Magazine Archive

Home -> Magazines -> Issues -> Articles in this issue -> View

Sweet Sixteen

Ensoniq EPS16 Plus Sampling Workstation

Ensoniq have transformed their 13-bit EPS sampling workstation with the addition of dynamically controlled 24-bit digital multi-effects, a much improved 16-track MIDI sequencer and full 16-bit sampling. The result is the EPS16 Plus. But does it pass? Kendall Wrightson invigilates.

Five years ago when John Major was a total unknown and 8-bit samplers commanded 5-figure price tags, an equally unknown Silicon Valley manufacturer called Ensoniq unleashed the Mirage digital sampling keyboard. At well under £2000, the Mirage sold by the truckload and firmly established Ensoniq as a new force in musical instrument technology.

Three years later Ensoniq further enhanced their reputation with the Ensoniq Performance Sampler, which offered the intriguing combination of 20-voice polyphony, 13-bit fixed frequency sampling, polyphonic aftertouch, and a built-in MIDI sequencer, for just £1695. Perhaps the most original EPS feature was its ability to load sounds from floppy disk without the need to interrupt playing, a feature we all expected to become de rigueur on samplers. It hasn't, and like so many of us, Ensoniq must be wondering why.


With only 480k of RAM, the original EPS's load & play facility was severely restricted — fortunately the new EPS16 Plus keyboard has 1 meg of RAM (2 meg in the EPS16R rack mount version), allowing load & play to be appreciated for the truly great facility that it is. The keyboard can be upgraded to 2 meg with the addition of an optional RAM card — the £499 ME16 Plus — though further expansion is impossible for both units. To compensate for this restriction, and the lack of provision for an internal hard disk (a highly desirable option for any performance sampler), Ensoniq have come up with an interesting new option — the FlashBank. A FlashBank is an internally fitted expansion card containing 512k or 1 meg of programmable read only memory (PROM). A FlashBank has all the advantages of ROM — instant loading and non-volatility — but being programmable, FlashBank memory can be loaded with new sounds at any time. It's a great idea, and I'm sure we'll see dedicated PROM players before very long, though at present PROM is rather expensive. Ensoniq are asking £299 for the 512k FB1 upgrade and £499 for the 1 meg FB2.

It's a shame that there isn't a small amount of PROM inside the EPS16 to hold its operating system, since that would avoid the necessity of loading the OS from the 800k floppy drive. This can be quite frustrating, because during normal operation the EPS16 Plus periodically asks to see the system disk. You can write the OS on to every disk, but this is rather a waste of valuable disk space. Another disadvantage of the 800k floppy drive is that two disks are required to save the full contents of the sampler's memory, and disk swapping rather undermines the load & play facility.

The way to overcome all these problems is to run the 16 Plus from an external SCSI drive, and to this end Ensoniq supply yet another expansion card, the £149 SP2 SCSI Interface kit. The SP2 can be fitted directly to the rack version, but the keyboard can only support it if an ME16 Plus RAM card is installed. However, the good news is that the EPS16 works with most Apple Macintosh compatible SCSI hard drives or CD ROMS, and Ensoniq have promised to have their first CD ready by the time you read this.

14 sound disks are supplied with the EPS16 Plus and it can read both EPS and Mirage Sound library disks.


Like the EPS, the EPS16 Plus is a fixed sample rate device. This means that the playback sample rate is constant, regardless of pitch. This technique means that transposed samples sound cleaner and less noisy. (See Sound On Sound July 1990 for a mere detailed explanation of fixed frequency sampling.) Ensoniq provide three playback sample rates on the EPS, and due to the extra computational power needed for the higher rates, there is a trade off with polyphony. At the default 29.8kHz playback rate, the 16 Plus is 20-voice polyphonic. 13 voices are available at 44.6khz, and at 78kHz polyphony is reduced to seven voices.

