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Upgrading the E5000 to E4XT Ultra + extras

They said it wasn’t possible! Considering the ridiculously high price of the E4XT Ultras these days (they go as high as $1.5k, depending on the condition and installed options) and how little I’ve paid for my E5000 (I think it was 250 notes), I’ve decided to upgrade it to E4XT Ultra, despite the “online community” saying it is not possible. It will be a fun project learning new things out. Browsing thru the web it was common knowledge that the E-6400 Ultra could be upgraded, but for some reason, the E5000 was listed as non-upgradeable. This didn’t make sense to me, as the E6400 and E5000 are technically the same unit, with the only difference being that the E5000 has four outputs instead of eight. So I started digging a little deeper…

Looking at the E5000’s motherboard, I noticed that it wasn’t fully populated, but the traces and pads were all there, meaning the additional outputs and polyphony could theoretically be added. Both the E6400 and E5000 Ultra are 64-voice units. E-MU offered an upgrade option for E6400 Ultra owners to double the polyphony to 128 voices and essentially convert it to an E4XT specs, but they never offered this for the E5000. Perhaps this is where the misconception about the E5000’s upgradeability comes from.

After examining the motherboard and seeing that it was identical, I had no doubt that the E5000 could be upgraded in both polyphony and outputs.

Chapter 1 Polyphony Expansion
Let’s first look into polyphony expansion. As long as you have one “G” chip (IC402) and two “H” chips (IC413), you should be able to upgrade the unit to 128 voices. Unfortunately, these chips are no longer in production. Many years ago, I bought the “H” chips from EPR Electronics, but this company no longer exists, so I can’t provide information on where to obtain these ICs now.

The purpose of this article is to document the process rather than serve as a technical guideline, as this is a delicate job that requires professional skills and specialized tools for SMD soldering. I won’t be able to answer any technical questions, as those who perform this type of work are typically already knowledgeable and don’t require additional guidance.

Here are the three ICs needed for the polyphony upgrade. The smaller one contains the voices and was desoldered from a broken Proteus 1000 unit with a damaged front panel and PCB. However, the voice IC itself was in good condition, though there was a lot of solder residue. The bigger two are the filters. They are ok to work with.

After about three hours, I finally managed to solder all three ICs with majority of the time spent on the voices IC (smaller one). The task was extremely challenging and needed to work exclusively under a magnifying glass. To give you an idea of how small the pins are, in this photo I placed a small CR2032 battery next to the ICs for size comparison. The work was incredibly delicate, especially because the “G” chip had excess solder and slightly bent pins. It took a lot of flux, patience, and effort, but I eventually succeeded.

Truth be said, I was extremely nervous during this entire process. These SMD pads are less than 1 mm in size, and any solder blob in the wrong location can cause serious trouble. I used a lot of flux, but accidents happen. The biggest mistake was using solder that was too thick. I used 0.7 mm solder when I should have used 0.25 mm, which I didn’t have at the time. I decided to take a gamble—a big mistake! This led to numerous issues, including solder bridges and a lot of stress. I had to clean them all with soldering wick far too many times. But I was impatient. I didn’t want to wait a week for the Mouser order with the ultra-thin solder. I guess this is what they call passion!

Moment of Truth
Then came the moment of truth: powering up the unit. And it worked! I couldn’t believe it. This was my first serious SMD project, involving pins smaller than the soldering tip itself, and it worked perfectly on the first try. No jumper adjustments or software modifications were needed—the unit simply booted up, displaying “128 Channel Card Installed.”

I was too anxious to test the playback immediately, but when I did the next day, everything worked flawlessly. We now have an Emulator E5000 Ultra with 128 voices!

Chapter 2 – Outputs Expansion
The E5000 has only 4 outputs, while the E4XT has 8, so our next task was to add 4 additional outputs. In terms of electronics, this actually means adding 8 analogue audio channels since the Emulator uses balanced outputs. This is why it might seem that some components around the outputs are “doubled” in quantity, but in reality, they aren’t. It’s simply the + and – of the same balanced signal going to each individual output.

Here is how the E5000 output section looks. As we can see, all of the SMD pads are present. They’re empty, but they’re there—and that’s what matters. Please ignore the grey wires; they’re from some phase tests I did earlier (more on that in another article detailing a design bug in the E5000 Ultra series, which also affects some E4XT Ultras).

Back to the topic. I placed a large order of parts from Mouser. To help myself, I drew the entire output section in vector software to precisely map out which component goes where. The Ultra service manual, which contains schematics, was incredibly helpful. With that information, all that was left was to go to Mouser and gather all of the necessary SMD parts. The only components not available at Mouser were the DACs, which I had to source elsewhere (eBay, etc.). Photo below shows the two DAC chips which I bought on eBay.

