John Harris samples the delights of the latest offering from Akai; the multi-talented S900

It doesn't seem so long ago that we were singing the praises of Akai's S612 6-voice sampler, yet here we are again with the much publicised S900 8-voice polyphonic sampler, retailing incidentally for not much more than the old S612 used to when it first came out. Well that's the fickle marketplace of the recording world for you, and sampling plays such a big part in that world now that we at H&SR were naturally keen to get our sweaty mits on this exciting new product and see exactly what all the fuss was about.

So what are the facts regarding the unit that some reviewers already say has got PPG owners gnashing their teeth and going green with envy? Well, like the S612 the S900 uses a disk drive but whereas in the aforementioned unit, the disk drive and sampler were quite separate, they are now combined in a 3U, nineteen-inch, rack mounting grey box. Disk size has also changed to the 3.5inch type familiar to Prophet 2000 owners. Unfortunately loading time has also changed from the popular quick disk format of the S612 to forty seconds for a full one megabyte disk on the new S900. No problem in the studio of course, but for live work it could have been a hassle if it weren't for the fact that the S900 probably has enough memory for a whole performance.

As most keyboard buffs will undoubtedly be able to tell you, the unit is eight voice polyphonic with eight independant sound outputs and can be triggered via MIDI, or with an optional PCB, by 8 audio inputs. Multiple sampling is possible, with up to 32 different samples. 11.878 seconds sampling time is available at the maximum audio bandwidth of 16kHz, expandable up to 63 seconds at a low bandwidth. In a recording situation the higher bandwidth is certainly able to cope with most things, except perhaps for cymbals and vocals requiring a lot of presence, which tend to need a lot of headroom. Offering a six octave playback range of samples the S900 will respond well to velocity information, pitchbend and modulation, but it also features Positional and/or Velocity crossfade, Warp (an automatic pitch bend particularly useful for brass and distorted guitar samples), Filter, LFO, ADSR, Looping, and reversed playback. And if that isn't enough you can link it up to Akai's own VX90 expander or AX73 synth for external processing via Akai's exclusive Voice Out system although this will negate the advantage of separate outputs. Sounds good so far!

Controls

What impresses most people who have reviewed the Akai is the sheer user friendliness of it. Finding your way round the unit initially is much easier than you expect it to be, partly helped by the fact that there aren't really many controls to deal with. The whole method of changing parameters by selecting a 'page' on the back-lit liquid crystal display and moving a cursor to the required parameter, then making your alteration, will be very familiar to those of you who have used Casio CZ series of synthesisers. But even if you haven't it's quick and easy to understand and use, as you are guided logically step by step through each stage.

The unit has eight functions, and you select which one you want by pressing one of the eight buttons situated underneath the LCD display — they are Play, Rec, Edit Sample, Edit Program, Midi, Utility, Disk and Master Tune. Every function includes several pages, each one covering a specific aspect of that function's operation together with several parameters. These can be changed in two ways, either by typing in a new number with the Parameter keys, which are situated in a grey rectangle beneath the LCD display, or by rotating a large incremental Control knob located to the right of the display. I've often wondered about the Japanese sense of humour, but when the command 'scroll with knob' appeared on the screen I wished I'd been able to sample the hoots of laughter this simple instruction caused. But back to more serious matters. On some pages you are expected to give an On/Off or +/- indication; two buttons are provided for these labelled On/+ and Off/-. The parameter to be altered is selected by moving an arrow to the appropriate position on the LCD display with two buttons labelled Arrow/Cursor (one for clockwise and one for anti-clockwise). In addition there are two buttons (Up and Down) which are dedicated to changing the page only. Sometimes you need to enter letters on the display rather than numbers — when naming samples, for instance — which is done simply by pressing a key marked Letter and rotating the Control knob until the desired letter comes up. If you want a space you can dial one up or press the Space key.