Regardless of the rate at which the sample was recorded (there are seven record sample rates, from 11.2kHz to 44.6kHz), samples will always replay at the currently selected playback sample rate. In practical terms this means that at the default 29.8kHz playback rate, samples recorded at lower sample rates will benefit from being replayed at 29.8kHz by sounding less 'grainy' when transposed. On the other hand, samples recorded at 44.6kHz will also be replayed at 29.8kHz, limiting their bandwidth to around 15kHz. By switching to 44.6kHz playback rate, the full bandwidth is available, though with only 13-voice polyphony. The 78kHz playback rate is provided so that sounds sampled at 44.6kHz will sound even better when they are transposed down.


The selection of the playback sample rate is hidden under the Effect Select/Bypass button, which seems like a strange location until you discover that, like polyphony, the performance of some of the effects is also related to the playback sample rate. The EPS16 Plus offers 13 digital effects algorithms in its 24-bit processing section, and as you can see in the spec box. Effect Types 2 and 5 are prefixed with '44kHz'. This is because a sample rate of 44.6kHz is selected whenever these two programs are chosen, in order to produce their particular treatments.

As with Ensoniq's VFX synthesizers, the digital effects section is not simply bolted on to the output stage, but is fully integrated within the internal Voice and bus routing structure. An EPS16 Plus Voice contains a Wavesample (a raw sample including start/end and loop points) and parameters which control keyboard range, pan, and the EPS16's massive armoury of synth-like processing and modulation facilities.

The output of any Voice can be routed to one of four stereo busses (1, 2, 3 and Aux). Bus 1 is connected to the left and right jacks on the rear panel of both keyboard and rack versions. The rack also has stereo outputs for the other three busses, and they can be added to the keyboard version through the purchase of an external output expander box (the £199 OEX6). All bus outputs are polyphonic — there's no limit to the number of voices that can be assigned to each bus — and by panning a Voice left or right, the four stereo outputs can be used as eight polyphonic individual outputs.

The routing of the digital effects depends on both the type of effect and the number of simultaneous effects the algorithm offers. For example, Effect Type 10 (Chorus, Reverb and Digital Delay) connects the delay line to Bus 3, the reverb to Bus 2, with chorus and reverb available on Bus 1. The assignment of a Voice can rotate between the busses every time it is triggered. As Aux 1 is permanently 'dry', this effects program would loop around chorus and reverb, reverb only, delay, and dry settings.

As Voice definition parameters include keyboard range, volume, pan and output bus, a drum kit (for example) can be given a 3-dimensional sense of space by carefully assigning each drum a unique wet/dry mix and pan position. Furthermore, effects parameters such as mix level, pan and so on can be modulated from several controllers, including key velocity, mod wheel and keyboard pressure. Like the original EPS, the EPS16 Plus features polyphonic key pressure.

Each effect has numerous parameters to play with, one of my favourites being the reverb pitch parameters, with which you can create an up or down reverb 'swoop'. As a subtle treatment, pitch swoop can make a reverb sound more interesting and natural, while extreme settings are a dub mix engineer's dream


At 44 6kHz (the highest rate), you have 11.44s of mono sampling (22.88s on the rack version). There are no plans to offer stereo sampling, which is rather sad — the EPS16's main rival, Emu's Emax II, now offers stereo sampling as standard. Another great Emax II feature is the speed and ease with samples can be recorded, and the EPS16 is just as fast. Having entered sampling mode, the large 28-character fluorescent display turns into a VU meter, and the audio input is automatically routed to the stereo outputs for easy monitoring.

Sample input gain is switchable between mic and line level, but no further adjustment is possible, so you have to get the input level right by adjusting the source. Sampling can be initiated by pressing the enter button, or by the input signal crossing a user defined threshold. The latter function has an adjustable pre-trigger which ensures none of the start of a sound is lost. Sampling quality is excellent, thanks to 2x oversampling A-to-D conversion with digital filtering.

