Polyphonic MIDI Sound Sampler
A real advance in the field of accessible polyphonic sound sampling. Tim Goodyer finds out if the 612's beauty is more than price-tag-deep.
The first affordable polyphonic MIDI sampler comes from synth newcomers Akai. But as our tests have shown, their lack of a music pedigree has had no effect on the machine's operational success.
Up until a couple of months ago, the art of sampling and manipulating sound was pretty much restricted to those with either outrageously expensive systems such as the Fairlight CMI, or personal computer systems - such as the Apple-based Greengate DS3 - that had ownership of some sort of home micro as a prerequisite to their use. With the notable exception of the Powertran MCS1, there was no product that attempted to offer a sampling facility to the keyboard player of modest means who already had an existing synth set-up. But then came the Frankfurt show in February, and the astonishing revelation that Akai, a giant of an industrial organisation but scarcely anything more than a newcomer to the world of music, were about to introduce a MIDI Digital Sampler that looked like being the answer to many a modern keyboard player's dreams.
The machine in question? The Akai S612, a six-voice, 2U-high 19" rackmounting unit, designed for external control by a MIDI keyboard or sequencer and offering a facility for saving sound samples using the company's own 'Q-disk' system, though more about that later.
We now know the S612 uses 12-bit sampling, has a playback frequency response of 25Hz to 20KHz, and has a comprehensive specification that allows pretty extensive control over the sample once it's been stored. Adjustable parameters include start and end points, overdubbing and sample looping.
Rumour has it that the 612's internals have more in common with a couple of pre-existing sampling machines than its manufacturers might be willing to admit. Remember a year or so back, when Syco Systems were selling quaint little sampling boxes with names like 'Instant Replay'? Well, the company that designed and manufactured the Instant Replay (and its more expensive brother, the Super Replay), US-based Electro-Harmonix, recently got into a spot of terminal financial trouble, leaving Akai to burst in on the scene and purchase the rights to manufacture the Replay circuitry. Which would explain the 612's remarkably short gestation period (from vague rumour to pre-production prototype in less time than it takes to boil a kettle - well, almost).
By a strange quirk of fate, 'pre-production prototype' is exactly the term I'd use to describe the state of E&MM's review model (which is why I've just used it), because although its front panel looked positively scintillating, a quick look at the back revealed a decidedly half-finished appearance. Unless, of course, Akai are seriously contemplating selling a unit that has a bit of masking tape stuck underneath its DIN sockets with the improvised legend 'MIDI In, Out, Thru' scribbled over it in biro...
Beauty before utility, however: let's begin with that front panel. This gives you a choice of either Mic or Line input jack sockets, and a Record Level control with which to adjust the sample volume in accordance with the LED level meter that sits in the panel's centre display section. It also provides you with a Monitor Level control, should you wish to hear just what it is you're sampling. Once the signal level has been adjusted to suit, Record mode is selected by pressing either the 'New' or 'Overdub' switches, depending on whether it's to be a completely new sample or simply an addition to an existing one.
The recording is initiated either when the level of the sound to be sampled triggers the S612 automatically, or when you trigger it manually using an appropriately-marked socket - this is also provided on the front panel. The stored sound can then be heard by playing it from the keyboard of the controlling MIDI instrument, though we're reliably informed that production versions will incorporate a switch allowing the choice of simple triggering from the front panel or remote triggering from another instrument.
It's the pitch of your intended sample that would seem to be the key to all this, as a low-pitched offering results in the appropriate Record LED flashing slower for longer (up to eight seconds, in fact), and a high-pitched one in it flashing faster but for a shorter period (pay attention, I'll be asking questions later). The consequent recorded sounds are consistent in their tuning (the review model gave results a little under a semitone flat with reference to the host keyboard, the tuning being adjusted from the front panel by means of a rotary pot that affords control over approximately a semitone sharp or flat). This arrangement is actually a lot harder to explain than it is to use, and once you've got over the culture shock of having so many important technical decisions taken out of your hands, it works extremely well.
Time I stated the obvious. It should be common knowledge by now that the well-worn motto 'garbage in, garbage out' applies as much to sound-sampling as it does to any other hi-tech process. Bearing that in mind, if you're using a microphone to channel audio information into something like the S612, it follows that the quality of the resulting sample will be to a large extent dependent on the quality of the mic. That said, the results I obtained using what I suppose you'd term a 'reasonable' quality mic (a Fostex M505, in fact) were agreeable to the point of making the final result dependent more on the quality of the sample being attempted than anything else. So as far as this particular sampling machine is concerned, you should get half-decent results so long as you steer clear of anything really grim in the microphone department.
