high frequency intermittent noise

Here is another recording taken early in the morning with no subway cars under my building:

https://clyp.it/ae0xgczb

Note there are 2 noises:

1. The consistent hash/whine
   
2. The intermittent noise
   

This is the worst I've heard it in the mornings.  It only lasted for a minute and a half, enough for me to record the 1 minute clip.

The Furman has buffered me from my refrigerator noise, I would hear a *click* in my system when the refrigerator would turn on, now it's silent.

@whart 

There is now cell phone reception in the subways too.  So each subway car or perhaps the subway tunnels are lined with these devices.

@james1969 - alas, another quiet oasis in NYC gone to hell. 
This thread is fascinating to me for the deductive work- i know suffering the noise sucks--we've probably all had our share of imponderable issues at times- but i'm learning as i read this. 
The solution will probably be something obvious and stupid (e.g., did you plug it in?)
In the meantime, here's my tin foil hat conspiracy theory connect the dots, Elvis is an alien idea: if the subways have these critters, and the noise coincides with the passage of a subway under or near your building....?

The subway goes right under my building.

@james1969 ,

You would need to establish a direct correlation between the subway train passing under your apartment building at the same times you are hearing the RFI noise through the speakers of your audio system. You need to start keeping a log.

I have been trying to research, over the net, noise in an audio system caused by cell towers.

From the Link toddverrone posted.

Keep phones away from audio gear

Stages are carpeted in audio gear. The farther mobile phones are away from this equipment AND (very important) their cabling, the less likely they are to interfere. Most good engineers seem to impose an effective but draconian policy on talent: absolutely no cell phones anywhere on stage or off stage. All personal electronics are to be left in the green room, no exceptions, and all those in violation, famous or not, are chastised. Engineers everywhere would be wise to adopt similar policies.

@james1969

LOL, "Do you know where your cell phone is at this very moment?" For a test turn the thing off and get it as far from your audio system as possible.

What wall is your audio system set against? Out side wall? Directly facing cell tower?
Adjoining wall with neighbor?

When it comes to GSM buzz, not just any ferrite core will do. You must use one that has the correct number of turns and is made from material optimized for attenuating high frequency GSM signal, which can be anywhere from 800 MHz to 1800 MHz.

GMS buzz?
LTE?
TDMA ?

In layman terms please!

Re: On-site Cell Tower Interference
« Reply #2 on: October 03, 2012, 10:03:56 pm »

It’s highly unlikely the cell site will induce RFI problems with any properly designed audio equipment, or any other system inside the building.

First, cellular/PCS sector antennas are highly directional. Directly below the antenna is a major null with signal levels easily being 50-70dB below on axis carrier level (based on antenna type and design) before building attenuation is considered.

Second, you can request engineering data from the cellular/PCS service provider(s) and/or tower management firm which will tell you antenna make(s) and model(s), antenna array(s) design, location(s) and ERP of each TX antenna. An outside RF consultant can assist in determining RFI potential. Logged Henry Cohen

CP Communications www.cpcomms.com
Radio Active Designs www.radioactiverf.com Tom Young

http://forums.prosoundweb.com/index.php?topic=140277.0

Send that guy an email, if possible.

@james1969

Can you see the antennas on the tower from your window? Higher? Lower?
https://www.google.com/search?source=hp&ei=mKoNWpfxCMrPmwGUyrK4Bw&q=picture+of+antennas+on+c...

Here’s some EE talk.
https://electronics.stackexchange.com/questions/32830/why-does-gsm-cause-speakers-to-buzz


Jim