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NEW model! This two-channel, Full Analog Tape Simulator/Optimizer, fattens up any audio signal, is great for tracking, mixing, mastering or enhancing playback. w/ Classic Knee Compression. New X-version incorporates 1176 emulation.

The DerrEsser is a multi function dynamic filtering device, in an API 500 series module format. In its basic “DS” mode, the DerrEsser is an effective, level insensitive de-esser, which is a device that will adjust the high frequency gain on overly trebly or spiky vocal, or other source. By using a crossover technique, and dividing the audio up into a high frequency range and a low frequency range, the DerrEsser can use its Voltage Controlled Amp to turn down comparatively high or harsh high frequencies in an extremely musical manner. However, unlike other de-essers, the device is not limited to just de-essing, and allows for multi use of its circuitry

Besides Bypass, there are essentially four modes of the DerrEsser:

DS Mode – (Bypass Button IN, all other buttons OUT). As a de-esser in the DS mode (HF Limit OFF), one can set the threshold to tame harsh S’s (sibilants) that result from an overly bright singer or from EQ’ing to make a vocal sound aggressive and clear. In this mode, the dyamic action is “level insensitive”, as the detector circuitry compares the High Frequency content to the low frequency content, Overall signal level doesn’t matter at all. When there is enough HF compared to LF, the threshold is exceeded and the DerrEsser starts to turn down the frequencies above the crossover point set by the Frequency control on the front panel. Again, great care was taken to ensure this DS section meets the Empirical Labs reputation for originality and ease of use. We use the latest technology VCA, specially selected for glitch free, distortion free, and noise free performance. The time constants were carefully selected and the corner frequency is user adjustable with a high performance active crossover.

HF LIMIT – (Bypass Button IN, HF LIM IN, all other buttons OUT). In this mode, the DerrEsser looks at the general level of the High Frequencies only. Think of it as a high frequency compressor. If there is enough high frequency content to exceed the threshold, then gain reduction occurs. It IS level sensitive, but responds much more to high frequencies. This mode can also act as a de-esser but is more of a general high frequency smoothing device.The HF limiter is probably the first carefully tailored soft knee HF limiter in existence. We believe both the DS and HF LIM modes offer the highest performance of any similar device

HIGHPASS – (Bypass Button IN, Listen IN, HP/LP OUT, HF LIM doesn’t matter). By using the “LISTEN” Function, the user can employ the superb filter circuitry inside the DerrEsser to process their audio. With the LISTEN button IN, and the HP/LP switch OUT, the user will be hearing the high frequencies that are being controlled with the dynamic/compression circuits. The corner frequency is adjustable by the Frequency knob. Once the LISTEN switch is engaged, all bargraph LED’s should light as indication.

LOWPASS – (Bypass Button IN, Listen IN, HP/LP IN, HF LIM doesn’t matter). With the LISTEN button IN, and the HP/LP button IN, the user is now listening to the low frequencies, those not affected by the VCA and dynamic/compression circuits. This is a 12 dB per octave filter whose corner frequency can again, be adjusted by the Frequency knob.

How many times have we heard ourselves, other engineers, and even musicians say “I like the sound of tape, it’s sooooo musical”? We hear it in recording schools, we read about it on forums, we think about it in our spare time; but seriously, who among us who isn’t on the wrong side of 40 has really experienced tape? …or enjoys the inconvenience of tape machines alignment?

Enter the FATSO “EL7” (Full Analog Tape Simulator & Optimizer), which can help eliminate the pining for the forgotten days of great big clunky analog tape machines (and ALL of their associated headaches!!). No longer did the production team have to decide between Scotch 250 or Ampex 456; no longer does the mix engineer have to decide between BASF 911 or Zonal 999 for final mixdown. No longer would engineers argue the merits of an Ampex ATR-102 vs a Studer A-80-RC because the FATSO can give you the positive attributes of ALL of these things, in an adjustable and repeatable manner, without having to stress over sticking with an initial decision!!

The FATSO can give you the same “harmonic generation” and “soft clipping” you hear when using tape or “classic” tube based devices. The FATSO can give you the “high frequency saturation” you could find by driving tape a bit harder than the design engineers had hoped you would (especially true of Ampex 456!!). The FATSO can give you the sweet high end and intimate harmonic overtones of transformers; the analog anomalies that are associated with the “classic” equipment of the 60’s, 70’s and 80’s, all without constant calibration or the “stop and wait” rewind time “vibe breaker”.

