Lowering the noise floor

I am coming to the conclusion that success in home audio reproduction is largely about lowering the noise floor. There are so many different types of “noise”, from so many different sources, that we only really “hear” by their absence.

Those components, cables, accessories and tweaks that SUCCEED at lowering the noise floor, can, and do, dramatically increase sound quality. Sometimes the type of “noise” dealt with is controversial, or not (yet) widely recognized as being a problem. Sometimes the explanation of how a product works is dubious. Sometimes the way it is marketed reeks of “snake oil”. Sometimes the reviews singing its praises go over the top. While these things will certainly put off some prospective purchasers, they do not negate the audible results that are there for anyone open to hearing them.
However, before you can benefit from a lower noise floor in your gear, you will need to lower the background noise in the listening environment. I just measured mine at about 35 dB on a Sunday afternoon, and that is low. When the house was designed we did a lot to achieve this. At that stage it is quite easy and cheap, unlike afterwards:
1 a quiet location, in so far as such a thing exists in a densely populated country like mine, and in a (sub)urban environment.
2 special window glass
3 muffled ventilation openings
4 quiet floor heating system.
5 quiet mechanical ventilation system that is only turned on when needed.
6 quiet water pipe layout.
7 quiet kitchen machinery like refrigerator and dishwasher.

It all makes a difference, but even then it is not concert hall quiet, and since maximum sound levels cannot be as high as in a concert hall, the dynamic range is inevitably smaller than in that concert hall.
I look at this topic in 3 different ways:
  • background noise
  • signal noise
  • environmental noise
Different products will affect the first two aspects of noise floor.
Sure but if for whatever reason the noise floor in your room is high, it will mask any noise from your electronics. Given the noise levels involved, this is not just a theoretical problem.
@willemj Yes, very good point.  Your environmental noise can easily mask any system noise you may have.  That is my case indeed.
Post removed 
Well - I’ve lowered the "noise floor" on my system and that translated into more clarity and details, larger image with 3D like sound, better bass control and faster dynamic performance - all of which is discernible - even with the "environmental" noise.

I use single ended RCA IC’s - because I (and a friend) observed they outperformed some pricey XLR IC’s by a significant amount.on a $50k system - Strange? but true!

I now use my own DIY cables that took me over 4 years of R&D - not elegant perhaps - but extremely effective

The use of these cables in a system also resulted in less heat being generated by solid state components.

But if you want store bought cables - checkout
I’ve auditioned/reviewed most of their product line and they are superb!

Their RCA’s may not look like anything special, but they are now one of the most used RCA’s by many companies that recognize their superiority over conventional RCA designs.

Their Bananas are also amazing - I’ve just installed them and my observations are posted here...

Even their lower end products will outperform many other products on the market.

And one last thing - Room Treatments!

Eliminating reflected sound makes a huge difference and one of the few things that actually masked the sound quality of my system by severely impacting clarity.

My most effective room treatments are related to the upper region  the room...
  • the introduction of a vinyl roller blind behind the listening position that dropped down about 15" from the ceiling (close to the wall). I also great success with this approach in a friends apartment with a 12 ft ceiling and concrete walls. You may need more than one curtain for complex rooms.
  • Some dampening material on top of a book case - again, strange but true.
So I agree entirely - eliminating the "noise floor" in imperative to improving sound quality - it does not matter how you get there - as long as you are aware of the issues, so you can do something to fix them

