Philly: Chirping noise. Caused by trains, apparently.

Anyone recording in Philadelphia should pay particular attention...

This article came out today describing a problem we've been having at our studio for about the last year. It's a strange seemingly random, sustained chirping noise that is amplified by, well, everything. Since our studio is in a warehouse where they do retail display fabrication, I figured that bossman probably got some new power tool that was making the noise. Turns out I might be even more SOL than I thought. Read the article, download the mp3, and if you're brave or have some time to kill, browse the reddit. Let me know what you think.

Article:
www.citypaper.net/news/Hot_Tracks.html


Mp3s:
http://railsounds.org

Time Hole:
www.reddit.com/r/philadelphia/comments/1dlhfx/this_sound_is_interference_caused_by_the_new/

"The solution was too good..."

no, no it wasn't. Instead of killing the noise being transmitted, they tried to scrub it from the receiving end... That's not a solution at all, that's a bandaid, and a bad one, at that.

The power utility around here uses test tones in similar fashion.  Once you hear them, you always hear them.  I've heard them on released records. 

I love the part where the train manufacturer designs some notch filter box for the train speaker system and gives one to the thread starter to use on all recordings. Yeah...

SkunkFunk said:

I love the part where the train manufacturer designs some notch filter box for the train speaker system and gives one to the thread starter to use on all recordings. Yeah...

Click to expand...

I feel guilty laughing  ;D Unbelievable!

A few years ago we designed a very nice Studio with my professional company for a client here in Switzerland - near by the local train station. after some testing, specially with single coil telecasters the client refrained from actually building the place. really a pity for the project in general and for the client. we did some additional testing but the return current from the trains (it rides back to the power supply and distribution through the tracks but also through ground) was so great we could not find a solution to make the place quiet. it's a electromagnetic field so simple shielding will have almost no effect. adding a mu-metal sheet was just not an option for a 150m2 large place ;-).
in an other project we had similar issues with the hearing aid system (induction loop). the basic hum pickup from some power line in that venue was so big it would almost override the signal. the printers shop beneath the room was supposed to emit that noise but even testing when the shop was not in operation proved not to be making the problem go away.

so three basic lessons learned:
- before investing in a studio do test the place with a simple single coil / amp setup. fender telecasters are a good choice....
- the noise will usually not be low frequency as you might expect from the 16.6 / 25 / Hz train line but would rather come from the train regulator. modern trains have a frequency converter to adjust the motor power, think of high power switchmode power supply with bad or no line filtering.
- current return might take an unexpected path an will be very difficult to shield properly...

- Michael

Isn't this what the FCC is supposed to be regulating? (In the us)