Review – Strum GS-2 from Applied Acoustic Systems

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AAS has released an upgrade to its already excellent Strum Acoustic and Strum Electric instruments.  Strum GS-2 combines them both with plenty of new capabilities on offer.


by David Baer, July 2015


AAS, the wizards of sound production through mathematical modelling, have upgraded yet another of their instruments, and make no mistake, this is a very significant upgrade.  Upon first glance for those familiar with the predecessor instruments, it might look like this was little more than a consolidation of two earlier instruments with a pretty new interface.  Upon looking closer, however, you will discover much to get excited about.

Strum GS-2 (hereafter just Strum for brevity) offers both acoustic and electric guitar sound production in a single instrument.  It replaces two separate earlier instruments: Strum Acoustic and Strum Electric and consolidates the two flavors of guitars into one tidy package.  We looked in depth at the earlier instruments in a SoundBytes Magazine review appearing in March of 2014.  You can find that article here:

I am not going to spend a lot of time rehashing the same material.  In particular, the information on how authentic guitar playing (strumming, specifically) has been adapted to keyboard input is inspired but somewhat involved.  I suggest you read the earlier review if interested.  Better yet, download the excellent documentation for a thorough explanation.  Also, AAS has several instructional videos that nicely demonstrate what’s involved here.  We will get to the videos in a bit.


The Big Picture

Modelling guitars involves a variety of things being modelled: string characteristics, pick characteristics, hammer-on/pull-off characteristics, palm and mute characteristics.  If the last few terms are not familiar, it’s because they are from the realm of guitar playing technique.  In addition to that just mentioned, Strum has two personalities: acoustic and electric. The other things being modelled depend upon which personality is being represented.  For acoustic, we have body characteristics that are pertinent.  For electric, we have pick-up characteristics.  Further down the line, we also have available effects to consider, but we’ll get to effects later.

Irrespective of the acoustic/electric personality at hand, there are three modes of playing: keyboard, strumming and looping.  These are identical for both personalities.  Here we have some of the significant improvements over the earlier versions of Strum.  To begin with, the strumming capabilities of the original Strum instruments have been brought forward with little or no change.  This is called Guitar Mode.  Again, I encourage readers unfamiliar with how this has been designed to read the earlier review, read the manual or check out the AAS demo videos.  It is inspired, it is clever, and it is too complicated to fully rehash here.

What’s new (and I was so very pleased to see this!) is Keyboard Mode.  In keyboard mode, you just play the notes like you would for any synth or sampler.  Why all the excitement?  It’s because just playing Strum as if it were another keyboard instrument was somewhere between awkward an impossible prior to GS-2.  Now you can use Keyboard Mode for either easily playing lead lines or simply playing transcriptions of favorite keyboard compositions.

The other mode is Loop Mode.  It was somewhat present in the earlier Strums, but not so nearly well developed and powerful.  In Loop mode, every preset has a set of seven MIDI-like loops that can contain strumming patterns.  You may easily switch between the seven patterns with dedicated key switch notes.

We will come back to what the modes offer shortly.  But before we leave this overview, we should look at what else is new.  First, there is the overall look, which has been made consistent with other AAS upgraded instruments and sports an improved browser.  Under the covers, Strum now runs in native 64-bit operation on both Windows and Mac platforms.  Also under the covers, AAS tells us it has completely revised some of the modelling to improve the realism of the tone.  On-board effects complete the upgrade picture and include a new limiter, EQ and compressor capability.


Modes – Guitar (Strumming)

Although Strum Mode remains pretty much what it was before, the UI has a couple of welcome additions.  First, the location of the strumming keys has been doubled, with a series of strumming keys both to the right and to the left of the chord keys, as can been seen in the convenient keyboard map right on the UI in Guitar Mode.



Even better, an easy strumming keys guide is a click away.  This will be invaluable for those new to Strum.  The assignments of the strumming keys were intelligently made, but they are not intuitive and it’s great not to have to break out the manual when learning to play strum in its most guitar-like fashion. 