Regards - Steve
One of my favorite quotes was by Shannon Dickson in Stereophile magazine, referring to CES in Law Vegas that year, “I went to the geek meet in the Desert, where once again almost all of the exhibitors failed to get up out of the noise floor.”
Power power supplies, power supplies, power supplies.....oh my what a difference maker they are when it comes to noise. Wether computer audio, amplifiers, ac from our homes etc ... they are the place to look for obtaining the best possible sound. Noise is indeed the biggest hurdle on the road to natural and beautiful sounding music.  I am talking about noise introduced into the signal path. Not background noise or hiss.  Power supplies are often the bottleneck to great natural sound and they are indeed in the “signal path”. 
     The largest reduction in the noise floor I've  ever perceived in my many systems over the past 40+ years occurred about 3 years ago when I first substituted a class D amp in my system after using class A/B amps for virtually my entire home audio life. 
      In retrospect, there have been many changes in my sources (vinyl to cds to Super Beta Audio recordings of my cds to DVD-A and SACD to my current computer audio with ripped cds and 24 bit/96khz downloaded files) and many changes in my speakers (no-name Pacific Stereo to Klipsch Heresy to Mirage to Maggie IIB with single sub to my current Maggie 2.7qr with 4 subs) but relatively few changes in amps (from Pioneer and Yamaha am/fm receivers to Adcom separates to various mid-level class A/B amps with a VTL tube preamp to class D stereo amps to my current D-Sonic class D mono-blocks).
      Without any doubt, the change from class A/B amps to class D amps in my system resulted in the biggest perceived lowering of my system's noise floor of any system changes I've ever made.  I was not expecting this dramatic perceived noise floor lowering with the switch from class A/B to D amps since I didn't recall it being mentioned by others who had switched to class D amps. 
       I did immediately notice other changes to the sound of class D that others had mentioned such as increased bass response, increased dynamics and a detailed but smooth mid-range and treble response comparable to good class A/B amps.  But the lowered noise floor, that made it seem like the music was emerging from a dead calm inky blackness, was just a big bonus that made all my familiar music sound even better.  I also think this lowered noise floor enabled my system to sound more detailed. 
     Given these results with a class D stereo amp,  I subsequently bought another stereo and a pair of mono-block class D amps to replace the remaining class A/B amps in my combo ht and 2-ch music system which has increased the performance of both. 

For what it's worth,
I have come to the conclusion that success in home audio reproduction is largely about speakers & room treatments.

Lowering the noise floor (EMF noise) can be very useful for digital audio - the most critical issue is to ensure galvanic isolation.

An isolation transformer for the whole thing is usually a good idea.  Dedicated lines are costly unless you are doing new construction anyway.
Power supply indeed. But also power cords and cables. I think of a power cord as an extension of the power supply. As for the cables, especially interconnect cables, it is quite obvious too. XLR cables have no inherent advantage with short lengths.
I don't care if balanced cables with XLR connections are actually superior or not.  I'm going to keep using them because they sound good in my system, provide very secure connections and, truth be told, are infinitely cooler than RCA cables and connectors.

Just my take,
Electing to chime in on this thread in particular because of those who have already chimed in **AND** because OP has created essentially the same post elsewhere on this forum.

In light of the aforementioned, see response here:


In my experience it has been power cords that dropped the noise floor the most. Most notably the Oyaide Tunami cable with furutech connectors.  
Sometimes you don't know how much noise you are hearing until it's gone.  Have you ever been in a room that you thought was quiet and then suddenly the room becomes dead quiet and you realize that the humming noise from the compressor in the refrigerator just stopped?  It's like your brain just said "ahh, thank you."  I believe we can sometimes detect the lower noise floor in our audio systems with changes in cables, digital gear, etc. and the music just sounds more clear and right to our ears but really to our brains because it has to work less hard to be believable.

jc4659, exactly.
I think that in many or most cases power cords should be upgraded before interconnects, eventually both, of course. I did it myself, the cost was high, but it was worth it. Besides other things, noise level dropped big, distortion too, and both weren't too bad before the changes.
Power cords, power conditioning, and the Gutwire grounding cable do wonders in my system.
I have one word. Cryogenics. Cryo everything! Eveything in the signal path and everything not in the signal path. ❄️
I have spent more than $10k on treating both my home and system to reduce all types of contributors to the "noise floor": shot noise, EMF/RFI (from land, sea or air), EMR, grounding issues and so on (all Alan Maher Designs). My system only cost me $6.5k, but that $10k was spent gradually over the last 8 yrs, starting off very slowly and only progressing in price as confidence increased accordingly. But, for me, it just goes to show how important the role of this kind of problem does in fact play in music reproduction. I kept pursuing these solutions because I kept finding the ones I that I was using were working...if they didn't I would've given up on all that long ago. Everything improves. The modest $6.5k system I have is certainly modest no longer.

I could have spent that $10k on better gear, but it actually, I think, would've been a mistake, really. Sure, I could have had the inherent *potential* for better sound, but I would still be dealing with all the usual suspects that everyone else seems to be dealing with: EQ that doesn't really work well enough to truly solve problems, digititis, ss sound, "harsh" or "bright" recordings, best listening only at 4 a.m., upgraditis, insufficient timbre, tonal color, presence or sound staging, dependency on things like $$$ cables, critical speaker positioning, room peaks and nulls/room treatments...it even tamed how noisy that fridge is...all of that and much more has been either greatly reduced or eliminated. And that doesn't even take into account the transformational gains in both sound quality and presentation, all the way around.

