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Creating Divided String Sections of Arbitrary Size

with Garritan Personal Orchestra (v4)

John Melcher

November 22, 2012

Summary

In 2009, I purchased the Garritan Personal Orchestra, mainly because I wanted a compact library I

could run on a laptop. I soon discovered that GPO and the Aria Player running it offer some

wonderful improvements over other products at any price. In particular, it offers an excellent

solution to the problem of dividing the choirs of the orchestra string section and getting a realistic

sound.

This paper explains how a real symphony orchestra string section divides itself to play more parts

simultaneously, how this is virtualized with traditional string sample libraries, and how Garritan

Personal Orchestra Ensemble provides a unique solution to building ensembles of virtually any size.

An original example is provided. Included are website links to Garritan Personal Orchestra Ensemble

files on my web site, which may be freely downloaded.

1. How Orchestral Strings Divide

2. Virtualizing Divided Strings

3. Divided Strings with Garritan Personal Composer

Violins

Violas

Cellos

Basses

General Notes

4. Issues

Sound

Velocity Layers

Completeness

5. An Example

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1. How Orchestral Strings Divide

A modern symphony orchestra string section comprises approximately 60 players arranged in five

choirs 16-14-12-10-8:

16 First Violins

14 Second violins

12 Violas

10 Cellos

8 Double basses

There’s a great amount of variation, reflecting the musical style – larger orchestras won’t use the full

string orchestra for Mozart or Beethoven, for example – as well as the acoustics and stage size of the

concert halls in which they perform, budgets and the Music Director’s idea of proper orchestral

balance. Generally, there are slightly more 1st than 2nd violins, and half as many basses. The smaller

number of violas in some smaller orchestras may also reflect a relative shortage of professional

violists.

San Francisco 68 18-16-12-11-9

Cleveland 64 18-15-11-11-9

Chicago 64 18-14-12-11-9

Los Angeles 63 18-15-12-10-8

London 62 18-14-13-10-7

Boston 61 16-16-11-10-8

Saint Louis 60 16-14-12-10-8

Dallas 59 17-14-10-10-8

New York 58 18-13-11-9-7

Pittsburgh 58 16-13-11-10-8

Cincinnati 58 15-16-10-10-7

Kansas City 55 16-13-10-10-6

San Diego 54 14-13-10-9-8

Minnesota 52 15-10-10-9-8

Atlanta 52 13-12-9-10-8

Indianapolis 51 12-14-8-9-8

Colorado 51 14-12-9-9-7

Detroit 46 12-9-9-8-8

Omaha 41 12-8-8-7-6

Phoenix 39 12-9-7-6-5

Typically, two violinists, violists or cellists share a music stand, or “desk” and play from the same

part. If the 1st violin section is further divided in two (A/B), each desk is divided, with the player

sitting closest to the audience playing the first (usually higher) part, and the other player the second

part.

When a section is divided into three or more parts,

complicated. Usually the exact

concertmaster to decide, though sometimes the compose

For example, in Stravinsky’s Rite o

1st violins are divided in

2nd violins are divided in

violas are divided in two (6+6)

cellos are divided in two, and then one half is furt

basses are divided in three

Figure 1

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three or more parts, it’s done by desk, and the situation

Usually the exact assignment of players to parts is left to the conductor or

, though sometimes the composer is specific.

e of Spring, at rehearsal marks 87-89 (The Exalted Sacrifice

in two (8+8, assuming 60 string players as described above)

to seven parts of one desk each (14 players total)

in two (6+6);

cellos are divided in two, and then one half is further subdivided (5+3+2 or 6+2+2);

three (3+3+2).

Figure 1 – Igor Stravinsky, Le Sacre du Printemp

the situation can become

left to the conductor or

The Exalted Sacrifice):

ing players as described above);

(14 players total);

her subdivided (5+3+2 or 6+2+2);

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Later, at rehearsal mark 142 (Sacrificial Dance):

1st violins alternate between unison (16) and divided in two (8+8);

2nd violins and violas are divided in three (5+5+4, 4+4+4), playing double- and triple-stops;

cellos and basses play undivided double-stops (giving the string texture a stronger bass).

