Clipping or Distortion on Vocal High Notes of Ripped Audio

[Trebor]

The distortion in the singer’s voice seems to be modulated by the piano ...

Porgi Amor Test- rumble enhanced- distortion in voice corresponds with lowest piano notes-.mp3

(234.82 KiB) Downloaded 285 times

[kozikowski]

In the posted sample there is a very high frequency whistle at about 15800 Hz

I was hoping for something further up. Like beyond 17.8KHz. Beyond that, the player has to guess at the data since 44100 is indeterminate up there, but video services is not.

There definitely seems to be some distortion on that top E...

That last note? I'll take your word for the pitch. Yes, I sorta heard it, too, but I wasn't looking for something barely perceptible in a quiet room. I was looking for something that would scare people in a moving car which is the complaint.

Koz

[kozikowski]

The distortion in the singer’s voice seems to be modulated by the piano: when the piano note fades out the singers voice becomes distorted.

Perfectly correct. But it's only distorted on the Music CD and only in the car. Play the CD anywhere else and it's fine -- or at least acceptable.

We need to remember that this isn't a top studio recording; this is as good as you can do by going to a digital video tape and through multiple bounces to a Music CD, which, for some reason, is magic. I would have expected that to work correctly. We do similar tricks at work.

I wouldn't be surprised if the digital camcorder had some AGC on it, but the result appears to be acceptable until the final step.

There is a cartoon (has to be New Yorker) where two scientists cover a blackboard with figures and calculations. In the middle of the board is printed: [Magic Happens].

That's what we have.

Koz

[Trebor]

I still think the piano is causing the distortion but I've changed my mind about AGC being the cause.

The distortion in the singing corresponds with bass piano notes (and the changes are too snappy for AGC).
If you compare these waveforms ... http://forum.audacityteam.org/viewtopic ... 01#p117901 [watch and listen to playback in Audacity, pan 100% left]

One is rumble enhanced: a low pass with 100Hz cut off. When the enhanced rumble track peaks so does the distortion in the singers voice.

If the sound system in the car is bassy that would make the distortion sound worse, as it's the bass notes which are causing it.

Filtering out a lot of the bass at this stage only helps a little: it doesn't remove the distortion the bass notes have imparted to the singer ...

Porgi Amor Test, before-after bass cut, (and other tricks)#.mp3

(559.18 KiB) Downloaded 99 times

[MLK3329]

Hi Guys!

I've just read all of your comments and I appreciate the input!

I've just listened to Trebor's rumble enhanced clip and the sound I hear on my car CD player is just like that only not so pronounced, of course. I would describe it as a kind of "fluttering" sound during certain passages, and by the way, they don't have to be loud or forceful passages either. I really don't notice this on my Mac with headphones as I've mentioned before.

Let me describe the room I was singing in and this might help you too:

It was an oval rotunda with a high domed ceiling and marble floors and walls. There was no mic, of course. I had hired a professional sound guy from a performing arts center to video the performance but at the last minute, he had to pull out. A friend of mine just happened to bring his camcorder with tripod or I wouldn't have had any record of the performance. I was so happy about that!

The camera was on the tripod off to my left and about 6 feet back, so what you are hearing is what is coming out of the left side of my mouth! LOL I had hoped that he would have set it up right down the middle of the room, but he didn't. It was difficult, since the audience was gathered in a semi circle around me and the piano so I'm sure that was the reason why he didn't set it up that way. As I said, I was just thrilled to have a record of the performance. I had to concentrate on my concert and not worry about the camera, etc.

Getting a late start today but will begin to redo a couple of the songs using your suggestions.

Thank you so much!
MLK3329

[Trebor]

I've just listened to Trebor's rumble enhanced clip and the sound I hear on my car CD player is just like that only not so pronounced

The rumble enhanced version was a visual demonstration of the association of singing distortion with bass piano notes: meant to be seen as it played on Audacity.

However this bass-cut remix is meant to be heard ... http://forum.audacityteam.org/viewtopic ... 07#p117907 [still distorted though]

[MLK3329]

Hi Trebor,

I just listened to the bass cut remix four times. I get your point and do see a difference. I'm beginning now to try to implement the suggestions that you've all been kind enough to make. Thanks!

MLK3329

[MLK3329]

Hi Guys,

Been trying to post the "Change Speed" to -19 clip for a bit now. I've cut it to 5 1/2 seconds cause each time I try to send it, I get an error message telling me that it's too large. Hope it works this time. Haven't tried it in my car yet but will do so shortly. Thought you might like to have it.

Thank you.
MLK3329

[Trebor]

"Change Speed" to -19

Drastically lowering the speed has cut the high frequencies and with them high frequency distortion.

But you’d be better off cutting back the high frequencies using the equaliser rather than slowing speed or pitch shifting …

Porgi Amor Test, before-after bass and treble cut, (see equalization curve).mp3

(555.1 KiB) Downloaded 90 times

The ‘after’ result of cutting the high frequencies (treble) is dulled,
but because the distortion was in the high frequencies, which have been cut, it becomes less obvious, (but it is still clearly there).

[steve]

Drastically lowering the speed has cut the high frequencies and with them high frequency distortion

The reason for the "change speed" suggestion is not as a "solution" to the problem. A 19% change in the speed makes little difference to the frequency range, but what it does do is to make a significant shift to where the peaks occur. My suspicion is that that the distortion is sounding a lot worse when played in the car than elsewhere due to resonant frequencies in the car sound system. By changing the speed we are in effect changing the musical key, so resonance should not occur on the same notes as before.

That last note? I'll take your word for the pitch.

You shouldn't it's roughly an E after the speed change. In the original clip it's between a G# and an A (about 850 Hz).
I'm guessing that the reason that this note is between G# and A is due to a sightly inaccurate clock speed in the original recording equipment (or elsewhere in the recording chain) and as this is classical music, it may be worth correcting to speed to bring it into concert pitch. It could equally have been due to the piano being tuned slightly off concert, but even then I think it would do no harm to shift it to concert pitch as the amount of speed change required is only about -1.1%, (but that is still enough to be noticeable to many classically trained musicians). Hopefully the pitch/speed is out by the same amount throughout the recording and does not drift.