Finding a way through this particular issue, for me, has proven to be the single biggest factor in finding that actual point at which I'm truly done with changing system hierarchy - exit strategy without compromise. I believe something like that might be the missing link for a lot of people. I suspect for most people that if they fail to investigate this aspect of music reproduction in their room space, they may be subject to the need to continually upgrade - and in vain perhaps because they might have reached their goals with less expensive gear, as I did - not by settling or compromising, but by finally solving all the right problems that were the ones that were actually standing in the way all along - and that would have continued to even after upgrading.

I think it's just possible we don't Rilly need the 'latest and greatest brand X', we just may need to focus more on what the longstanding audio problems actually are and how they can be fixed and what it might take to do that. Not for everybody for sure, but I can say that it was well more than worth it for me. No going back here. 

Once again a lot of voodoo science, and some suggestions that may have to do with sound quality but not necessarily with noise levels.
If you want lower noise levels (i.e. greater S/N) to increase dynamic range and detail resolution there are a few things you can do:
1 lower background noise (see my post above). In real life this is probably the most effective option because it is backgroud noise that masks the usually pretty good S/N performance of modern electronics. There is no point in listening to low noise gear if you are living next to an interstate with the windows wide open.
2 If you still think you can benefit from lower noise levels, look at the parts of the chain that have the worst S/N: FM radio, Phono inputs and rca interconnects, in that order.
FM radio is terrible with typically perhaps some 70 dB S/N, and there is nothing really you can do to get it close to the quality that can now be achieved by e.g. internet radio.
Vinyl and the necessary phono inputs are much worse than digital sources and line level inputs. Go digital and you have a far better S/N ratio. On most amplifiers the difference in S/N between phono (80 dB if you are lucky) and line level inputs is at least some 10 dB, which is not surprising given the amplification that is required, combined with the massive RIAA equalization.
Using balanced vs rca interconnects usually improves S/N by some 5 dB or more. Since these are typically used between a DAC/preamplifier and a power amplifier, we are already dealing with noise levels better than some 95 dB which is so good that the improvement may not necessarily be audible. But if you want the best, this is the way forward.
FM radio is terrible with typically perhaps some 70 dB S/N, and there is nothing really you can do to get it close to the quality that can now be achieved by e.g. internet radio.
That's silly. There's no way that low-resolution, lossy-compressed Internet "radio" can compare to the resolution of the best FM radio. Of course, the fidelity of the best Internet "radio" can be better than an awful FM signal. But the best FM signal - on a good tuner with a proper antenna - can offer incredible fidelity. That so few stations achieve this degree of fidelity accounts for the misguided notion @willemj states here. 

No it is not. FM has serious limitations, even if internet radio has as well, and they are of course hard to compare directly. FM once was a big improvement over and above MW, but it has quite a few limitations. First, there is S/N, second there are relatively high levels of distortion and third there is only limited channel separation. As a consequence, no FM broadcast is done without (these days automatic) dynamic compression, in the best cases only to a quite limited extent, but quite often rather invasively.
Compare that to internet radio. There is no need for dynamic compression, nor does it suffer from any of the other compromises inherent to FM. On the other hand there is of course data compression, sometimes rather badly, depending on the bit rate that is chosen. However, the algorithms that are used are marvels of psycho acoustic technology with exceptionally small reduction in sound quality, particularly at the higher bitrates. BBC Radio 3 is broadcast in 320 kbps and their and others' research has shown that this is virtually indistinguishable from full Red Book CD (there are quite a few blind tests on the internet to take yourself - few people can identify above 256 kbps). Even so, the BBC is now experimenting with full red book CD internet streams in FLAC (i.e. some 600 kbps depending on the type of music). So, the comparison is between the kind of signal degradation from the FM technology and the degradation from data compression of the digital stream. In my experience (with  an excellent FM tuner and good signal) the sound quality of internet radio at the higher bit rates that are increasingly common is significantly ahead of even good FM. That is the conclusion of the BBC, and I could not agree more. Moreover, the good news is that bit rates have been and are going up all the time.
In all seriousness, the greatest contributor to the noise floor of your system just might be the refrigerator in your kitchen when its compressor is running.  In my old rental house, I would unplug that janky fridge for listening sessions... right up until my wife found melted ice cream in the freezer.  Now we've got an LG that's whisper-quiet.