Guitar mode (and loop mode which is similar but includes auto-playback of strumming patterns) does much to translate the keyboard notes selected into valid and realistic guitar fret patterns.  The results of those calculations can be seen in the display (as seen in the image to the right).  The keyboardist just plays enough notes for Strum to detect what chord is being sought.  Strum turns those notes into bona fide notes you’d hear from a guitarist.

The strumming capability and keyboard-to-fretboard mapping constitute the heart of Strum, and mastery of this instrument’s strumming keyboard technique is what it’s all about to become a Strum virtuoso.  The serious student should plan to spend a number of hours learning the keyboard techniques and then spend even more hours making them become second nature.  Be realistic; this is going to require some work.  However, when you consider that actually learning to play the guitar well would require thousands of hours (and perhaps a fair amount of money for lessons), the fact that an accomplished keyboard player can get to a reasonable level of guitar virtuosity in a few hours is little less than remarkable.


Modes – Keyboard

New to GS-2 is Keyboard Mode.  For the most part, MIDI notes 40 through 93 result in a guitar string pluck sound when the key is depressed.


In this mode, we don’t precisely get a guitar string pluck beginning to end.  If we did, then the timing of the associated note off event would not affect the sound.  A real-world guitar obviously has no note-off event other than a) hand muting the string, something not supported in Keyboard Mode but available in the other two modes, or b) another pluck happening on the same string.  Nevertheless, this approach of forcing a rapid release decay works well in my estimation.  The results are musically pleasant, even if they do not completely reflect reality.

Hammer-on and pull-off is supported in Keyboard Mode.  Hammer-on happens on a guitar when a new note one or two frets above the current one is achieved with the left hand while the right hand does not pluck the string.  Pull-off is similar but the current fret position is abandoned and the new fret position, which is one or two frets down, becomes the current one.  In both cases, we get a new pitch but little or no plucking sound.  To get hammer-on or pull-off in Strum, one simply plays notes that are one or two semitones apart in legato fashion.  The hammer-on or pull-off happens automatically in Keyboard Mode.

As much as I’m pleased to have Keyboard Mode available, I do have a couple of gripes.  The first is that I wish there were a way to turn off hammer-on/pull-off.  It’s great that this feature is supported because it would be next to impossible to get this kind of sound otherwise.  But if you don’t want it, you’re only recourse is to play non-legato, which may not fit the phrasing you’re after.  It would be ideal to have the choice of using or not using the hammer-on/pull-off playing style, or perhaps requiring a MIDI CC when either engaging or defeating it.

The other complaint is that Strum will play no notes lower than MIDI note 40 (E in the second octave below middle C) unless via pitch bend.  Why not give the user a few more notes if needed?  I already actually found one situation where I did in fact need them and had to resort to pitch bend to get them.  Pitch bend allows production of tones up to an octave lower than the E.  At an octave down, things sound pretty dodgy, but a major third down from the low E sounds fine and a fifth down still sounds acceptable.  After all, the sound is produced synthetically.  What harm in giving the player additional options?  I’d very much like at least another fifth or so down into the bass realm.


Modes – Loop

Finally, we have the substantially improved Loop Mode.  The original Strum instruments had a playback capability, but the new loop mode is much more powerful for real-time playing.

An octave of keys provides a key-switch area in which the white keys allow the selection of one of seven loops.  All presets have an associated set of patterns, always seven in number.  The loop pattern is a strumming pattern equivalent to what one might play in real time when operating in Guitar Mode.  The patterns (I’ll just call them loops hereafter) play back synchronized to host tempo.  The names of the loops (as supplied by AAS) have a tempo designation in the names, but this is simply to help find the right style for the job at hand.

One selects the current pattern using one of the assigned keys (see image right).  Two additional keys allow one to mute the current sound or stop the loop playing.

