[AliG]

All,
  It's funny that I'm still asking myself this question after being in this hobby for 3 years. Can someone pls explain to me how can you tell if one piece of equipment (say preamp or amp) has very low noise floor?? Can you tell by listening to music, or you stop the music and put your ears next to the speakers listening to any "hissing" or "clicking" sounds that's coming out of the speakers with the electronics swtiched on?


Thanks
barry

[ted_b]

I think of the noise floor as the sum of all the non-music noise in your system; so yes, in a way, it's the slight noise coming out of your speakers when the music is playing but is between songs or notes.  Don't just turn on your system and play nothing, cuz the signal that your source puts out while playing is part of the noise floor too.  Obviously, the goal is to lower (or reduce) the noise floor to absolute silence (so music comes out of a totally black background).   Things like good power condtioning, clean layout of power cords and other cables, and tight connections/quiet tubes are all part of the equation.

[rabpaul]

The lower this is the more musical details you hear. Instruments, music previously hidden can suddenly be heard.  Dynamics, as in one instrument/voice is softer/louder than another, becomes apparent instead of everything having the same volume. My favourite example with regards to noise floor was hearing a harpsichord in background together with a full orchestra for the first time in a recording I have listened to many times for over 15 years. Listen to the "sound" between tracks. If the noise floor is high you will sense as if there is something there but you can't hear it or put a finger on it, while it will be dead black if the noise floor is really low. If you hear something you have not heard before on any system as compared to your own then its very likely that system has a lower noise floor. Imaging will also not be precise as you won't have depth and width and the separation of instruments in the soundstage.

[Imperial]

Amp + musics selfnoise is a sum of things.
Then there is the rooms ambient noise...

Now, depending of what type of harmonic the noise consists of you can hear quite
deep into the noise part of the signal itself... This then counters the ambient room noise to some degree.

Then, and that is why people turn up the volume to hear better... but at some point you get compression...in the speaker
clipping from the amp (it runs out of power)

The extremes are.. onset of clipping - room ambience... = noisefloor...I think.

Imperial

[AliG]

Ok..thanks for your comments..sounds like the general consensus is that you get a sense of the noise-floor by listening to music.

So the noise from tube when no music is played is not part of the equation?

[arthurs]

I would count tube noise as a contributor to my noise floor Barry...FWIW my 2 cents...hope all is well with you and yours!

[ted_b]

Ok..thanks for your comments..sounds like the general consensus is that you get a sense of the noise-floor by listening to music.

So the noise from tube when no music is played is not part of the equation?

All system noise is part of the equation.  All I wanted to add above was that the tube noise without a signal going through it might be different than intratrack or inter-note noise....don't assume that if you don't hear anything coming out of your speakers when the system is not playing that your noise floor is sufficiently low.  The distortion and noise when the signal flows through the system is part of the noise floor.  And yes, all aspects of soundstage, imaging, dynamics (especially) and tonality are affected.

[Wayner]

Ted,

What if your system had incredible gain, especially in a phono section? Then all of your statements really don't stand tall. I do see where you are coming from, but I think you have to quantify it a bit.

To keep is simple, lets say we are listening to music that is loud enough that we have to talk in each others ears to hear each other. When the music stops (in between songs) that is the noise floor at that particular level.

I've heard some incredibly loud and dynamic systems that had a fairly high noise floor, but the dynamic capabilities were astronomincal. On the other hand, I've heard some very quite systems that had music fall out the speakers and crawled on the floor. Very quite and very boring.

I guess I'm saying that quite noise floor does not equal high dynamics, soundstage, etc. However, not to piss on your parade, I will say that it is a wonderful experience to listen to music on a system that is dynamic, projects a soundstage and can quite down to nothing in-between songs. That would be the sound you would hear from very high powered electro-static speakers. Fast, dynamic and quite. May I say Martin Logan?

Wayner

[ted_b]

Wayner,
I think we are in violent agreement.     A dynamic system can overcome a fairly high noise floor, but lowering it makes it even more dynamic.  My point was to simply (bad word) say that lowering the noise floor can increase all the above, without having to change speakers, etc.  The OP wanted a definition and/or understanding/concurrence of "noise floor" and we've pretty much exhausted the options of what it means if it's low vs high. 

So many folks think that their system ought to sound dynamic and produce black backgrounds just because their speakers don't hiss or gurgle at rest.  It's only one ingredient of the total noise floor, the "at rest" noise.    Heck, even cables and power cords can highly affect the floor, yet they typically don't exhibit any "at rest" noise per se. 

[satfrat]

Wayner,
I think we are in violent agreement.     A dynamic system can overcome a fairly high noise floor, but lowering it makes it even more dynamic.  My point was to simply (bad word) say that lowering the noise floor can increase all the above, without having to change speakers, etc.  The OP wanted a definition and/or understanding/concurrence of "noise floor" and we've pretty much exhausted the options of what it means if it's low vs high. 

So many folks think that their system ought to sound dynamic and produce black backgrounds just because their speakers don't hiss or gurgle at rest.  It's only one ingredient of the total noise floor, the "at rest" noise.    Heck, even cables and power cords can highly affect the floor, yet they typically don't exhibit any "at rest" noise per se. 

I'm in total agreement with you Ted, but I would take it much further than just cleaning the power source as I believe ground noise can come from inside the components circuit boards, from interaction between components, from cabling,,, from any part of the electronic journey. I believe cryogenics lowers ground noise, that's why I've had all my components cryoed, not just the cabling. There is much one can do to lower ground noise and in doing so simply allows the music to flow more pure, hense dynamic. It doesn't bother me that there are many folks who don't buy into this philosophy, those folks enjoy their system as do I and that's all that matters. 

Cheers,
Robin