[Bob in St. Louis]

Would someone mind giving me a clear, easy-to-understand definition of what "floor" or "noise floor" means? And explain to me exactly why it is important to have a low noise floor? I thank you in advance (and will thank you in arrears too).

In general, the term noise floor is in reference to the decibel level your ears are picking up.
For instance, your listening room may be 30 decibels when everything is "dead silent". That is your noise floor. Now, let's say your furnace turns on, your noise floor may now be 35 decibels.
I assume this could be the definition of any item, situation, or location being referenced, so it could also be the "bottom level of quiet" of an amp.

Another example:
Your car on the highway may be 65 decibels, but with the wife talking it may be...oh, never mind. 

Hope that helps,
Bob

[Baumli]

Bob et alia,

First it's important to note that it's a good thing Bob stated "never mind" because he was fast traversing the pathway of error. If I'm traveling down the road in the car, does the decibel level go up if my wife starts talking? How would I know, since she is never not talking? And as for the noise the car makes: It makes less noise when she gets in the car, because that machine knows better than to incur her ire by competing for aural "space."

Now, as for Bob's explanation. It doesn't quite make sense to me. Maybe I am looking at it as a philosopher, rather than as an electronics geek or an engineer. I understand what Bob is saying, but it doesn't seem to jive with what J. Gordon Holt is saying. And what about artificial situations, e.g., an anechoic chamber where the decibel level is almost zero? And what about the claim by astronomers that the earth is always emitting an infrasonic noise of about 30 dB? How does this fit in?

I think it would be best if I understood what the practical merits are of talking about noise floor. E.g., what do I gain by having an amp with a lower noise floor than the one I now have? It seems to come back to what I had opined before. That this merely means that if I put my ear to the speaker while the amp is on "idle," I hear less hum if the amp has a lower noise floor? Right?

Your token simpleton,

Francis Baumli

[macrojack]

Use of the term "floor" would seem to indicate a baseline or starting point. Just as you measure your height from the floor up, you would consider your "noise floor" to be the dividing point between desirable and undesirable "noise".
Out here in Colorado, I live on the floor of a valley at an altitude of 4600 feet above sea level. That means that a 12,000 ft. peak in my neighborhood would rise to 12,000 ft. above sea level but only 7400 ft. above the surrounding terrain. Similarly a crescendo of 100 db would seem more impactful rising from an ambient sound environment of 50 db than from one of 70 db. Make sense?

Of course it doesn't. It can't because the term "noise floor" is an artificial, undefined creation of a person groping to establish a definition without any defining criteria. Like so much of our subjective audiophile drivel, it massages the imagination without providing anything to hang the hat on. We, as a group, seem happy to attach ourselves to any abstract consensus that gives us a sense of knowledge we are too lazy to possess by actual scientific process. And at the same time that we envy the machines that science has brought us, we excoriate the scientific process as being insensitive to "what I know I'm hearing".

There is a concurrent thread running on this site about the definition of "listener fatigue", another mythical signifier of nothing real  with which we have all grown to identify. It puts me in mind of the greatest epidemic to occur in American history. I refer, of course, to PMS. One day no one had ever heard of it and the next day there were 100 million acute cases. The power of suggestion works wonders.

Well, gotta go. My phantom center channel has started to drift toward the background again. I think I put too much acoustic chafing tape on the back wall causing polarization of the black levels and a subsequent drenching of my separation factor. What the hell is that tuba doing in the violin section?

[nickd]

I think the noise floor should be talked about in context of perception (perceived noise floor vs. measured noise floor). While the measurement numbers in decibels are helpful to engineers, for the layman audiophile it can add confusion.

Having been in an anechoic chamber a couple of years back, all is I can say is it was quite uncomfortable. The guys at the facility said you would go crazy in there with the door shut in just a short time. It appears we need that "noise floor" or point of reference to calibrate our thoughts, distance, direction etc. Perhaps moderate noise in our hi-fi rig is comforting in some way? I have always loved tube gear despite the higher "noise floor". I just don't own any because of heat and maintenance issues. 

A noisy amp or pre-amp (hiss, hum, whatever) will loose my attention in a relatively short time. That said, I remember drooling over the Apt gear back in the 80's when it was a bit out of my reach.

[mjmsound]

"Noise floor" the amount of noise the children or grandchildren make in the room when trying to listen to music!!!
If you have a soundproof room, "noise floor" would be a major issue. If you have a room like mine, it isn't.
If you like the sound of your system why worry about all the "noise floor", "ceiling" or anything else.
A well designed system that meets your needs and sounds to your liking is really all that matters.

[Niles300z]

You guys sound smart.
I think ceiling could mean potential, but its true that some who measure on fancy equipment and are more mathematically and electronically inclined than i could think a  more spec induced meaning relating to high frequencies as the opposed bottom or noise floor although nobody said noise has to be low frequency. The confusing part for me is the noise floor, if intending to be low, might therefore make the ceiling higher in noise, and is a high floor and a low ceiling the same. Was that a run-on?
Tom

[ZENTISH]

Hi Baumli,  Take a look at Arthur Salvatore's website, he talks a lot about noise floor.


Good Luck! TISH

[ZENTISH]

OOPS, Old Thread!