What is noise floor?

Discussion in 'Audio Hardware' started by HDOM, Jun 17, 2018.

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  1. HDOM

    HDOM Well-Known Member Thread Starter

    So?
     
  2. sublemon

    sublemon Forum Resident

  3. punkmusick

    punkmusick Amateur drummer

    Location:
    Brazil
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  4. Dennis0675

    Dennis0675 Hyperactive!

    Location:
    Ohio
    The stuff you can hear that doesn’t sound like music.
     
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  5. F1nut

    F1nut Forum Resident

    Location:
    The Mars Hotel
    It's a level of grunge and distortion that you don't notice until the level drops. Cleaning up the incoming power is the best place to start dropping the noise floor.
     
  6. chervokas

    chervokas Senior Member

    It's the baseline level of noise that's present regardless of the signal, or as Wikipedia will tell you, "the the sum of all the noise sources and unwanted signals within a system, where noise is defined as any signal other than the one being monitored," in this case, the music.
     
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  7. machinestool

    machinestool Forum Resident

    Location:
    Crawfordville, FL
    Mostly used in Cellular networks to define unwanted signals, like stated above. A high noise floor on a cellular network would also be an indication of possible interference.
     
  8. tumbleweed

    tumbleweed Innocent Bystander

    Also, the level at which small signals cannot be distinguished because residual noise is louder. Picture someone standing next to you speaking quietly; if you have good hearing you'll still be able to distinguish what they're saying. Now picture same scenario, but someone else standing next you going "hissssss" - that's what you'll hear, because the other person's voice is below the noise floor.
     
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  9. machinestool

    machinestool Forum Resident

    Location:
    Crawfordville, FL
    yup, and just like a sporting events. The more calls at once during peak time of a game the noise floor skyrockets! Sporting events are the most challenging events for carriers.
     
  10. Dillydipper

    Dillydipper Space-Age luddite

    Location:
    Central PA
    It's apparently every frikkin' wooden slat I step on, creeping into the bedroom when my wife has already gone to sleep.
     
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  11. Mal

    Mal Phorum Physicist

     
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  12. chervokas

    chervokas Senior Member

    It's a phrase particular to cellular networks, it's a very common phrase in audio engineering and has been for generations to describe the baseline thermal and power supply and mechanical noise of a playback system or recording chain or recording medium.
     
  13. HDOM

    HDOM Well-Known Member Thread Starter

    But is it because no matter what, you get it when you master or remaster?
     
  14. HDOM

    HDOM Well-Known Member Thread Starter

    So it had to do whit electricity?
     
  15. htom

    htom Senior Member

    Location:
    Montreal, Canada
    Noise in a signal has only to do with the data and the medium the data is transmitted through. That medium doesn't have to be electricity.
     
  16. Dennis0675

    Dennis0675 Hyperactive!

    Location:
    Ohio
    I think of it like this, how high can you turn up the volume before you start to hear noise from equipment. If your equipment has a lower noise floor, you can give it more volume before it starts to sound ugly. Generally speaking.

    A turntable is a great example. A cheap one has a high noise floor and you hear those noises at a low volume. Spend 10K on a table and that noise floor is much lower. Tube equipment generally has a higher noise floor than SS. Crank the volume and you might hear some hiss from the tubes where the SS stuff has a blacker background (noise floor).

    The master vs. remaster question is all over the place. Generally, a remaster should have a lower noise floor due to some digital restoration. An example where one might prefer the original and a higher noise floor.
     
  17. Anachostic

    Anachostic Forum Resident

    Simply put, when the hiss is louder than the music, you've found the noise floor.
     
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  18. allied333

    allied333 Audiophile

    Location:
    nowhere
    -60db down noise is usually quiet enough, but not a great specification. My TT is -78dB down. Modern electronics such as CD players are at least -90dB and often over -100dB down.
     
  19. F1nut

    F1nut Forum Resident

    Location:
    The Mars Hotel
    That's where at all starts. You can't build a house without a solid foundation.
     
  20. Doug Sclar

    Doug Sclar Forum Legend

    Location:
    The OC
    It's a lot of things. For starters, the level of hum can define the noise floor.

    I used to be involved in lowering the noise floor in recording studios. It was a very complex proposition and once you removed the worst offender, the second worst offender had to be dealt with and on and on.

    Hum can be caused by a lot of factors and I was able to lower the hum in our Helios console by close to 20db by using a lot of techniques including a dremel tool. That may seem hard to believe but it's true.

    Hiss is another type of noise and can come from analog tape recording as well as normal circuitry. You can tell a lot about a system by listening to the hiss. In my case when I put my ear up to to my speakers while they're at a high gain position I can hear the hiss and it's extremely smooth, sort of like the sound of air rushing around.

