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question for RemyRAD about 15,750hz horiz. sync.

Discussion in 'Recording' started by liquisound, Jan 29, 2006.

  1. liquisound

    liquisound Guest

    I saw this post in a previous thread:

    "If you are taking or attempting to take a sample from a video, it is already probably 16-bit 48kHz. There is no advantage to trying to transcoding to 24/96 what's the point? Work with it in its native domain. It can be done. Don't waste your time with what you're trying to do as there is no advantage. Chances are it is already riddled with a nasty spike and 15,750 hertz which is horizontal sync. Few people realize this. "

    Is that nasty 15.75khz spike just a fact of life with video or is there a way to prevent it? (also were you referring to miniDV?)

    what's the best way to deal with it once it is in the audio?

    I didn't know what it was but after you mentioned it, I now know what I have been hearing - it all makes sense.

    thanks
    dave
     
  2. Massive Mastering

    Massive Mastering Well-Known Member

    I don't mean to jump in, but I'd bet that 25% of the projects that come in here have mild to moderate video whine. As irritating as I find it, I understand that many simply can't hear it, and many speakers don't readily reproduce it.

    All the same, I hate it -

    But it really is one of the easier things to deal with. If you have something with an FFT-type filter, it's as easy as cutting a notch at the offending frequency. If not, a parametric with an incredibly tight Q can take care of it easily - Even at the mastering stage, I consider it more of a "nuisance" than a serious problem. Although it surprises the hell out of me to hear some fairly big-budget recordings with teams of pros all the way through that have video whine popping in and out all over the place. I could see it getting past one phase, but to get past the tracking guys, the mixing guys AND the mastering guys?

    For a great example of this, get the soundtrack to "Lemony Snicket's - A Series of Unfortunate Events" - I had to rip (with the proper authorization) and edit some pieces for a dance company a couple years ago.

    Every single damn time the orchestra comes in, there it is, plain as the nose on your face. Drove me absolutely batty (Although I was the only person in the room that could hear it at the time... :lol:)

    Anyway, my rig is pretty solid. My hearing is pretty good also. But the number of ears that must have heard that recording before it was released... I can't even imagine what happened on that one. And that's just one CD.
     
  3. JoeH

    JoeH Well-Known Member

    I've seen it in the spectral viewer for Algorithmix's "reNOVAtor". It's amazing to see. (So is 60hz hum and 120 hz buzz!) Hard to believe that stuff creeps in, and no one hears it.
     
  4. SME

    SME Guest

    Once again Mr. Rad is wrong with her theory, the 15.7K sound is NOT part of the audio signal. Its the sound you hear when you have a television on in the room, its called a flyback converter frequency, and only gets recorded when you try to record the TVs speaker. NOT the on air audio.

    Horizontal sync is 31.5 K at 2 fields per NTSC frame, you will audibly hear 15.7K from your TV set.

    Stop trying to influence beginners with your vast unfounded knowledge.
     
  5. RemyRAD

    RemyRAD Well-Known Member

    I have found horizontal sync (15,750 hertz) on many recorders/records/CDs. That frequency is generated within the television and then amplified through numerous coils to produce a significantly high output. It outputs audio, as many people can hear it. It outputs radiofrequency interference or RF interference and a I think truly also couples into the AC power lines? The spite you see on a spectrum analyzer may appear small or large. The larger spikes will certainly interfere with your music. It will fake out limiters, MP3s and increased general intermodulation distortion by its presence. This can be somewhat combated by creating a deep notch filter at the center frequency. I remember in 1976 when the Rolling Stones released " Black and blue", there was a terrible horizontal sync squeal throughout the entire record! I can only surmise that they were watching the football game (even with the sound down) while they were cutting vocals! I didn't give it much airplay.

    Eeeeeeeeeeeeekkkkkkkkkkk(15,750)
    Ms. Remy Ann David
     

  6. I'm thinkin you oughta leave the video decks alone till you get this "male/female" thing down pat. Don't want ya tryin to plug the wrong cables into the wrong holes, so to speak.

    ~S
     
  7. mpd

    mpd Guest

    How wide is this signal? I had a VO talent send me some pickups she recorded at her home studio that had some noise in this area, and wasn't able to figure out what was causing it. In my case, some of the harmonics were aliasing into lower frequencies which made it a pain to remove.
     
  8. huub

    huub Guest

    I guess for the lemony snicket soundtrack, the orchestra had video monitors creating that high frequency.. hmm, there's lcd screens for that nowadays..
     
  9. RemyRAD

    RemyRAD Well-Known Member

    Ouch! NOT BACK THERE!!!

    The nerve..... I mean Neve
    Ms. Remy Ann David
     
  10. RemyRAD

    RemyRAD Well-Known Member

    Horizontal sync will infest everything in your studio. You will get it acoustically and electrically since it is also somewhat RF in nature. It will certainly make compression to MP3 all the more awful sounding if it is not notched out, first. It is relatively easy with many different kinds of software to create a FFT, notch filter that is very narrow at 15,750 hertz. A tight notch will not adversely affect your audio and may actually improve it since the horizontal sync spike can interfere with your dynamics processing and other compression oriented applications.

    As to the other poster that indicated it was a high-voltage fly back function, that is correct but what is high-voltage fly back? It is a radio transmitter! And at the same time it is a quite audible squeal. It permeates unbalanced and balanced audio, along with all condenser microphones. It's a beautiful world!

    Out of sync
    Ms. Remy Ann

    David
     

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