This channel is sponsored by u-he

u-he are makers of award-winning software synthesisers and effects including Diva, Repro-1, Zebra2, Hive, Bazille, Presswerk and Satin.

Visit U-he

Making It Steeper

The OB-8 has a 24db/octave filter. In this case, whilst it is more aggressive in terms of frequency removal, its maximum resonance is tamer.

Pic 17a - f.plot - noise only - 4-pole - full res.

An altogether different beast is the Roland TB-303, which attained classic status despite its clear deficiencies – on paper at least. It has a choice of two simple wave shapes and an extremely basic envelope, but the filter has a distinctive watery quality, most noticeable when resonance is increased and the cutoff is controlled by the decay envelope. As the TB-303 has no means of external parameter control, this has to be done by hand in real-time.

Here we used only the square wave and tweaked filter cutoff, resonance, envelope modulation amount and envelope decay time. Notice how the low end drops in level as resonance is pushed up.

Many classic uses of the 303 involved the addition of a distortion pedal (Josh Wink’s ‘Higher State of Consciousness’ being one classic example), but the sound of an unprocessed 303 is still immediately recognisable. Here we see how a filter sweep of a raw sawtooth wave sounds with three different resonance settings:

Pic 21a - spectrogram.

Pic 21b - spectrogram.

Pic 21c - spectrogram.

As mentioned earlier, Bob Moog was famous for – amongst many other things – his 24 dB/octave low-pass filter. We can experiment with this in the digital realm by using the UAD Moog Multimode Filter and FilterFreak both switched to 4-pole low-pass mode.

Both plugins allow you to tweak how the audio level interacts with the filter. Driving a filter harder and/or pushing up the resonance can lead to saturation – something that works well if a ballsier tone is required.

Once again, we can put Diva to the test with an analogue-style saw wave and a ‘vintage’ 24 dB/octave filter sweep.

20th October, 2015

Technique is sponsored by


u-he are makers of award-winning software synthesisers and effects including Diva, Repro-1, Zebra2, Hive, Bazille, Presswerk and Satin.

Download the demos and try them for yourself at




  • Thanks !
    Good basic article, but I would assume the typical reader of attack mag already pretty much knew about filter frequency charts resonance, poles, comb filters, etc.
    It would have been maybe interesting after a short introduction covering these topics, to move on to discuss in more detail the phase effects of filters, the different uses and possibilities of modulations routes, what makes a moog, DSI, arturia filters, sound so different, etc…

  • Good article! I enjoyed the example filter types (Oberheim, Korg, Moog, Arturia). I often look for ways to describe differences in filters. I also appreciated the learning that analogue filter slopes are rarely linear. Guess I’ll have to go play with Ableton Lives new Cytomic filter types.


Leave a Reply

Your email address will not be published. Required fields are marked *

You currently have an ad blocker installed

Attack Magazine is funded by advertising revenue. To help support our original content, please consider whitelisting Attack in your ad blocker software.

Find out how