How to prototype analog audio processing?

Should I merely trial with analog electronics or should I simulate the circuits in software first?

Particularly, I'm interested in discovering new forms of processing. Fine tuned designs over existing designs. I have ideas regarding "what I want to hear", but how should I attempt reaching it?

  • 1
    \$\begingroup\$ Particularly, I'm interested in discovering new forms of processing. Go for it, don't let anybody tell you it's all been discovered. A simulator won't tell you what you're going to hear, but it can be a good way to make sure things are going to work before you build them, or debug what you think should happen when it doesn't. \$\endgroup\$
    – Neil_UK
    Dec 31, 2017 at 12:25
  • \$\begingroup\$ @Neil_UK But how am I supposed to interpret the sound of the circuit using a simulator? Since it's digital and the real electronics would contain analog? Also what tools allow passing audio signals through the circuits and listening the output? \$\endgroup\$
    – mavavilj
    Dec 31, 2017 at 12:27
  • \$\begingroup\$ Perhaps this? livespice.org Any others? \$\endgroup\$
    – mavavilj
    Dec 31, 2017 at 12:29
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    \$\begingroup\$ @Neil_UK LTspice takes wav files as inputs and can generate them as outputs. I've done this multiple times to simulate how certain filters could sound before I build them. Hard to do stuff like monte carlo simulation etc though :) \$\endgroup\$
    – pipe
    Dec 31, 2017 at 12:37
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    \$\begingroup\$ Can't say enough good about Wolf's SpectrumLab for Windows: en.freedownloadmanager.org/Windows-PC/Spectrum-Lab-FREE.html It works intimately with a PC's audio codec, and has lots of tools that can be inserted into the audio path. Learning-curve is considerable, but it is very capable. \$\endgroup\$
    – glen_geek
    Dec 31, 2017 at 18:38

2 Answers 2


A simulation will not tell you anything about the subtleties of what a circuit sounds like, so you should plan to breadboard your ideas with real components. Breadboard sockets are particularly useful at audio frequencies, since you're not dealing with RF or high impedances.

However, as Neil_UK says, simulation can tell you whether an idea is feasible at all, or help you debug a circuit that isn't behaving as expected.

  • \$\begingroup\$ What breadboards would be large enough? \$\endgroup\$
    – mavavilj
    Dec 31, 2017 at 12:40
  • 3
    \$\begingroup\$ That depends entirely on the circuits you want to build! One trick to expanding the capacity of a breadboard is to build up commonly-used subcircuits on something like these Uni-SIP boards, and then plug them into the breadboard to create higher-order circuits. I use them all the time. \$\endgroup\$
    – Dave Tweed
    Dec 31, 2017 at 12:55

My approach to this is generally twofold: 1) Simulate circuits to ensure that things are working as I expect (bias is appropriate, nothing is railed, signal has an appropriate path, etc...) 2) Put on a breadboard and test.

Make sure you keep track of what you build and what you change so you can reproduce it properly at a later time.

Also, I believe that LTSpice has an "audio input" simulation mode so you can actually put in an audio file and hear what the output would be. Depending on what you are doing I would take that with a grain of salt, though, since SPICE models are not always 100% accurate, especially at corner cases.


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