Nose floor vs audible effects

[sandyk]

Portugese cork!..........things just keep getting better here with no signs of slowing down I see. Keep up the great tweeks and mods guys. It's doing wonders for the credibility and survival of this wonderful hobby!

 

A lot cheaper than finding and buying something like a high quality R Core transformer with suitable ratings, if they do even exist !

[sandyk]

So even though we can measure things such as the noise floor and say one thing is more quiet than another... it can possibly be perceived by our minds, but may no necessarily by our instruments to measure (or vice versa).

 

 

I would suggest that there are measurable differences, if you know what you are looking to measure.

I feel sure that if you were to do non sighted listening with the same participants in the same room, under the same conditions, and with the same source material, that the differences would still be there, and you would still choose the same one as sounding better.

[Miska]

The one that has more harmonic distortion may sound louder, even if the peak level is virtually same...

[Miska]

To be more precise if you got something like below:

 

[ATTACH=CONFIG]14796[/ATTACH]

 

How we can interpret it and more importantly if it can be audible in some situation - which one if so?

 

Looks like a jitter measurement with huge amount of jitter. Probably quite audible...

[Miska]

For instance, it is quite usual for us to be able to hear our name across a crowded room at a noisy party--even when we can't make out any other parts of the conversation at the same level.

 

Although you can get pretty good at it with some practice when you focus on listening for that specifically.

 

When I was training passive sonar operators in navy, I've seen them developing the hearing skills recognizing all kinds of sounds from the background sea noise. And I went through the same process earlier and continued to develop the skills over the years.

 

When you know how some defect sounds and focus on listening for it, you can recognize it even in presence of very loud unrelated sounds.

[mayhem13]

......sorry but the skills simply don't transfer to complex music in three dimensional acoustic spaces. Chamber music through closed ear phones, maybe........but Ten Years After through a dynamic pair of three ways with 100db peaks, forget it.

[Jud]

I remember reading some while ago that there is pysho-acoustic evidence that we find listening more 'comfortable' if there is some very low level random noise in the background. Apparently we become 'unsettled' if the noise floor is too low. I can't recall the source of this finding unfortunately.

 

[Don't want to derail this thread but this factor may be part of the reason many audiophiles prefer vinyl reproduction to digital - I know Michael Fremer did some blind tests not so long ago and found that listeners preferred the more 'noisy' of two high-quality turntables.]

 

That's what the consultant at my wife's workplace said, with the result that a white noise generating system was installed. This has had precisely the opposite of the purported effect for her and other women she works with. They find it unbelievably irritating.

[Jud]

Nobody is able to chime in with explanation?

 

Hi Krzysztof. You ask a very fair question about which you are absolutely right to be curious. As I do not have the technical expertise to help with that aspect of things, let me talk about some parts of this question I think may be going relatively unexamined.

 

- I feel we concentrate to some extent on whether distortion or noise can be heard (to what extent signal masks noise), and too little on how much of the signal at very low levels can't be heard due to noise (to what extent noise masks signal).

 

- I feel we pay attention quite properly to whether we can hear signal through noise, but not nearly enough on what that does to our perception of the signal as natural or artificial. Yes, we can hear and appreciate a great performance on vinyl, for example, listening through the LP's surface noise. But the illusion that we are sitting in the hall or room listening to a real performer is completely shattered the moment we hear the first tiniest tick. Even noise at levels we don't consciously notice may have substantial effects on our comfort and enjoyment as we listen. (Has anyone *not* had the experience of being relieved at the cessation of a noise that you hadn't even consciously noticed while it was going on - e.g., when the fluorescent lights in an office are switched off?)

[beanbag]

And while you are at it, dumb it all down with additional software equalisation ?

 

The only dumb thing about EQ is refusing to use it to improve fidelity.

[mkrzych]

Hi Krzysztof. You ask a very fair question about which you are absolutely right to be curious. As I do not have the technical expertise to help with that aspect of things, let me talk about some parts of this question I think may be going relatively unexamined.

 

- I feel we concentrate to some extent on whether distortion or noise can be heard (to what extent signal masks noise), and too little on how much of the signal at very low levels can't be heard due to noise (to what extent noise masks signal).