Line signals, on the other hand, are inherently easier to handle from the sampler's point of view. They're of better quality from the outset, since you remove the physically strenuous conversion of air movements into electric signal by starting off with electricity in the first place. And you'll be glad to know that the Akai behaved itself remarkably well on both conventional musical instrument signals (like the output from a synth, for instance) and sounds from records (a teeny bit naughty, I know, but fun all the same), though one point you need to bear in mind if you're undertaking the latter task is that you have to provide a mono signal from your record or tape deck. That is, if you want to avoid discovering that the sound you wanted to sample is predominantly on the stereo channel you left unplugged.
In answer to the inevitable question - yes: quantisation noise was audible on a number of samples, but it doesn't generally become prohibitive so long as you set an appropriate input level at the sampling stage.
But, and this might be the most crucial point of all, the Akai doesn't just provide the means to make good samples. It also allows you to manipulate samples once they've been made, and the list of manipulation options from which you can choose is pretty extensive. First off, you can set the sample's start and end points using - logically enough - two slider controls marked Start Point and End Point. The Start Point slider is graduated from 0% to 100%, whilst its End Point counterpart gives you a choice of both positive and negative end points on a centre-zero slider, graduated from 0 to 30 units at each extreme. This makes it possible to play through the sound backwards, simply by setting the Start Point some way into or at the end of the sample, and the End Point at or near the start of the sample. Easy!
"Quantisation noise was evident on a number of samples, but it doesn't generally become prohibitive if you set an appropriate input level at the sampling stage."
Now, all this is achieved using the Akai's 'One Shot' setting, as opposed to the 'Looping' and 'Alternative' options that are also offered as part of what is endearingly termed 'Sustain Mode'. The Looping option allows looping of the sample from the point marked by the Start Point slider to the point marked by the End Point one. Note that this section only plays forwards and then repeats. The reason I point that out is that the 'Alternative' setting runs through this section of sample first forwards, then backwards, then forwards again ad nauseum.
If you set your Start and End Points with some care (and this takes a bit of experience as well as a large slice of common sense) you can achieve reasonably glitch-free looping in both Looping and Alternative modes, the main advantage of the Alternative setting being that it gives twice as long a section of sample (which is only half as repetitive, if you see what I mean) before reaching the start of the loop again. Not wishing to offend the sensitivities of anybody who might be interested in doing something 'experimental' with the sampling process, Akai have thoughtfully made it equally easy to so arrange the Start and End Points of the sample to give pure, unadulterated glitch. Just what you always wanted, huh?
However, no matter how carefully you set the sliders, and no matter which of the two looping modes you're using, it isn't possible to loop a sample for its entire length. How great a drawback (if any at all) this represents is up to you to decide as a free-thinking, free-creating musician, of course. Personally, I wouldn't lose any sleep over it, as I place more importance on having the reverse effects that can be achieved in One Shot mode using the technique described above.
That's just about it as regards the mechanics and aesthetics of sampling with the S612. Didn't think it would be so simple, did you? We haven't finished yet, though.
To begin with, a small but effective output section gives you, the lucky user, the following collection of sound-controlling goodies. First off, a Filter with which you may lop the upper frequencies from your sample (to help eliminate problems caused by aliasing); then a Decay control, which determines the decay time after the release of a key (provided that the sample hasn't reached the end set by the End Point control - if you're in One Shot mode); and finally a Level control, to turn down the volume of your sample (about time you found that - Ed).
Yet another manipulative device provided on the S612 is a fairly standard Low Frequency Oscillator - LFO for short. Its associated parameter switches allow control over its Rate, Depth and Delay using three appropriately marked rotary pots. This should need little further explanation, except to say that it's certainly capable of adding an indefinable sonic something to certain types of sample that needed dirtying, for want of a better expression.
What a pity, though, that the LFO waveshape is fixed as a sinewave (or possibly a triangle masquerading as a sinewave?), since it would have been interesting to have been able to compare the relative effects of sine, square and ramp (to name but three) waveforms on everyday acoustic sounds. A facility for using an external source as the modulating oscillator would have been nice, too, but I suppose you can't have everything.
The MIDI facilities on the S612 need little said about them. As the more alert amongst you will already have guessed from my hint-dropping during the masking tape episode, there's one of each of MIDI In, MIDI Out, and MIDI Thru sockets provided on the rear panel. These linked the 612 with no bother at all under test with a Casio CZ1000 and a Korg Poly 800, which is certainly encouraging.
