Recording audio of "noise"

Hi all, I’m working on a project where I need to record samples of what certain rolling wheels sound like when they roll across different ground surfaces. The problem is that I’m located in an urban environment. For a few recordings, I want to capture rolling over asphalt and sidewalk concrete.

So far, I’ve tried to record extra samples without rolling and then samples that I need. Then I use Noise Reduction, pick a sample without roll. The outcome seems a bit off though even after tweaking the defaults many times.

I’m using a samson meteor mic attached to my laptop for reference, maybe this is not the correct mic to use for this job?

Alternatives would be scouting out some indoor locations / parking garages but even then I think I will run into some issues with ambient noise.

The problem is that I’m located in an urban environment.

That’s a very serious problem. Traffic and urban noises is one of the conditions Audacity isn’t particularly good at.

Then I use Noise Reduction, pick a sample without roll. The outcome seems a bit off though even after tweaking the defaults many times.

Correct. I don’t think you’re going to be able to Noise Reduce your way out of this one. Much past a medium Noise Reduction of 9, 6, 6, you will probably hear the reduction in the show as a gargling or tinny sound, and that’s if you had perfect conditions which you don’t. Noise Reduction doesn’t like constantly waving, rumbling and changing noise profiles. We’re good at refrigerator noises, but put a TV or conversation in there and that’s the end of your show.

This is a job I would be turning down. Your choices are go out to the much quieter country and recording there or using a much more serious shotgun microphone.

That’s one of the ways of hearing video dialog without the surrounding sound overwhelming the show.

Matt in a windy interview on The Park Bench, is holding about $1000 there. It looks clunky, but the dialog is perfect. Matt is good at this.

The only other way to hand a difficult sound shoot is to get close. Can you hang out the window with the microphone on a stick like the middle picture? Your problem is exactly why they are doing what they’re doing.


Contact microphone ?

What’s the budget and do you have control over the wheels? Are they yours?

If you can’t move the shoot to someplace quieter (and no echoes), this may be a challenging shoot.


Thanks for the input guys. @kozikowski there’s no budget per se, but I’m not sure if I could justify picking up ~1k in equipment. The goal of the project is to convey acoustic characteristics of different wheels in real world scenarios. I was hoping there’d be a good Audacity-based solution :slight_smile:

I’ll try the contact mic idea that trebor suggested, but I’m not sure if that would be the same. Perhaps I could attach a lapel mic near a wheel and just turn the sensitivity on the mic down? Would that achieve a similar effect?

I was thinking of going on location to other areas, but as kozikowski pointed out this location must also be quiet and without echoes. The local parking garage took out a lot of noise (in one secluded corner) but then I ran into echoing. It’s surprisingly hard to find paved concrete sidewalks indoors.

Many years ago, I had to record some sounds for an audio play, including the squealing sound of a bus applying its breaks.
At that time my selection of microphones was very limited, and there was zero budget.

I made a rigid tube out of chicken wire, about 7cm diameter x 1m long, and wrapped it in towels, leaving the ends free (open).
Then I took the most directional mic that I owned (a $20 electret mic) and wrapped cloths around the handle, so that I could jam it inside one end of the tube, a bit like this:

|. . . . . . . . . . . . . . . . . . . . . . . . .|
XXXX       ___
XXXX______/   \
(_________     )
XXXX      \___/
XXXX. . . . . . . . . . . . . . . . . . . . . . . .

The toweling helped to muffle sounds from the sides and rear of the mic, making it more directional from the open end of the tube.
Armed with this contraption, I was then able to record squealing breaks at the bus station, until told to move along by a bus station jobsworth.

The result was good enough for the play to appear on BBC Radio, and ironically, paid for my next microphone :mrgreen:
So if you’re brave enough to wander around, looking like a complete idiot pointing a roll of towels at things, then that’s my suggestion.

There are cheap ($5-$10) clip-on contact mics for guitars.
They’re designed to pick up vibration from the thing they are attached through, not through the air.
If your wheeled-thing has an engine running it’s going to pick that up, big-time.

Steve, I may very well try that! Looking ridiculous with a giant towel-padded cylinder is secondary to getting the job done :wink: Now to get my hands on some chicken wire. Which also reminds me, the Home Depot nearby has some concrete-paved indoor areas… perhaps they’d be generous enough to let me record there? :laughing:

Trebor, thankfully there are no engines involved or I wouldn’t have accepted this task! Think more like caster wheels. The more “silent” the better. I might give the clip-on a shot and clean it up in Audacity.