Reducing high-pitched buzz, how to?

Discussion in 'Tracking / Mixing / Editing' started by Aaron, Jan 25, 2016.

  1. Aaron

    Aaron Active Member

    An acoustic group I recorded was playing on stage in a room that didn't have the greatest lighting. The two main lights were high-wattage bulbs and hanging from low-rafters just above them and that high-pitched buzz noise from such bulbs is constant background noise throughout the recording.

    I'm using Logic Pro and have read about possibly using the 'Noise Gate' feature, but not sure exactly. Can anyone please recommend a strategy for reducing or even eliminating this noise, without compromising the dynamics of the instruments of the performance? Is this even more difficult considering that noise is part of the recording and not a hardware issue?

  2. bouldersound

    bouldersound Real guitars are for old people. Well-Known Member

    A gate won't work for this. You need a more sophisticated fix, some sort of noise detection/removal process. You're more likely to find that in an audio editor (Sound Forge, Audition) than in a DAW.
  3. pcrecord

    pcrecord Don't you want the best recording like I do ? Well-Known Member

    Actually a gate is good for silent parts of a recording but not to remove certain content without affecting instruments.
    If the noise is always identical, you could use a Spectrum analyser to find the frequencies and reduce them with an EQ. This will remove those frequencies in the recording as well so you have to decide levels that will lower the noise without compromising the recording too much. If the noise is narrow, you may not be damaging them too much...

    Other Tools like Izotope RX have better Tools but none that I know will do it without affecting the sound of instruments.
    If you had, close mics and room mics, you could use more of the close ones in the mix to compensate..
  4. thatjeffguy

    thatjeffguy Active Member

    Izotope's Denoiser handles these types of things effortlessly. I have never noticed any change in the sound of the instruments because Denoiser samples the buzz or hum and reduces only the exact signature of the unwanted noise. This has been my experience, others may not agree.
  5. pcrecord

    pcrecord Don't you want the best recording like I do ? Well-Known Member

    Most of the time it's true Jeff ! But I had customers bringing me audio with more noises then instrument a few times.. so I'm being carefull when talking about audio restoration ;)
  6. Aaron

    Aaron Active Member

    Thanks for the recommendations. I wasn't familiar with that and may have to give the Denoiser a try. There's definitely some other things I need to purchase before spending $350 on that but Izotope has 10-day trials so I can see how it goes, and for the future full purchase.
    I'll say that it's 'not that bad', but it's noticeable and makes it sound like the pre-amps are a bit noisy during those quieter sections but those are crystal clear so I would like to clean up the buzz as much as is necessary.

  7. Sean G

    Sean G Well-Known Member

    I have to agree with my asteemed collegues above...(@pcrecord & @thatjeffguy )...

    Yep, Izotope RX (I use 4 but 5 has been just released) is great for audio repair of this kind, and much more as well.

    You can't go past it
  8. DonnyThompson

    DonnyThompson Distinguished Member

    Beyond what my colleagues have mentioned here regarding tools to fix the problem, it may be pertinent to add that the source of the problem will continue to be a problem at that venue until it is taken care of.

    Any type of lighting with ballasts /power supplies /dimmers - phosphorous, Neon, fluorescent, even regular incandescent if it's on a cheap dimmer switch - can all present problems with adding noise to audio through both RFI and through the internal electrical circuits of the venue; both in recording and with PA, in terms of buzz, hum and other anomalies. It's also possible that the lighting isn't the source, and is instead in the electrical service in the venue.
    If the hum was coming from the PA system itself, and that was your audio source, and you were recording that with your own mics, then there's not much you can do as a remote engineer to counter that, othet than the various filtering tools mentioned here as being available in digital post-pro.

    If the noise wasn't eminanting from the PA, and was attacking your gear through electrical outlets or RFI that you were also plugged into, then you might want to consider a power conditioner of some sort in your remote recording rig to attenuate the problem, although it would be rare that the problem wouldn't be evident with any gear tapped into the electrical circuit of the venue... including the PA, so even if you were protected yourself, the buzz could still be coming from the house PA system, and if you are using mics to record, you're still gonna pick it up.

    Finally, If you're familiar with the venue owner, or know one of the acts who is, you may want to suggest that they look into something like LED lighting instead. It runs much cooler in temperature, and runs cheaper - because it requires little power to run (no special power supplies or heavy circuits) and is available in all the same colors as normal par can stage lighting is. Besides being cheap to run, it's also pretty inexpensive to buy.

    Of course, if the electrical in the venue is faulty, then it won't matter what lighting is being used, although those ballast-type lights mentioned above could exacerbate the original problem, too.

    Unfortunately, this isn't an uncommon problem, nor is it new - bands have been facing these kinds of problems for many years. But even newer clubs have the problem too - often building on the cheap, and then paying off inspectors to overlook code violations, or, who decide that hanging up a slew of neon signs every three feet - which are often given to them for free from the big beer distributors - is a good idea when having live entertainment.

  9. Aaron

    Aaron Active Member

    Sage advice from a master; thanks for the words Mr. Thompson. Not only might it be pertinent to add that the source of the problem will continue until it is taken care of, it's an absolute. I've only just begun recording, yet I cringe at anything that wouldn't make the result 'perfect'(which we all know doesn't really exist; does it?). Even with the idealistic environment of a studio, you(those reading this who have recorded in studio) know of all the variables that would make recordings less than perfect, let alone the uncontrollable forces of live capture, in an unknown venue. With that being said, I nearly cringe over the fact of having to fix something that was beyond my control. Those bastards! ;^)

    There was no PA system in the room, just un-amplified acoustic instruments. It was also definitely the bulbs and nothing with the electrical system, unless of course we call the bulbs part of the electrical system. The unwanted sound was like needles piercing my brain, like a dog whistle to a dog maybe, and was looking all around during rehearsal asking myself 'What the hell IS that?' I saw the lights above stage that looked like they were from 1980, walked up under them and sure enough they were the source; blaring directly over the musicians, therefore into my microphones in front of them.

    When I heard that was the problem I was thinking how I would love to cut those lights and rig tiny wireless led lights on each of the musicians music stands so the main problem was eliminated, but of course that wasn't going to happen. It's a venue that I'll 'probably' only record in for that one time, although I definitely won't be counting out returning to the place given the various performances I may be interested in there in the future; so, I'm not going to fight for them to change their entire 35-year+ lighting system for the sake of my meaningless(to them) audio recording.

    However, I did have a few great chats with Len, the 75+ year old maintenance person of the building, during the few hours I was there, who I would now consider an acquaintance. If I do go there again I will certainly be mentioning the fact that they're wasting money on their lighting system and, more importantly, creating unwanted noise in my recordings!

    Cheers to all, and thanks again for the wisdom and conversations!

    Until next time,

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