Amazing SFX with contact microphones for under 15 bucks! – Do it yourself

posted in: Creativity, Gear, Production | 2

Last week I posted a video on Youtube about recording sound effects with marbles and a contact microphone. Today I wanna write a bit more about this because this is an incredible way to make amazing sound effects for under 15 bucks all by yourself. So please prepare yourself for this (rather long) blog about how to make amazing SFX with contact microphones and marbles!

Before we move on though I recommend you watch the video itself to get a better understanding of what this is gonna be about today.

What you need


Not much to talk about here, you can get them for almost nothing in any toystore. Or maybe you even have some laying around somewhere.

Contact Mic

As shown in the video, you’ll also need a contact microphone. For those who don’t know what that is, let me quickly try explain it to you.

Contact microphones aren’t that different from your normal microphone. Important is how you use it. While with other microphones you’re supposed to have it in a certain distance to the sound source to make your recording sound nice, with contact microphones you have to stick the mic directly onto the sound source. This makes it work pretty much like a pickup for guitars etc. meaning it takes the vibrations directly from the source without them having to travel through the air first.

You can get cheap ones for less than 15 bucks on the internet. This is pretty much all you have to pay for because the rest you need, you will have at home.


To make your own SFX with contact microphones, you certainly need something to record. No need to specify anything though, find stuff. Any stuff? Yeah. Well, you should be able to stick the contact mic onto the piece of stuff. Otherwise, yeah.

Let’s get started

As you can see in the video, I’ve used five different items. First I used a cymbal from my drum kit. Any cymbal is a great choice because they all have a certain texture to them. Plus they’re made out of quality metal, so when you let a marble roll around on it you get a full and unique sound.

Another interesting thing is the variation you get when you let the marble roll through the bulge in the middle of the cymbal.
So if you happen to have a cymbal at home make sure to record this combination!

The next item I used is a small metal box. I don’t remember what was in there once but luckily this doesn’t matter. The reason I used this is that if you flip it over there is a very distinct texture due to the writing and other things on the lid (watch at 0:55 for that). You can feel these little elevations and bulges on the inside as well so you know what the next step was – stick a marble in there and get going. (What a weird sentence..)

I doubt that you’ll have this exact box at home but any kind of container with a certain texture on the inside will do just fine.

Pile of Stuff (amazing sfx with contact microphones)
My pile of stuff looks kinda fancy I must say

Item number three: A can. I don’t even know why or where I have this perfectly prepared one from but again, it’s not hard to get one of these, maybe you even have one at home already. Then it’s only two steps:

  1. Eat what’s inside
  2. Let the marble roll over the riffles on the sides.

Next item!

Number four is a bit more tricky. What you see in the video is a metal mortar. I bought this on a flea market some time ago and I suppose it’s not that easy to get one like that today. But what matters more than the fact that this is a mortar is the characteristics of this item. It’s a solid, metal object what makes for a very fine and resonating sound. I think you could be successful if you went to your local hardware store and looked for something of similar material. Actually, you’ll be surprised how many cool things you can find in a hardware store!

The last item in the video is your friendly neighborhood pvc pipe. For real, you can get these in all lengths and sizes or you just take something similar to this. In fact it is a real goldmine for self-made SFX with contact microphones. The simple sound of a marble rolling through the pipe from one end to another is such an awesome source for all kinds of sound effects. You’ll see why exactly in the next section.

Also check out this bass pluck sound I recorded with the same pipe!

The editing

Once the recording session is done you can get to the editing!

This is where it gets really creative and interesting. First up though, I should note that recordings made with cheap contact microphones usually lack bass frequencies so you should be prepared to get some of those back in the editing process. But this won’t keep you from making those SFX with contact microphones. You just have to make some adjustments beforehand.

I won’t waste time breaking down how I manipulated all the different recordings step by step. Rather I’ll just give you the two (in my opinion) most impressive examples.

Example 1

The first one is how easy it was to turn the mortar sound into the sparkly, otherworldy, shimmering sound effect with just two VST plugins.

One is called ‘Quadravox’ by Waves Audio while the other one is ‘Hysteresis’ by Glitchmachines.

Hyteresis is a free (!) creative delay VST with crazy modulation and delay options, one of which is the ‘Stutter’ feature. This feature creates a certain type of stuttered delay or something and you can get really creative with it. Very important here is the ‘Reverse’ button that comes with it. As you can probably guess, this reverses the created sound, contributing to this otherworldy, complex sound texture.

‘Quadravox’, the other plugin used for this sound, is also really amazing. It’s pretty straight forward but can make all the difference. You get up to four different pitched delays to your source sound, each with individual time and pitch settings! This makes it incredibly easy to make a whole sound world out of that one recording. Adding a lower and higher octave plus some slightly pitched delays worked best for me but of course this is a matter of taste and what you’re aiming for.

Quadravox Interface (amazing sfx with contact microphones)
Quadravox Interface | Copyright © 2020 Waves Audio Ltd.

You might complain that this plugin costs 100 bucks. Which it does. It was free for some time but now it’s back at normal price.

But in principle you could recreate this effect with stock plugins.

Simply create an fx send track or just duplicate the track with the dry sound in your daw. Now after that, add delays and pitch shifting to said duplicates, crank the Wet all the way and there you go – pitched and differently timed delays.

Example 2

The second example I wanna talk about is the pcv pipe one. As I mentioned before, the sound of letting a marble through the pipe is so simple, yet so incredibly versatile.
What I did to this recording is called ‘Paulstretch’. This is a software you can download for free. It basically works like your normal stretch feature that comes with any DAW. But it ‘ultra-stretches’ your stuff, so to say. You can literally make a 30 minute audio file from a 3 second sample with the so called ‘Hyperstretch’ feature without any strange or distorted artifacts.

In addition to the stretched layer of the original pipe sound I just added the recordings ptiched down a called octaves to add some bass.

The end product now works as a huge impact or atmosphere sound but you could also go the other way and speed the original recording up, add some highs and make it a nice transition ‘swish’ effect


As you can see, there are so many awesome things you can do with just a contact microphone, marbles and random stuff that you probably won’t run out of amazing sound sources to make your own SFX with contact microphones and just a couple of edits. And all this for under 15 bucks! I totally recommend this way to create your own sounds, because you can get so creative with this and also learn some sound design tricks along the way.

Thanks for sticking around again! Also make sure to check out other blog episodes, who knows what interesting content there is waiting for you?

Until next time!

2 Responses

  1. Rubi Rose
    | Reply

    I epsecially love this post!! I think it’s amazing all the free VST’s that you know about and share. Thank you!! <3

    • Lars Grages
      | Reply

      Thanks a lot for the comment! I will definitely do a designated post about my go-to free tools soon! 🙂

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