Guitar Speaker Simulations Audio Test

Bob Leggitt | Sunday, 13 December 2015
Guitar amp simulator Mesa V-Twin in close-up showing the glow of its internal valves

I thought this quick addendum would make a useful follow-up to my previous post, which explored the formative years of direct injection in electric guitar history.

I’ve recorded a short audio test, which enables you to hear how the mysterious original Hughes & Kettner Red Box compares with a couple of other methods of speaker simulation. I’ve used both valves and solid state electronics to create some distortion sounds. You'll hear those sounds sent straight to the mixer completely dry, then you'll hear them treated with some speaker simulations. The concept of the test, apart from acting as a sonic reference for some other posts on this site, was to show that speaker simulation is not exclusively the preserve of the tech industry. It’s something we can all achieve using equalisation. The better the equaliser, the more accurate the simulation we can feasibly create.


I’ve narrated the audio test, so you’ll know what’s what, but in case you’re trying to weigh up whether you’ll benefit from listening to this, or whether it’ll basically just be five minutes of your life you’ll never get back, the schedule is as follows…
  • Mesa V-Twin valve pre-amp alone, sent straight to the mixer from its pre-amp output, with no speaker simulation at all.
  • Mesa V-Twin valve pre-amp routed through the Hughes & Kettner Red Box ‘Cabinetulator’.
  • Mesa V-Twin valve pre-amp, sent straight to the mixer, but this time using its own onboard speaker simulator.
  • Rat Mk.II solid state distortion pedal, sent straight to the mixer, no speaker simulation at all.
  • Rat Mk.II solid state distortion pedal, routed through a home-made speaker simulation, consisting of equalisation plus a subtle amount of compression.

Here's the demo...


In the audio stream, I gave details of the very basic equaliser treatment I used to simulate a guitar speaker. You’ll hear that it’s not the most accurate simulation in the world, but it is roughly in keeping with the early commercial simulators – arguably better than some. However, if you want to render a more sophisticated simulation and you have a graphic EQ, you could try the following tweaks…
  • Cut off all frequencies above approximately 6 KHz.
  • Compensate for the loss of high trebles by boosting the ‘bite’ region between 4 KHz and 5 KHz. How much you should boost these frequencies will depend on your personal taste. If you’re a Marshall fan, you’ll want to boost these frequencies more. If you’re more into the classic American distortion sound, you’ll want to boost them less, and you may not feel the need to boost them at all. It also depends on the source of your distortion of course.
  • Subtly boost the 2 KHz area of the spectrum to add a little ‘tubey’ upper midrange colour.
  • Perhaps add some bass around 170 Hz to simulated the rumble of a bigger speaker. This probably won’t be required if you’re simulating a smaller combo.
These are the rudiments of guitar speaker simulation, and the great thing about knowing them is that, provided you have a graphic EQ, they allow you complete flexibility in crafting a cab sound to your exact taste. If you’ve used the above recommendations to EQ your own guitar speaker sim, but it’s just a little lacking in warmth, add a boost around 600 - 700 Hz.