 

- I feel we pay attention quite properly to whether we can hear signal through noise, but not nearly enough on what that does to our perception of the signal as natural or artificial. Yes, we can hear and appreciate a great performance on vinyl, for example, listening through the LP's surface noise. But the illusion that we are sitting in the hall or room listening to a real performer is completely shattered the moment we hear the first tiniest tick. Even noise at levels we don't consciously notice may have substantial effects on our comfort and enjoyment as we listen. (Has anyone *not* had the experience of being relieved at the cessation of a noise that you hadn't even consciously noticed while it was going on - e.g., when the fluorescent lights in an office are switched off?)

 

Hello Jud,

I perfectly understand what the DR is and why noise can mask the low passages of the classical music - for instance. That's however is more audible when the environment around the listening room is not so quite being in the living room etc. It may explain why many people (including me) love long nite listening sessions where it's quite and you do not need to put the volume on your amp more than at 10 o'clock.

 

Reading all the review where you can easily find already mentioned measurements I started wondering to what extend those data are audible? It's easy to say in the supplier's flyer that it has 5ps jitter, but how much of that is audible in fact? The same with the S/N ratio, but this time it's quite related also to the resolution of the DAC for instance. As we've already said, almost none of the current DAC's can be truly 24-bit, maxing around 20-22bits, when we can say that this particular DAC (based only on measurements) got these truly exceptional - just to let say settle the border line where above this line we may hear some distortions? I am not saying of course that exceptional measurement values are in pair with sound quality in the perceptional, individual meaning.

[sandyk]

The only dumb thing about EQ is refusing to use it to improve fidelity.

 

Additional post digital software processing degrades transparency, especially if used with high res material.

It's no coincidence that many who do use it, don't believe that there is any advantage to high res material over RB CD.

IIRC, Barry D. does not believe in it either, preferring conventional room correction techniques.

[mkrzych]

Additional post digital software processing degrades transparency, especially if used with high res material.

It's no coincidence that many who do use it, don't believe that there is any advantage to high res material over RB CD.

IIRC, Barry D. does not believe in it either, preferring conventional room correction techniques.

 

Well, kind of preference, but I also prefer direct sound without any EQ at the end.

[beanbag]

Did you know that all speakers have EQ built in?

[sandyk]

It may explain why many people (including me) love long nite listening sessions where it's quite and you do not need to put the volume on your amp more than at 10 o'clock.

 

The fact is that most amplifiers and preamplifiers have far too much gain, and we may need to use up to 30dB (or more of attenuation at normal domestic listening levels, throwing away valuable signal to noise ratio.

IIRC, the new Benchmark PA has only around 9dB (?) gain for this reason.

[sandyk]

Did you know that all speakers have EQ built in?

 

Did you know that for many people you have become more than a wee bit annoying with your smart ass replies ?

[beanbag]

Additional post digital software processing degrades transparency, especially if used with high res material.

It's no coincidence that many who do use it, don't believe that there is any advantage to high res material over RB CD.

.

 

It's no coincidence that many who do use it, also use DSP, digital XO, and software room correction to actually improve the fidelity of their music.

[beanbag]

Did you know that for many people you have become more than a wee bit annoying with your smart ass replies ?

 

Did you notice that your reply has no technical content but only ad hominem attacks?

[sandyk]

Did you notice that your reply has no technical content but only ad hominem attacks?

 

Stop making smart ass replies then. Do you really think that the use of the Latin phrase "Ad hominem" makes you sound more technically knowledgeable?

[Sam Lord]

...It depends on properties of the noise floor. If noise is white, you can hear quite a bit below it's level, usually at least 20 - 40 dB below the total level (if it's a discrete tone vs noise).

 

First, if you have pretty quiet normal room, it has background noise of around 30 dB SPL...

 

Indeed, and some fairly normal rooms can be *far* below that level if local machinery is turned off.

 

IME, the file bit depth is totally unrelated to the DR. Some of the most exquisite and dynamic music ever recorded is red book. Given the forgoing and even the best rooms only have maybe 90db of DR, how is 144db of DR beneficial for home reproduction?

As Miska stated, if your ears can manage 120dB you can usefully discern something close to that in a normal quiet room. And that 90dB just isn't as good as a higher figure. Those 90dB DR recordings would have been be better still with 110dB SNR. Maybe not more musical, but more dynamic, more realistic.

 

What I am rather interested is the fact if measurement is showing peaks around 1kHz discrete signal up to let say -90dB which is not so good assuming for a good DAC, we won't be able to hear those distortions when not listening at 90dB level. Correct?

 

Yes, turn it up. With good recordings that have high crest factors, I usually listen within 10dB of the maximum output of my system. the -10dB figure means peaks at about 100dB and average SPL at around 85dB. I don't do that for very long, and there are many quieter sections, so my ears are pretty safe. Note, that still means 1850/10 wpc peaks = 185 wpc. Well sue me, my mains are inefficient.