A few days later, my Mouser order arrived, including the output jacks.

It was go time. I’ve prepared the paper containing the graphics which I drew in vector software (Inkscape), showing the rough location and component values so I knew exactly what to solder and where. As soon as a component was soldered, I used a pen to cross out the corresponding square. Without this graphics this would have been a total nightmare with an error or accident awaiting to happen any moment.

A few hours later, all of the squares were crossed out. Meaning the output expansion work is finally completed!

I actually used a regular soldering tip for all of the passive SMD parts, it somehow worked better. I would apply a little bit of solder, bring the component and let it go. Then I would solder the other side and move to the next component. It wasn’t really hard as I have this kind of experience. And here it is the before:

And after:

Sharp-eyed readers will notice that I used through-hole tantalum capacitors. This was because I accidentally ordered the wrong SMD version from Mouser—I chose too small of a physical size. I’m not sure how I made that mistake, but fortunately, I had the through-hole versions at home, and they weren’t too large either.

So, I tested the new balanced outputs, and the Sub2 output (left) didn’t work at first. Cue the moment of cold sweat. But after a few seconds, I realized that I had inserted the audio jack too gently, and it didn’t click all the way in. I re-plugged it, and it worked! All 4 new outputs now work flawlessly! I guess we can say—another myth busted. The E5000 can be upgraded to a full E4XT. But wait, we’re not done yet. Something very important is still missing. A few things actually, but we will take care for that in the chapters that follow.

Hard to believe all of these bags were full of parts. And these parts are now installed in my E5000. Total cost was around $100 which includes to DAC integrated circuits.

If you decide to upgrade the outputs, I have prepared the above graphics in PDF file that list every component value and location and is available here. There is one error in the graphics: the resistor networks are not 4.7 but 4.7k. When I was creating these graphics, I was referring to the service manual, which lists them as 4.7. However, after reviewing the schematics and applying some common sense, it’s clear that the resistor networks are definitely 4.7k. On the motherboard, they are located near the DAC area. Resistor Network 10 (RN10) needs to be removed as shown in my PDF file, in order for the new outputs to be seen by the sampler (special thanks to Ricardo Dias). Regarding the service manual, I don’t have the bandwidth to share the entire document with all the schematics, but it is available for anyone to download in the “EMU Samplers & Software” Facebook group. In general, the graphics I created are all that’s needed to make the parts order and install the components in their correct locations, in order to expand the E5000 to 8 outputs.

Chapter 3 Designing And Building A New Display Bezel
What’s the point of upgrading our E5000 to an E4XT Ultra if the front panel still says E5000? Fortunately, I took the time to create new graphics using vector software and found a way to manufacture a new bezel. It’s a bit pricey, but what other options do I have?

In order to initiate the manufacture, I had to order a batch of several bezels (it’s a big studio and they don’t have time for little projects). By the time I am writing this, unfortunately all of the bezels have been sold out. But if anyone is interested, leave a comment below. The price is $60 plus shipping – sorry it ain’t cheap – but that’s a brand new bezel for your screen, no scratches no damage. It would be cheap if I made 1000 of them, but I didn’t. If you have a scratched or damaged bezel this might come handy. To install the new bezel I first removed the original one. A hairdryer came very useful to help loosen the adhesive. Then I attached the new one using double-sided sticky tape. Prior to that the entire area should be thoroughly cleaned with alcohol, benzine, or a similarly strong solvent. I highly recommend applying hot glue just to be on the safe side, at least that’s what I did. Here are a few shots of before and after.

Old display bezel:

New display bezel:

This E5000 now proudly says E4XT Ultra. We are heading into good direction however there are couple of more things to add to make it a true E4XT Ultra. More on that in the chapters that follow.

Chapter 4 DWAM Board
The E4XT Ultra comes stock with the DWAM 6862 board. It provides the ASCII port for connecting an ASCII keyboard to the sampler, a second set of MIDI ports (MIDI channels 17-32), coaxial Wordclock in and out ports, as well as AES/EBU ins and outs. This board requires the AES chip, which must be fitted into the socket on the Ultra series’ mainboard.

Fortunately, I know someone who owns an E4XT but never uses this board, so I bought it from him. For some reason the board was extremely dirty, so I desoldered some of its components and literally washed everything with dish soap—that’s how filthy it was. The ribbon cable was so gross that I decided to build a new one. A few hours later, an almost new-looking DWAM board was installed in my E5000.

