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Yamaha Motif Rack

128-voice Rackmount Synth
Published June 2003
By Nick Magnus

Yamaha Motif Rack.Photo: Mark Ewing

It seems simple enough — take the successful Motif workstation, remove the keyboard, and release it as a more affordable rack unit. But there's lots more to the Motif Rack than meets the eye...

As the owner of a studio best described as compact and bijou, I have always applauded the practice of repackaging synthesizers and other keyboard instruments into space-saving rack modules — and latterly, zero-mass software! In many cases, it can be some time after the release of the original keyboard version until the rack module makes an appearance — time enough for the manufacturer to gauge the success of the original instrument, and thus infer a viable market for a module. Yamaha claim on their web site that a modular version of the Motif has been their most-requested product — so, one-and-a-half years after the release of the acclaimed Motif 6, 7 and 8 workstations, the Motif Rack is born.

The Motif 7 was reviewed in depth by Derek Johnson and Debbie Poyser in SOS September 2001, so I recommend referring to this for a detailed description of the Motif synthesis engine and other features. The Motif Rack can essentially be described as 'the sound of the Motif in a box' — however, there are some significant functional and feature differences between the keyboard and rack versions.

Leitmotif

The Motif Rack is a 1U rack, measuring 35cm in depth. The front silver-and-blue liveried panel hosts the 20 buttons, rotary encoder dial and 160x64 backlit LCD display that control the synth within. A master volume control, headphone socket and power switch complete the line-up. Round the back we find the usual wall-wart power connection and MIDI In/Out/Thru. There are six analogue outputs (a stereo Master plus four assignables), S/PDIF and optical digital outputs as standard, and a USB connector.

Anyone familiar with the numerous controls on the Motif keyboards may be wondering how on earth all of its features can be condensed down to 20 buttons and a dial. Obviously the control faders and knobs of the keyboard are absent, as are the (redundant) master keyboard controls. Two other principal features of the keyboard versions are also missing from the Motif Rack. Firstly, the Motif Rack has no onboard sampling, nor is there any facility for importing samples — hence no internal sample RAM. Secondly, there is no onboard sequencer — the Motif Rack is purely a tone generator. The Motif synth engine has nevertheless not been compromised in any way as a result of these omissions — if anything, it has been given a shot of steroids

What's New?

The basic Voice structure remains the same — AWM2 (ie. sample-based) waveforms, four AWM2 elements per Voice with subtractive synthesis, each element having ADDSR envelopes for Amp, and HADDSRs for both Filter and Pitch, 20 filter types (six low-pass filters, two high-pass filters, four band-pass filters, one notch filter — or band-elimination filter, as it is called here — and seven dual filters) and one LFO. The major enhancement here is a polyphony of 128 voices, as opposed to the Motif's 62. The effects have also been upgraded to Business Class; the Global effects now boast eight new reverb algorithms (totalling 20) and there are 44 chorus options, which include a selection of 25 reverb/delays and 19 chorus-type effects (see the 'Rack Vs Keyboard Versions' box below). The two Insert effects have also had a makeover — each Insert now has a range of 107 effects to choose from, whereas the Motif had 25 for Insert 1 and 104 for Insert 2. The number of Preset Voices has been upped from three banks to five — each with 128 Presets, totalling 640. There are now two user-programmable banks of 128 instead of one, and even the outputs have been augmented to a total of six — one master stereo pair and four assignables.

Due to the absence of an onboard sequencer, the Motif Keyboards' Performance and sequencer Song modes are now represented on the Motif Rack by a Multi mode. This actually handles both of the latter modes in one. You can either dial up a Multi directly from the User bank, or you can access a preset 'library' of Multis. On the review model, this library contains 124 configurations, arranged into two Banks. Bank 1 consists of 59 Performance-type Multis — ie. up to four velocity and keyrange-scaleable parts, all receiving on one fixed MIDI channel, thus making complex layered sounds, some with a drum groove at the lower end of the keyboard overlapping with a pad in the middle and a lead sound at the top. Bank 2 contains 65 Multi-type presets, or 16-part multitimbral configurations, for use with a sequencer. Setups for a variety of musical genres are available here; if you wish, you can simply select the library preset closest to your requirements, then copy it to the temporary buffer. From here you can edit it out of all recognition if you desire, then save it to the Multi User bank.

The Arpeggiator remains basically the same as on the original Motif, save for the absence of a User bank — so no bespoke patterns can be created. Nevertheless, fans of Philip Glass will have a whale of a time with the 256 patterns on offer — especially the chordal types. There are various ways to manipulate the patterns; notes can be sorted in the order in which they are played, key velocity can be acknowledged or ignored, and key and velocity ranges can be set. The velocity range is especially useful — if you set the arpeggiator to engage above a certain point, say velocity 120, then any notes played below that threshold will play the voice as normal. In this way you could play an acoustic guitar melody, then hit a chord hard for an instant flamenco flourish — olé! Unlike the Motif, the Motif Rack transmits its arpeggiations from the MIDI Out port, enabling you to arpeggiate any external synth, or to record the arpeggios into a sequencer. My only wish would be that you could have more than one instance of the arpeggiator in a Multi — unfortunately it can only be assigned to one Part, but this is exactly when the ability to record the arpeggio's output to a sequencer should come in very handy indeed.