Sampling Made Easy

And it is. Two inputs are provided on the front panel, one mic and one line, together with a record/playback trigger socket for an optional footswitch, the PS-X80. Press Rec and you enter sampling mode. In this function the pages have no numbers as they are always accessed in the same order and are changed by pressing the page up/down buttons. It's so logical you could probably manage to figure out how to do your first sample without consulting the manual at all. The first page asks you to name the sample to be recorded, while the next one down, entitled Monitor, allows you to monitor a previously recorded sample or the straight through signal for tuning purposes. Level for the latter is adjustable via a Monitor level knob. The third page asks you to specify sample type, of which there are three choices: 1. Normal, 2. Velocity Crossfade Soft, and 3. Velocity Crossfade Hard. If Normal is selected then the keys assigned to that sample will play just that one sample, but if you want to introduce dynamics when using a velocity-sensitive keyboard, you can sample a soft sound as 1. and a hard sound as 2. Soft key strikes will produce the soft sample, and hard key strikes will produce the hard sample. At increasing velocity levels in between these two extremes the soft sample becomes quieter whilst the loud sample becomes louder (crossfading). This is excellent for recording any sound sources with dynamics like piano, guitar, cello etc, making them sound realistic and allowing the player a certain amount of expression that is lacking from non-dynamic sampling. Alternatively you could sample two completely different sounds, like the editor of H&SR belching over the Hallelujah chorus (always good for a laugh) which would give an unusual effect. For more serious users bells over strings, brass and xylophone, you're really only limited by your imagination. This crossfading pair of samples is referred to in the Akai S900 and its manual as a Keygroup.

Audio bandwidth can be set from 3kHz to 16kHz, while recording time can be set from 250ms to a maximum which depends on the selected audio bandwidth and how much memory has been used on previous samples, if any. Maximum sample length at full bandwidth is close on twelve seconds, while at 3kHz bandwidth it's just over 63 seconds. To conserve memory for future samples it's best not to have the sample time longer than you need it, although you can edit it afterwards if necessary.

The next page down is for you to enter the pitch of your sample, and this is done by playing the appropriate key on your keyboard. Following on from this is the Select Trigger page which gives you three options for beginning sampling: 1. by pressing any key on the keyboard 2. by pressing a footswitch connected to the footswitch socket on the front panel and 3. when a particular audio threshold is reached (audio triggering). Making your selection moves you on to the next page which contains a bar graph VU meter sideways-on. This is for you to set your recording level (with the Rec Level control). If you selected 3, a letter T indicates the trigger threshold and this can be moved to wherever you want it with the Control knob. Then all you have to do is initiate sampling by hitting a key or the footswitch. While you are making your sample, an arrow on the display moves from left to right to show you how much sampling time you've used.

In practice if you were putting a whole drum kit into the Akai you certainly wouldn't need to have the maximum bandwidth for the bass drum, and you could probably get away with a 13-14kHz sample for snare and toms, it's only hi-hats and cymbals which need the full 16kHz. Also, dependent upon whether you're recording ambient or digital reverb with the sounds, you can have fairly short sample lengths for snare, tom, hi-hat and bass drum sounds. Even with a room sound on, it a snare isn't going to be much more than 500mS. So there's plenty of room for a whole kit and more.

As far as sound quality is concerned the acid test these days seems to be trial by compact disc and the S900 came out with flying colours on this score when recording for twelve seconds at the full bandwidth. Transients were admirably coped with (not always easy for samplers), and I'd be nit-picking to spot any significant difference in sound quality, so the Akai should satisfy the professional recording world as well as the semi-pro users and enthusiasts. Needless to say, at 3kHz the sound is rather muffled, but as the Akai has so much memory I can't honestly see anyone using it at this bandwidth.