With this board, we can use an ASCII keyboard to name samples, projects, and utilize shortcuts. More importantly, it makes it much easier to integrate the Emulator digitally into my DAW setup. Now, I can sample anything I find interesting playing from my speakers—whether it’s coming from the digital TV/radio, or online—all in the digital domain using the AES input on the DWAM card.

For analog sampling I connected a coaxial cable from my RME UCXII Fireface to the DWAM’s Wordclock input to take advantage of RME’s famous Femtosecond technology. This provides an incredibly precise clock, far more accurate than the Emulator’s internal clock, ensuring the highest possible quality when sampling analog signals into the Emulator. DWAM board was installed in here to actually be used, rather than just thrown in for historical purposes.

Here is how the back side looked like originally:

Here is how it looks now:

With 8 outputs available and DWAM board installed our E5000 is now officially E4XT! Well…almost. There are still a few things left to do.

Chapter 5 Hard Disk & SCSI Adapter
The Emulator E4XT Ultra came with a hard disk, so in our unit we have to install a hard disk. There is internal IDE port into which I have installed a relatively “modern” 80GB laptop hard disk which is silent enough that no noise is emitted from my unit. I will format it in FAT, as the FAT file system is far superior when it comes to banks, hard drive space, and overall hard disk management compared to the old (and outdated) E-MU format.

Regarding the SCSI port, I need it for a SCSI-to-IDE CF adapter, which will go to the front of the unit in the floppy bay. This way, I can easily remove the CF card and insert it into my computer, which natively reads CF cards formatted in FAT. This method is much faster to work with than ZuluSCSI.

To be fair, I do have a ZuluSCSI that I can connect to the back of the unit, giving me access to all three storage systems simultaneously: the internal IDE disk, the internal CF card, and the external ZuluSCSI. The advantage of using the CF card is that since Mac or PC computers natively read the FAT file system, this method significantly speeds up sample transfers, banks, programs, etc. The Emulator can also read and save .wav files, making the workflow even faster. This is why I chose not to install the ZuluSCSI in the floppy bay.

I have ZuluSCSI Rp204 and have to work with .ISO images, and you can’t access the card natively. While this is fine on other samplers, on the Emulator, it adds an unnecessary step of taking out the card, mounting the image, and then accessing it. Although macOS can do this, Windows 10 can’t even mount FAT16 .ISO images. This makes the solution I chose, using the SCSI-to-IDE bridge, far superior. For traditional .ISO images of my E-MU sample CD-ROMs, I will use ZuluSCSI connected to the back of the unit via a standard SCSI cable.

There is a better alternative which I would recommend since now it is available as of recently. ZuluSCSI V 6.4. Not only it can work natively with the card but you can access it via USB directly. For Emulator users this literally means one can install ZuluSCSI 6.4 drive in the unit and add a simple USB port adapter on the back of the unit as a sleek solution to access the card, transfer files without any cable clutter or removing the SD card.

Chapter 6 Hardware Restoration
Given the fact that this device is now 25 years old, it would be a good idea to restore its usual weak points: the power supply, the encoder, and the tact switches. Another order to Mouser, and here we are.

The first task was to have the power supply recapped. I also installed a noiseless fan in the PSU case, ensuring that no noise is ever released by this emulator.

I replaced the old tact switches with new ones, making the unit more comfortable to operate as each switch responds to the lightest touch.

And of course, the encoder in the later Ultras wasn’t of the best quality, so I installed a new one. No more skipping values or erratic behavior—it’s such a pleasure to work with now.

Chapter 7 Output Upgrade
I bought this output expander many years ago for the E5000 because as we all know E5000 has only 4 outputs, which is too few for some serious work. With the expander, my E5000 became 12 outputs, which was enough.

Since my Emulator now has 8 outputs, I was thinking about selling this expander, but after some thinking the conclusion was to keep it – especially given how expensive these expanders have become. Plus, it gives me access to the “sound” of the non-Ultra Emulator, the E4X (Classic) as it features the same converters as the Classics. Spoiler alert: the difference is minimal (I have documented it on this website). Back to the bench! At this stage, my Emulator was in individual parts, and it was time to reassemble it all together.

This was a good opportunity to clean the inside of the metal casing.

The freshly upgraded motherboard installed.

With the DWAM card, output expander, and disks installed, this Emulator is now pretty crowded inside. In the picture, you can see the noiseless fan I mentioned earlier.

The back of the unit now proudly sports a DWAM board and a total of 16 outputs. This looks like a serious instrument now.

Chapter 8 E-Synth And Max RAM Upgrade
E-Synth is probably one of the best ROM upgrades that E-MU ever designed. Think of JV-1080-style presets but with much higher fidelity and plenty of complex modulations. It’s a great upgrade that essentially upgrades the Emulator with ROM-pler like features (waveforms in the ROM, presets remain in the memory after power down).

