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Kurzweil SP7 Grand

Stage Piano By Gordon Reid
Published September 2023

Kurzweil SP7 Grand

Kurzweil’s new stage piano makes the case for simplicity as a virtue.

There was a time when almost all electronic stage pianos were horrid affairs capable of generating a small range of sounds that sounded nothing like their namesakes. Then Kurzweil changed the landscape forever with the sample‑based piano in their K250. Soon after, the market was awash with digital pianos from the likes of Roland, Kawai, Korg and Yamaha. A decade or so later, workstations got in on the act and, while early attempts lacked the quality of dedicated instruments, this changed in the 21st Century, and the choice of keyboards offering high‑quality acoustic and electro‑acoustic piano emulations is now extensive.

Throughout all of this, Kurzweil held their heads high. Following on the heels of the K250 plus its K1x00 spin‑offs, VAST synthesis appeared in 1991 and, for more than 30 years, almost all of Kurzweil’s synths and pianos were based upon this. Indeed, recent Kurzweil pianos such as the Artis (SOS May 2014) and Forte (SOS November 2015) offered access to the full VAST synthesis engine including its KB3 organ extension. But last year, the company announced a pair of 88‑key stage pianos — the SP7 and SP7 Grand — based upon a hugely simplified sound generator that they call ATST (Authentic Timbre Synthesis Technology).

You probably want to know what the differences between the two models are and, to my surprise, there are not many; the Grand sitting beside me has a metal case that makes it feel more robust than the plastic SP7, it uses a Fatar rather than a Medeli keybed, it boasts a 7‑inch touch‑sensitive screen rather that the cheaper model’s 4.3‑inch screen, and it’s black not white. In the other direction, the SP7 has four cursor buttons and an Enter key deemed superfluous on the Grand. Then there’s the... umm, well... no, there’s not. As far as I can see, those are the only differences between the two models, so the rest of this review is applicable to both.

Introducing ATST

ATST itself draws upon Kurzweil’s huge sample library but, instead of allowing you to edit and control everything you can think of (and some things that you probably haven’t) it offers a selection of preset sounds that you can tweak to taste. It has also dispensed with the common Patch/Multi architecture and replaced it with a single programming environment called Sound Mode, which is, in essence, a 16‑part multi‑timbral... umm, Multi. A number of manufacturers have dabbled with this approach in recent years and I wish that they would stop — it doesn’t make it easier to understand or program an instrument, and I would venture that it makes it less so.

You can place up to 16 presets in a given Sound. Each occupies a Zone with its own key and velocity ranges so that you can create complex multi‑timbral setups as well as lush layers. The presets are drawn from 14 categories: pianos, e‑pianos, organs, brass and so on, plus a User category into which you can save your own tweaks. Unfortunately, there’s no way to create categories into which you can, for example, save Sounds for specific projects.

Much of the Zone editing is aimed at performance; for example, you can select the destination and value range of each physical controller for each of the Zones. The choice of destinations looks impressive but, as I later discovered, it’s far less flexible than I had assumed and it lacks many capabilities that I had expected. You can also modify the presets themselves, although the range of parameters is tiny: velocity response, a simple ADR contour generator, a filter with controls for cutoff frequency and a mild resonance, vibrato, portamento, fine‑tuning and pitch‑bend. You mix the Zones using the Channel Mixer, and this provides access to the pan and volume for each preset as well as its sends for the four insert effect busses and the main chorus/delay and reverb effects. Unfortunately, the manual offers neither a full description nor a block diagram of the effects architecture, so I fear that (like me) you’ll have to experiment to find out what’s happening.

Each insert effect bus offers four pre‑defined slots — dynamics, EQ, modulation/wah, and delay/tremolo — that can host your choice from 21 editable effects algorithms. You can only pass the sound from a given Zone down one bus at a time so you can’t use the modulations slots in two busses to apply (say) phasing and flanging to the same sound. But, despite the limitations, you can obtain some pleasing results. There’s also a four‑slot auxiliary effects section that, in my view, should be named the Master Effects section. You can determine whether or not each Zone and the output from each effect bus is passed through this, at what level, and how the delay, chorus, reverb and EQ within it interact.