Likewise, your HVAC system, when circulating air through its vents, could be an order of magnitude noisier than your power supply.  

It’s Interesting and not terribly surprising how pervasive ignorance is among audiophiles on the dodgy subject of cryogenics. I realize how hard it must be to break out of the paradigms of the 70s and 80s. It’s like trying to get an electron to move to the next higher energy orbit. In fact, cryogenics itself improves SNR of all wire, including cables, fuses, transformers, inductors, power cords, wall outlets, what have you. It improves SNR by improving conductivity. This is why most high end cable manufacturers routinely employ cryogenics for their products. Because they know they cannot compete in the marketplace unless they do. Duh! 😛 It’s also why you see some (enlightened) manufacturers like Tannoy and Meitner employ cryogenics for their electronics. For digital gear reducing vibration means, you guessed it, improving SNR by reducing jitter. I.e., reducing noise. For structural or mechanical elements such as tonearms, racks, nuts and bolts, turntable platters and even LPs and CDs, cryogenics improves the strength and reduces brittleness, make them less prone to vibration. As I said, everything should be cryo’d. ⛄️
No it is not. FM has serious limitations, even if internet radio has as well,
Most of FM's "serious limitations" aren't inherent - they exist because of the execution. Internet radio is much the same. That’s why it’s silly to argue that:

there is nothing really you can do to get it close to the quality that can now be achieved by e.g. internet radio.
There’s no argument that Internet radio can sound very, very good, btw.
You can do wonders with spread spectrum communications. Noise disappears out of the equation. 
I agree with the goal of reducing background noise to allow your system to be at its best. I tried a DSP product last month but rejected it for several reasons. One, it significantly increased the noise floor hum. This might have been related to the fact that my preamp output voltage was over the recommended input limit of the DSP. I’m not blaming the DSP per se, just that it was not suitable for my system.

My goal of late is to minimize the ringing in the room in the low frequency range. I put this in the same category as noise because the music signal is fighting to be heard thru this unwanted sound overhang. To the extent I’m able to improve the decay time, the music becomes clearer. And it’s amazing how changing the location of a minor piece of furniture (basket full of magazines) alters the decay rate. I would not have believed it if I hadn’t seen the waterfall measurements.

I am going off topic now, but that level incompatibility could have been cured with a very simple set of inline attenuators.
And I fully agree with your desire to reduce room modes, even if I would not classify them as noise but as a deviation from the ideal frequency response. I have been very succesful with an Antimode 8033 room eq.

"I have one word. Cryogenics. Cryo everything! Everything in the signal path and everything not in the signal path. "

I sure hope geoffkait is right about the cryogenics treatment on everything; I've got an appointment tomorrow to have my entire body cryogenically treated.  Our ears and brains are in the signal path, right?

 The doctors warned me that my entire body will become very brittle after the treatment, like fine crystal.
  They said a high, sustained tone at just the right resonant frequency or even being nudged or bumped could cause me to shatter into 1,000 pieces.  
     I'm sure everyone's in agreement that these risks are definitely worth taking for a bit better system sound, right?
    My wife's trying to talk me out of it but our commitment to better sound trumps any silly marital vows, right?
   Okay, all systems  are a go for the treatment unless geoffkait tells me before 2 pm that he may have exaggerated just a scooch on this cryo stuff. since the cryo treatment  is non-reversible.