Figure 2 - Igor Stravinsky, Le Sacre du Printemp

These two score examples thus require that the string section be divided at various times into

ensembles of 16, 14, 8, 5, 4 and 2 violins, 12, 6 and 4 violas, 10, 5, 3 and 2 cellos, and 8, 3 and 2

basses.

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3. Virtualizing Divided Strings

Two technical issues make accurate virtualization of orchestral string parts with sampling technology

much more complex (and expensive).

1) A full set of samples for every possible articulation AND every possible ensemble size is ideal.

Using full string choir samples for divided strings makes the sound not only louder but

unrealistically “thick” and hard to balance in the orchestra. This would be especially noticeable

in Example 1, with its texture of muted harmonics.

2) The samples for each ensemble must be unique – separate samples for two half-choirs, three

third-choirs, for quarter-choirs, etc. Otherwise, whenever two or more parts play in unison

(rehearsal number 143), with identical sample triggered at exactly the same time, the result

sound is one instrument but 3 dB louder. If the samples are offset a few milliseconds, which is

very likely, the two samples combine to create a multi-bandpass “comb” filter, creating a

distinctly artificial sound that’s actually quieter than a single sample.

Ideally, this example requires 28 unique ensembles:

1st Violins: 16, 8+8 players (i.e. 2 unique ensembles of 8 players each)

2nd Violins: 14, 5+4+4, 2+2+2+2+2+2+2

Violas: 12, 6+6, 4+4+4

Cellos: 10, 5+3+2

Basses: 8, 3+3+2

A sample library with virtually all possible ensemble size for every articulation would be extremely

unwieldy and expensive. The 1st violins would have up 33, not including solo instruments:

16, 15, 14, 13, 12, 11, 10, 9, 8/8, 7/7, 6/6, 5/5/5, 4/4/4/4, 3/3/3/3/3, 2/2/2/2/2/2/2/2

Some libraries provide only full section and solo string samples, often only one set of samples for

both 1st and 2nd violins, with not every articulation or playing style available in every choir.

For example, Hollywood Strings Diamond Edition (East-West/Quantum Leap, MSRP $995) provides

a 57-player string section with half-choir samples only, which are combined to get a full choir. There

are no solo strings:

1st Violins: (16) 9, 7

2nd Violins: (14) 8, 6

Violas: (10) 6, 4

Cellos: (10) 6, 4

Basses: (7) 4, 3

LA Scoring Strings (Audiobro, MSRP $1,399) is one of the largest (24 GB) and most CPU-intensive

library; two dedicated computers are recommended. It provides a 67-player section with samples for

full choir, half choir and two quarter choirs (which are combined two make the other half), plus ten

solo “first chairs”.

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1st Violins: 16, 8, 4, 4, 1

2nd Violins: 16, 8, 4, 4, 1 (derived from 1st violins)

Violas: 12, 6, 3, 3, 1

Cellos: 10, 4, 3, 3, 1

Basses: 8, 4, 2, 2, 1

According to the LASS manual, 2nd violins are “derived From Violins I” and “programmed to avoid

phasing issues”. This provides less depth and variety that separate samples, but it’s an acceptable

compromise, also used in GPO. There’s no accurate way to divide by three without making the

ensemble too large (8+8+8 violins, for example) or too small (4+4+4) and risking unison phasing.

A full-blown option is the massive Vienna Symphonic Library Complete Strings bundle. It comprises

5 separate libraries of different ensemble sizes: Solo Strings, Chamber Strings, Dimension Strings,

Orchestral Strings and Appassionata Strings:

Solo Chamb. Dim. Orch. Appass.

Violins 1 6 8 14 20

Violas 1 4 6 10 14

Cellos 1 3 6 8 12

Basses 1 2 4 6 10

Size* 5 21 32 52 76

*Virtual orchestra size, violin samples used for both violin choirs.