    Besides minimizing noise in circuitry, a good engineer has to have a good grasp of gain structure. It has to be optimized at every step of the way to avoid the buildup of noise, especially when you consider how many active electronic sections there are in the process.

    I'm very well trained to hear noise. I can hear it even when listening to loud music. Just last night I was listening to some recordings and I kept hearing weird noises. I'd hit the mute button and they all went away. One was a growling sound, and there were also some thumps. Oh, they're not very loud, but I hear them and require absolute quiet when I do my critical listening.

    Even when listening loudly, I can hear if there is a TV on upstairs, or some other noisey event happening. That's why I hit the mute button. Sometimes it's hard to tell if the noise I'm hearing is from my listening environment or something that is coming out of the system. Often, as in the above mentioned case, it's on the recording, and many times it's unintentional.

    Many classical recordings have road traffic on them. That's also a noise floor issue. Even in well isolated studios, sometimes the low rumble of outside traffic gets through especially during a quiet passage. I hear these all the time and once again have to use the mute button to verify that they're not in my environment. I can also hear the AC going on in recording rooms at times, and that's another type of noise floor.

    I'm cursed to hear things that most don't, and I'm sure that is due to my training and experience. I had to be able to spot any sounds that were not intended to be on recordings if I had any hopes of correcting them or helping others to do so.
     
  21. allied333

    allied333 Audiophile

    Location:
    nowhere
    Wow Doug. Incredible ears. I once whispered in my garage attached to house & door open with my daughter on the far side of house 'do you want 5 dollars'. Although music was being played in house in-between us, she heard what I said. Unbelievable!
     
  22. Doug Sclar

    Doug Sclar Forum Legend

    Location:
    The OC
    I don't think it's that my ears are incredible. I think it's just that I've trained them over the years. I believe most of us can hear these types of things with a bit of training. It's largely a spectral matter. If there are sounds coming out of my system that are in the same frequency range as the minute sounds in the environment they will be much harder to detect.

    Btw, I developed a technique back in the 70s to hear problems with our large scale PA systems by simply putting my fingers in my ears. Yep, I could move then around and create a variable band pass filter of sorts. I could concentrate on each driver range (lows, mids, and highs) and hear any distortions coming from it, despite the loud overall volume levels and the reverberation.

    Once I learned how to do that, I got to the point where I learned how to discriminate. I still remember my early studio days when I'd walk into the control room and hear weird things that others didn't. Sure enough once they would solo things they always found out what I was hearing and often were able to correct it. The first day in a control room I heard a 15k pitch that nobody else heard. They trusted my ears so began to investigate and sure enough it was the video monitor so they could see who was at the front door. I was the only one to notice and I was the newbee in the room.

    I can listen to loud music but if the noise is in a frequency range that is not present on the recordings I can generally hear it. I think part of that is the quality of my system in that it generally only puts out what is on the recordings.

    If you have a room in which sounds can linger, it will make that much more difficult. Hit the pause or mute button and the sound should stop instantly. In many rooms, including some hi-fi salons, the music lingers for a bit. That also makes it much harder to hear extraneous noises and blurs whatever you are trying to listen to. It's not much different than print through on recordings which most hear only at the beginning of a song, but of course it's there for the duration of the song blurring things just as bit.

    Regarding good ears, Cassie who is a 26 year old that lives with me, can hear me talking quietly when I'm downstairs and she's upstairs. It's actually scary at times. She can do so many things better than I can now, but that's because she's just entering her peak years and I'm .... well I had my peak years and I enjoyed the heck out of them.

    I have no doubt that she could hear more from my system than I do, but it would take lots of experience for her to be able to discern the distinctions like I can.
     
  23. HDOM

    HDOM Well-Known Member Thread Starter

    So you low the noise floor in the studio equipment and with the room acustic?
     
  24. HDOM

    HDOM Well-Known Member Thread Starter

    I see , about remastet i had hear is more easy with 24 bit /192 kgz, for working with the noisefloor?
     
  25. Doug Sclar

    Doug Sclar Forum Legend

    Location:
    The OC
    Nothing with the room acoustics. We did all this by simply changing grounding techniques in the console and with all the outboard gear.

    In our case the console completion was rushed to get it to us on a predetermined deadline. If not, they might have had more time to to have done much of this work themselves. I've never seen a large scale console that hadn't been modified to some degree, often by the factory. Cut traces with jumpers was always a clue to that.

    As it turned out, our console sat in the control room covered with plastic, while we finished building the control room. In hindsight it would have been best for them to keep it for another month until we were totally ready for it.
     
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