How to create a rumbling techno bass with convolution reverb

The Dark Rumbling Techno Bass Sound

What is it?

This sound which is becoming very popular amongst techno producers can be characterised as a fairly indistinct and atonal low end rumble. This sustained noted carries a lot of the weight of the low end and works in cohesion with the kick drum and offbeat hats to enforce the groove.

There are a variety of different methods for creating low-end techno basses from the use of tuned percussion to overdriven synthesisers, but in this tutorial we will explain how this sound can be created with some careful manipulation of convolution reverb.

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The Techniques

Before we start, a very important general concept to take away from this tutorial is that these techniques can be applied to many different DAWs or sub-genres. It is not the actual settings that matter, but the thought processes and logic used at each stage which gets us from a raw sound to our final bass sound which can sit neatly into a finished track.

With time, practice and some good ears to listen critically to what is happening with the sound, it becomes much easier to quickly understand what must be done at each stage of the sound design process.

We can create this low rumbled bass sound by splitting the process into a few stages:

1. Place a reverb device on the kick drum

2. Filter the reverberated kick

3. Resample the kick’s audio

4. Place the resampled audio onto a simpler device

5. shape the sound and add motion with a filter

6. increase the sounds density and punch with saturation and distortion

7. make the sound mono compatible

8. control the dynamics of the sound

TECHNIQUES IN DETAIL

1. Place a reverb device on the kick drum

The choice of reverb device and preset used will make a considerable difference to the overall sound. We recommend MaxForLive convolution reverb pro which comes free with Ableton Live 10.

Different presets will have varying amounts of density and low end damping, but this can be tweaked in the further settings of the reverb.

As a general rule we want the reverb tail to be fairly long and dense, but not so long that it carries on for a long time, as this may cause problems later on if it interferes with the kick drum. This can be sorted using a gate or compressor but it is best to choose good source material from the outset.

2. Filter the reverberated kick

This can be achieved with either an Eq8 device or auto-filter. This allows us to shape the sound and jump between the settings of the filter and the convolution reverb till we get a reverberated kick sound that works.

Try out different combinations of filter slope, cutoff frequency and resonance. Sometimes some great and interesting tones can be created with higher resonance settings.

3. Resample the kick’s audio

Now that we have the reverberated kick in the right ball-park, lets get it resampled to audio to reduce the CPU load on our computer and also allow us to solo and manipulate the sound much easier than working with audio that is being fed from the output of a different track.

Ensure to double check the dry/wet of the convolution reverb is set to 100% before resampling to a new audio channel.

4. Place the resampled audio onto a simpler device

Once we have resampled the audio, we can now create a new midi track, consolidate the audio and place it onto a simpler or sampler device for further processing.

This allows us to easily play our reverberated bass up and down the keyboard and also gives us much further control over the filter, amplitude and pitch envelopes if we decide to make changes from within the simpler device.

5. shape the sound and add motion with a filter

At this stage we listen to the sound and decide to add some very subtle modulation with an auto-filter. This modulation could be achieved with pitch bend or a variety of other techniques to alter the timbre of the sound, but in this case we use the LFO section of an auto-filter to carve away some of the higher frequencies of the reverb as the sound decays. A secondary way this could be achieved is by using the damping settings when we initially set up the convolution reverb.

6. increase the sounds density and punch with saturation and distortion

To increase the sounds power and punch we can add extra harmonics to the signal with either saturation, distortion or both. Distortion can range from full on guitar amp style distortion right through to much the more subtle warming of a signal by running it through a gentle saturator.

Distortion and saturation will alter the frequencies within a sound so sometimes a Eq will be needed after the distortion to re-shape the sounds tone.

7. make the sound mono compatible

This is the most important step in the entire process aside from filtering. Most reverbs are stereo devices and will output both a left and right channel of audio that are different from one another. We need to either choose one of these channels or collapse the signal to mono. This ensures a punchy and powerful bass that comes straight down the middle of the mix with no phase issues. Mixes that have bass in the sides of a mix or with lots of stereo tricks in the low end will come across as sounding muddy and lacking focus.

To collapse to mono we can use Ableton’s utility device which allows us to collapse entirely to mono, to reduce the width to a percentage, or even to only collapse frequencies below a given cutoff to mono whilst leaving the higher frequencies in stereo.

8. control the dynamics of the sound

The final stage in this case is to alter the dynamics of the signal. This may require us to compress the signal with a standard compressor if the sound is too dynamic and it may also mean to use a side-chain compressor to make sure the kick and bass are not interfering with each other.

To explain this further. In most genres, and techno in particular, we have to make some mix decisions early on in the production process.

Is the kick going to dominate a certain frequency range or the bass?

Is the bass going to have lots of midrange and sit above the kick, is it going to be pitched to the same note as the kick, or maybe we could pitch it a few tones below whilst still keeping it in the key of the track?

All of these questions come down to your own creativity, but its important to understand that all the questions I just mentioned are relevant to the frequency domain. We can also do some processing to keep the bass out of the kicks way in the time domain. This is done by using a side-chain compressor which ‘ducks’ the bass down each time the kick hits.

Sometimes this may be unnecessary, but in genres such as techno it can definitely help to be mindful of the kick/bass relationship in both the time and frequency domain.

Check the Soundcloud link below to hear the bass in the finished track which is also available to download as an Ableton Live 10 project template file.

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