Even at this size (111.4 GB) and cost (MSRP E4,280, ~$5,500), there are issues. There’s only one set

of violin samples. There are no choir divisions at all; Chamber Strings provide approximations of half

choirs, but nothing smaller. None of the sets matches the size of a typical American symphony

orchestra (58-60). Appassionata Strings and Dimension Strings were recorded later under different

circumstances and may not blend perfectly.

A newer, bottom-up approach is the 70 DVZ Strings Library from Audio Impressions (MSRP $1,495).

A large string orchestra of 70 players (18-16-14-12-10), it actually comprises 32 ensembles playing

together: 10 solo, 14 single-desk (2-player) and 8 two-desk (4-player) ensembles. Individual

ensembles can be switched out to form a smaller overall string section. More significantly, it

includes “real-time divisi processing”. There are five channels, one for each string choir. If a choir

has to play more than one note, DVZ intelligently divides the notes among all the players in the choir

in real time.

This works in simple cases, but not always. In the second Stravinsky example, in the bar before #143,

2nd violins and violas are each divided in 3, but part C has double-stops. Thus each note of the four-

note chords is played by 1/3 of the violins. 70 DVZ will instead split them into four parts. And it won’t

work if the parts use different articulations or are playing significantly different material.

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4. Divided Strings with Garritan Personal Composer

When I first heard about Garritan Personal Orchestra, a full orchestra of instruments in one package

for $149, I assumed it was too basic, like a multimedia sound card and not suitable for serious

performance. However, Garritan always pushed the envelope with its libraries, which had much to

do with Gigastudio’s success. When I learned that ensembles could be built up from individual parts,

and that it was available as a download, I bought version 4. After two years, I’m using it more than

ever, still generally satisfied with the sounds and very happy with its programming versatility and

simplicity. It’s not perfect, but it provides an elegant solution to the problem of creating ensembles

of different sizes.

One of GPO’s strongest features is the number of unique solo instruments available, and the ease of

building ensembles by layering up to 16 solo instruments. Each layer can be detuned and placed

anywhere within a stereo field, and pitch and timbre (brightness) can be randomized by an

adjustable amount to give a richer sound.

For each orchestral instrument, using a process not explained in the manual, the sustain samples of

Solo instruments are modified to create additional “Player” parts. The manual warns that Player

instruments “must not be used with the solo instruments from which they are derived, to avoid

phasing problems.”

I decided to test this warning with the violins, recording a 3-octave G Major scale with all four

versions (1 Solo and 3 derived Players) of Violin 1, 2, and 3 onto separate tracks, then mixed them

together into three quartets. Listening carefully to the Solo instruments together with each of the

Players in turn, and to the quartet mixes, I didn’t hear any phasing.

Figure 3 - Tracks top to bottom: violins 1 mix, violin 1 solo, Player 1, Player2, Player 3

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Creating an ensemble of up to 12 instruments is very simple; just load the individual instruments

into 12 channels of the ARIA player and assign them all to the same MIDI channel. A GPO Ensemble

can comprise up to 16 instruments, so some instruments must be duplicated to make a larger

ensemble. To minimize phasing among these duplicate instruments and thicken the texture the way

additional unique instruments would, a small amount of random pitch and timbre variation can be

introduced, using MIDI Controllers #22 and #23, respectively.

Of course, it’s simpler and less CPU-intensive to use a full section instrument instead. Building string

ensembles from multiple layers is more useful for divided string choirs, and very straightforward;

just set the MIDI channel assignments and panning appropriately.

The WinZIP file GPO4_strings_divisi.zip containing ensemble (.aria) files for string choirs

divided in various ways. It may be downloaded from my web site:

http://www.johnmelcher.net/GPO_strings.html

I suggest creating a subdirectory inside your Ensembles directory called “Strings divisi”. By default

(on Windows), this is “C:\Program Files\Garritan\Personal Orchestra 4\Ensembles”.

