That would be a massive 60hz hum... But the FFT display states F1 60hz and F2 7khz, and F1 higher in amplitude than F2, To do an intermodulation test TWO sinus signals are required, and often F1 is 12Db higher in amplitude than. F2, - just as the diplay states- so that those F1 F2 really looks like a IMD test signal. If F1=60 is not part of the IMD test signal what other is the F1?
I see some other signals at about 950? and 1050? hz, I suspect those are the “ simultaneous “crosstalk” L and R , since the level is different, The IMD from L channel signal and R channel crosstalk can explain the 2000hz as an intermodulation sum product. But that would be a surprising way to do a IMD test.
The side bands at 2000 hz can be the 2 harmonic of the 950/1050 hz. And the third at around 3000.
The side bands around 7khz can be the intermodulation sum and difference from 950/1050.
Looking at the peak at ca 88hz it could maybe be the be the difference IMD 1050-950 if the values where 956 and 1044.. And the peaks at 120/240/300 are the harmonics from 60hz..
If the 60hz I present in other screen captures from other systems we could better judge if the 60hz is a test system disturbance or a real signal .
AM is an intriguing software and probably do things /analyses beyond my imagination , but interesting to try to understand what is going on. I consider buying one Analog Magic, when I get rich..
EDIT: post 317 shows the VTA IMD track taken from the AM developers facebook, and is show a high 60Hz peak too , not likely that that is Hum too, so I conclude that the IMD signal is 60:7000 Hz in 4:1 ratio.
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