Help identifying interference (sample included)!

[Karri]

I'm doing a reality show at the moment and am sometimes getting this strange interference on wireless.

The wireless in question is a Sennheiser 2000 series with a DPA d:screet 4060 mic going into a Nomad. Like you can hear from the sample, it is a quiet pulse not too far from a digital "phone ring" sound. Now I want to ask if anyone might recognize what it is? I'm guessing it might be 4G or 3G phone interference or some other type of interference from a smartphone bleeding into the signal? If it is, then I suppose I'm S.O.L. since the talents of the show are on their phones all the time. Luckily the interference is not worse than that.

interference.wav

[VASI]

Hi Karri,

One: http://blog.rfvenue.com/do-cellphones-and-wifi-interfere-with-wireless-audio-equipment/

Two: http://blog.rfvenue.com/how-to-prevent-cell-phones-from-interfering-with-audio-equipment/

[Karri]

Well, certainly not many phones operate with GSM nowadays (unless your provider has no 3G/4G coverage in the area) and as you can probably hear, the sound is totally distinct of how the classic GSM interference sounds like. But if it isn't the phones, I'd certainly like to know what it is. As we can hear, it also doesn't mess with the signal so far as to distort the voice or anything, it just gets mixed in.

[WJJZ1069]

Hi Karri,

One: http://blog.rfvenue.com/do-cellphones-and-wifi-interfere-with-wireless-audio-equipment/

Two: http://blog.rfvenue.com/how-to-prevent-cell-phones-from-interfering-with-audio-equipment/

​Has anyone actually used an RFI Choke on a wire? What were the results?

[syncsound]

Well, certainly not many phones operate with GSM nowadays (unless your provider has no 3G/4G coverage in the area) and as you can probably hear, the sound is totally distinct of how the classic GSM interference sounds like. But if it isn't the phones, I'd certainly like to know what it is. As we can hear, it also doesn't mess with the signal so far as to distort the voice or anything, it just gets mixed in.

​True, though if your service reception is limited, a phone on T-Mobile or AT&T in the US will default to GSM to maintain voice connectivity. When I travel outside of coverage areas with my phone, I can see its signal indicator drop from LTE to HSPA to 3G to EDGE. The times I've gotten interference (between takes!) has usually been with EDGE coverage.

[Karri]

Yes, this is highly unlikely though since this is in the Helsinki centre and the talents are usually browsing Instagram etc when this particular issue occurs.

The building has some heavy elevator and other renovation going on, wonder if those guys might have any equipment that could be the cause.