Processing clean audio to sound like degraded shortwave radio

Question

I'm trying to mimic the sound of a cold war era shortwave radio signal from halfway around the world.

I've identified a few things to get me close:

• Bandpass to reduce frequency bands to a narrow spectrum
• Light distortion - mostly clipping
• Noise

But there are a couple of things I can't seem to get right.

Drifting

There's a kind of 'drifting' quality to shortwave signals that I'd like to capture. Probably caused by changing densities in the atmosphere through heat and cold layers - I've tried using a phaser but it's not quite right and just sounds like I've simply put a phaser on the track

Dropouts

A lot of shortwave radio signals seem to have a 'stuttering' quality that appears to be uneven and random - Although they seem to be around 8-12Hz (ish), the timing constantly varies and the level of dropout seems to vary with every instance.

Crackle

I have added noise but there's a crackle that is more uneven that I just can't replicate.

Limitations

I'm doing this within Cubase so I can't make use of any hardware solutions. I'm having to rely on a combination of VST synths and effects.

I don't mind reconsidering everything including the things that I think I've got right so I'm open to almost any suggestion but I'm not prepared to hire a transmitter ;)

I'd love to hear what suggestions everyone else has.

Answer 1

Are you open to a paid solution that will save you a lot of time and last you a long time? Audio Ease Speakerphone has specific modules and presets that achieve what you're looking for, all in one plugin. https://www.audioease.com/speakerphone Others have taken a stab at it, and sure you could try to deconstruct and learn something valuable from each step of this signal processing, but Speakerphone remains such a unique and comprehensive solution. See the "RADIO TUNING" mentions in the manual, https://www.audioease.com/speakerphone/files/speakerphone-manual.pdf

Answer 2

For the drifting effect, try sweeping the frequency on a ring mod effect. Not sure if Cubase has one standard, but ring mod is a good sound design tool to have around. A little goes a long way, as the voice soon becomes unintelligible, but that’s what happens on radio transmissions, so you can perform the effect and record automation data for further tweaking. You can also put a plain old sine wave through the ring mod, sweep the frequency around and layer that behind your dialogue to taste.

Answer 3

You should experiment with a comb filtering effect. Try cloning your audio clip to a new track and restrict the bandwidth even further with the bandpass (BP) filter. Invert the phase of this new track and mix it back in with your original audio. Try sweeping the frequency and changing the bandwidth of the BP filter on the new track, perhaps with automation.

If you're not changing your main track BP filter (both frequency and bandwidth) over time, you should also try that.