Weird "chorus like" interference playing in the subway

Creating a home studio for recording the classical guitar. Equipment, software and recording techniques. Amplification for live performance.

Weird "chorus like" interference playing in the subway

Post by kiki47 » Thu Apr 26, 2018 5:20 pm

Hello guys,

So, I've been playing classical guitar in the subway of Paris for almost 3 weeks now. I'm using this stuff:
-Plain classical Guitar
-Condenser microphone pickup: AKG C411 L
-Phantom Power ("pre-amp"): AKG B29 L
-Portable PA system: Behringer MPA40BT pro

The sound is decent, when acoustics are fine. But i'm having an issue with a weird chorus sounding interference.

Whenever I'm playing in a confined space and a large group of people pass near me, their smartphones make some interference that sound like if I had a cheap chorus pedal as an effect. I have trouble repeting the experience at home but I believe it must be people's smartphones.

It's annoying to hear when you play Cavatina and stuff. I'm not sure where is comes from in my gear.
-Doesn't seem to be the PA according to some test.
-Could it be the more than 5meters XLR cable ?
-Or is the C411 mic, a small part of the wire is naked ?

Any help is welcomed :wink:

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Stephen Kenyon
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Re: Weird "chorus like" interference playing in the subway

Post by Stephen Kenyon » Fri Apr 27, 2018 11:06 am

Well with lots of phones going by you might find they interact with the amplifier, I always notice this as a kind of chuntering sound, it normally only lasts a couple of seconds, but if there is an active download going on it can be protracted. But I wouldn't describe is as a chorus-like sound. If it is that or related to it I'm not sure there's anything by way of shielding you can do :(
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