Once you have taken a sample, the EPS asks for a root key and stretches the sample across the entire 61-note keyboard. Samples remain noise-free even when transposed a full five octaves up or down, which is very useful since such extreme transposition often produces interesting textures. Multi-sampled instruments can be quickly created thanks to the automatic sample assignment feature; when a new sample is recorded and assigned a root key, the EPS automatically splits the keyboard half way between the two root keys.

All the essential sample editing tools are provided, including truncate, mix, merge, splice, reverse, normalise, compression and fade in/out. Looping is also well supported, with a whole host of crossfade looping techniques — reverse cross fade, ensemble cross fade, bow-tie (!) and many others. In addition to this, the EPS16 allows sample start, sample end, loop start, loop end and loop portion to be modulated by any of 15 different controllers (see spec box).


Having edited individual Wavesamples, the EPS16's massive armoury of Voice parameters lies in waiting, screaming to be tweaked. I don't have space to tell you about them all, but here are the edited highlights.

There are three 6-stage envelopes, and you can set the velocity response of each stage of each envelope quite independently, by specifying Hard Vel levels and Soft Vel levels at each stage. With so many parameters to edit, Ensoniq have thoughtfully provided 16 envelope templates — from useful Piano, String and Percussion types to more esoteric Repeat Ramp and Blip varieties. All envelopes can be set to play normally, cycle (ignore key-off), or repeat (play the first four stages repeatedly). Envelope 3 is hard-wired to the amplifier only, but Envelopes 1 (pitch) and 2 (filter) can also act as additional modulation sources.

The digital filters offer 4 modes: 3-pole low-pass + 1-pole low-pass; 2-pole low-pass + 2-pole low-pass; 3-pole low-pass + 1-pole high-pass; 2-pole low-pass + 2-pole high-pass. Unfortunately, the filters have no resonance control. However, on the plus side, the EPS16 offers a pitch envelope, monophonic glide, micro tuning, and a random oscillator which can be used to randomise pitch, filtering or the amplifier. There are also plenty of velocity, key number and attack time scaling functions for all three envelopes, plus a 7-waveform LFO which can be modulated from other controllers to modify its speed as well as depth.


A collection of Voices (up to 127 of them) is called an Instrument, and Voices are arranged within the Instrument as a set of up to eight Layers. Eight Instruments are instantly available from the Instrument selection buttons located directly underneath the central display. Each button has two LEDs above it, the upper one indicating that an Instrument is currently available, the lower indicating that it is selected.

Rather wpnderfuily, double clicking on subsequent buttens will stack Instruments up — all eight of them if you want — while the data entry slider can edit the most recently selected Instrument's volume.

The eight Layers allow you to program extremely complex velocity switch/crossfade arrangements, including one which assigns different Layers on key up and key down. A good example of this is to simulate the key thump that piano or harpsichord hammers make as keys are released.

If you think that eight Instruments is rather miserly, you'll be glad to know that three further combinations of Layers within each Instrument can be programmed as Patches, which can be brought into play momentarily or permanently by the two Patch Buttons located above the pitch bend wheel. So, in a sense, you actually have 32 Instruments available. The Patch Buttons can be used to bring in a modified version of the current Instrument (perhaps transposed, or with deeper effect depth) or even a totally different sound copied from another Instrument. The ability to play a Patch momentarily (as the Patch Buttons are held down with the left hand) is a great performance feature.

Another unique EPS16 facility is that as Instruments are selected, the previous Instrument is still available if any part of the new Instrument's keyboard range has nothing assigned to it. For example, if a full 5-octave piano is selected, followed by a bass which only covers the bottom two octaves, the piano will still be available on the top three octaves of the keyboard.

Once you've programmed a fabulous stack, with copious layering and multiple Patches, the whole lot can be saved as a Performance Preset, which also saves transpose, key range and MIDI program values for each Instrument. Eight Performance Presets can be created and stored.

Each Instrument contains an effect program, but if several Instruments are stacked together, the first selected Instrument's effect program is the one which takes precedence.

