Ever wonder what it sounds like to be inside a 3D Printer as it's printing? Well, let's find out!
Step 1: Equipment Used
First off, we'll need to pack equipment for this sound mining adventure.
tl;dr list: Sound Recorder, Microphones, Preamps. Read on if you want to experience gear nerdery.
http://www.aquarianaudio.com/h1a-3.html with a http://www.aquarianaudio.com/contact-mic-adapter.h... contact mic adapter
http://www.amazon.com/Telephone-Microphone-Suction... I can't find the radio shack link right now but it might be worth checking stores). If you're in Europe and want one with some of the limiting circuitry removed, try http://hydrophones.blogspot.com/2010/09/induction-...
Step 2: Where and How To Record
Now that we've got our equipment, where do we put it? We've basically got three options here:
Step 3: Results: Induction Coil Mic
So let's start with the low hanging fruit, the induction coil mic. The print head has all sorts of motors and fans in it running with different sorts of digital control, meaning we're pretty much guaranteed it will make pretty sounds for us. All we have to do is put the mic on the glass over the print bed, and boom:
But what's better than 1 mic? 2 mics above a model, spaced at about the average length between human hears! I panned these mics to reflect their position in this recording, meaning you're basically hearing what would happen if you stuck your head in the print bed and also could hear electrical fields (which you certainly wouldn't want all the time unless you like living in a world of migranes).
In summary: Induction Mics are fantastic at making the future actually sound like the future.
Step 4: Results: Condenser Mics
While I had originally wanted to use shotguns, it turns out all I had access to were REALLY long shotguns that would've been very difficult to mount around the bed of the printer. So, I just used a stereo pair of small cardiods. That said, they picked up the sound of the print head motors quite nicely, even if there was a ton of noise from the ventilation and cooling systems. In the recording below, the first half is unedited recordings. I turn noise reduction on about halfway through to try and take out some of the ventilation noise, but there's only so much you can do in an environment like this.
Step 5: Results: Contact Mics Around Printer
Before we start putting mics directly under the print head, we explored the outside and on the printer bed with them. It turned out that we got some very nice low motor tones putting the C-Series mic again the outer frame of print bed, while the H1-A with adapter picked up some nice things nearer the print head and on top of the glass.
Note that this sample doesn't have noise removal like some of the others. I'll go over this in the post processing step, but you can hear how much noise we pick up from around the print lab otherwise.
Step 6: Results: Contact Mics Under Print Head - Preparation
Ok, now for the grand finale: Let's see if we can get the sound of the material coming out of the print heads! My strategy for this is the model above. I measured the height of the C-Series contact mics, and made a block model that would just barely fit one of them. Then we can shove a mic in it when it's part of the way done, and listen to the rest of the print happen above it. Sounds genius, right?
Step 7: Contact Mic Under Print Head - Consternation
Here's how the plan actually went, with the help of http://www.instructables.com/member/gabrieltaft
Unfortunately, this ended in a LOT of clipping on the recorder, meaning something was coming directly in contact with the mic. We figured out it was the roller hitting it on each pass. The printer wasn't damaged, but it didn't sound great either. Also, there was no real way to tell if we were recording the sounds of the material coming out of the print head.
Step 8: Contact Mic Under Print Head - Desperation
But, when life gives you 3d printed lemons, remove them from the print bed and just put the contact mic directly where they were.
Yup, we made an even bigger mess, and it sounds like this:
You can hear the printer spin up, and then it starts breathing heavily in your ear. I believe that sound is actually the roller wheels again, except this time we've got at least 5-8mm between the mic and the wheels, so we don't get spikes from direct collisions.
Even so, there's still nothing that's obviously sounding like the material hitting the mic. I think the amount it lays down per pass is simply too small to pick up via this method. I don't think it's impossible, just more complex than I'm willing to get for the moment.
Step 9: Post Processing for Noise Removal
Part of the goal of this project is to try to keep the integrity of the sound, removing and changing as little as possible. That said, room noise sucks, and the 3D Print Lab is a VERY noisy room due to the air filtering systems going pretty much constantly. To remove the dull background roar from some of the contact mic samples, I use FIR filters (specifically, either ReaFIR or Izotope Rx4 Denoiser). These allow you to build a filter that "learns" what noise sounds like in a sample, and then removes it from the whole sample. It's not perfect by any means, but with some tuning it allows you to hone in on what you're looking for. Assuming you don't want to go the VST route, there's an instructable for doing noise removal in the open source swiss army knife of sound editing, Audacity: http://www.instructables.com/id/Removing-Excess-N...
Step 10: Conclusion
Well, that's it for our 3D Printing Recording experiment. While the results may not have been exactly what we were looking for, it was still fun and we got some neat sounds out of it.
Now to find other printers to record!