Holy Bot

Bedroom music production, gaming and random shit


January 2016

In lack of a real article here’s the corner of the bedroom. Not much have actually changed sinced the last man cave shoot. (I’ve bought and sold some gear, such as another SH-101, another Juno-106 and a Kick Lancet.) The latest addition to the setup is the mighty Analog Four. I’ve also made a couple of tracks in this corner of the world. The item on the far left of the desk is a sewing machine – not mine though.


Drum Versus Drum

Here’s a short demonstration and comparison of two analog drum machines from the early eighties – Roland TR-606 Drumatix and Boss DR-110 Dr. Rhythm Graphic.

The same patterns are programmed on both devices and then cross-cut. The tempo is roughly 110 BPM. Both drum machines were recorded on mono, using high-grade Cirrus Logic converters, via a Mackie 1202VLZ4 mixer. The signal is otherwise dry, no effects or EQ were used.

All individual controls of Instrument Mix on the TR-606 are set to the center, and so are Balance (between drums and hihats/cymbal) and Accent on the DR-110. Accent is only used on step 13 of each 16 steps on both drum machines. Moreover, the closed and open hihats are sometimes played at the same steps, which makes a third hihat sound.

Other than that I strived for a not too muddy, slowish beat so that you’re able to hear the individual sounds, but still in context of a beat.

The TR-606 has seven sounds: kick drum, snare, low tom, high tom, cymbal, open hihat and closed hihat. It has DIN sync and two trigger outs. A cool feature of the TR-660 is the ability to switch between Pattern Play and Write mode while running.

The DR-110  has six sounds: kick drum, snare, open hihat, closed hihat cymbal and hand clap. It also has a trigger out that emits a pulse at such intervals as Accents have been written. The DR-110 has a LCD with a grid and showing other information – graphic.

Small Sawtooths and Low-Pass Filters

I got a few small analog synths that I put next to each other for comparison. The test pattern is defined as follows:

  1. The raw sawtooth waveform of the synth, 100% open frequency cutoff and resonance at null.
  2. Manual filter cutoff sweep, resonance at 0%.
  3. Manual filter cutoff sweep, resonance at 50%.
  4. Manual filter cutoff sweep, resonance at 100%.

The input levels are adjusted to roughly peak at -6 dB on each audio clip (maybe that was a bad decision). All synths were connected to a Mackie 1202VLZ4 mixer before being recorded using high-grade Cirrus Logic converters. No normalizing was added in post.

First is the Korg volca keys. When resonance is added, the volume is intensely boosted. The filter section uses the circuitry of the Korg miniKORG700S (which used dual 12 dB per octave low-pass and high-pass filters that were combined). Given the 128 steps that can be controlled via MIDI, the filter sounds very steppy on high resonance (peak).

Next is the Korg volca bass with the second and third VCOs muted. I’d say it has a little buzzier tone than the volca keys. Its filter is also much smoother, especially on high resonance. It’s a fine-tuned analog filter with a bright and crisp sound, with the resonance going from a clean peak to an increasingly distorted sound. As for the volca keys, the volume jumps with resonance.

The toyish Gakken SX-150 Mark II has a quite nice thick tone, with low resonance that is. Slightly less bottom end content than the volca modules perhaps. Unfortunately the pitch slides some due to me messing up operating the stylus pen. Raising the resonance seems to lower the overall volume. With filter cutoff set to fully open and resonance at 100%, the filter is making a loud noise (hiss). I think the synth has a voltage-controlled filter, Sallen-Key low-pass type, 12 dB per octave.

As a bonus the Yamaha CS01 from 1982 is included. The oscillator (labeled VCO, but is in fact a digital tone generator) lacks of woof and weight compared to the others. The first audio clip is the sawtooth 100% open frequency cutoff and resonance set to low (this model is equipped only with two resonance settings). The high setting follows after. The filter is a 12 dB resonant voltage-controlled filter.

Not sure what conclusion could be drawn from this, if any. However, there are some discussions about which of the volca modules are the best sounding et cetera, and maybe this could help deciding. Although this is just a comparison of their isolated sound engines and filters. Interface, voicing options and such have not been regarded.

P.S. You might be interested in a low-pass filter test I made, running a SH-101 trough the filters of a MiniBrute, a Minitaur and an Analog Four,

Mixer Setups

I wrote about my mixer some time ago, and you might wonder how it’s connected and how recording is done.

There are several options to route the signal flow of the Mackie 1202VLZ4, although my setup is kind of generic and should work for many different rigs. It goes like this: The DAW connects to the audio interface via USB, with communication in both directions. The audio interface, through stereo outs, connects to left and right audio ins of the monitor speakers. The main stereo outs of the mixer routes to the audio interface via line in pair. All instruments and mic go to different line ins of the mixer.

DAW > Audio interface > Monitor speakers
DAW < Audio interface < Mixer < Instruments and mic

In this setup, the main stereo out of the mixer is routed to the line in pair of the audio interface, and the monitor speakers are connected to the stereo output of the audio interface.

If you prefer to have all audio signals (software and hardware) going through the 1202VLZ4 mixer, you should be able to connect the XLR main outs to the monitor speakers, and route the TRS second main outs back to the line in pair of the audio interface. Also, on the 1202VLZ4, there are control room outs with selectable source (main mix, alt 3-4 stereo bus, soloed channels, or the tape input) that you can use to route to the line in pair of the audio interface.

Generally when recording in a DAW, you just create an audio track, and select line in of the audio interface as audio input. You can choose to record in stereo or mono. Don’t record too hot, keep some headroom.

Sometimes I miss being able to record to several audio tracks simultaneously (multichannel recording). Although with Overbridge (Elektron’s integration software) the Analog Four – which only has a stereo output – can now output all four tracks individually to Ableton Live. In that way it can function as a multi-tracking USB sound card of sorts.

Happy New Bass

If you’re reading and following this blog you ought to be interested in bass. And because of that, I’m giving you two – not so obvious – techniques on how to accentuate your synth bass sound.

Using the high-pass filter to boost bass

Okay, so you know what a high-pass filter is right, and that its cutoff frequency is the point at where the filter limits the low frequencies and lets the high pass.

You also know about resonance, and that it’s generally used to give a brighter/thinner sound. (And when the resonant setting is cranked to max, some filters go into self-oscillation and which make them scream.) But when high-pass resonance is added, the note and overtones near the cutoff are boosted – in other words, this is lifting the bass.

Just use keyboard tracking to make the resonant peak follow the pitch of the note and cutoff to follow the keyboard. The fundamental note will now be boosted while the surrounding spectrum is unaffected.

Use two filters in series if possible, set the other to low-pass filter and reduce harsh elements of the sound.

Get bigger bass by focusing on midrange

To get louder bass it’s not always necessary to pump up the level or to boost the lower frequencies, no you could just draw more attention to the bass element. Add midrange to it – it’s almost a mindtrick, and it shouldn’t make the bass any muddier.

So saturate the overtones of the bass or sculpt the thud of the kick drum. This is also valuable when there are several sounds competing for room in the low end.

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