The Noise Floor

[GaryProtein]

What exactly is "the noise floor" and what contributes to it?

 

[microstrip]

What exactly is "the noise floor" and what contributes to it?

It can have many meanings in audiophile slang - and unless we know exactly which we are addressing we will end in big chaos. IMHO it could be nice if you could be more explicit in the OP.

The wikipedia has a technical definition of it. http://en.wikipedia.org/wiki/Noise_floor

 

[amirm]

Noise floor is the minimum signal randomly (or pseudo-randomly) generated by the specific component or system in question. For an amplifier is hiss and noise. For digital audio, it is quantization noise (generated by the fixed minimum sample value).

Note that we "hear through" the noise so the noise floor does NOT set the lowest audible level of signals.

 

[andromedaaudio]

People with a isolated listening room so no out side noise is coming in have the advantage .
Regarding inside produced noise apart from the attendants , i d say source noise / amp noise tubes in particular and speakers to a lesser degree , imo a speaker which doesnt resonate will have a lower noise floor (blacker background ) as the unit membrane is not set in motion by the housing itself

 

[Speedskater]

A real nice listening room might have a 20 dB SPL background noise level.
But most rooms have a 30 dB or high SPL background noise level.
Classical music recorded in a concert hall is lucky if it's much under 30 dB SPL.

 

[jkeny]

I believe Amir covered background room noise nicely in his article here

 

[thedudeabides]

Absent the usual suspects (tube noise, ground hum loop, etc) what's ironic about this phenomena is you don't realize the "base level" noise floor in your system until you add / change something that allows you to hear the reduction.

 

[Steve Williams]

Absent the usual suspects (tube noise, ground hum loop, etc) what's ironic about this phenomena is you don't realize the "base level" noise floor in your system until you add / change something that allows you to hear the reduction.

you are right on

 

[jkeny]

Absent the usual suspects (tube noise, ground hum loop, etc) what's ironic about this phenomena is you don't realize the "base level" noise floor in your system until you add / change something that allows you to hear the reduction.

Exactly!! How many have heard the effect of a ground loop on digital audio - not a hum or buzz from the speakers - it throws a veil over the music, reducing dynamics & taking some of the "life" out of the music. This is not normally noticed until it is removed.

 

[Audioseduction]

A real nice listening room might have a 20 dB SPL background noise level.
But most rooms have a 30 dB or high SPL background noise level.
Classical music recorded in a concert hall is lucky if it's much under 30 dB SPL.

What weight?

 

[ipadasher]

The lowest background noise level on my room at listening position is 24 db

 

[Audioseduction]

The lowest background noise level on my room at listening position is 24 db

Weight A or C? What are you measuring with?

 

[ipadasher]

C. Measuring with two different decibel meters

 

[Audioseduction]

C. Measuring with two different decibel meters

That is excellent!!!