Violins

GPO provides three unique (and very nice) Solo violin instruments: Gagliano, Stradivari and Guarneri.

Each of these includes six standard articulations, which are “keyswitched” by sending MIDI Note On

messages outside the instrument’s range:

Sustain, open and muted (con sordini)

upbows, downbows, alternate up/downbows

pizzicato

tremolo, open and muted

semitone trills, open and muted

whole-tone trills, open and muted

For each of the three Solo violins, three Player instruments are derived, for a theoretical total of

twelve available violins, or 9 according to the manual. Only the sustain articulations is available for

the Player instruments.

Figure 4 shows the 1st violins divided into three parts, 6-5-5. Instruments 1-6 are set to MIDI channel

1, 7-11 to channel 2, and 12-16 to channel 3. Each of the three parts has a different combination of

the 12 available instruments and is assigned to a unique MIDI channel (1-3). In this case, it’s assumed

that the violins divide by desk (with one exception), so they’re panned in pairs from near center to

far left. The equivalent 2nd Violin ensembles have slightly different combinations of instruments to

give a subtly different timbre, and are panned slightly more toward the center.

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Figure 4 - 1st Violins divided 6-5-5

GPO4_strings_divisi.zip includes several violin combinations:

Violins 1 (16) 8-8, 6-5-5, 4-4-4-4, 2-2-2-2-2-2-2-2

Violins 1 (12) 12, 6-6, 4-4-4, 3-3-3-3, 2-2-2-2-2-2

Violins 2 (16) 8-8, 6-5-5, 4-4-4-4

Violins 2 (12)12, 6-6, 4-4-4, 3-3-3-3

Violas

GPO has only one Solo viola (18th Century, manufacturer unspecified) and three Player variations, so

the largest possible ensemble without duplication is 4 instruments. The best one can do is create

two duplicate ensembles and apply pitch randomization a bit more liberally than for the violins. A

second Solo viola (and 3 derived Players) would be a great help.

GPO4_strings_divisi.zip includes two viola combinations:

Violas (12) 4-4-4

Violas (9) 3-3-3

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Cellos

GPO includes 3 Solo cellos (Vuillaume, Montagnana, Gofriller). There are actually more available

cello instruments available (12) than are usually needed. GPO4_strings_divisi.zip contains

several combinations:

Cellos (12) 12, 6-6, 4-4-4, 3-3-3-3, 2-2-2-2-2-2

Cellos (10) 10, 5-5, 4-3-3

Basses

Interestingly, the GPO manual lists one Double Bass Solo instrument (18th Century, unnamed), along

with a keyswitched version, and the usual three derived Players. However, the regular (unswitched)

version isn’t available when loading instruments. It could be a bug.

To make ensembles of 4 basses the keyswitched instrument has to be included. This should work

okay as long as it’s switched to the default sustained articulation.

GPO4_strings_divisi.zip includes three double-bass combinations:

Basses (8) 4-4, 3-3-2, 2-2-2-2

General Notes

No pitch variation (VAR 1 MIDI CC#21) was added to any ensemble. I think the sound is thick enough

without it. If phasing occurs, it can be easily changed to 5-10 with a single Controller message. If

increased to 15 or more, the effect is similar to amateur orchestra with bad intonation.

Timbre variation (VAR 2) is set to 20 on each voice. Setting it much higher creates an occasional low-

frequency “thump” when changing from one note to another. It can mostly be filtered out during

recording with a high-pass filter set with a very sharp cutoff (24dB/octave or more) at approximately

180 Hz for violins, 120 Hz for violas.

Auto Legato is turned ON. If there are double-stops, turn Auto Legato off and use the Sustain

controller (#64) instead.

Equalization, Stereo Stage and Effects are turned OFF to reduce CPU load. In any case I prefer to

record a stereo mix in Pro Tools and add processing there.