Expandability

Although the Motif Rack lacks the sampler functions of the keyboard Motifs, it still retains the option to install plug-in boards from Yamaha's PLG range. These plug-ins offer different types of synthesis — analogue modelling, FM and acoustic physical modelling, for example. Not only do they add a complete new instrument to the Motif Rack, they also add their own polyphony and effects — meaning the Motif Rack's own engine is augmented, not compromised. See the 'Plug-In Boards' box for a list of the boards currently suitable for the Motif Rack. Whereas the keyboard Motifs can accommodate three such plug-in boards, the Motif Rack can only take two, due to the obvious size restrictions. The Presets for these boards are already in the Motif Rack's OS, so the sounds are ready to roll from the moment you install a board.

Software Bundle

The Motif Rack ships with a CD containing audio demos of the PLG plug-ins, plus various application softwares. As well as the requisite Yamaha USB drivers, there are various voice editors — Voice Editor for Motif Rack, editors for each of the PLG plug-ins, and a sequencer, SQ01. Of these, the voice editor and SQ01 sequencer are of particular interest here. The Motif Rack's 160x64 display and 20 buttons, while not too painfully minimalist, are about as economical as they could be without being obstructive. The software editor therefore comes as a welcome bonus, and it was a simple matter to install the USB drivers and software. The voice editor is well-thought-out and very intuitive, making deep-level voice-editing of Motif Rack sounds a relative doddle. Sadly you cannot edit Multis in this program, which means you must endure a certain amount of cursoring and dialling. Nevertheless, you can download the entire voice contents of the Motif Rack to your computer, edit and rearrange the voices, save them, edit effects and so on. There's also an integral librarian function, so all your sounds can be archived to your hard drive.

SQ01 deserves a special mention too — it is a fully functional MIDI + Audio sequencer, and while it may not exactly be Sonar or Cubase SX, I was surprised at the extent of the facilities it offers for a free program. Certainly it would be a great help for anyone starting out on a limited budget who wants to get into some serious Motif Rack action while waiting for the funds to accrue towards a sequencer upgrade. The bad news is that SQ01 is only available for Windows...

For a 1U rack, the Motif Rack offers a decent number of outputs (one main stereo pair plus four mono assignable outs), plus the MIDI and USB connectors.For a 1U rack, the Motif Rack offers a decent number of outputs (one main stereo pair plus four mono assignable outs), plus the MIDI and USB connectors.Photo: Mark Ewing

Ulterior Motif

Editing without the software editor can be fairly slow — there's a lot of cursoring to be done, and the rotary dial can sometimes be annoyingly slow when going from one parameter extreme to the other. An Undo facility would help when you're experimenting with values — my dialling finger would certainly agree. Some voice parameters are perhaps not as detailed as on other synths — others more so. For example, each element has only one LFO, with a choice of only three waveforms, and the LFO delay time is combined into one parameter with the fade-in time. By comparison, Roland's XV synth tones have two LFOs, each with 11 waveforms, separate LFO delay and fade, and four fade modes. That said, the Motif Rack voice has 20 filter types as opposed to the Roland's six, not to mention a global Common LFO that enjoys 13 waveforms, and the Motif's amplifier and filter keyboard scaling is blessed with four adjustable breakpoints — very nice — in contrast to the Roland's linear slope.

There are a few other editing issues: there is no means of editing two or more elements simultaneously, and you can't copy the settings of one element to another within the Temp Edit buffer. This is true even when editing from your computer. You can copy elements from already saved voices, but each time you want to copy an element, you have to save the sound you're editing before you've finished, which isn't too sensible. In Multi mode, you can make some basic 'offset' type edits to voices while they are in situ within the Multi, but you don't have access to fully detailed, individual element parameters.

The amount of reverb and chorus applied to a Voice is global — in other words, there is no individual send level for each Voice element. Although up to four Insert effects can be used per Multi, they must have been programmed into the relevant Voices first. While this is not as flexible as on some other synths, the quality of the effects is consistently first class.

One disturbing thing came to light whilst constructing a test multitimbral piece in Sonar — the Motif Rack exhibited some conspicuous timing problems when playing a simple six-part tune. Initially, I thought it was due to the Motif being sluggish to respond over its MIDI ports, but the problem persisted, even when I banished MIDI in favour of the USB port. Loading the same song into SQ01 produced the same timing errors. In order to confirm there was no problem within the sequencers, I copied the drum part to an adjacent track, and routed it to a completely different synth module. This played the drum part back perfectly in time — while the duplicate Motif Rack drum part stumbled conspicuously, and was noticeably late in triggering. In order to get some idea of exactly how much, I recorded an audio snippet of the twin drum parts and inspected the waveform at a high zoom factor. The results showed an average discrepancy of around 1800 samples — ie. 40 milliseconds at 44.1kHz sample rate (the sequence was at 86bpm). Mindful of the fact that sequencers prioritise the scanning of tracks in numerical order (the Motif drums were on track 10, according to their default MIDI channel) I moved both drum tracks to the top of the track list. The problem was slightly ameliorated, but there was still a distinct flamming between the part from the Motif and the one from the other module, more than would otherwise be expected from 'normal' MIDI-timing discrepancies. This time, the delay measured on average 400 samples, which translates into around nine milliseconds — better, but still perceptable. This is a potentially serious problem for a multitimbral synth.

