USB Whine FIltering (Yeti Curse)

[flynwill]

Also, do we know that the Yeti Curse is always on a base frequency of 1000 Hz?

If it is USB in origin then it will be 1kHz. A 1 mS polling period is written into the standard. However it probably isn't an particularly accurate 1 kHz as that would be subject to the accuracy of clock source for the buss master, and there probably is a fair bit of AM & FM modulation on any sample, so you can't make your notches too narrow, but there might be some gain if you can tune to the particular source.

The way the buss works is every 1 mS the master wakes up and polls all of the slaves for any data that they have to send or receive. In the typical case where the USB sound device has the bus to itself this results in a ~125 uS burst of data every 1mS. (Or two such bursts in rapid succession if the device is both recording and playing).

There are probably a myriad ways that the noise can get coupled into the microphone preamp. The data transmission is not quite truly differential, there is a buss state called "End of Packet" where both of the lines are pulled low at the same time, so there will be some common mode radiation from the data lines. Also the power consumed by the driving the buss will cause the power rail to sag and the ground rail to rise.

[kozikowski]

If it is USB in origin then it will be 1kHz.

What he said.

Also the power consumed by the driving the buss will cause the power rail to sag and the ground rail to rise.

I try and avoid saggy rails. Not chic. At all.

ringing artifacts

Thanks for the reference. I noticed that it uses an infinite fall-time step function to illustrate the point. If you don't apply step functions in favor of normal speaking voices, can I assume the effect is a lot less extreme?

I see the ringing is pretty high pitched. Where does ringing for the 16000 notch go?

The illustration also uses one notch. If you use multiple notches as we plan to, what's the possibility of some ringing artifacts falling into cousin notches and vanishing forever? There's no shortage of harmonically related notches. And even if they don't fall in and vanish, if you produce enough of them, don't they just turn into white-ish noise?

And down to earth for a second, what's the voice distortion or damage difference between 5 and 16 notches? Any of it audible?

Is that difference worth the additional operating complexity over, say, 10 notches fixed and and execution that always looks like:

Effect > Mosquito-Killer > OK.

Koz

[kozikowski]

Mosquito-Killer3.ny

What's the Q of a selected notch of 8 at 8000? I can't tell where the code is going and I can't duplicate the shape of the notch manually.

Koz

[Trebor]

I see the ringing is pretty high pitched. Where does ringing for the 16000 notch go?

I think the ringing is the same pitch as the notch.

The illustration also uses one notch.

The illustration is 2 notches versus 8 notches

And down to earth for a second, what's the voice distortion or damage difference between 5 and 16 notches? Any of it audible?

The additional notches won't alter intelligibility.
Steve did write code which will notch up to 1/2 the sample-rate, (so 22 notches on 44100kHz, 11 on 22050Hz ) ...

kHz-Killer.ny

(474 Bytes) Downloaded 54 times

The notches above 16kHz aren't going to make an improvement, so just a waste of processing time.

[kozikowski]

I've been going some real-world testing with Mosquito-Killer3 (8).

With setting of 8 instead of 5, I was able to search multiple instances of mosquitoes and vanquish all of them, including the killer nasty one from 2014. This is the one that originally called for 20 iterations of suppression to get rid of all the tones. I can't tell if 9000 and up are still there and not objectionable, or I just can't hear them.

ringingsound.wav

(1002.49 KiB) Downloaded 65 times

I dug out the clean, WAV copy I have of a Sarah Vowell AudioBook CD and compared before and after voice quality. I can see 'after' holes in Spectrum View, but I can't hear them while rapidly switching between the two versions.

http://www.kozco.com/tech/audacity/clip ... -Plain.wav
http://www.kozco.com/tech/audacity/clip ... quito8.wav

So with the idea of this being a lifeboat filter and some very tiny tonal shifting may be acceptable, I would like to move the default up to 8, bolt the Nyquist frequency limit code in there (that was Rev3, right?) and ship it. Rev4?

Koz

[Gale Andrews]

Is this progressing far enough to move to the Nyquist board for new plugins?


Gale

[steve]

I think the ringing is the same pitch as the notch.

Indeed it is. This shows the ringing produced by Mosquito-Killer3 (default settings) when applied to white noise that ends abruptly.

notch-ring.png (80.48 KiB) Viewed 1391 times

[kozikowski]

Is this progressing far enough to move to the Nyquist board for new plugins?

I guess???

I keep waiting for someone to be horrified over some mistake.

Isn't that where I write Purpose, Use and Comments? Shouldn't I write that first?

Koz

[Trebor]

I've been going some real-world testing with Mosquito-Killer3 ...
... I would like to move the default up to 8 ...

Sounds like a fair compromise between utility & speed.

Is this progressing far enough to move to the Nyquist board for new plugins?

Jo[e] Public also refers to the problem as ...
"USB mic high pitched whine" / "USB input high-pitched whine"
Only some compare it to a "mosquito".

[kozikowski]

Only some compare it to a "mosquito".

I bet it's safe I'm the only one that calls it the Yeti Curse.

Since the whine has no easy, natural name, I suspect a majority (or all) the time we will be pointing a poster to it. Nobody is going to find it on their own. I guess if I'm clever with the description, someone could find it that way.

Koz