Instruments are panned to imitate a typical orchestra seating plan. For sections divided in two, each

desk divides, so both parts spread across the field; division into 3 or 4 parts is done by desk, so part 1

in near the center, and part 3 or 4 toward the outside, except for basses, which is the reverse.

Not all orchestra follow the seating plan above, and in performance, concert hall acoustics are

designed to blend these instruments so the sound is balanced for all members of the audience.

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Figure 5 - Control settings applied to all instruments

Figure 5 - typical orchestra seating chart

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5. Issues

Sound Quality

The samples themselves are generally excellent, with a few problems. I can hear some background

“grit” in high violin and viola notes, which sounds like compression artifacts. Also, an artificial vibrato

has been added to the Player sounds; it’s obvious when you listen to the low viola C or violin G

(which can only be played on the lowest open string). Generally, ensembles built this way sound

audibly inferior to the section samples. And the high strings sound a little “organ-like” for some

reason.

Velocity Layers

Instruments have a different timbre when played soft or loud; it’s not just volume, and it’s not just

brightness; loud playing makes instruments behave nonlinearly, distorting tone, pitch and volume in

complex ways. A violin sampled only at fortissimo won’t sound like it’s played softly when the

volume is reduced, even with lowpass filtering. The traditional solution has been to sample every

note at multiple dynamic levels, the appropriate sample played back according to MIDI velocity.

Unfortunately, this creates a new problem, because timbre changes between layers can be abrupt.

The worst case is two layers per note, one soft and one loud. If the layers switch between MIDI

velocity 64 and 65, a musical passage with notes that crescendo from velocity 48 to 72 will sound

very bad across the break. It’s possible to interpolate between layers, usually by blending, but it

usually sounds exactly like two instruments playing in unison and works best with larger string

sections.

More velocity layers are added to make the transitions smoother. Good sample libraries usually offer

at least 3-4 levels for standard patches. Usually 4 layers is enough to make breakpoints unnoticeable

in an orchestral texture, though more levels and some tweaking are still required to hide them in

solo passages. This works if every single sample is exactly right. Making such a library is enormously

complicated and exhausting, and prone to errors. Every library has a few “clinkers”, notes where one

or more velocity layers is noticeably too loud, too soft, too bright, out of tune, has a different attack,

etc. And these libraries are proportionately bigger and more expensive, and requiring more

computer resources.

The GPO solution is acceptable but not ideal. There appears to be just one velocity layer, but two

samples per note (the manual doesn’t say). One sample is the sustained note and the other is the

attack. Overall note dynamics (ppp to fff) are controlled by MIDI Modulation (#1), Breath Control

(#2) or Expression (#11), and relative attack volume is controlled by Note On velocity. These control

both volume and timbre (tone). This method eliminates all the rough edges that would occur

between velocity layers, though I hear very little timbre differences at lower dynamic levels. It

sounds to me to be like simple lowpass filtering, optimized for louder playing.

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Completeness

The greatest omission is Player instruments derived from the full key-switched Solo instruments, so

string ensembles can be made for other playing styles. The only workaround is an ensemble with the

three key-switched Solo violins or cellos, duplicating as necessary; you’re out of luck with violas and

basses. Certain articulations are missing entirely; the Stravinsky fragment above requires harmonics.

I’d also like at least two more Solo violas and one more bass, and four Player variations of all Solo

instruments (all key-switched, of course). That would provide 15 violins, 12 violas and cellos and 8

basses for all playing styles. Even better would be to make the “derivation” algorithm real time,

maybe burning into ROM on a processor card or a separate thread on a multi-core CPU, so it could

create 8 or more Player instruments on the fly.

6. An Example

I tested these ensemble files with a short excerpt from a recent orchestral project. The 1st and 2nd

violins and violas are all divided in three parts, cellos and basses in two parts (but only half the

basses play).

An MPEG audio file of this excerpt virtualized with GPO (recorded and mixed with Pro Tools) is

available on my web site: http://www.johnmelcher.net/GPO_strings.html

Figure 6 – excerpt from Third Symphony, 1st

movement