 

EDIT: Oops, you (and I) forgot distortion. Very few equipment sets have less than 90dB distortion at full scale. So those differences show up before well before the noise floor. With 2nd-order harmonics present, I'll bet you can hear unpleasant distortions more than 60dB below thei level. I think it helps to consider our ears as partly gain-ranging transducers.

[Jud]

Did you know that all speakers have EQ built in?

 

Yes, absolutely. Speaker crossovers are one of the many *interacting* points of signal change even in a system built with "purist" intent. The general question is whether there are advantages gained by additional interacting signal change points.

 

But that's a general question, and somewhat afield from the specific one Krzysztof is asking.

[beanbag]

The general question is whether there are advantages gained by additional interacting signal change points.

.

 

The general answer is "yes" if it improves fidelity. How would you like it if your DAC were missing a filter or two?

[Jud]

The general answer is "yes" if it improves fidelity. How would you like it if your DAC were missing a filter or two?

 

As I hinted in my last comment, perhaps not clearly enough, it's a worthy conversation to have, just not here in Krzysztof's thread. If you'd like to start another thread on the topic, I'd be happy to participate as far as I'm able.

[mkrzych]

As I hinted in my last comment, perhaps not clearly enough, it's a worthy conversation to have, just not here in Krzysztof's thread. If you'd like to start another thread on the topic, I'd be happy to participate as far as I'm able.

 

Ditto

[sandyk]

Originally Posted by Jud View Post

 

As I hinted in my last comment, perhaps not clearly enough, it's a worthy conversation to have, just not here in Krzysztof's thread. If you'd like to start another thread on the topic, I'd be happy to participate as far as I'm able.

 

Hi Jud

The Forum area DSP, Room Correction, and Multi Channel Audio was created specifically for this purpose, and is where many of the "bits are bits" and "RB CD is as good as it gets" brigade can hang out without further heated discussions as to why additional further digital processing is needed, or is even a good idea.

We really don't need any further acrimonious discussions on this subject in General Forum. That's why that area was created originally.

 

Regards

Alex

[gmgraves]

Nobody is able to chime in with explanation?

 

 

What this generally refers to is the dynamic range mathematically afforded by the number of bits being used, not the actual real-world signal to noise ratio of the DAC or the system in which it's being used.

 

So, when figuring the noise floor, it is important to keep in mind that this is a measure of dynamic range (the maximum difference between the loudest and the softest sounds that can be captured.), not absolute noise levels (which will vary with actual listening volume on playback, and the actual SPL (Sound Pressure Level) at the microphone diaphragm during recording). Electrically, this parameter, is measured in dB as some level below 0Vu (representing full use of all available bits). Since this measurement equals both the loudest and the softest levels which can be represented by whatever digital system is being used, it is also referred to as the system's dynamic range. The noise floor of 16-bits is measured to be -96 dB (meaning that the level at which the noise is measured with no signal present is 96 dB below 0Vu. In 24-bit, that noise floor is technically around -144 dB. But in both cases, this is the digital specification only. Unfortunately, in order for digital audio to capture and play-back music, it must have analog stages before quantization (conversion from analog to digital) as well as after conversion back to analog. These stages vary, according to design, in their signal to noise ratios, and that must be factored in to the overall system's noise floor. While, with today's electronics (even op-amps) it is possible to get amplifier s/n (signal to noise ratios) of about -127 dB, this is rarely achieved. Where the problem comes into play is when one is trying to correlate the dynamic range of a DAC which is fixed by the number of bits available, with the audibility of that DAC's noise floor when listening to one's stereo. Obviously, the higher your playback volume, the higher the noise floor will be relative to your peak volume. The dynamic range of your system won't change, but it's like turning your volume all the way up with nothing playing. At some point your system's noise floor will reveal it self as hiss (and perhaps AC hum) in your speakers. Turn the volume control back to where you normally listen, and it's possible that you won't even hear hiss or hum when you press your ear to the speaker at that level. So real noise is relative. The point is that at normal listening levels of 80-90 dB*, the noise floor on any 16-bit or higher DAC will be below the human threshold of hearing and will be inaudible. I hope this is clear.

 

 

 

 

 

* Assuming the threshold of human hearing (at 1KHz) to be +05 to +10 dB (when 0 dB represents total silence) and +120 dB being the threshold of human pain.