When needed, this board can be disabled from the menu. The machine then reboots, and you’re back to a standard Emulator sampler. The key point is that E-Synth can be used alongside all of the sampler’s functions, but in that case, the memory is limited to 64 MB. If your Emulator only has 64 MB, this doesn’t matter, but if you have 128 MB, you would need to reboot the machine with E-Synth disabled to use all 128 MB.

There is one extremely important thing to understand about the E-Synth. Although it contains some presets on the board, these are not the actual E-Synth presets but rather a generic GM set. Many people were misled by this, thinking, “E-Synth sounds weak and boring,” not realizing that what they were hearing wasn’t even the real E-Synth.

To properly install the E-Synth into the Emulator, two additional things are needed: Flash RAM and the E-Synth programs floppy disk. You load the E-Synth programs from the floppy, write them into the Flash RAM, and only then do you have the actual E-Synth, which retains all of its presets even after the Emulator is powered off. It literally behaves as if it were a ROM-pler. The patches, as I mentioned, are excellent. Anyone who loves JV-1080 and JD-990 types of patches will love the E-Synth.

Here is the E-Synth ROM that I bought many years. Again back when Emulator 4 related stuff was still affordable. Most importantly, it came with the floppy. Without that floppy, don’t even bother with the patches on the card—they have nothing to do with the actual E-Synth.

But what’s the use of this ROM if all of the presets are lost once the unit is powered off? Fortunately, I received E-MU Flash RAM with the E-Synth, something I rarely see these days from people selling E-Synth expanders. With this Flash RAM, the presets remain in the unit even after powering down the Emulator.

I mention this because E-Synth is one of the most sought-after expansions for Emulator samplers, and I hope people won’t make the mistake of buying just the ROM without the Flash RAM and the floppy disk containing the E-Synth presets.

With the Flash RAM installed, we now have E-Synth presets permanently stored in the Resident memory. This is non-volatile memory that retains data even after power is turned off, unlike the Preset memory, which loses data after a power cycle. In the image, you can see that with E-Synth enabled, the sampling RAM is limited to 64 MB, even though the unit has 128 MB installed. When E-Synth is disabled, the RAM returns to the full 128 MB.

I found this 128 MB upgrade on eBay a few years ago. It was gathering dust in a drawer, but with this upgrade project, it was finally time to maximize the RAM.

Chapter 9 Display
The E5000 uses a green display. However, as we all know, the E4XT uses a white backlight high-quality display. Fortunately, there is a company in Germany that offers these displays: https://studio-services.de/. At the time of writing this, their display is still being developed, but it should be available within a few weeks. As soon as I receive it, I will update this chapter, and that will conclude our original mission of upgrading the E5000 into an actual E4XT Ultra. The final photo will be provided showing the final result.

To be continued…


E-MU Emulator 4 Part3: Making sense of its Compressor, Expander and Limiter

Continuing from the first two episodes, we will now examine the behavior of the limiter in all three threshold configurations: center, below, and above. We will also perform some audio normalization and observe which of the limiters applies the strongest compression for those who prefer heavy audio limiting. Dynamic audio limiting is a process used in audio production to control the volume of a signal by setting a maximum threshold. When the audio exceeds this threshold, the limiter reduces the gain to prevent distortion or clipping. Unlike compression, which reduces dynamic range more gradually, limiting focuses on preventing peaks from going above a set level, ensuring consistent and controlled output.

We will skip the explanation of how to read these graphs and what each column and row in this graphics above represents, since we have explained that part in the first episode. Let’s start with the middle row. This is how a typical limiter is supposed to work: after a set threshold, a signal is limited to the desired ratio. In this case, we used 1:100. Once again, we can observe strange behavior on the downward slope. Why this happens, we may never know.

In either case, I think we can conclude that for limiting functions, an external limiter should be used, as we are clearly losing around 3 dB of volume. Right after the audio passes the midpoint in time, the limiter starts applying some extra limiting, dropping the audio from -10 dB down to -13 dB. Afterward, it slowly recovers; however, during this time, strange ripples are produced, as if two functions are fighting each other. Eventually, the audio recovers to -12 dB, losing around 1 dB of volume, and then, after the threshold is passed, the limiter disengages. Here is a full-resolution picture to better illustrate what’s happening:

Ideally, none of what happens in the second part of the audio should occur. This waveform should be completely flat, as it is in the first part of the recording. The reason for this is, as we explained in the first episode, a source was a constant sine wave at a constant pitch was used. There shouldn’t be any of these rippling or volume loss effects.

