Noise Floor

[UltraFast69]

The objective is to lower the noise floor through various means, but how low is too low if even such a thing?

Comments?


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[aKnyght]

can't imagine it is possible to lower the noise floor too much in one's system -- just thinking out loud here, if it were possible to get the noise floor to zero then one is hearing only the recording... which is the whole point, right?

in practice, while i do everything i can to minimize the noise floor in my system it is the noise floor in my environment that needs some serious lowering... the noise that is absolutely killing me are the leaf blowers, the occasional aircraft fly-over, telemarketing calls, a/c in the summer, furnace in the winter, etc, etc, etc... seriously, i don't even know why i try.

[kiwi_1282001]

The objective is to lower the noise floor through various means, but how low is too low if even such a thing?

Comments?


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Noise is the enemy. Lower noise = increased dynamic range and frequently better resolution to.

That said, the complete absence of noise is unnatural. Have you ever stepped inside an isolated and acoustically sealed anechoic chamber? The best of these are so quiet you can hear your heart beating. Its a 'freaky' and for me at least an unpleasant experience.

[Mike Lavigne]

what you want is the maximum of ambient information in the recording, the sense of space, the murmur of the audience, the rendering of spacial clues.

the best way to express this is between cuts on an Lp you have zero sound, nothing but groove noise; then there is a pressurization of your room as the recording starts, a beat prior to that first note. if your noise floor, both signal path and control of potential outside of the room ambient noise, is really low, then that room pressurization should lay out the recording venue assuming that the recording chain retained it. the music then erupts from it's own space. a space your low noise floor allowed (to a lessor or greater degree) to be heard.

low noise means that there is a sense that the music is happening in a natural space. then the suspension of disbelief can happen.

some recordings don't have a low noise floor. lots of modern recordings are like this. or maybe the ambiance of the recording venue is not there, it's just nothing. what should happen is every recording should sound different. that's another piece of evidence your noise floor is low. you are hearing those differences and there is not an overlay of system noise every time.

there is more to noise than just signal path and ambient noise; there is resonance noise, there is acoustic reflective noise, it's all forms of distortion......something other than the music. then there is the ease of how your amps might be controlling the speaker. does your amplifier have a wondrous first watt? most of the music lives in that first watt. if your amps don't have lots of headroom then while not actually noise per se, that sense of the music being just happening naturally is lost as it more forced and hard. maybe your speakers need lots of juice to come alive, and at modest SPL levels there is no life to the music. this is a problem of speaker-amp relationship. or maybe the room is too large for the speaker to hook up.....in which case that ambient layer never get's fully rendered. the music sounds small and lost. lastly; there is the foundation and authority from having the bottom octave fleshed out. this is where that sense of space and rendering of the room comes from, control in the deep bass.

so the perception of low noise floor has lots of different components.

[Speedskater]

Almost all of the noise floor is determined in the recording process and in the ambient playback room. Oh, and add the vinyl playback system.
As for modern digital and audio playback equipment, if they are correctly setup, they don't enter the listening noise floor picture.

[mep]

I started a thread about the noise floor of our systems on AN sometime ago. Here is a link:

https://www.audionirvana.org/forum/t...of-our-systems

[Puma Cat]

Almost all of the noise floor is determined in the recording process and in the ambient playback room. Oh, and add the vinyl playback system.
As for modern digital and audio playback equipment, if they are correctly setup, they don't enter the listening noise floor picture.

So, some facts for the gang: it is possible to lower the noise in a "system", but is impossible to eliminate it completely. When something is powered, there will always be some level of noise.

Additionally, the noise from the power supplies of ampilfication components can and does go back out of the power supplies of the components via the power cord to be re-distributed into other components in the amplification chain.

Regarding modern digital and audio playback equipment: These devices are some of the most egregious and prolific sources of noise because the types and degree of the noise components they produce.

1) Computers of any type contribute signficant high-bandwidth RF and impulse noise from their CPUs and GPUs that audibly impact and degrade the sound quality of a stereo system. Additionally, this high-bandwidth noise can be picked up by many speaker cables (most which are unshielded for sound engineering reasons), and which literally function as antennas for these high-bandwidth noise components, and be fed backwards into the power amplifier, only to be reproduced again as amplified noise by the power amplifier. Any smart devices in the home, e.g. mobile phones, Wifi routers, tablets, non-audio computers, and smart devices also contribute the high-bandwidth RF and impulse noise in listening rooms. One of the best things you can do to improve your audio system is to move any computer-based music server, e.g., laptops, Mac Minis, Intel NUCs, etc. out of the audio rack and well away, distance-wise, from the main system as they are very "dirty".