Editing

Once you're happy with your sample (checking it is simply a matter of going on to the next page and pressing the Ent key or hitting the Play key) you'll probably want to try editing it. Pressing the Edit Sample button presents you with a series of pages, the first of which invites you to Rename or Delete an existing sample or Copy one sample to another, keeping both in memory. On page 3. the Volume and Pitch of your sample may be adjusted. The next page is concerned with replaying the sample, and there are three options: one shot, where on holding down a key the sample will play through once and then stop; Looping, where the sample will play from the start point to the end point and keep repeating for as long as the key is held down; and alternating where the sample repeats, as above, but plays first forwards, then reversed, then forwards again etc. You can adjust the start point and end points of your sample, the direction (Normal or Reverse) and define the portion to be looped by choosing the L; Length, which in effect moves the start of the section you are looping (not to be confused with your sample start point). As it's quite a time consuming task getting a loop without glitches in it, (clicks caused by abrupt changes in the waveform) there is an Auto function, where the computer picks a hopefully suitable loop length for you, but it's usually necessary to give it several goes before it comes up with one you are happy with. In fact I found the auto-loop a bit disappointing at first, and so I resorted to the human method which the manual rather pompously states is an 'Art and a Science', and while this may sound like a cop-out, it is essentially true that looping is a process which requires skill and effort.

If you find you are running out of memory there are two memory-saving features, Re-sample and Discard. With the first of these you can re-sample the original at half bandwidth, thus using up half as much memory but of course giving you a less bright sound. For many samples this will not be too noticeable, but as re-sampling erases your original it's wise to copy it first. Alternatively Discard will scrap the parts of the sample before your chosen start point and after the end point, this is also irreversible. With the S900 you can also mix samples together (layering) or splice two samples end to end. As splicing is, like looping, difficult to achieve without glitching, they have thoughtfully provided a crossfade option so that you get a smooth changeover, and you are able to dictate the time this takes.

Multi-sampling

Because a sampled acoustic sound will, as a rule, only sound natural within a small transposition range (3 or 4 semitones up or down), to get an instrument such as a piano to sound realistic it becomes necessary to make several samples over a wide range of notes and allot them to the relative points on the keyboard. Alternatively you might want to have your mate's drum kit sampled on the bottom octave of the keyboard (bass drum on C0, snare on C#0, toms on D, D# and E etc.) your friend's bass on C1 to B1, your Hammond organ on C2 to B3, your girlfriend's vocal from C4 to C5, and play the whole lot from a MIDI sequencer! (Who needs a band?) In both these cases you have to enter the exciting (?) world of multisampling, and Akai have decided to call this, the allocation of certain samples to certain notes, a Program.

A Program can consist of up to 32 individual samples or Keygroups (crossfading pairs), and to write your Program you have to select Edit Program with the function buttons. This mode has a mere 16 pages; page one dealing with selecting, copying, re-naming and deleting Programs (you can have up to 32). Page 2. is concerned with the loudness of the notes according to their position on the keyboard as it's possible to make the notes louder or quieter the higher on the keyboard they are. Also on this page is an option for Positional crossfading On/Off which is for when you have overlapped the high range of one sample with the low range of another; when On is selected the lower sample fades out as the higher sample fades in over the range of the overlap. This is very useful when multi-sampling one instrument, as it helps to create a smooth changeover from one sample to the next.

After selecting which Keygroup you want to deal with, the next page asks you if you want Velocity Crossfading, (if you have chosen to have a Soft and Loud pair of samples) which gives a smooth transition from Soft sample to Loud sample as you play softer or harder, or Velocity Switching which provides an abrupt changeover, at a point you specify. If you've selected Velocity Crossfade Off, i.e. Velocity Switching On, playing softly will give the Soft sample, playing hard will give the Hard sample.

The following series of pages deal with assigning the Keygroups to the particular notes on the keyboard. For each sample you specify the lowest and highest key of the range you want to be able to play it over. Soft and Hard samples can be assigned independently. Each sample level can be adjusted with respect to its opposite number, in the case of a Keygroup pair and with respect to other samples allotted to different sections of the keyboard; in other words samples with unequal levels can be evened out without having to go back to the Edit Sample mode; a point of great practical consideration.

