Ensoniq EPS

Way back in 1990 or so, I bought myself an Ensoniq EPS keyboard. It cost me somewhere around $2500 as I recall. I needed a real keyboard, but I also wanted a sampler so that I could use it for production work in my studio. In the end, the EPS worked out ok for me. The sounds available aren't all that great, and it would occasionally crash on me. I did use it successfully to fly in vocals from a demo into a final version of one of my bands' "hit" songs. I developed a minimal wavesample editor for the PC that could transfer wavesamples to and from the keyboard via MIDI.

The Ensoniq EPS is also known as the Classic, Original, or 13-bit EPS. The rackmount version was called the EPS-M. It was a step up from the 8-bit Ensoniq Mirage. After the EPS came the EPS 16 Plus (? or was there an EPS-16?) which was a full 16-bit sampler. I believe the EPS worked with 16-bits internally, but the analog to digital and digital to analog converters could only handle 13 bits. This meant that EPS-16+ disks could be loaded by the EPS with no problem. Anything that was specific to the EPS-16+ was simply ignored. Unfortunately in practice there are differences that can render EPS-16+ sounds useless on an EPS Classic. See the discussion below.

Now, in October of 2007, I've started getting back into music again. I've backed up my EPS sound floppies using OmniFlop. I've also been shopping around a bit for sounds to add to my collection. I created this page to collect my research.

EPS-16+ and EPS Classic Compatibility

It appears that the EPS isn't really 100% compatible with sounds for the EPS-16+. I've tried the SL-4 library of piano sounds for the EPS-16+, and it sounded terrible on my EPS. Then I read a post to the EPS Mailing List from 1/16/1992 by Kelly Larson who theorizes that the EPS-16+ has "an extra pre-amp parameter ... that the original EPS doesn't have, and so the gain between waveforms [is] all messed up". Another EPS Mailing List post:

"NOW I STILL have trouble playing EPS-16 samples on my EPS-M (they are supposed to be compatible). I have had to adjust the individual sample volumes to try to get a reasonably even sounding instrument across the keyboard (i.e. for a piano sample). Again I have not done too much of this (only so much spare time :-) and I know that you might have to convert a filter setting also. But, I still have no sure way of acceptably converting an EPS-16 sample for my EPS. Some work some don't.

"Are EPS owners locked out of the current (EPS-16) sample market? Are we limited to sampling our own from CD's and other sources? Any tips out there?" - Dan Peters 3/16/1992 EPS Mailing List Digest 10

The gain was certainly all over the place when I tried the SL-4 sounds. So, avoid the SL libraries and any other EPS-16+ libraries if you have the EPS Classic.


Ted-200 - A collection of sounds that I've sampled. Mostly samples of cheap synths. The file is in OmniFlop raw image format. Should work with any software that cuts floppies from raw images and supports 10 sectors. Info about OmniFlop is below.

Sound Reviews

Sounds for the EPS vary from fantastic to horrid. Unfortunately, when you buy sounds, you can't return them if they are bad. I've bought many bad sounds. I'm hoping these reviews will guide EPS owners to the best sounds and save them some money. The mp3 demos should be particularly useful as the proof of a sound's worth is in the hearing.

Ensoniq EPS Grand 88 Sound Review - The best grand piano sound for the EPS.

Ensoniq EPS Ambient Kit2 Sound Review - One of John Robinson's drum kits from his signature series disks.

Ensoniq EPS Dig E-Piano1 Sound Review - Nice electric piano sound.

EPS Sound Reviews - a list of all the sounds I have, and short reviews of each. The reviews are incomplete, but might be useful. Over time I hope to expand this by doing full reviews like the ones above.

Ensoniq Disk Cross-Reference - This file is based on my own collection of disks, so it only covers a subset of the disks that Ensoniq produced. This file connects a disk by its "ESD" number to its sound library (e.g. SLT-1). I organize all my disks by ESD number, while other sites list them by sound library. This cross reference lets me work both ways.


OmniFlop will copy your Ensoniq EPS floppies to your PC for archiving and backing up. I've been using it to archive all of my floppies, and it works far better than EDM (see below). It's also free. I was able to image all my 100+ EPS floppies with OmniFlop in just a few hours.

OmniFlop is a little tricky to get working, though. To work with EPS diskettes, you have to install OmniFlop's floppy driver (this procedure is explained in the OmniFlop User Guide). Then you have to either let it automatically detect the floppy format for you (slow but foolproof) or select the format from a list (error-prone but fast). The format you want for EPS floppies is called:

"80/2/10x512 (Ensoniq EPS 16+/Classic DD) 800kB"

Note the "10" as it is subtle, but VERY important. It will then require you to register (this may no longer be the case with newer versions), which is free, and everything will work fine.