2) The dreaded switch-mode power supply aka SMPS: this ubiquitous device powers almost everything these days, from computer's internal power supplies to streamers, network bridges, routers, NAS' and external hard drives, switches, fiber media convertors, etc., etc.. They are very dirty and nasty sources of noise as they create both low-impedance and high-impedance AC leakage currents, which travels down the DC power buses and lines, USB or coaxial cables ultimately to our DACs. In particular, high-impedance leakage currents are particularly insidious as they cause increased jitter and most importantly, clock phase noise.

3) Cheap clocks: The el cheapo clocks in consumer-grade cable modems, network routers, Ethernet switches and fiber media convertors also contribute notable clock phase noise to the analog square wave voltages that are the actual embodiment of the digital music file bitstream, and the more of them in the configuration, the more the original signal is degraded.

4) Flip-flops on Ethernet Switches, etc.: The flip-flops in consumer-grade cable Ethernet switches, routers, and fiber media convertors are also really cheap, and also contribute notable clock phase noise, just as with the clocks referenced above.

5) Noise on copper Ethernet cables. Copper Ethernet cables are are susceptible to number of noise factors, including RF, EMI, the low- and high-impedance leakage currents described above, (lack of) galvanic isolation, and common-mode noise. A good mitigation strategy for this is to use a run of optical fiber between music server and network bridge/streamer/DAC.

6) The transformers and transformer cores on isolation transformers on Ethernet switch's RJ45 jacks are susceptible to the AC leakage currents described above "jumping" to adjacent jacks.

7) Noise on power cables for digital device power supplies: Even if high-quality linear power supplies are used to power the digital devices referenced above, the power cords for these power supplies are susceptible to impulse noise.

Bottom-line: there is noise virtually everywhere with digital audio systems...



*– High-impedance leakage currents were only actually discovered 2 years ago, because existing test equipment did not exist to detect it. It was discovered and detected by John Swenson in Oct. 2017 after building bespoke test equipment to detect it.

[Mike]

Good post Puma Cat!

The MSB amp I had, was just spooky with the noise floor. I heard micro details in songs like Diana Krall Live in Paris, I never heard before.


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[Puma Cat]

Good post Puma Cat!

The MSB amp I had, was just spooky with the noise floor. I heard micro details in songs like Diana Krall Live in Paris, I never heard before.


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Funny how that works...

[BlueFox]

So, some facts for the gang: it is possible to lower the noise in a "system", but is impossible to eliminate it completely. When something is powered, there will always be some level of noise.

Additionally, the noise from the power supplies of ampilfication components can and does go back out of the power supplies of the components via the power cord to be re-distributed into other components in the amplification chain.

Which is why Shunyata power cords, and power conditioners, are so effective. They remove both incoming noise on the power line, and remove outgoing noise generated by the gear.

[Spock]

Bottom-line: there is noise virtually everywhere with digital audio systems...

And it is perhaps because most audiophiles ignore these aspects that many do not support "digital" sound.

[Kingsrule]

Which is why Shunyata power cords, and power conditioners, are so effective. They remove both incoming noise on the power line, and remove outgoing noise generated by the gear.

And mute, diminish dynamics, and basically suck the life out of the system.....but they sound "quiet"..must be good.....

[nicoff]

I am trying to understand the relative importance of this ‘digital noise’.

When my system is off, the average noise in my room is 35db. With my system on at the volume that I usually play my music at (but not playing anything) I cannot tell the difference in noise by ear. Using a dB meter, the noise measurement is pretty much the same (maybe, 0.1-0.2db although the difference may only be because the measurements were taken at different times and other outside factors may have contributed). So pretty much I have the same noise floor whether the equipment is on or off.

If I go through all that effort of updrading all my digital stuff to "audiophile" grade, what do I have to gain? Maybe 0.1-0.2db if I am being generous? That makes no sense to me.

For the record, I don't have any audiophile-type router or switches or fancy cables or Cat 8 Ethernet wires. I got cheap cables everywhere and a computer running Roon and HQPlayer sitting about 4 feet away from the equipment rack.

I admit that my NAS with the 5 hard drives working all the time is mechanically noisy but it sits in another room so I don't hear a thing.

Again, I am trying to put this in perspective. How many audible decibels would I be able to actually gain in dynamic range? Maybe technically there are decibels to gain, but if that gain is below my room noise floor then I cannot hear it. So what is the point of this whole exercise? Trying to be practical here.

[BlueFox]

I am trying to understand the relative importance of this ‘digital noise’.

What is digital noise? Are you talking about electrical noise created by digital electronics, or electrical noise created by digital devices (modem, router, etc.).

[nicoff]

What is digital noise? Are you talking about electrical noise created by digital electronics, or electrical noise created by digital devices (modem, router, etc.).

Digital noise is all that 'stuff' mentioned in Post #7.