Moving back to our table above. Looking at the first row, we see the most extreme type of limiter the Emulator 4 provides. Of course, this is created using the threshold center setting. It will literally flatten everything. Use this if you really want to sound loud, although, as many would say, loud = boring after a while.

Looking at the bottom row, as expected, since the threshold is in the ‘below’ configuration type, the affected audio is below our threshold point. Use this to dirty up drum samples recorded in a live environment, as it will keep the original transients while exaggerating all the background noise. Let’s now try the same but with extreme settings.

As we can see (just for fun) I decided to push the limiter to the extreme (a threshold at 70% is something you will rarely use) just to see if the problem with volume loss still occurs—and it does. In the middle row, we can see an inaccuracy in the restoration of the original signal. Although the area is below the threshold, it is still, for some reason, undergoing compression. The two sloped lines (representing the descending stage of the audio) should be parallel, but they aren’t.

And last but not least, let’s see, once we normalize the audio, which compressor configuration is the ‘strongest,’ with the least amount of unfortunate volume loss. Looking at the results, there is no clear winner. Although the third row looks the best with the least volume loss, we need to keep in mind that it’s compressing a huge amount of audio (70%), which is not something we would do in everyday use.

This concludes our exploration of the compressor effect in the Emulator 4 series. It was something I always wanted to do, as I’ve always found the results sounded a bit odd at times. Some of the findings confirm that, but on the other hand, they also inspire us to try some of the more exotic options available and hear the results in more common applications, such as guitar, drum, or vocal sounds. These have much more dynamic content compared to static white noise or a constant-pitch sine wave, which we used here to determine the overall envelope of the compressor/expander curves. It was an interesting journey, in any case.

E-MU Emulator 4 Part2: Making sense of its Compressor, Expander and Limiter

In the last episode we have learned that E-MU Emulator 4 gives us three distinct compressors, rather than one. Sharp-eyed readers likely noticed that we didn’t mention one feature of the compressor—a setting that provides two additional options and is related to the compressor analysis mode, which can be either Peak or RMS based. This wasn’t an omission but rather a deliberate choice to avoid making the text too lengthy—and potentially tedious to read. However, in the case of a compressor, limiter and expander, using the correct mode can be a critical setting worth understanding.

RMS (Root Mean Square) compressors measure the average power or energy of the audio signal over time, which closely aligns with how humans perceive loudness. Instead of responding to short, sharp peaks, they consider the overall “energy” of the signal. Characteristics:

  • Smoother, more natural compression.
  • Ideal for leveling overall volume rather than reacting to transient spikes.
  • Often used for vocals, bass, and mix bus applications where consistent loudness is desired.

An example usage would be reducing the overall loudness variation in a vocal track without reacting to quick peaks like plosives.

Peak compressors respond instantly to the highest signal levels or transients, regardless of the overall energy of the signal. They focus on capturing and controlling sharp, sudden peaks. Characteristics:

  • Precise and reactive.
  • Ideal for controlling sharp transients and preventing clipping.
  • Often used for instruments with pronounced attacks, such as drums or percussive elements.

An example usage would be taming the attack of a snare drum or preventing distortion in a highly dynamic recording.

Feature RMS-Based Compressor Peak-Based Compressor
Response Reacts to average levels Reacts to instantaneous peaks
Perception Matches human loudness Focuses on signal transients
Application Overall leveling, smooth Precise control, anti-clipping
Tone Natural and transparent Can be aggressive

Armed with all this knowledge, let’s now get back to our Emulator 4 and run some more tests. This time, we will test the expander in all three threshold configurations: Below, Center, and Above.

The Expander
A dynamic expander is an audio processing tool used to increase the dynamic range of a signal by amplifying the differences between loud and soft parts. Instead of reducing the range by lowering louder signals, an expander decreases the volume of sounds below a set threshold, making quieter sections even softer relative to the louder parts.

This behavior is useful for noise reduction, as it can lower background noise levels when the main signal (such as speech or music) falls below the threshold. Expanders can operate in downward expansion, where the quiet parts get quieter, or upward expansion, where louder parts are made even louder. This is where our Emulator 4 comes into play as it offers all two options, plus additional one called “Center” which is in a way the combination of the two.

The key parameters of an expander include the threshold, which determines when the expansion begins, and the ratio, which controls the degree of expansion – for example 1:2 ratio doubles the dynamic difference. Unfortunately Emulator 4 does not provide us with rational numbers for the Expansion control (e.g.,1:2, 1:3, etc.) instead is uses Real numbers like 0.50:1 which in this particular case would be equal to 1:2 expansion ratio.