On the front panel are three switches marked 'Mono/Poly', 'Channel Up' and 'Channel Down'. The precise purpose of the Mono/Poly switch is a little uncertain, but it appears to give the 612 the facility of mono or poly working in a MIDI context. Quite what this provision is for, I don't quite know, as although it's expected that production S612s will have separate outputs for each of its six voices, it'll still only be able to hold one sample (or a combination of samples merged together to form one sound) at any time. Maybe time - and further product development on Akai's part - will tell.
The MIDI channel switches are a little easier to explain: all they do is select the receive/transmit channel from one of ten (0-9) available, though why Akai should have chosen this figure instead of the full 16, I'm not sure.
"With an anticipated price of £1350 including quick disk drive, the S612 does a fair bit to bring polyphonic sampling into the 'affordable' category."
The performance-oriented amongst you will be pleased to know that both pitch-bend and note velocity (values of between 1 and 127) are recognised as incoming MIDI information, though aftertouch is not.
In addition to all the other items on the review model's rear panel were two unmarked pushbuttons and an LED. A little investigation revealed these switches to be a party to octave transposition over no fewer than five octaves. The precise details of this function remain shrouded in mystery, despite diligent investigation and extensive enquiries to the appropriate authority, namely Akai in Japan. The only information forthcoming from our normally reliable - but this time strangely cautious - sources was an assurance that the switches would break their cover and appear on the front of the production model.
You'd be right in thinking that there's little point having sampling and manipulation facilities as extensive as these without some means of storing the sound permanently. And as I've already mentioned, Akai will shortly be offering just such a facility in the form of their Q-disk (quick disk) system. The drive will link up with the outside world using two connectors on the 612's rear panel, one for information transfer and one for the required eight-volt power supply.
The Q-disk (model number MD280) is also a 2U-high, 19" rack-mounting affair, and will be sold, initially at least, only as a package with the S612. The MD280 will store two samples per 3.5" disk (one on each side) and have a retrieval time of a couple of seconds. Not bad, assuming it turns out to be reliable, though bear in mind that at about £2 a throw, disks are never going to be a particularly cheap storage medium.
The 612's disk control section resides directly beneath the three MIDI control switches in the middle of the front panel. Reading left to right, these take the familiar form of Save, Verify and Load, and having succumbed to a passing urge to press one of these switches, I was greeted with a lone 'c' appearing in the area of the central display (Save or Load) corresponding to the switch pressed, but no further activity. This leads me to the inevitable but ultimately disappointing conclusion that the dump won't work without the drive for which it was designed. That'll teach me not to live in a fool's paradise.
All in all, the Akai S612 is a very welcome addition to the world of digital sound sampling and, with an anticipated retail price of around £1350 including the Q-disk, does a fair bit towards bringing polyphonic sampling into the 'affordable' category. And the music world being what it is, it probably won't be long after the package's June appearance that its actual selling price goes down further.
There remains the ulcer-inducing question of reliability, of course. Can you be sure that when you play that vitally important link from the atmospheric introduction of your latest masterpiece to the first million-selling verse, the sound you hear will be an eerie Aboriginal chant, and not the backwards car engine from the previous number? Since the review period wasn't really long enough to test for long-term reliability, I can't do anything more concrete than say the 612's construction and layout don't suggest it'll ever be a problem. Come to think of it, mistakes are far more likely to occur due to human, rather than technological, error.
Incidentally, another project currently in Akai's collective mind is the creation of a central sound library, comprising the disk equivalent of a series of factory presets. It's envisaged that there'll be an initial archive of 25 disks (and therefore 50 samples) from which S612 users can choose. So now you needn't actually do any of your own sampling at all, you lazy thing.
I imagine Akai are rather keen to develop the sampling system's market as quickly as possible, hence the 612's rush-release and the advent of the Akai Active Audio Club (see this month's Newsdesk for details). Because it can't be long before a lot of rival manufacturers come up with competing machines that do a very similar job, robbing Akai of their current (virtual) monopoly and introducing some welcome variety to the sound-sampling marketplace.
Until then, the S612 has certainly introduced some variety on its own account. It's not an Emulator beater, but so long as you're prepared to put up with its limited bandwidth and maximum sample time (and at this sort of money, you ought to be able to), you can't help but be impressed by it.
So now there's a truly viable, polyphonic, MIDI-equipped alternative to cutting up bits of tape in the hope of recreating Peter Gabriel's favourite Fairlight samples. I have only one more point to make. Whatever you do, don't sample scratched records - your ears will never forgive you.
Further information on the S612 and MD280 from Akai UK, Electronic Music Division, (Contact Details).
Review by Tim Goodyer
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