The features don’t stop there.  One can drag the loop and drop it into most DAW sequencers where it becomes MIDI data.  That data may be manipulated in many ways to add or modify characteristics of the original.  An important point to make is this: once the data has been MIDI-ized, you must change the Strum mode to Guitar, which makes complete sense if you think about it briefly.  The following shows a typical strum pattern when dropped into a MIDI editor.  What you see is the strumming octave notes.  It remains the responsibility of the keyboard player to supply chords so the Strum knows what the strumming patterns are to be playing.

You can also create your own loop sets.  There are just a few well-documented rules that need to be followed to do this.  It’s all in the manual.


Creating/Editing Instruments

Thus far we’ve focused mainly on the ways in which Strum can be played.  Serious sound designers may also wish to dig deeper and create their own instruments.  You might expect that the top of the decision tree in instrument creation would be to find a switch that says Acoustic or Electric.  But it doesn’t work like that.  One must start with a preset from either the Acoustic banks or the Electric banks.  Internally, the two personalities have sufficiently different DNA that AAS backed off from the idea of a switch.

The play tab of the acoustic personality is seen in the screen shot at the top of this article.  That of the electric is just above.  The main differences on this tab are which effects are seen.  Only reverb is common to both.  Notably, Electric has the expected accoutrement of Amp, etc.

Most of the work in defining or customizing a preset is done on the Edit page, that of Acoustic appearing below.

The edit page of Electric differs only in the rightmost block, as seen to the right.  I am not going to get into any details here – the specifics of the modelling parameters are thoroughly documented in the manual.

Be aware that there are a completely adequate number of presets included, so only those wishing to get their audio-geek on will worry about building an instrument preset from the ground up.  Some may wish to do minor tweaking, and this is actually quite easy – you do not need to deeply study the documentation, although that never hurts!  Just find a preset that close to the sound you are after and try altering the obvious parameters.  Just be aware that each of the six strings has its own tab, so make sure you’re listening to the string that you are editing.



Lastly let’s briefly visit the Effects tab, seen below.  This tab is identical for Acoustic and Electric.  Some of the controls here are duplicated on the Play tab, which ones depending upon the Acoustic/Electric personality.

These are all very good effects.  Beyond that there’s nothing more that really needs be said.  It’s all standard fare of good quality.


Is Strum for You?

I liked the original Strum instruments, but I’m even more enamored of the current offering.  However, those wishing for a truly authentic acoustic experience may not be quite as enthusiastic.  You’ll have to judge for yourselves.  I think that many of the Electric presets are absolutely convincing.  As for the acoustic presets, I probably would rarely notice that a synthetic instrument was being played unless specifically and carefully listening.  In any case, what one gives up in authenticity is repaid in a clean sound that lacks many of the finger noises of the real thing.  It all depends what you’re looking for.

AAS has supplied two new videos which nicely demonstrate the operation of Strum:


The amazing keyboard wizard Thiago Pinheiro demonstrates Acoustic and Electric in these:

But for all the entertainment value supplied by Mr. Pinheiro, you are probably better served going back to a video made for the earlier Strum Electric as demonstrated by Yves Frulla.  This video shows what is almost certainly to be a more realistic way that most players/producers will want to employ the instrument.  Although the video demos the earlier Electric instrument, just keep in mind that the new version only improves upon its features.

Strum GS-2 is available in all major formats, 32-/64-bit for PC and Mac.  Unfortunately, the introductory pricing period just ended but AAS has the occasional sale, so patience is usually rewarded.  Full price for Strum is $199 USD.  An upgrade from either earlier instrument can be had for $39, a no-brainer price to my way of thinking.

For more information or to purchase Strum, go here:


This Just In

Just as I was putting the final touches on this review, AAS has just announced a summer sale which lasts through 8/31/2015.  Strum GS-2 is available for full purchase for just $89 USD.  In fact all the worthy AAS instruments that normally go for $199 are reduced to $89.  No time to dawdle – these are some seriously good prices.



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