We will skip the explanation of what each column and row in this graphics above represents, since we have explained that part in the first episode. Now let’s start with the third (bottom) row, as it uses the expander in a threshold configuration set to “Below.” This is how your average expander is supposed to work. At around -6 dB, it starts applying dynamic expansion, and everything seems to look correct. However, when we examine the falling slope (the second half of the waveform), we can notice a strange feature: the expansion is not symmetrical.

In fact, it brings us back to the compressor “issue” or feature that we mentioned in the first episode. While I can understand a compressor having such a feature, I can’t figure out why this would be done for an expander, which is primarily a tool for “repair” rather than adding character. What’s happening is that the expansion on the falling slope is not being applied as it should. It misses almost 3 decibels of audio before starting the expansion in that part of the audio. One can’t help but notice the similarity in behavior to the compressor. But then, we have to keep in mind that this is the same compressor algorithm, which I guess explains this “feature”. I know the image is very small for detailed inspection, but in the high-resolution version, I can clearly see how the expander misses the -6 dB mark and starts expanding at around -9 dB. A bug? I guess we’ll never know.

Now, let’s examine the middle row. Remember when we mentioned earlier that some expanders make loud portions of the audio louder? That’s exactly what the expander in the “Above” threshold setting does. As we can see, it doesn’t affect any audio until -6 dB, after which it starts expanding, making the middle of the waveform (the peak) even louder. In this case, it results in overdrive. Therefore, I’d recommend never using normalized (maximized) audio in this configuration, as it will definitely produce distortion/overdrive.

Finally, in the top row, we have a rather exotic type of expansion—a sort of “extreme” expander. This mode combines the previous two methods by attenuating audio below -6 dB and applying gain above -6 dB. This could have potential for percussive or drum-type sounds buried in heavy noise, as this expander effectively removes that noise. Again, be very careful with the gain control, and don’t normalize the audio before using it in this configuration. Here is another example of expansion with different settings:

This time, the original audio was set to -1 dB to prevent clipping phenomena for the two expander threshold types that make loud parts louder. Slightly stronger expansion was used this time, with a 1:2 ratio at -6 dB. In hindsight, I should have set the source to -3 dBFS for even better preservation of the peaks in the middle of the wave (the loudest portion), but when zoomed out so far, it would have been difficult to see other details. So, I opted for this approach.

Let’s start with the third row. Again, the expansion is not symmetrical—something isn’t right in the descending part of the audio. I also noticed “leakage” in the low-energy area, as if the expander didn’t entirely reduce the volume in a 1:2 ratio but suddenly shifted to something closer to a 1:1.1 ratio (or less). I’m not sure why this happens; perhaps I’m missing something.

The vertical scale in all these graphs is logarithmic, which means the displayed volume reduction should appear linear—but it doesn’t. The other two threshold options behave as expected: the “Above” setting makes the area above the threshold louder, while the “Center” threshold option once again shows us a rather exotic, extreme expansion taking place. I guess one could create quite sharp percussive sounds using this threshold configuration. In the next episode, we will look into a limiter and conduct some tests with normalized audio.

E-MU Emulator 4 Part1: Making sense of its Compressor, Expander and Limiter

Among its many tools, the E-MU Emulator 4 features a compressor, expander and limiter for processing audio samples. The manual explains their usage, although not in the most straightforward way. It also includes some rather exotic settings for the threshold in three modes: Above, Center, and Below. The best way to understand how they work is to see them in practice. The explanation in the manual describes their behavior as follows:

  • Above: Only signal levels above the threshold % will be affected by the compressor.
  • Center: Signal levels above and below the threshold % will be affected by the compressor.
  • Below: Only signal levels below the threshold % will be affected by the compressor.
  • The % determines the threshold level as a percentage of 100% of 16-bits.

My understanding is that only in the position labeled Above does the compressor behave in the way we’re accustomed to. In the Below configuration, it acts as an inverse(?) compressor, which can be a bit hard to grasp, while in the Center configuration, it seems to function as a combination of the two. I know it’s confusing, hence let’s move to the graphics instead.

The explanation from the User manual might satisfy some, but it still leaves a few questions unanswered, especially when we factor the Expander into the equation. Instead of trying to explain this in detail, the best approach is to display the results graphically. Each row in the table below shows the settings that were used and the resulting output. Although the source signal is the same, it’s displayed alongside the processed result in every row for clarity, which is why it repeats. In the first series of tests, white noise was used at 0 dB FS, and in the second series, a sine wave was used at -1 dB FS. In all tests, a 10 second long waveform was used.

