Empirical Labs EL-DS 500 Series DerrEsser Dynamic High Frequency Fixer

The first entry by ELI into the 500 series format, the Empirical Labs EL-DS DerrEsser is a multi function dynamic filtering device. Available in vertical or horizontal versions. A perfect fit for our EL500 powered rack. In its basic “DS” mode, it is an effective, level insensitive “de-esser” – a device that will adjust the high frequency gain on overly trebly or spiky vocals or other sources in an extremely musical manner. However, unlike other de-essers, the device allows for multiple use of its powerful circuitry.

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.

Need to house your 500 Series DerrEsser? Try the Empirical Labs El-500 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.

“We were primarily interested in the DeEssing, but were pleasantly surprised at the HF limiting. As it turns out, we’re using them for the limiting way more than in De-Ess mode. Who’d have thunk? Excellent job, man. The DerrEsser is an amazing new piece of gear.

We came for the De-essers, but stayed for the HF Limiter.”

– Bob Weston, Chicago Mastering Service

The Empirical Labs DerrEsser is also available in a horizontal configuration for use in 1U horizontal racks like the EL500.

• 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
• Power Consumption - 8 Watts max. 4 Watts Typical