The DocDerrEsser features 1 EL-RX and 1 EL-DS installed into a EL500 1U horizontal rack.
One of the newer members of the Empirical Labs family is the DocDerr, a 500 series multi-purpose tone enhancement module that houses six different sections of digitally controlled analog processing. With over two years of meticulous development and testing behind it, the DocDerr provides an unprecedented combination of power and musicality in a compact, easy to use format. Empirical Labs' first compressor in the API 500 format.
An extremely low-noise preamp capable of working with line level or instrument level signals, is followed by four sections of EQ combining a two position high pass filter with three parametric bands, each with its own set of carefully tuned frequency presets. An internal jumper can turn the DocDerr into an unparralled instrument preamp with 16dB of gain, ideal for acoustic guitar, bass, synths, exotic plucked instruments, etc.
The versatile EQ is followed by a unique dynamics section which offers renowned Empirical Labs compression at an unprecedented price, and an extremely musical tape emulation circuit that softens and tames high frequencies and transient spikes. We believe it's the best single knob "knee" compression available in this format.
One of the pivotal features of the DocDerr is the "Mix" knob which allows the user to blend the uncompressed EQ's signal with the compressed and saturated signal. This parallel compression technique, used by top recording and mixing engineers for many years unlocks a whole world of sonic possibilities.
The DocDerr is ideal for tracking, for fine-tuning tracks during mixing, or as a killer solution for the gigging "acoustic" musician in search of studio quality tone control. It is indeed a Tone Doctor...err... DocDerr.
The Derresser has four modes
DS MODE - (Bypass Button IN, all other buttons OUT). As a de-esser in the DS mode (HF Limit OFF), the threshold can be set 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. The DS threshold is not level dependant, and compares the amount of high frequency content to the low frequency content, so adjusting the overall level does NOT affect the threshold. Easy to set and forget. 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 essentially acts 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 is more of a general high frequency smoothing device, and is probably the first carefully tailored soft knee HF limiter in existence.
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.
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.
Model EL500 Rack
As far as value, it's hard to beat 500 Series compatible modules. Their smaller physical size let you get a lot of performance out of a smaller space, they tend to cost less than their larger counterparts, and - the best part - you can customize your own combinations of them.
When ELI started making our own 500 series products, we looked at the power supplies on the market and couldn't help but notice a need for a better single height dual module rack unit. On other single height rack units, the modules protrude from the front panel, and don't look sturdy or attractive. Power supplies were often noisy, frequently reducing the performance of any module mounted in them. Also, only XLR ins and outs were provided to the user, limiting the device's applications.
The Empirical Labs EL500 rack eliminates these obstacles. At the heart of the unit is a super quiet power supply - over 30 dB quieter than some supplies we've seen - that will ensure optimal performance from any compatible device.
All 500 series modules will flush mount cleanly in the EL500, providing a much more professional look and feel. The EL500 offers both XLR and phone rear panel inputs and outputs to allow it to interface perfectly with any system.
In addition, a ¼" instrument preamp/direct box input is provided on the front panel, which will automatically switch the left 500 module's input to this front phone jack once something is plugged into it - a feature we're sure will prove to be extremely useful. In fact, it has become the first call bass DI for many engineers. Switches to link compressors and engage a 48V phantom supply are also provided.
Whether you're already invested in 500 series modules or they're something you're thinking about adding to your arsenal, the EL500 rack will make any 500 series compatible module perform ideally and interface effortlessly into just about any audio application.
Six digitally controlled sections of analog processing
Frequency response - 3 Hz to 180 kHz on eq section (-3dB points).
Dynamic range - 120 dB from maximum output (.5%THD soft clipping) to minimum output. Noise floor with Mix on 0 is typically - 91dBu.
Distortion range - between .0006% and 10% at 1KHz, depending on mode and settings
Maximum Input before hard clipping - +22dBm, " Line In" mode. Maximum Output (Mix at 0) - +28.5dBm
Compressor Dynamics Time Constants - Attack time is around 1mS. Release .2 sec, fixed internally. Stereo Linkable for stereo tracks. With the EL500 powered rack, the push of a button enables linking.
Input Impedance - 120k Ohm, Instrument In Mode, output impedance is less than 75 ohms. 20K input impedance in balanced Line in mode.
Freq. Response is 3 Hz to 120 kHz (-3dB points).
Dynamic Range - 115 dB from maximum output (.5%THD soft clipping) to minimum output. Transformerless noise floor typically - 93dBu.
Distortion Ranges between .0035% and .01% depending on mode and settings.
DC coupled Input and Outputs
High quality audio caps used internally.
Input Balanced, Output single ended but with balanced impedance. Pin 2 hot
Input Impedance is 20k Ohm. Output impedance is less than 51 ohms.
D-S Dynamics Time Constants - Attack time is less than 1mS. Release .04 sec, fixed internally.