 
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
|
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
81.152.195.92
In Reply to: Re: Noise floor vs. uncorrelated noise posted by Peter Qvortrup on February 23, 2007 at 01:48:27:
"What you say does not disprove the fundamental truth in my statement, fact is that analogue media have audible and recognisible signal artifacts well below their noise floor"No, they do not.
"There are no other stimuli, for example, from someone sitting with their back to you in a restaurant, but you can still hear what they say even if it is below the ambient noise in the room."
ambient noise is not a noise floor, much in the same way that groove noise is not a noise floor, just uncorrelated noise.
Music making the painting, recording it the photograph
Follow Ups:
"No, they do not"Yes they do.
"ambient noise is not a noise floor, much in the same way that groove noise is not a noise floor, just uncorrelated noise."
Background noise in a room is most certainly a noise floor whether correlated or not. HOwever; information that is correlated can be heard below a normal noise floor. This is more difficult if the noise floor is correlated with the music signal.
Ever listened to analog tape? There is a constant hiss from the tape mechanism. This is the tape noise floor. Now you can easily hear sounds that are softer than the tape hiss, can you not?
I think Peter's point is that there is information below the nominal noise floor of vinyl and that as this is musical information and therefore correlated it can be aubible even through the noise (tape hiss is another example). Obviously, the lower this noise is the better because it has less chance for masking.
An example of correlated noise floor is the example given by Crowhurst regarding negative feedback in amplifiers. He demonstrates that feedback generates a forest of peaks that look like noise; however, these peaks are coming from the signal itself and as such are frequency and level dependent. So the "noise floor" shifts in frequency and level with the signal. With this kind of noise floor you will surely run into a situation where infromation below this floor is masked.
thanks for the correction vis--vis noise floors, that said the principle here is noise decorrelation, if the noise is decorrelated then a signal may be retrieved, the principle applies to both analog and digital alike, or is there any reason why analogue is unique?"Ever listened to analog tape? There is a constant hiss from the tape mechanism. This is the tape noise floor. Now you can easily hear sounds that are softer than the tape hiss, can you not?"
tape noise, groove noise, dithered noise, birds of the same feather but different applications, you simply repeated what I said in the post you responded to :o, aren't both groove noise or tape hiss simply different types of uncorrelated noise.
I will ignore the off-topic point on negative feedback.
Music making the painting, recording it the photograph
I guess undithered digital is somewhat different but I don't have sufficient knowledge there to really comment.The amp comment is not off-topic if you think about it. The argument is that negative feedback CAUSES a signal correlated noise floor below which it would be difficult to extract signal because of masking.
A no feedback amp would not have this issue and is perhaps why users of SET type amps (or even Class A PP amps with no feedback...I have one of those as well) feel that the low level resolution is superior because in terms of the correlated vs. uncorrelated noise it IS superior. This would never show up on a static distortion measurement.
This post is made possible by the generous support of people like you and our sponsors:
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2025, Audio Asylum, all rights reserved ]
