NwAvGuy

Amazing blog, glad I found it and the other articles look great too! Very interesting history of computing. Can you use an arbitrary waveform generator to make these sounds accurate or differences nonexistent? Do you think that good audio can be “solved”? I’ve heard of Harmon tuning and people’s preference for it, and how good speakers are all tuned the same but high end headphones don’t. I remember this person who knew electronic design destroying the credibility of head-fi. https://nwavguy.blogspot.com/ what do you think of forums like audio science and his findings?

My favorite audio resource for those designing or evaluating audio amps and DACs is NwAvGuy's blog[0]. The blog posts explain what performance parameters matter, what don't, and evaluates the performance of various products and components. Equally interesting is the mysterious story about the anonymous author himself [1] [0] http://nwavguy.blogspot.com/ [1] https://spectrum.ieee.org/tech-history/silicon-revolution/nwavguy-the-…

I don't know much when it comes to audio amp design, but this reminds me greatly of the O2 headphone amp[0] - that anecdotally a few of my friends have soldered for their personal use. [0] http://nwavguy.blogspot.com/2011/07/o2-headphone-amp.html

This guy is fantastic. Having spent a little time around professional audio, it doesn't surprise me that he did amazing stuff for 18 months (anonymously) then vanished from the web. This piece on his site has lots of interesting insight into the audio industry. It also relates to objective, critical thinking in general. http://nwavguy.blogspot.com/2011/05/subjective-vs-objective-debate.htm…

The best resource I ever stumbled upon on the subject is NwAvGuy's blog : http://nwavguy.blogspot.fr/2011/05/subjective-vs-objective-debate.html

Update: E-Bay UK has them in buckets... about £140 for the leading item right now... http://tinyurl.com/7tuotsf Great news that the Pi is shipping, there must be a lot of eager people out there, cannot wait to see the first wave of responses, genuinely exciting times ahead :) Oh, and don't forget to add one of these to the order for open audiophile audio out :) http://nwavguy.blogspot.co.nz/2012/04/odac-released.html "We now have in excess of 100,000 confirmed orders for the Raspberry Pi globally and can confirm that everyone who ordered before 18th April (i.e. today!) will definitely receive their Raspberry Pi before the end of June 2012, whatever your existing order confirmation says! "

The root is that at some point (late 20th century) the cheap wine became as good as the good wine. So the key differentiating metric for most of the space turned from performance to marketing. The high-end got pushed into the stratosphere (I'll never own a pair of electrostats) and everything else is good enough (hopefully, sometimes there is incompetence). So if it's all good enough for the mass market then the audiophiles need to look in the mirror and ask what they're after. Some will say a mystical, ethereal experience. Some will say total control over the signal chain from outside the body to inside. These are orthogonal wants crammed into a single market. The second path is harder, but it at least the end result is some form of truth. Very few engineers want to devote themselves to a pointless crusade for a tiny market of consumer goods. There's better things to do on the weekend. However, when they do it's special. http://nwavguy.blogspot.com/

>16 bit enough It is so believed (although there's a lack of supporting evidence, and knowledge that human hearing has excellent dynamic range), but only as long as the mastering work was well done. 24bit allows for much less destructive human error and is very welcome. Much more so than absurdly high sample rates (96KHz, reproducing sounds up to 48KHz as per Niquist), which are of dubious value. >my sennheiser hd600s are 300Ω At some frequencies. At some others, it's more like 600Ω. Impedance is seldom stable across the frequency range in headphones. Amplifier design should account for this and still provide enough power[0]. Output impedance of headphone jacks should be low enough (1:10 is commonly cited, which means <2Ω in practice as 20-30Ω headphones are very common) relative to the low end of the headphone impedance range, in order to prevent the impairment of frequency response. >Not -all- onboard cards suck of course But most do. The design of audio circuitry in motherboards doesn't get that much attention. None of my motherboards have good sound. Flaws vary. Some are lowpassed (greedy anti-aliasing filter). Some are noisy. Most have excessive output impedance (typically more than 6Ω, and at times higher than 15Ω). None can output enough power[0] for hd600 (my favourite pair). [0]: https://nwavguy.blogspot.com/2011/09/more-power.html

> I noticed a difference in clarity using Audio-Technica ATH-M50s and Beyerdynamic DT 990 250Ω. Specifically, the Beyerdynamics could be driven "good enough" for me with the iPhone SE jack, but I wasn't happy with how they sounded on the Lightning dongle. Scientifically speaking, it should be noted that the adapter performs exceedingly well to the point of audible transparency[1]. You are not going to hear the distortion components as they lie below 90 dB. The fact of the matter is that your ears simply cannot be trusted, not when it comes to discerning differences in DACs and amps. There is a beautiful read[2] that illustrates this by NwAvGuy, it's worth checking out even for non-audiophile. And Xiph's Digital Show and Tell[3] (again, a must-read) tells us that the 44kHz of the dongle is more than enough for audible transparency to humans. The differences you hear are likely due to incorrectly matched volumes. If you volume-match to a fraction of a decibel, you probably would not be able to tell the difference in a blind test. There are other potential differences like a different impedance etc but these should only effect a very small subset of IEMs, let alone your headphones. [1]: https://www.kenrockwell.com/apple/lightning-adapter-audio-quality.htm [2]: http://nwavguy.blogspot.com/2012/04/what-we-hear.html [3]: https://wiki.xiph.org/Videos/Digital_Show_and_Tell