Really worn out floppies will be hard for OmniFlop to read. Just make fresh copies of them over to a new high quality floppy, then use the copy with OmniFlop. Also turn off "Skip Bad Sectors" so that it will abort on a read error. No sense making a bad image.

Here are some EPS floppy images to try:

Pocket Song - Demo that all the EPS dealers had. It's not too bad.

Blank EPS Floppy - An image of a freshly formatted EPS floppy for OmniFlop. Use this to clear a floppy. OmniFlop is much faster at formatting than the EPS. I'm not sure whether this can be used to format a blank floppy, but it definitely works for clearing a floppy that has been formatted previously.

EPS OS 2.40 Floppy - An image of my EPS OS 2.40 floppy for OmniFlop. If, like me, you have old firmware in your EPS (mine's 2.00, the last was 2.40), you may need this older version of the EPS OS. The last EPS OS version was 2.49, and you can find this with a Google search. Syntaur also sells both the 2.40 firmware EPROMs and the OS 2.49 floppy.

In the older version 2.01k of OmniFlop, if you do not install the floppy driver, you will see an Ensoniq format that starts with "80/2/9x512 (Ensoniq EPS...". Note the "9". DO NOT USE this format as it is wrong and will make useless images. Always test the images you make by writing them to a blank freshly formatted floppy and loading them on your EPS. If the image files you are making are 737,280 bytes (720KB), you are using the wrong format. Image files for the EPS must be 819,200 bytes (800KB). [You may wonder why this useless 720kb EPS format is provided at all. It may have something to do with a trick that some EPS hackers used to use. They would mark the 10th sector in every track as bad (even though it wasn't really). This would reduce the EPS to only using 9 sectors per track. This made the floppy compatible with the standard DOS floppy drivers. Bizarre.]

Giebler Enterprises
Makers of Ensoniq Disk Manager (EDM) which allows a PC to access the contents of diskettes from Ensoniq keyboards. I used this originally to archive my sound collection to my PC in case something happens. It's ok, but unreliable. It also records your name and EDM serial number to each disk you format with it (see Scott Fisher's post to the EPS mailing list on 3/20/1992 in EPS Digest 10) which makes it possible to track down who has been copying what. OmniFlop is better.

EDM's file formats are documented here in case you want to write your own software to work with them.

I had to go through a number of rituals to reliably transfer EPS floppies to .ede files on my PC. It might be that my floppy drive is bad (it did eventually die, but I wonder if EDM didn't kill it). Here are the tricks I used in case they are helpful for others...

Fresh Copy. Before you try to read an EPS floppy on the PC, make a fresh copy of each floppy on the EPS. This ensures there is a strong enough signal for a PC floppy drive to read. In a pinch you can copy a floppy back onto itself, but this is dangerous. If the power goes out, you lose your floppy. Make sure you are using high-quality name brand floppies. 720k floppies work best, but 1.44MB floppies can usually be coaxed to work.

Recalibrate the Drive. EDM appears to do a less than perfect job recalibrating the floppy drive. If EDM is unable to recognize a floppy as an EPS floppy, exit EDM, insert a DOS floppy, do a "dir" until you see the files on the DOS floppy, restart EDM and all should work fine. This works best in Windows 95 as Win95 does some partial seeks across the disk (track 10 or so) followed by recalibration seeks to track 0 when it is having trouble reading a disk. Windows 95 is very reliable at recalibrating a floppy drive. EDM is not so good. DOS is also pretty bad, so once EDM has hosed the calibration on your drive, DOS won't be able to recover it. Always use a Windows 95 command prompt (all the other versions of Windows should be ok too).


Syntaur Productions - Syntaur sells all the original EPS sound disks licensed from Ensoniq. They also have a great index of all the disks so you can see what you're missing in your collection. They even sell the disks that came with the EPS, the User's Manual, the Maintenance Manual, the EPROMs for upgrading to firmware version 2.40, replacement keys, and more. If you want to trick-out your EPS, this is the place to start.

Greytsounds - Greytsounds sells a large EPS sound collection. I've ordered some pianos and a harpsichord sound from them. They were all good, but some suffered in the wavesample transition department, or had static sustain.

Rubber Chicken - EPS sounds. Haven't tried these guys yet.


Synth Zone - A collection of links related to Ensoniq keyboards.

Copyright ©2007, Ted Felix. Disclaimer