The next seven pages are concerned with modifying the sound. Your sample may be transposed (you might have chosen to sample it at the wrong note) and its pitch changed, and a low pass filter is available (you specify the cut-off point). Keyboard tracking of the filter is possible. There is also an envelope generator for the output volume with four adjustable parameters — Attack, Decay, Sustain and Release which help to put dynamics back into looped sounds and can be used for special effects such as giving a guitar a slow attack like a violin. The Note-On velocity can be made to control the Loudness of the sound, the cut-off frequency of the Filter (so that the harder you play, the brighter the sound), and the Attack, which you can set to give you a slow attack when playing soft and a fast attack when playing hard. The Release time (the time taken for the note to die away after releasing a key) can also be controlled by the Note-Off velocity. A feature called 'Warp' adds a pitch shift to the beginning of the note so that you can make it start slightly sharp or flat (you decide which and how much) and glide to normal pitch in a specified time. Warp can also be velocity-dependent. The LFO page gives depth, rate, and delay control over the low frequency oscillator, which modulates the sound, to give a vibrato effect. Each of the S900's voices has its own LFO and these can be synchronised so that all the notes vibrato together, or de-synchronised so that each note has its own vibrato effect. Vibrato depth can be controlled separately via Aftertouch or by a Modulation wheel. The last two pages in this mode are concerned with assigning the Keygroups to MIDI channels and to the audio outputs. Each Keygroup may be assigned to any MIDI channel (Omni mode can be Off or On), and to either the Mix Out jack, or one of the eight Mono outputs, or to the Left or Right Out jacks.

MIDI and Disk

The S900 has fairly extensive MIDI facilities which are accessed by pressing the MIDI function button. These deal with the incoming MIDI information from an external controller such as your MIDI keyboard. Omni mode can be on or off, and the S900 can be made to receive only information from a particular MIDI channel. Page 3. of this function provides a useful monitor of the incoming MIDI information and indicates the MIDI channel that the information is coming in on, the last note played by the MIDI controller, and the velocity of the last note played. On the next page the S900's response to pitch wheel operation can be adjusted from +/-1 semitone to +/-12 semitones. Page 5 deals with switching control of the S900 from MIDI to the RS-232 port included on many home computers, which will at some stage provide computer access to samples as a visual aid to editing.

The disk facilities are pretty all-encompassing, allowing you to load and save samples, or programs with samples, to and from disk, as well as formatting new disks, erasing entire disks, and erasing a sample or a program from disk. The Akai's ability to load individual sounds will prove useful if you are making a compilation set of programs up from studio disks to use live. The error messages are clear and helpful and tell you what you've done wrong in a non-patronising manner — preceded by a cheerful 'OOPS!' When loading, saving and erasing you are told precisely what's going to happen before you enter the function, for instance, instead of just flashing up Load for loading from disk you get 'Clear memory and load entire disk', reminding you that loading a disk will erase whatever you have in the memory at the time — the sort of thing you often don't realise until it's too late, especially if you are new to the world of computers.

Conclusions

User-friendliness is one of the most important advantages of this machine (if only it were so for everything we had to review!). You rarely need to refer to the manual, it's all on the screen where each page helps you by prompting the responses and it really is idiot-proof with no confusing number codes or abbreviations. It's a shame that there aren't more library disks currently available because at the moment the S900 comes with only the Piano and Chopper Bass samples, but apparently moves are already afoot to improve the situation so don't let that put you off.

What will be really appealing to all potential buyers, professional or otherwise, is the fact that the S900 has eight individual voice outputs. In the recording field this puts it up there in the big league with the Emulators and PPG's of this world in terms of versatility. What's more, with the extra PCB you have the option of triggering the voices from sound pads, drum machine voices or whatever as well as via MIDI.

Multi-sampling is not easy to achieve on the Mirage or Prophet but the S900 allows you to do this quite quickly and many excellent effects can be achieved with the Filter, Warp, Velocity and Positional cross-fade facilities. It's a shame there's no dynamic filter envelope though, because further processing involves more financial outlay in the shape of an expander; like the Akai VX90 synth module. If you're not a fan of Akai synths this could prove to be a bit of a bummer. However there are further developments from Akai on the way in the form of a Harmonic Synthesis software package, a Long duration Looping Recorder package, and a Sample Waveform Editing package which will expand the capabilities of the S900.

In terms of sound quality the 16kHz bandwidth is ample for most uses. There's little more to add except that with an asking price of £1699 it's not cheap, but at the same time given the spec, it's remarkably good value for money. I suspect we'll be seeing a lot of them around.

Further information maybe obtained from: Akai (UK) Ltd, (Contact Details).