To spice things up a bit, there are eight latchable arpeggiators that can act in the traditional fashion or as simple step sequencers. If the former, three modes, three tempo ratios, four swing settings, four gate times and two velocity modes are provided, and you can also determine the range of notes within which the arpeggio will be played. Alternatively, you can use the step‑sequencer grid to program patterns of up to 32 steps. In addition to the type of event occurring on each step, you can choose which note in a held chord is affected, and define its pitch and velocity. Although it’s quite a simple system, some impressive results — including rhythms and accompaniments — can be obtained.

In Use

It didn’t take me long to get to grips with the Grand once I had worked out its effects structure. The touch‑sensitive screen was a large part of the quick learning curve; in general, its menus are well designed and, although some of the icons are grouped rather closely, selecting the wrong one became relatively rare once I had discovered that you have to touch them slightly above where they appear on the screen.

In contrast, I must admit that I didn’t much like its Fatar TP/110 keybed, although switching the action from the factory default to a lighter one and tweaking the velocity responses of some of the sounds was a significant improvement for many of the piano and e‑piano presets. But I never fully made friends with it. Let me explain... In addition to all of its other non‑piano sounds, the Grand includes a selection of drum kits, but I found it hard to play these rapidly without missing beats. Of course, a piano keyboard isn’t ideal for organ swipes and synth soloing either, reinforcing the view that Kurzweil see the Grand as a digital piano with bonus sounds rather than an as all‑encompassing keyboard.

The SP7 Grand weighs 16.3kg and measures 132 x 37 x 12cm.The SP7 Grand weighs 16.3kg and measures 132 x 37 x 12cm.

A small, programmable joystick takes care of pitch‑bend and modulation duties. I have no gripe about this choice of controller because omitting a performance panel to the left of the keybed helps to keep the instrument manageable, but it’s not ideal for some performance purposes. Another thing that bothered me slightly was the choice of three toggle switches to control the audio inputs (see box). These look and feel incongruous and I can’t say that I’m a fan. But these are minor quibbles compared with the omission of aftertouch, which is becoming far too common on expensive instruments. Sure, it would be an irrelevance on a dedicated piano, but the Grand offers all manner of additional sounds that would benefit from it.

Polyphony is a generous 256 voices although, unlike previous Kurzweil pianos that included the KB3 engine, its sample‑based organ sounds eat into this when you use them. And, in common with all keyboards that offer Multi modes, layering presets reduces the polyphony proportionally.

Given the reduced range of sounds on offer, the Grand’s ROM is significantly smaller than that of other modern Kurzweils, although I was surprised by the scale of the reduction — just 2GB here versus the 4.5GB of the K2700 workstation and the 16GB of the Forte. Clearly, its library comprises a lot fewer or shorter samples (or both), especially since Kurzweil claim higher resolution in the Grand. Having said that, the specification suggests that the higher resolution is used in the maths of the filter rather than in the storage of the underlying PCMs, so who knows what’s going on?

There are 301 factory programs and 512 Multis (the company’s terminology is not wholly consistent) with 128 User memories and 128 slots for Favourites. This seems rather parsimonious given the cost of memory in 2023, so it’s just as well that there’s an editor/librarian in preparation. I would have liked to have included a few screen grabs of this but it was still unavailable at the time of writing.

I started my audio tests with the grand pianos and, if I’m honest, I wasn’t a fan of these when I first played them because they sounded rather flat and uninspiring by modern standards. So I set about hunting for a reason and soon found it; both the string resonance and damper resonance are defeated in the factory settings. Switching these on and adjusting them to suitable values added depth, warmth and playability, and I was much happier. Had I invested in a half‑damper pedal, I would no doubt have been happier still. Nonetheless, as on the K2700, which supplied the flagship pianos for the Grand, they weren’t entirely to my taste. They can sound great when playing rapid, percussive passages, but for slower — dare I say it, romantic — compositions they lack the deep, rolling bottom end of my favourite grand pianos and their best emulations.