The Compressor
Let’s explain what’s shown in the image below. There are three columns. On the left, we have the Emulator 4 screen display with the compressor (or expander) settings. In the middle (shown in green), we see the source waveform, which starts at -96 dB, fades in all the way to 0 dB, and then fades out back to -96 dB during the period of 10 seconds. It’s literally a heavy zoomed out waveform display of a simple fade-in and fade-out waveform designed to reveal the envelope of the compressor (and expander). In the right column (shown in green), we have the processed waveform, again zoomed out heavily. Layer below it, in gray, is the outline of the input waveform, making it easier to see how the compressor’s envelope affects the signal. Since we have three threshold types (Center, Above, Below) we have three rows.

Threshold type: Above
Let’s first look at the middle row, which represents the threshold type setting: Above. This setting is how your average (normal) dynamic compressor works. Let’s now focus on the settings that were used. With the threshold set to 50%, it seems to activate at -6 dB, which I guess is correct. Still, it’s a pity they didn’t use a dB scale, as working with percentages is very tricky. It essentially involves trying to manipulate a logarithmic scale using a linear tool. Unfortunately, it is what it is, and we can’t change that.

The ratio was set to 5:1, and we can see the gain reduction falling somewhere around -5 dB. This seems reasonable, as for every 5 dB input, we should get a 1 dB increase. Using this calculation, it’s approximately 6:5, or around 1.2 above 6 dB. Apologies for the image being small (there were simply too many tests / images involved to place at the same page). Looking at the vertical axis on the right side of the graph: the top tick is 0 dB, the second tick is -3 dB, then -6 dB, -12 dB, and so on. So far, everything seems correct.

However, examining the envelope shape, it seems that something is “off”. Either there’s an error in design (which I doubt, as E-MU was kingpin back then), or the compressor was modeled after a very specific type of design. Unfortunately, the manual doesn’t provide enough detail to clarify. We observe a nonsymmetric response during the descending (fade-out) stage, which shouldn’t happen. The signal should be compressed symmetrically in both directions, but instead, on the descending slope, it rapidly loses volume, then pauses in amplitude briefly before almost morphing into expansion.

This behavior is indeed strange, and I’m trying to understand what this design might be modeled after. It’s certainly not a classic opto compressor—it must be something else entirely. Keep in mind that this test uses a 10-second long sweep. Just imagine such a drastic change of volume on short sounds like kicks and snares. We also need to note how the compression seems to continue even after the waveform has reached its peak and passed below the threshold. In fact, compression occurs throughout most of the sample, from the middle to the end, at what appears to be a 5:1 ratio. This is easily noticeable, even on this small image—just observe the angle of the descending slope of the processed signal and compare it to the original, which is shown grayed out in the background. All in all, it’s a rather intriguing and unconventional design!

Threshold type: Center
Let’s now look at the top row, which represents the threshold type setting: Center. This appears to be a compressor that works with the average signal value, seemingly combining the behavior of the second and third rows, which represent the Above and Below threshold settings, respectively. In this configuration, it seems to automatically gain the volume below the threshold while compressing the volume above it. This results in a rather interesting type of compression.

Threshold type: Below
Next, let’s examine the bottom row, which represents the “Below” threshold setting. As expected, it behaves as described—it leaves the area above the threshold untouched while compressing and auto-gaining the area below the threshold. This is quite an exotic and unique compressor design.

Such functionality could be particularly useful, as it maintains the integrity of transients while adding gain to the quieter portions below the threshold. Honestly I’ve never encountered a compressor like this before—it must be incredible for drum and percussive sounds!

Gentle compression
In the image below, we have another example of compression—this time with a mild 2:1 ratio set at 50%. The numbers appear to be correct, although the output should not exceed -3 dB. Between -6 dB and 0 dB, there should only be a gain increase of 3 dB, resulting in an endpoint exactly at -3 dB, rather than the observed -2.8 dB (hi res picture shows peak at around -2.8dB). However, let’s not forget, this slight discrepancy could be a feature of the particular (analog modelling) design being emulated here.

Conclusion
It seems that E-MU has provided us with three distinct compressors hidden under the hood, each offering completely different results and envelope shapes. Some are excellent for “rounding” the waveforms, while others are entirely exotic types of compression. In the next episode, we will explore the similarly intriguing behavior of the expander and limiter, providing tests with normalized data, among other things, and determine which compression technique produces the loudest sound—a trend that seems to be popular these days (though not among the author).

E-MU Emulator Ultra series – a major design flaw and a solution mod

Intro
While sampling sounds from my Nord Lead 2X into Emulator for one project and seeing them later on the computer, I noticed something unusual. The Nord Lead 2 saw wave is a classic upward sawtooth; however, when observing it on my screen, it appeared inverted—it was a downward sawtooth. Additionally, it sounded thinner compared to the original! This left me totally confused.

