[Ty Ford[_2_]]

On Thursday, September 6, 2018 at 1:02:58 PM UTC-4, John Williamson wrote:
On 06/09/2018 17:36, mcp6453 wrote:
Here's what I've found. The problem is definitely EMI. There's a cell
phone tower less than a block away. Moving the mic in the room can
exacerbate or eliminate the noise. Unfortunately there is not a
practical position that will eliminate it. So, I took an RE15, RE18,
MD421U, and Beta 87A. All of the mics eliminated the noise although
there was still a little with the 421. Since the 87As were the only ones
I had two of, I used those. They didn't sound so good for this
application and need to be replaced.

If the interference is from a cell tower a block away, then it is RFI,
and can probably be stopped dead by putting ferrite beads on the mic
cables near the mic and mixer (If used). Cell interference has a
characteristic sound, and is not a hum.

EMI is much shorter range, will be a constant or intermittent hum or
buzz, and will likely be from a transformer or light fitting choke
you've not found yet. Moving the mic will show where the field is
strongest, and lead you to what needs to be turned off. Changing the
angle of the mic may help with this, as the sensitivity depends on the
relative angles of the mic and the field, though changing the mic angle
will also foul up the recording...


--
Tciao for Now!

John.

I'm with John on this one. 3 million years ago when I got my first DAW (AKG DSE7000) I set it up only to find that the CRT was blowing a ring of noise right at my 421. I moved on to a Gefell M71.

Wow looks like a newsgroup post from what 20 years ago?

Regards,

Ty Ford