The FATSO has 4 meticulously tweaked compression modes. There is the “BUSS” setting that gives gentle transient saturation that is synonymous with tape, and settings reminiscent of the SSL® “Quad Compressor”. “SPANK” gives you the subtle knee followed by the hard limiting many of us grew to love on SSL® “E Series” consoles. The new “ELEVEN” setting gives you the wonderfully unique texture of a vintage 1176 LN run at 20:1 set to its slowest attack (which is still quite fast!) and rather quick release that nets the full force and unique impact of the transients of a sound (think snare drum) with radically limited dynamic range throughout the rest of the signal. Then there is the TRACK-ing compresso,r which is closest to the classic Empirical Labs EL8 “Distressor” sound, and even easier to use.

Additionally, there are seven (7) different “warmth” settings which help emulate different tape formulations and machine anomalies, along with the greatest button ever installed on any unit ever built: the “TRANNY” button which gives you the final “over the top” harmonic content, compelling low frequency focus, while adding breath and urgency to any sound it meets.

With the choice of XLR or ¼” inputs along with the ability to link several units together for 5.1 operation, the FATSO can cure any of the lameness found in the most common analog to digital converter sets, while giving your music the width and breadth that makes folks wax nostalgic for $300 reels of tape and 500+ pound tape machines.

You have already heard the FATSO thousands of times on major and minor recordings over the years! If you’re serious about your recording work. you owe it to yourself to arrange a demo from your favorite reseller in order to discover the magic you can uncover with this unique instrument (that doubles as a piece of your recording kit).


Arguably the coolest and most unique device in the Empirical Labs arsenal, the FATSO (Full Analog Tape Simulator and Optimizer) is a digitally controlled analog device that gives musicians and engineers easy access to many of the desirable characteristics exhibited by older tube and Class A electronics and magnetic tape mediums. This two channel audio processor musically integrates frequencies and transients, increasing the apparent volume while keeping tight control over peak levels.

With the FATSO, recording studios and audio production facilities can enhance and soften the sound of Hardware Digital Recorders (HDRs) and Digital Audio Workstations (DAWs). Mix engineers will have the option not to have to use bulky, expensive analog tape recorders to get the warmth and sweet high end they’ve come to rely on for so many decades. Owners of DAWs and HDRs can finally put a stop to complaints about the coldness and brittle edge of their mixes and instruments. Even audiophiles can benefit from the FATSO, bringing back the warmth and ambience of LP’s and tapes to their CD players and other digital reproduction mediums

As with most Empirical Labs products, the unit is incredibly easy and fun to use. Large Distressor-style knobs control the input and output levels. Four meticulously tweaked compression modes - including the extremely popular “Buss” setting and the legendary “Spank”, a subtle knee followed by hard limiting resembling the SSL talkback compressor - can be selected (and combined!) with the push of a button. Seven different high frequency saturation “Warmth” settings are accessed just as easily. The FATSO also features switchable transformer circuits, which can add the musical artifacts generated by classic devices like NEVE, API, etc such as low order clipping & inter-modular distortion, transient clipping... and some other very musical nonlinearities. True to it’s name, the FATSO Jr. is rather sturdily constructed - you’ll be impressed with how well built it feels when you first lift it out of the box.

The FATSO Jr. has been the “secret weapon” of studio and live engineers for many years, allowing them to add the elusive magic of vintage gear to their sound. Once you start using it, you’ll never want to be without it!


Harmonic Generation and Soft Clipper (Distortion Generation) - this class A circuit gently rounds the peaks like saturated tubes or tape.

High Frequency Saturation (Warmth) - a one-of-a-kind dynamic low pass filter which softens high frequencies when they “pile up” on a source.

Transformer & Tape Head Emulation - a simulation of the effect of input and output transformers of older devices, which adds the low frequency harmonics that characterize characterize them, as well as analog tape.

Classic Knee Compression - your typical automatic leveling device found on just about every instrument and vocal track as well as on the overall buss, done Empirical Labs compression – smooth and sweet, but in your face!

  • Frequency response - 2 Hz to 60 kHz in clean audio mode (+0, -3 dB).
  • Dynamic range - 110 dB from maximum output (20%THD soft clipping) to minimum output.
  • Greater than 100 dB signal to noise.
  • Distortion/Saturation range - between .06% and 20% depending on mode and settings.
  • Warmth Section – Dynamic sliding LP filter with HF gain reduction shown at 20KHz
  • Soft clip features modeled after broadband tape saturation, but WITHOUT THE NOISE!
  • Smooth clipping up to 20% THD
  • Compressor Time Constants - Attack range 1mS-60mS. Release range .05 sec-3.5 sec.
  • Attack and Release are set by the compressor selection
  • Compressors easily modifiable by users. Future proof.