FM3 Noise Spectra Problem?

[ruso]

You NEVER, EVER use a cable where one end is floating. You will get hum, especially when the equipment is grounded to the mains.

Literally an antenna.

 

[JJunkie]

It’s pretty clear that, with one end unplugged, the cable is working as an antenna and FM3 is being used merely as a tool to measure the “environment” EMI.

The point that OP is raising in this experiment is that the “environment” has more EMI when FM3 is on than with the zoom, which means fm3 is leaking more EMI to the environment than the zoom.

While it’s an interesting experiement, the problem here is we can’t conclude anything whether is too much EMI leaking or not as the measurement is not calibrated to any standard.

We can ask for a usb powered version of FM3 though

Does this help clarify?
https://www.dropbox.com/s/0bo38stmxyoylao/20220519_082328.mp4?dl=0

 

[USMC_Trev]

untuned TV in this case

 

[fcs101]

Where the heck is @Ugly Bunny ?!? We've got graphs and analysis going on here! We need a latency report stat!

 

[steadystate]

You NEVER, EVER use a cable where one end is floating.

I can remember at least one instance in my younger days (after "partaking"?) where I created a spontaneous composition through a cranked amp with heavy effects by touching the floating end of a cable randomly to my forehead.

 

[Ugly Bunny]

Where the heck is @Ugly Bunny ?!? We've got graphs and analysis going on here! We need a latency report stat!

Sorry, I didn't smell anything about the Virtual Capo being discussed so I haven't even been to this site in a couple days

 

[mechenix]

Yea, just close it up. To summarize,

As I said in the op, the cable was being treated as an antenna. The emi in that room wasn't that bad. The USB audio interface shows less 60 hz because it gets DC directly. The AC and rectifier in the unit causes more 60 hz, it's not a big deal for consumer grade stuff. FM3 still makes pretty sounds. Let's move on.

 

[FractalAudio]

Yea, just close it up. To summarize,

As I said in the op, the cable was being treated as an antenna. The emi in that room wasn't that bad. The USB audio interface shows less 60 hz because it gets DC directly. The AC and rectifier in the unit causes more 60 hz, it's not a big deal for consumer grade stuff. FM3 still makes pretty sounds. Let's move on.

No, the "AC and the rectifier in the unit" does not cause more 60 Hz. The unit is grounded to the mains. Mains ground always has 60 Hz "pollution" on it. When hooked up correctly this is not an issue. When one end of the cable is disconnected the shield of the cable contains this 60 Hz pollution which will couple onto the center conductor since the source impedance is nearly infinite.

Connect the end of the cable to something (like a guitar) and now you have a low impedance source and the pollution will not couple to the center conductor.

The FM3 is not "consumer grade". All our products are "professional grade".

 

[fcs101]

...it's not a big deal for consumer grade stuff.

FractalAudio beat me to the punch, but I had no idea that professional musicians out there are recording albums and performing live using these "consumer grade" modelers!

 

[mechenix]

No, the "AC and the rectifier in the unit" does not cause more 60 Hz. The unit is grounded to the mains. Mains ground always has 60 Hz "pollution" on it. When hooked up correctly this is not an issue. When one end of the cable is disconnected the shield of the cable contains this 60 Hz pollution which will couple onto the center conductor since the source impedance is nearly infinite.

Connect the end of the cable to something (like a guitar) and now you have a low impedance source and the pollution will not couple to the center conductor.

The FM3 is not "consumer grade". All our products are "professional grade".

Makes sense, good explanation.

 

[sprint]

for consumer grade stuff. FM3 still makes pretty sounds. Let's move on.

"consumer grade"? hmm - not a comment that promotes others here to "move on" - not sure about the "summary"