Wish me luck,
also, look at the parts of the chain that are most susceptible to noise causing SQ decrements

electrical noise isn't just something you hear on super quiet passages, it can also reduce spatial and transient aspects of sound reproduction

- whether it is doing that in your system is hard to determine - a star-quad style DC power cable is cheap ($10 to $50, DIY vs. bought); an LPS can cost a lot more but might be worthwhile

eliminating ground loops and providing galv. isolation may cost up to $100

wasting huge amounts of money on snake oil AC power cords when you SHOULD get an isolation transformer for $300 to $700 is idiocy
@noble100, wishing you great success on your upcoming procedure and please keep us posted.
@randy-11,   Spot on about LPS and using a good starquad DC power cable. I made two of these for use on my LPS units and they did indeed improve my overall sound quality. 
@randy-11 stated: "wasting huge amounts of money on snake oil AC power cords when you SHOULD get an isolation transformer for $300 to $700 is idiocy"
I've done both of what you've stated above with wonderful results. Much lower noise floor after "wasting huge amounts of money on snake oil AC power cords". In fact (word used intentionally even though it can't be measured because science simply hasn't caught up to our hobby [or apparently a lot of audiophiles ears] yet) as I've stated above, the largest noise floor reduction was had AFTER I put the "snake oil AC power cords" in my system.  
Ok then, let's talk specs. 

Alan Maher Designs:

"AQUA EMI Wrap Specifications:
Filter Frequency: 0Hz to 200+ GHz (max frequency of our test equipment)
Noise Suppression: 95% to 98% based on 120/240v incoming electrical service
Noise Floor Reduction: Greater than -200db max suppression of the entire frequency range (max of our test equipment)
Power Factor Correction Stabilization: 72 Hours (the fastest EMR correction to date from this product line – normally its 200 hours). 

Installed at the meter, AQUA is capable of neutralizing magnetic frequency below earth all the way down to 0Hz. What makes AQUA special compared to the other models we have offered in the past, AQUA is the first of its kind to extend frequency past the 5G wireless band. In actuality, AQUA extends the frequency band more than 2.5x the max FCC approved 5G spectrum past in 2014 (radio: both outdoor and indoor scenarios in the 28, 38, 60 and 72–73 GHz bands were published in 2014; multimeter: up to 90 GHz)." - Alan Maher  

Application: a thin paper-like material (roughly 24" x 6") that is wrapped around the pvc pipe at the incoming power path a few inches below the meter...a legal app in all 50 states. Weatherproof and seals with electrical tape. About $200.


"The Quantum TDT Fuse is the first of its kind to be released for the audio / video market. The Quantum TDT Fuse is essentially a miniature power conditioner built into a fuse application. Check out the specs:

Volume resistivity of 0.0001 Ohm per cm
Temperature Extreme: -58 to 257 degrees Fahrenheit

RF/EMI Attenuation:
10 to 100 kHz - 84 dB to 89 dB
100 kHz to 1 MHz - 82 dB to 93 dB
1 MHz to 10 MHz - 56 dB to 79 dB
10 MHz to 100 MHz - 51 dB to 70 dB
100 MHz to 1 GHz - 70 dB to 81 dB
1 GHz to 10 GHz - 62 dB to 83 dB
10 GHz to 18 GHz - 48 dB to 70 dB
18 GHz to 50 GHz – 70 dB to 45 dB

As you can see you’ll have a hard time finding a power conditioner with better noise suppression specifications." - Alan Maher

About $150 ea.


Platforms (18" x 12" x 2.25"):

"The AQUA Active Platform is a marvel of creation. For the first time we have been able to extend the filtering bandwidth above 100 GHz with a noise suppression level below 200db across the entire frequency spectrum. The AQUA Platform is a game changer for the entire industry.

AQUA lowers the ground impedance for the entire circuit down to .001 ohms of resistance – The low impedance acts as a turbo charge for all installed AM Designs products throughout the home." Alan Maher

About $3000 ea.

I have 2 of these which I snagged on a promotional sale. Tremendous sound quality improvements.

=======================================================Alan has perhaps a hundred different products at different price levels and different apps for tackling different A/V problems, so these here are just the tip of the iceberg.



I hate to jump to conclusions but it certainly appears I’ve completely avoided a huge amount of RFI/EMI interference of ALL frequencies from 0 Hz to umpty ump GHz by completely circumventing the house AC. I’ve also completely avoided all magnetic interference produced by transformers and by current running through wire and cables. I’ve also circumvented all issues related to power cords, fuses, interconnects, large capacitors, digital cables and speaker cables, including directionality issues. I’ve also circumvented ALL issues related to room acoustics. AND I’ve avoided the costs associated with dealing with all of those issues. I’m a big believer in cost avoidance. AND reducing the Audio Nervosa Quotient as much as possible. 🤪 I don’t like tips of icebergs and I don’t like icebergs.
What, you mean you've avoided all that by going cryo?? Not sure I get the drift here...forgive me if I'm a little slow today...battery powered headphone set up?? 
If it Is a battery powered headphone setup we’re talking about, then except for cost and audio nervosa, I’d say that you have not **completely** (to use your word) avoided all the noise issues. There is the noise from the components themselves at the very least, just for example. I’m not saying that you **have** to solve it this way, just that you could make gains with it if you wanted to. Nor am I saying that the approaches that you’ve used, or that others use generally, are somehow invalid...just that there are usually other ways to skin the audio cat (I prefer to just swing them around). From what I understand, cryo’d wire measures lower in EMR than the same untreated wire, in effect lowering resistance and increasing power efficiency.