I then tested the electric pianos. The underlying tones of many of these were nice, but the velocity transitions could be quite brutal in some of the key ranges of some of the presets. So I moved onto the Clavis and harpsichords and encountered uneven sampling (meaning that the tone of one key could be somewhat different from that of an adjacent one) in addition to velocity switching. Many of the strings also exhibited audible velocity transitions, as did... well, I don’t need to belabour the point further. Of course, velocity switching and uneven mapping are far from unique to the Grand, and you’ll encounter them on almost every PCM‑based instrument. But whereas some modern synths and workstations allow you to ameliorate any adverse effects using facilities such as velocity crossfading, ATST does not.

I moved on to the organs to see whether a small selection of sample‑based sounds could replace the KB3 organs of other Kurzweils. I started playing — hmm... not too bad, I thought — and was comfortable with the lack of any means to alter the registration because that’s the nature of the beast. But then I tried to change the speed of the rotary speaker effect. Then I tried some more. It didn’t occur to me that this wasn’t possible so I checked every page in the menus and every page in the manual but eventually had to concede that it’s not possible. You can program the effect to be fast or slow in any given preset, but you can’t switch between speeds. This renders the rock/pop organs almost useless for me. Unfortunately, there’s nothing in Kurzweil’s blurb to suggest that KB3 (or a modern equivalent) will be reinstated in the Grand, nor is there the top‑panel hardware to support it.

Having discovered the limitation with the Leslie emulation, I checked whether any of the other effects allow real‑time control. Unfortunately, none of the parameters within the insert effects can be assigned as controller destinations. You can only affect their output volumes, pans, and send levels to the master chorus/delay and reverb. I was surprised.

Unfortunately, I also experienced some operational glitches while conducting these tests. In no particular order, these included a locked screen and locked editing controls when modifying the effects on a 12‑string guitar preset (the only cure for which was a power cycle), a sitar preset that suddenly developed a noise like a helicopter behind it (a factory reset was needed to eliminate this) and a short but deafening burst of digital hash that I thought was going to blow my tweeters when I was editing the aux effects. In addition I noticed that, when you select a new Sound with the damper depressed, the Grand maintains the existing Sound until you release the pedal (which is good) but that, if you’re still playing when you release the pedal, there’s a glitch. (I’m guessing this is caused by the effects processors reinitialising.) A quick check showed that the review unit was running the current OS, so I couldn’t blame any of this on pre‑release software. Nonetheless, I started to wonder if the Grand had been rushed out before all of the wrinkles had been ironed out. Whether it has or not, I hope that these prove to be transient problems that will be eliminated in the update that Kurzweil assure us is forthcoming.

Something else that needs addressing is the lack of MIDI editing. You can determine whether each Zone transmits to the local sound generator or over MIDI or both, but that’s all. You can’t even change the MIDI channel number: Zone 1 is always MIDI channel 1, Zone 2 is MIDI channel 2, and so on. What’s more, if a Zone is transmitting to the outside world, it always sends Program Change messages when you scroll between Sounds or insert a new preset, which is infuriating. Similarly, you can’t program some Zones to receive sustain pedal or expression messages and others to ignore them... and so it goes.

Despite all of its shortcomings, playing the Grand can still be quite rewarding. It’s relatively straightforward to insert the presets you want into a given Sound then tweak them to taste.

Despite all of its shortcomings, playing the Grand can still be quite rewarding. It’s relatively straightforward to insert the presets you want into a given Sound then tweak them to taste. Having done so, the eight Zone buttons mute and unmute the first eight Zones so you can activate or defeat the presets at the touch of a button, whether to add layers or to replace one sound with another as you play. (Unfortunately, there’s no Shift key that might allow you to control all 16 Zones at any given time.) Behind these, eight knobs provide coarse control over the global EQ as well as the time constants and levels of both of the master effects. Consequently, I could see the Grand being wheeled out at festivals for bands that need pianos with (maybe) a bit of strings or something of that ilk, but it faces serious competition in that arena.