Individual Instruments and effect programs can be stored to disk, but unfortunately not single Wavesamples, which means that assembling combo disks can involve rather a lot of erasing and disk shuffling. You can also save a Bank — the entire contents of the EPS16's memory — which includes all Performance Presets, Instruments, a Bank Effect (which takes precedence over all Instrument settings, user effects programs, system exclusive files, Sequences, and one Song.


Until the EPS came along, built in sequencers tended to be rather simple affairs, with minimal editing facilities. In this respect, the EPS was one of the first true low-cost workstations, and even today its sequencer is more sophisticated than many dedicated devices.

The EPS16 uses the same 80 Sequence, one Song structure of the original EPS sequencer but it offers several significant improvements. The most important of these is that the recording resolution has been increased from 48 to 96 ppqn, giving a much more accurate recording of a live performance. There are eight Tracks in each Sequence, and each is assigned an EPS16 Instrument and a MIDI channel (to play external devices). A Sequence can be up to 999 bars long, and you can use conventional, add (merge), and loop recording. The latter loops like a drum machine, but when the loop ends the EPS drops out of record and the display prompts you to keep the new or revert to the original Track, while the Sequence continues to loop.

All the important editing facilities are provided — copy, replace, merge, append, transpose, filter, shift, scale event and event edit/insert (a sort of step time) — apart from swing. Sequencer memory is shared with sampling memory, but if you reserve around 100k, you'll get around 16,000 events. When building a Song, individual Tracks can be muted, soloed or transposed, which drastically reduces the need to copy Sequences. Finally, and this is the best bit, once a Song has been constructed, a further eight Tracks can be overdubbed on top of the song, though Tracks 9 to 16 must use the same Instruments as Tracks 1 to 8.

The next software release will allow new Instruments to be loaded while the Sequence is running, thereby replacing Instruments which have finished playing, if necessary.


The EPS16's closest competitor is Roland's 12-bit W30 (reviewed Sound On Sound June 1989), but with 16-bit sampling, an extra five voices of polyphony, and digital effects, for only £145 more, the EPS16 makes the W30 look rather old fashioned. This means that the EPS's closest rival is the Emu Emax II (reviewed December 1989), which recently dropped in price by £450 to £2395 (both keyboard and rack versions) while its specification was improved to incorporate 2 meg of RAM and true stereo sampling. While the EPS16 keyboard is only £1795, the Emax II also includes built in SCSI and three extra stereo outputs. Adding these options to the EPS16 Plus (three stereo outputs £199, SCSI option £149, and 1 Mb RAM £299) brings the EPS16 price up to £2442 — £47 more than the Emax II.

This fact illustrates Ensoniq's unrealistic upgrade pricing, particularly the 1 meg RAM expansion card — for £299 you could buy 6 meg of RAM for a Macintosh, or treat yourself to an Alesis SR16. There will no doubt be a rash of third party RAM cards, but as Ensoniq point out, the SCSI option will not work without the ME16 RAM expansion — so be warned.

The £1825 EPS16R, with its extra outputs and 2 meg of RAM, compares more favourably with the Emax II rack, requiring only the SCSI adaptor kit to match the Emax II's spec, making the Ensoniq configuration some £421 cheaper than the Emax II rack — a differential which further illustrates that Ensoniq's upgrade prices are rather unfair.

Comparing features, the EPS16 Plus has five more monophonic voices (at 29.8kHz), polyphonic aftertouch, a fully-fledged sequencer, digital effects, the ability to load whilst playing, and an option to fit up to 1 megabyte of FlashBank PROM. I emphasise mono voices, because the Emax II is 16-voice polyphonic whether the voices are mono or stereo. The Emax II can also boast stereo sampling (a significant advantage), resonant filters, the capacity to fit an internal hard disk, and RAM expansion beyond 2 meg.