[BlueFox]

Digital noise is all that 'stuff' mentioned in Post #7.

Okay. Except for number 7, none of the other is in my system. As I mentioned, Shunyata power cords take care of the noise from number 7.

[kiwi_1282001]

I am trying to understand the relative importance of this ‘digital noise’.


When my system is off, the average noise in my room is 35db. [...]

Bingo. I can’t understand why some audiophiles overlook the noise floor of the listening room. Yes, as Puma Cat insightfully lay’s out there is noise throughout the audio system (dreaded consumer grade switch-mode power supplies, noisy cable Ethernet switches et. al.) but what about the noise floor of the actual listening space?


I have long believed in the benefit of quiet spaces in which to enjoy music. Quietness demands noise control and by extension isolation from unwanted noise. The benefit for audiophiles of a quiet environment is multi-fold.


First, unwanted noise such as the sound of cars passing on a nearby road or the footfall of children in nearby rooms – which is distracting – can be eliminated or a least reduced.


Second, a quiet room, one with a very low noise floor, will improve the possible dynamic range of your audio system. Simply put therefore, the quieter the room the more things you will hear from a recording and the less distracted one will be by noise (unwanted sound).


I’ve built two listening rooms and detailed my efforts in my AS system thread. The later room shell measured nearly 50dB at project start and I managed to get it down to just below a 30dB noise floor [calibrated SPL meter, c-weighted; and similar z-weighted response using an XTZ room analyser pro]. A very significant gain in dynamic range which greatly improved reproduction of low level classical recordings.

[Puma Cat]

And it is perhaps because most audiophiles ignore these aspects that many do not support "digital" sound.

That's a good point.

[nicoff]

And it is perhaps because most audiophiles ignore these aspects that many do not support "digital" sound.

The noise floor of my analog set up is higher than my digital (I think I got my phono preamp to blame for that). So my analog set up will never have as much listenable dynamic range as my digital gear.

I think that the “most audiophiles” that you are referring to are likely to be folks that are not at ease dealing with computers and digital components/electronics.

[UltraFast69]

IMO, the arrangement of a system is an art: components, speakers, cables and all things audio show best in their placement - I'm sure compulsive OCD or similar.

One critical comment of the etherREGEN is the front and back (in/Out) should be the rounded sides and the rounded sides should be the front, or similar.

[Puma Cat]

IMO, the arrangement of a system is an art: components, speakers, cables and all things audio show best in their placement - I'm sure compulsive OCD or similar.

One critical comment of the etherREGEN is the front and back (in/Out) should be the rounded sides and the rounded sides should be the front, or similar.

The case for the EtherREGEN is the same case design and "metal" used for the LPS-1.0 and 1.2 power supplies. Alex used this case to keep the COGS for the BOM down as much as possible, to keep the overall retail price as low as possible. This is just good "parts bin engineering".

Morever, I can't even imagine what it would like to try to cut holes for, and assemble, RJ45 Ethernet jacks, SFP cages, & DC barrel jacks into the curved sides and surface of the case for EtherREGEN. That would increase scrap, rework, and drive up COPQ, lower process capability, drive up inspection costs, and on the whole, create major headaches for the assembly operators.

[UltraFast69]

The case for the EtherREGEN is the same case design and "metal" used for the LPS-1.0 and 1.2 power supplies. Alex used this case to keep the COGS for the BOM down as much as possible, to keep the overall retail price as low as possible. This is just good "parts bin engineering".

Morever, I can't even imagine what it would like to try to cut holes for, and assemble, RJ45 Ethernet jacks, SFP cages, & DC barrel jacks into the curved sides and surface of the case for EtherREGEN. That would increase scrap, rework, and drive up COPQ, lower process capability, drive up inspection costs, and on the whole, create major headaches for the assembly operators.

I can see I didn’t quite say it right and cutting holes in the curve is a non starter.


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[Puma Cat]

I can see I didn’t quite say it right and cutting holes in the curve is a non starter.


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LOL. No worries!

[Kingrex]

Originally Posted by Puma Cat
Bottom-line: there is noise virtually everywhere with digital audio systems...

And it is perhaps because most audiophiles ignore these aspects that many do not support "digital" sound.

Good point Spock. I have focused on cleaning and optimizing the power supply to playback gear and to all my digital devices such as Router, modem and switch. As well as good cables to the digital devices and playback equipment. My digital is very pleasant. Far far better than it was before I started. It has been a long learning curve, but worth it.

[tube-vds]

arthur salvatore has written some smart lines over this topic - and the difference between "noise floor" and the much more relevant "sound floor".

http://www.high-endaudio.com/rec.html#Noise

>> in a noisy place like a huge concert hall (even in the empty hall; the dB level will never come under 35-40), but you can hear even the drop of a small needle including all the 3D sound information.