Saturation in the RE-2A (and DC-offset issues in Reason)

The character of the RE-2A comes from a very useful peak reduction method + additional harmonics which are generated by saturating the signal.

Cakewalk RE-2A

The RE-2A is my favourite compressor in Reason. When used on voices/vocals the sound will stay natural while killing some annoying dynamics to make the voice sound more upfront/in-your-face and simply easier to listen to. Not that other compressors are not capable of this, they are, but the RE-2A has its own character and is super simple to operate.

The character of the RE-2A comes from a very useful peak reduction method + additional harmonics which are generated by saturating the signal.

Analog harmonics

Using a perfect sine wave in Thor I am able to find the overtones the RE-2A generates. With Peak Reduction at 50% and higher settings I got this:

  • A3 (root)
  • A4 around -45 db (even, 2nd harmonic)
  • E5 around -50 db (uneven, 3rd harmonic)
  • A5 around -70 db  (even, 4th harmonic)


DC-offset issues!

Then I decided to add a Selig Gain device between Thor and the RE-2A. By adding 24 db of gain the level of the harmonics generated by the RE-2A increases a lot too. Add another Selig Gain device (note: see update below) in series and the RE-2A will start to produce loud harmonics which are almost as loud of its fundamental/root. Unfortunately DC-offset becomes a major problem.

If we start overdriving a signal that contains DC-offset we get a shitty sound. Unfortunately no device in Reason (and no RE I am aware of) is capable of reducing DC-offset! (note: see update below)

In Ableton the fantastic Utility has a DC-offset switch. Smart thinking Ableton, smart thinking! (note: see update below)

Sound examples

Check out the sound examples I made:

  1. orginal loop
  2. loop overdriven with 2 Selig Gain units into the RE-2A
  3. loop 2 overdriven using the Ableton Saturator with DC switch off
  4. loop 2 overdriven using the Ableton Saturator with DC switch on (DC offset is reduced)

Update 1: RE developer Lectric Panda suggested: “Any highpass filter would be able to eliminate DC, MClass EQ’s LO CUT or the Reason mixers EQ HPF down to 20Hz.” And when I asked “But wouldn’t be re-aligning the audio be much better?” he responded with: “From a signal processing perspective, you can’t re-align DC offset in realtime, because you need to calculate the average of the entire waveform. So, the only way you can deal with it in real time, is a high pass filter with a very low cutoff.” Makes sense! So the DC switch on the Saturator in Ableton Live must be a HP filter as well because it runs in real-time.

Update 2: Giles Reaves of Selig Audio pointed me to the manual of Selig Gain which shows how the Mega-Gain Booster Combinator can generate 72 dB boost. That sounds like fun to me 🙂

Update 3: the DC offset errors in my examples are caused by the rx2-loop. Unfortunately some of the included Reason rx2-loops contain DC offset which is a bit silly because ReCycle has that “remove DC offset” one click solution. DC offset is related to analog signals. If a plugin introduces it, it’s a bug.

1 Comment

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.