Nonetheless, the EPS16 Plus is a true workstation (as the excellent demo sequences prove) and its load & play, polyphonic aftertouch and digital multi-effects facilities are totally unique. Sound quality is exemplary, and at £1795 it represents the cheapest way into the world of 16-bit sampling workstations.


EPS16 Plus keyboard £1795 Inc VAT.
EPS16R Plus rack E1B25 Inc VAT.
ME16 Plus 1 meg RAM upgrade (for EPS16 Plus) £299.
FB1 512k FlashBank upgrade £299.
FB2 1M FlashBank upgrade £499.
SP2 SCSI Interface £149.
OEX6 Output Expander £199.

Sound Technology plc, (Contact Details).


Quantisation: 16-bit linear, 2x oversampling
Output Conversion: 16-bit, Stereo DAC system
RAM: 1 meg, expandable to 2 meg (EPS16 Plus): 2 meg (EPS16R)
Sample Rates/Times (1Mb): 44.6kHz - 11.44s
29.8kHz - 17.2s
22.3kHz - 22.88s
17.9kHz - 29.12s
14.8kHz - 34.85s
12.8kHz - 40.57s
11.2kHz - 46.29s
Polyphony: 20-voice @ 29.8kHz
13-voice @ 44.6kHz
7-voice @ 78kHz
Outputs: L/R Stereo output jacks, Output Expander Socket (EPS16 Plus); Four stereo outs (EPS16R); Stereo Headphones.
Inputs: Audio In jack (mono); 2 footswitches (via one stereo jack); Stereo control voltage pedal Input (stereo Jack).
Floppy Drive: 800k, reads EPS and Mirage DSK files.
Keyboard: 61-note, velocity and note/channel pressure sensitive.
No. of simultaneous Instruments: 8
Patches per Instrument: 4
Performance Presets (per Bank): 8
Sequencer: 16-Track with Automated mixdown; 96 ppqn; 80 Sequences up to 999 bars long; 1 Song of up to 99 steps; Sys Ex recording.
Synthesis (per voice): 3 Envelopes; 16 Envelope Templates; Multi-mode filters; 7-waveform LFO.
Mod Sources: Low Frequency Oscillator; Random Generator; Envelopes 1 & 2; Velocity; Velocity Variation 1; Velocity Variation 2; Pressure; Pressure & Velocity; Modulation Wheel; Mod Wheel & Pressure; Keyboard Tracking; Pitch Bend; Foot Pedal; External MIDI Controller.
Effects Processing: 24-bit
Effect Types: Hall Reverb; 44kHz Reverb; Room Reverb; Dual Delays; 44kHz Delays; Chorus & Reverb; Phaser and Reverb; Flanger & Reverb; Rotating Speaker & Reverb; Chorus & Reverb & Digital Delay; Compression & Distortion & Reverb; Distortion & Chorus & Reverb; Wah & Distortion & Reverb.

Also featuring gear in this article

Previous Article in this issue

Dear Santa...

Next article in this issue

Korg S3

Sound On Sound - Copyright: SOS Publications Ltd.
The contents of this magazine are re-published here with the kind permission of SOS Publications Ltd.


Sound On Sound - Jan 1991

Gear in this article:

Sampler > Ensoniq > EPS16 Plus

Gear Tags:

Polyphonic Aftertouch
16-Bit Sampler

Previous article in this issue:

> Dear Santa...

Next article in this issue:

> Korg S3

Help Support The Things You Love

mu:zines is the result of thousands of hours of effort, and will require many thousands more going forward to reach our goals of getting all this content online.

If you value this resource, you can support this project - it really helps!

Donations for May 2021
Issues donated this month: 0

New issues that have been donated or scanned for us this month.

Funds donated this month: £21.00

All donations and support are gratefully appreciated - thank you.

Please Contribute to mu:zines by supplying magazines, scanning or donating funds. Thanks!

Monetary donations go towards site running costs, and the occasional coffee for me if there's anything left over!

Small Print

Terms of usePrivacy