I eventually traced the issue to the audio jacks at the Main output port, while the Sub output turned out to be fine. This discovery was a shocker for me. I should note that I have an E5000, but since it is an Ultra, and all Ultras share the same motherboard, it gave me an unsettling feeling that all Ultras might be affected.

For those who still doubt whether an inverted phase is an issue, I recommend listening to the two audio files I am submitting and hearing this issue in person: one coming from the Main output and the other from Sub1. On my speakers (Neumann KH120) and headphones (Beyerdynamic DT 880 PRO), I noticed poor bass response from the Main Output. I assume this might vary from speaker to speaker, but you should have no trouble hearing the difference for yourself. I am providing the raw wave file so that anyone is free to analyze the data / audio response in their listening environment.

Sub Output: sub.wav
Main Output: main.wav

Have you encountered this issue with your Emulator Ultra? Share your experiences in the comments below.


“Holy Batman, that ain’t no Nord Lead saw wave! Something isn’t right!”

I eventually designed a modification to address this, assuming some technical knowledge. Hence, I won’t go into extensive detail, as any competent service technician should already know how to fix the issue. However, I will share four junction points where I connected the new wires to pick up the audio and route it to the audio jacks to give you a starting point. Any service technician with an oscilloscope and adequate knowledge should have no trouble performing this modification.

Why the Phase Issue Matters
At first glance, this might not seem like a deal-breaker. After all, inverted phase shouldn’t make a difference. But in practical applications, particularly for bass-heavy sounds, this flaw can cause real-world issues due to the way speakers and headphones process phase differences. Let’s dive into why this happens and how to fix it. Most of the time, the phase inversion between the main and sub outputs won’t have a noticeable impact. But with bass sounds, the problem becomes significant. And if you are mixing your Ultra on the external mixer that has no phase inversion switch then you have a serious technical problem. Here’s why:

Speaker Response: Low-frequency waveforms like bass sounds create movement in speaker cones. An upward ramp waveform (positive phase) will push the cone outward, while a downward ramp (negative phase) will pull it inward. While both waveforms might cancel each other out in a null test, they produce different tactile and auditory sensations in real-world playback and membrane response.

Headphone Dynamics: Similarly, headphones can react differently to inverted bass signals, leading to perceptible variations in sound quality and timbre. This difference can affect your mixing decisions, especially if you rely on consistent output.

For producers relying on the E-MU Emulator Ultra’s multiple outputs for complex routing, the phase inversion can lead to mismatched signals when combining audio from the main and sub outputs. The result? A muddy or inconsistent mix, particularly in the low-end frequencies.

The Solution: Modifying the Main Outputs
After identifying this issue, I designed a modification to fix the phase inversion. It involves physically altering the hardware by cutting PCB traces and soldering new wires. If you’re comfortable with SMD (surface-mount device) work and have the right tools, this modification can restore proper phase alignment. What You’ll Need:

  • A magnifying glass or microscope for detailed PCB work.
  • A high-quality soldering station with fine tips.
  • Fine wires for re-routing connections.
  • Basic PCB repair tools (e.g., trace cutter or precision knife).
  • You will have to completely disassemble the unit and remove the mainboard which is hosting audio jacks
  • Identify the Output Traces: Locate the PCB traces connected to the sub output jacks. You’ll need to consult the schematic or visually trace the connections.

Find the traces that lead to the audio jack tip and ring and cut them carefully. Precision is key here—accidental cuts can lead to further complications. Above is a photo that shows 4 connections onto which you will solder new wires or jumpers (I used the combination of the two). I routed the wire to the bottom side of the PCB to avoid any crosstalk (by wires being too close) and solder them directly into the audio jack connections or onto the PCB trace.  Test the Outputs: After completing the modification, test the outputs with audio software or an oscilloscope to confirm proper phase alignment. Reassemble and Verify: Once you’re satisfied with the modification, reassemble the device and test it with your preferred audio setup.

The End Result
After applying this modification, your E-MU Emulator Ultra will have properly aligned phase across all outputs. This adjustment ensures that bass sounds are rendered accurately, preserving the integrity of your mixes. For producers who rely on the Emulator Ultra for its unique sonic character, this fix transforms a flawed design into a reliable tool. If you’re willing to invest the time and effort, the payoff is well worth it. Have you encountered this issue with your Emulator Ultra? Share your experiences in the comments below!

Main output port now blasting a proper signal that is in phase with Sub output. And good bye to weak Nord Lead bass sound! One think to keep in mind – while this fix resolves the phase inversion, it requires a steady hand and attention to detail. If you’re not experienced with SMD soldering or PCB modification, consider seeking help from a professional. Mishandling the process could damage your Emulator Ultra. Take care and happy sampling!