Antelope Audio Impresser
Classic Knee Compressor

6. Distortion Tips

The Impresser distortion modes are designed for subtle analog distortion. Engaging “2nd Harmonics” gives out “Class A” tube-like warmth, producing 2nd-order harmonics when compressing. Likewise, “3rd Harmonics” adds both 2nd and 3rd order harmonics for a sound similar to tape distortion.

To obtain analog tape saturation, set the ratio to 2:1, turn on 3rd Harmonics, and add about 3db of gain reduction. Use fast attack and release times. Try a higher ratio and more gain reduction to emulate over-saturated tape.

Bear in mind that going over 5dB of gain reduction will sound less like tape and more like compression!

7. Starting Points For Different Instruments

Here are some example settings for treating different instruments with the Impresser!

7.1 Vocals – Standard
Ratio: 6:1
Attack: 5
Release: 4
Apply 3dB to 17dB gain reduction

7.2 Vocals – Classic Compression
Ratio: 10:1 (Opto mode)
Attack: 10
Release: 0

7.3 Vocals – Aggressive Compression
Ratio: 6:1
Attack: 2.5 to 3.5
Release: 0 to 2
2nd Harmonics engaged
Apply 17dB to 20dB of gain reduction, which will be felt on louder passages only

7.4 Bass
Ratio: 4:1 to 6:1
Attack: 5
Release: 4
Use fast attack and release times to keep clacking sounds from pumping. Apply liberal gain reduction.
Try Opto mode

7.5 Electric Guitar
Start with a ratio of 6:1 and all knobs at noon. From there, apply fast attack and medium release times to smooth out the pick attack. To get rid of harshness in solos, play with the band-pass filter control to bring forth softer notes and sustain higher notes. Feel free to try Opto mode as well.

7.6 Acoustic Guitar
Ratio: 6:1
Input: 7
Attack: 2
Release: 5
Output: 7

7.7 Piano/Keys
Ratio: 6:1
Input: 5
Attack: 5
Release: 5
Output: 5

Start with these neutral settings, then lower the attack and try slightly increasing the release. Opto mode sounds good on piano, too.

7.8 Drums – Snare, Kicks, Toms
Ratio: 3:1 to 6:1
Input: 6
Attack: 5
Release: 5
Output: 6

⦁ Short release times bring out drum decay.
⦁ If crackling occurs, try longer attack and release times.
⦁ Try Opto mode for kick drums, with Attack on 10 and Release on 0.

7.9 Drums – Room Mics
Ratio: 20:1 or Nuke
Input: 10
Attack: 6
Release: 2.5
Output: 6

For a John Bonham type of larger-than-life sound, try setting Attack to 5, Release to 3, and applying up to 20dB of gain reduction. Feel free to add some grit with the 2nd and 3rd harmonics distortion as well.

8. Emulating Classic Compressors

The versatile architecture of Impresser enables convincing emulation of nearly all classic compressor designs. Here’s how to get Impresser to take on the personalities of some well-known units!

8.1 Opto (LA-2A, LA-3A, LA-4A)
Switch to 10:1 ratio and adjust the Attack to 10, Release to 0, Input and Output to taste. Attack settings above 4 keep the opto feel. Faster attack times provide a more aggressive sound. Adding 2nd and 3rd Harmonics to the concoction gives out a tube-like character.

8.2 Over E-Z Type Sound
Set ratio between 2:1 to 6:1, Attack to 9, Release to 2. Don’t use distortion.

8.3 1176LN Feel
Set the ratio between 3:1, 4:1. 6:1, and 20:1 to simulate the 1176LN’s original four ratios. Set the Attack 0 to 3.5, Release 1 to 10.5, and don’t use distortion. Keep the Attack below 4, as the 1176LN has extremely fast attack times.

8.4 Fairchild IGFET
Set ratio to 6:1, Attack between 3 and 5, Release between 2 to 7. Keeping Attack and Release at 4 is a good starting point.

9. Contacts

Having difficulties with the Impresser or anything else Antelope? Get in touch with us by the following means:

European Direct Support Line
+44 2039578550
10:00 a.m. – 10:00 p.m. (EET), Monday – Friday

USA Direct Support Line
+1 734 418 8661
7:00 a.m. – 6:30 p.m. (EST), Monday – Friday

Online (live chat and e-mail)
Antelope Audio Support Page

10. Glossary

Attack: Adjusts how quickly the compressor starts to work after the signal exceeds the compression threshold.

Release: Controls how soon the compressor will stop after the signal goes below the compression threshold.

Ratio: Controls how much compression is applied. For example, a 3:1 ratio means that every time the input signal crosses the threshold by 3dB, output signal will be attenuated 1dB.

Threshold: The Threshold is the level above which the compressor considers the signal too loud and starts applying compression.

Knee: Knee and Attack have a lot in common, but they are not the same. Like Attack, Knee controls how the compressor will react once input signal passes the threshold. Hard Attack makes the compressor engage immediately while Soft Knee shapes its attack time to make it slower and smoother.

Opto (optical) Compression: The main influence over how a compressor sounds is the gain control element. This can be a tube, a FET (field effect transistor), a VCA (voltage-controlled amplifier), a digital processor, or an optical photocell (a light source and light detector). Opto compressors are based on the latter. A typical characteristic of theirs is non-linearity, which results in a very distinct sonic character.

Thus, transparent compression is not usually their forte – although there are modern designs that come close to VCA compressors’ precision. But that’s certainly not what the Opto mode on the Impresser is going after! Rather, it nails the larger-than-life sound of classic opto compressors like the LA-2A, 3-A, and 4-A. You can hear these on countless records, often used to add presence and warmth to vocals.