Conclusion

As a performance synth, the Motif Rack is a fine-sounding machine, made all the more attractive by the option to add plug-in synth boards. The sounds it produces cover a vast palette of musical genres, and are well-suited to meet the increasing demand for an all-purpose synth that can tackle pretty much any style of music. However, as a multitimbral workstation module, the Motif Rack fared less well at the time of this review due to the timing problems reported above. Yamaha were made aware of this problem, and at the time of going to press were trying to nail it down and see if it was something that could be resolved with a software upgrade, as opposed to a more serious hardware-based problem. Depending on what they find, UK customers may have the benefit, as the Motif Rack was about to start shipping in the UK when Yamaha found out about the problem, and the release has been delayed at the time of writing. As we went to press, Yamaha had the following to say on the subject: "To date, we're unaware of any problematic issues relating to Motif Rack, however thanks to the diligence of the Sound On Sound team we're taking steps to fully investigate this situation, and will be able to respond shortly. Unfortunately, because of the deadlines involved with this issue, we cannot make a full statement, but will of course do so before the product ships within the UK market. For any updates and news, please keep an eye on the SOS web site, where you'll be the first to hear the latest."

I really do like the Motif Rack as a synth, so the altruist in me feels compelled to find some way to make it workable as it is. If you used the Motif Rack as your sole sound source, and adopted the practice of assigning any timing-critical parts to the lowest possible track numbers (ie. to the top of the list) then the timing issues might be considered negligible. However, I'm duty-bound to point out that the discrepancies begin to show up when the Motif Rack is part of a larger MIDI setup, in which context it is, after all, likely to be used — so this is clearly an issue which has to be resolved at the earliest opportunity. Taking the optimistic view that a solution is possible, I'll round up by saying that, given the choice of similarly priced (and cheaper) alternatives now available in the sample-based, multitimbral synth module arena, it is the additional sonic potential of those plug-in boards that is most likely to sway potential buyers in favour of the Motif Rack.

Motif Rack OS version reviewed: v1.01.

Rack vs Keyboard Versions

MODEL

Keys

Onboard sampling

Onboard sequencer

Polyphony

Plug-in slots

Smart Media storage

USB

SCSI

S/PDIF & optical digital out

AIEB2/mLAN8E card slot

Backlit LCD

Arpeggios via MIDI

Custom user arpeggios

Global effects

Insert effects

Preset voices

User voices

Analogue outputs

Audio inputs

MOTIF RACK

None!

No

No

128

Two

No

Yes

No

Yes

No

160 x 64

Yes

No

20 reverb, 44 chorus**

107 + 107*

128 x 5

128 x 2

Stereo + 4 assignable

None Two

MOTIF 6, 7, 8

61, 76, 88

Yes

Yes

62

Three

Yes

Yes

Yes

Yes

Yes

240 x 64

No

128

12 reverb, 25 chorus

25 + 104

128 x 3

128

Stereo + 2 assignable

None Two

* up to four parts can
use their own Insert
effects (as programmed
for the relevant Voices)
in a Multi.

** chorus options
actually include
25 reverbs/delays
along with
the 19 choruses.

 

Plug-in Boards

The modular plug-in boards currently available for the Motif Rack are:

  •  PLG150 AN (analogue modelling).
  •  PLG150 PF (pianos).
  •  PLG150 DX (FM synthesis).
  •  PLG150 VL (virtual acoustic modelling).
  •  PLG150 DR (AWM2 sample-based drums with dedicated effects).
  •  PLG150 PC (AWM2 sample-based percussion with dedicated effects).
  •  PLG100 XG (multi-part XG/GM synth).

One Of Our Options Is Missing

Since Yamaha have been championing the mLAN cause by fitting the Motif 6/7/8 with a slot for an optional mLAN8E board, it's interesting to note that they have omitted this option from the Motif Rack — especially in view of the recent launch at Frankfurt of the mLAN-equipped 01X Production Studio. As we know, mLAN is supposed to be able to cope with many hundreds of MIDI channels and up to 128 channels of audio down one cable, and while this may be more relevant to the Motif 6/7/8 (with its integrated sampling sequencer), surely it would also be a useful feature on the Motif Rack? Particularly since the 01X can also function not only as an audio mixer but as a complete MIDI control surface — which could naturally be used to extend the performance potential of the Motif Rack.

At present, it's not too clear when or whether other manufacturers will embrace mLAN (much less stick to the same set of rules...), so maybe Yamaha are biding their time until they release the next incarnation of the Motif.

Published June 2003