But, as far as the icebergs go, I can only offer that you try and relax and just enjoy the cruise while it lasts. If you’re looking to guarantee smooth sailing, I’d say that you’re likely in the wrong hobby. In case you haven’t noticed, there are rather a lot of icebergs all around at any given time anyway. I’d say that we are all on that same Titanic ya know, whether we are into rearranging the deck chairs or not.

I never said I eliminated all noise. What I said or at least intended to say is I eliminated all RFI/EMI type noise produced or carried by the house AC, cables, fuses, power cords, AND all magnetic type noise produced by transformers (induced magnetic field) and the induced magnetic fields inherently produced by current traveling through cables and wire. And no GROUND issues. I thought I was pretty clear. Furthermore, by minimizing the player itself, which is a portable player, noise and distortion produced by the player itself is obviously MINIMIZED, e.g. NO BIG TRANSFORMER. NO FUSE. NO BIG CAPACITORS. Capish?
I think I understand what you’re saying with the magnetic type noise (mu metal, yes??) and also the minimized player. It’s the "...all RFI/EMI type produced or carried by the house AC, cables, fuses, power cords..." part that’s confusing me...not sure what method of noise removal here you are referring to??
I'm not sure what Geoff is referring to either, but I'd like learn. Are you off the grid, Geoff? ( sounds like you did something more than that though). That's something I'd be interested in doing and believe it would greatly lower the noise floor. Adding the battery powered Concert Fidelity DAC to my system greatly lowered the noise floor and as the OP pointed out, that allows the music to really come forth. I'd be very interested in pursuing off the grid solutions for my entire system but don't know much about doing so. Would love to hear people's experiences here. 
I've never actually tried that, but it may be 'somewhat' worthwhile to at least look at I think. There is less noise with batteries, but from what I've gathered it never totally goes away. But, you could expect rather good results with all except most amplifiers...just not enough playing time or dynamic oomph to satisfy according to what I've seen, so going **completely** off the grid would be rather complicated and expensive, possibly to the point of being impracticable. But, with the lower wattage devices, perhaps very likely it's feasible.

Also, homes with solar power apparently often have noise problems from the cheaply made solar panel supporting electronics. Solutions have been found there too, but again, get rather pricey and specialized.
Bingo! I’m off the grid! I use a portable battery powered player, a Walkman. I use Grado RS 60 headphones. By getting off the grid I avoid all the ills associated with the grid, and all the ills associated with cables, fuses, and the other stuff I already mentioned. Trust me, it’s audible, even on my modest system. I mean, I still can tweak it, right. I use only treated batteries and everything has been quasi cryod at a minimum and everything is mechanically isolated. And some other, you know, stuff. 😬 No more grid, no more noise, no more distortion. No more teacher’s dirty looks. Since technically SNR is the power of the signal over the sum of the Noise + Distortion powers, eliminating ANY type of Noise or Distortion would be a good thing, right? Just on the level of Signal to Noise Ratio. Including induced magnetic fields’ distortion and the distortion of wires, fuses or cables that are in the wrong direction, etc.
Thanks for the explanation.

"...eliminating ANY type of Noise or Distortion would be a good thing, right?" 

Most certainly sir.
By getting off the grid I avoid all the ills associated with the grid, and all the ills associated with cables, fuses, and the other stuff I already mentioned. Trust me, it’s audible, even on my modest system. I mean, I still can tweak it, right. I use only treated batteries and everything has been quasi cryod at a minimum and everything is mechanically isolated.

Wonder why professional rock bands don't do this.
Oh, they could. But it would take, what, 10,000 car batteries? And crew of a hundred.