer's Dream offers both large and smaller ensembles, the smaller representing significantly more players than SSPro. Although VSL Chamber Strings comprises a similar number of players to SSPro, its tone and performance style is distinctly classical, and not specifically geared to 'modern' styles. Audiobro LA Scoring Strings: the full version of LASS provides the means to build ensembles to the required size, making it the most likely to match the equivalent 'weight' of SSPro. It also includes the ART Script tool, which surely inspired SSPro's own Animator. And the cost? Session Strings Pro is approximately half the price of the first two examples, whilst LASS carries a substantial four-figure price tag.

System Requirements

  • Kontakt or Kontakt Player 4.2.2 or higher.
  • Windows XP (latest Service Pack, 32-bit), Intel Core Duo or AMD Athlon 64 processor, 2GB RAM, Windows Vista or Windows 7 (latest Service Pack, 32-/64-bit).
  • Intel Core Duo processor, 2GB RAM, Mac OS 10.5 or 10.6 (latest update).

Smooth Me Over

Realistic note transitions (such as true legato) were once the Holy Grail for sampled instruments, and most high-end libraries now boast their own implementation of this feature. Whilst SSPro doesn't rise to the same levels of sophistication as the bigger libraries in this respect, it nevertheless makes a brave stab at the task. SSPro provides three monophonic transitions: legato, glissando and portamento. The legato articulation is fairly believable across one- or two-semitone intervals, but as the intervals become progressively larger they don't 'smear' quite as seamlessly as they should. Ironically, when large-interval transitions are played with the polyphonic sustain articulation and butt-joined notes, the release samples provide enough glue to create fairly seamless joins. Glissando transitions use a fixed-speed semitone slide up or down to the target note, regardless of the starting note, and these can work well when used sparingly for smaller intervals. Larger interval glissandi can be faked by playing a rapid scale of overlapping notes, triggering a series of slides that blend the 'missing' notes together. Portamento is a faster, more subtle version of the glissando articulation, and again works best when treated in the same way as glissandi.


Session Strings Session Strings Pro
Accented Sustain 1 Dynamic 4 Dynamics
Normal Sustain 2 Dynamics 3 Dynamics
Legato 2 Dynamics 3 Dynamics
Portamento No 3 Dynamics
Glissando 2 Dynamics 3 Dynamics
Glissando fast up 2 Dynamics 3 Dynamics
Glissando fast down 2 Dynamics 3 Dynamics
Glissando slow up No Yes
Glissando slow down No Yes
Fortepiano No Yes
Diminuendo No Yes
Fortepiano Crescendo fast Yes Yes
Fortepiano Crescendo slow No Yes
Crescendo fast Yes Yes
Crescendo slow No Yes
Falls fast Yes Yes
Falls slow No Yes
Scoop fast Yes Yes
Scoop slow No Yes
Spiccato 2 Dynamics 4 Dynamics
Spiccato up bow No 4 Dynamics
Spiccato down bow No 4 Dynamics
Staccato 2 Dynamics 3 Dynamics
Staccato bow up No 3 Dynamics
Staccato bow down No 3 Dynamics
Pizzicato 2 Dynamics 3 Dynamics
Tremolo 1 Dynamic 3 Dynamics
Trill semi tone No 2 Dynamics
Trill whole tone No 2 Dynamics
Adjustable bow noise No Yes
Stereo Width control No Yes
Animator customisable patterns No Yes
Animator presets 48 36
Published December 2011