Finally, there’s the question of the price. At around £2000$2000, the Grand occupies the same range as instruments such as the Roland RD‑2000 and Yamaha CP88. But the price comparison that may be the most telling is with Kurzweil’s own K2700 workstation, which, for not much more wonga, offers much more of... well, everything. Capable of creating all of the Grand’s sounds and a gazillion others, the K2700 is vastly (on this occasion, pun intended) better value so, as far as I can see, the only justification for the Grand is its simplicity. Whether you view that as a boon or a shortcoming is, of course, up to you.


I have huge affection for Kurzweils and, even today, I use my K1000 racks and K2500 for some sounds that are simply nicer than the equivalents produced by my other synths. But, after a few weeks with the Grand, I still couldn’t think what it would replace or where it would sit in either my studio or my live rigs. So why does it exist? I can only conclude that the powers‑that‑be at Kurzweil believe that there’s an untapped market of (primarily piano) players who don’t want to edit in any depth and simply want access to a library of bread and butter Kurzweil sounds. They may be right, but I think that they will have to sort out a number of shortcomings and teething problems if it’s to be a success.

The Rear Panel

Kurzweil SP7 Grand

As befits a stage piano, the rear panel is not particularly dense. It begins with dual audio inputs that accept both XLR and quarter‑inch plugs and feed the audio input mixer, input effects and vocal processor. Next to these you’ll find quarter‑inch main and quarter‑inch monitor output pairs, and a quarter‑inch headphone output. There are three pedal control inputs: two switches that default to sustain and sostenuto, and also offer half‑pedalling if you buy a suitable pedal, plus a volume pedal. An SD card slot is provided for updating the firmware, and a USB port (which can also be used for updates) carries both MIDI and bidirectional stereo, 24‑bit/48kHz audio. Audio received from a Mac or PC can be passed through the effects and returned to the computer in real time.

Traditional 5‑pin MIDI in and out sockets (but no thru) are provided, and the final hole is for the output from the external DC power supply. Inevitably, I’m not happy with the use of an external PSU; having one hang off the back of a £2000$2000 instrument designed for stage use is a surprising choice, especially since there’s no cable restraint for the barrel plug. What’s more, the PSU delivers 2.5A at 15V, so it’s unlikely to be something that you’ll be able to replace at the local electrical store if you forget yours at home on the afternoon of a gig.

Vocal Processing

The Grand offers two audio input channels that allow you to mix and process external sources, either for keyboard karaoke or to add vocals to your performances. You could even use them to turn the keyboard into a three‑channel mixer for small performances.

Each channel offers a useful range of input effects including gating, dynamics, rumble filtering, EQ, modulation, delay and tremolo. The output from each can also be passed through the instrument’s chorus/delay and reverb processors. But perhaps the most powerful facilities that you can apply to any external audio are pitch correction and four‑part harmony generation. There’s a lot of flexibility here, with formant shifting (emphasising male or female vocal qualities), pitch transition smoothing, delayed vibrato, and all manner of harmonisation including major and various minor keys, 10 voicing variations, humanisation (slight pitch inaccuracies in the generated voices) and portamento. The output quality is also rather good, so there’s a lot to like.

However — and this is a huge however — there doesn’t appear to be any way to make the harmonisation follow what you’re playing so, for example, harmonies in C melodic minor at the start of a song remain in C melodic minor no matter how it develops. This renders the harmony generation almost useless. One sensible way to correct this would be to define a Zone that controls the vocal processing, so we can only hope that this (or something similar) is in the pipeline for a future revision.


  • Its simplicity may be attractive to players who don’t want to delve deeply into sound design.
  • Editing on the Grand’s 7‑inch screen is fast and simple.
  • Like all Kurzweils, it can sound very nice...


  • ... but it can suffer from audible velocity switching and sample inconsistencies across the keyboard.
  • Important MIDI editing facilities are conspicuous by their absence.
  • You can’t use the performance controls to modify any parameters within the effect units.
  • You can’t control the key or scale of the vocal harmonising.
  • No aftertouch.
  • There are operational glitches that suggest that an OS update is needed.
  • It uses an external power supply.


Despite being a product of one of the most loved and highly respected brands in the keyboard world, I have a feeling that the SP7 Grand may have missed the mark. It will be interesting to see how it develops, as I feel it must.


£2280 including VAT.

Sound Service MSL +44 (0)207 118 0133.


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