I greatly respect NwAvGuy and agree with almost everything he says, but I think in practical terms that's a slightly over-simplified perspective. Look how inaccurate even these headphones are [1], arguably the best or one of the best ever made. Getting the inaccuracies to be the right inaccuracies is quite subtle and very important in my opinion. See for example this review of his [2] and in particular the paragraph near the end: >AN EQ EXPERIMENT: I tried using highly configurable parametric EQ to tweak my Denon D2000s to be similarly forgiving and I failed. When I filter out equivalent amounts of sibilance and harshness with the Denons, more of the music is gone and the result sounds veiled and artificial. The HD 650, to my ears, somehow works more like polarized sunglasses. They largely remove what I don’t want while revealing more of what’s left. It’s not just a simple frequency response difference. My objective side wants to pin down what’s going on but I don’t have a full explanation besides the HD 650’s lack of distortion. [1] http://www.innerfidelity.com/images/StaxSR009.pdf [2] http://nwavguy.blogspot.co.uk/2011/06/sennheiser-hd-650.html

The rules of thumb about "60% of maximum volume for 60 minutes" and "if you can't hear your surroundings, it's too loud" are nonsense. Dangerous volume settings depend on a headphone's sensitivity, the output device power, the headphone's isolation ability, and the recording. These parameters vary. Wildly. A well-fitting isolating IEM can slice off 25dB of noise, more than enough to (mostly) eliminate background conversation noise at any location short of a hip restaurant. These IEMs tend to be so sensitive that they become earsplitting at a tiny fraction of the maximum output volume, way less than 60%. Learn approximate dB levels of various sounds, compare various noise with a meter (even an uncalibrated app will give you a ballpark idea of what you're dealing with), and listen to music at an average 65dB or less (this will obviously vary with dynamic range of your music; occasional 80-85dB peaks won't kill your hearing). One trip to a dance club or rock concert without earplugs (100-110dB on average in my experience, 120+ has been known to happen) will do more hearing damage in a few minutes than a lot of headphone listening while working. I'm pretty sure the busy street near my home routinely hits a 90dB average at rush hour, solidly in the danger zone compared to reasonable headphone use. Edit: To learn more, read the following: - http://www.rane.com/pdf/old/note100.pdf - http://nwavguy.blogspot.com/2011/09/more-power.html

For context, the NwAvGuy O2 amp[0] design is pretty famous now. The dude even lays it down right there[1] in the comments of the linked article. And then soon after that iirc he just disappears? [0]: https://nwavguy.blogspot.com/2011/07/o2-headphone-amp.html [1]: https://nwavguy.blogspot.com/2011/02/headphone-amp-impedance.html?show…

http://nwavguy.blogspot.com/2011/02/sansa-clip-measured.html Very good

i think we all want to know: is it the awesome sound of 24k gold or the washed out garbage of mere 18k gold? disclaimer: my audio card has swappable op-amps :D https://www.asus.com/Motherboards-Components/Sound-Cards/Hi-Fi/Essence… (i still use a Sansa Clip+ with RockBox firmware) http://nwavguy.blogspot.com/2011/02/sansa-clip-measured.html

The double-blind scientific approach to audio testing ("ABX") has long been a major point of contention between "objectivists" and "subjectivists"[1]. This has been a godsend for the marketing marketing of some snake-oil companies in audiophile circles. Really glad to know Spotify is on the side of science, here. [1]: This blog has got to be the most interesting I ever read on whatever topic it touches, including the objective vs subjective debate: http://nwavguy.blogspot.com/2011/05/subjective-vs-objective-debate.htm…

We'll never have the luxury of laser-trimmed resistor or matched transistor, an integrated opamp usually outperforms discrete designs, at least for low-power applications. But yeah, it's much fun to build an integrated component from scratch and see how it works. BTW, NwAvGuy, the audio guru who have vanished, has some interesting criticisms on the dismissal of opamp in the audiophile community. https://nwavguy.blogspot.com/2011/08/op-amps-myths-facts.html

If anyone is looking for a low cost, open source, high quality Headphone amp + DAC combo which rivals gear costing 16 times as much, take a look at NwAvGuys stuff. Headphone amp: http://nwavguy.blogspot.com/2011/08/o2-details.html#resources DAC: http://nwavguy.blogspot.com/2012/04/odac-released.html

The duplicated amplifier as ground design is pointless and pretty much strictly worse than using a normal ground, but has somehow become semi-popular among certain misguided parts of the audiophile community. Good article about it here[1]. The problem with just using the middle of the batteries as ground is that it creates a potentially headphone-damaging DC offset if the batteries drain unevenly for whatever reason. The resistor bridge is the simplest way to avoid this problem, though there are lots of ways to create a dual rail power supply with various tradeoffs[2]. [1] http://nwavguy.blogspot.com/2011/05/virtual-grounds-3-channel-amps.htm… [2] https://tangentsoft.net/elec/vgrounds.html

NwAvGuy has some not-very-nice things to say about Schiit. Basically, that they don't know how to design audio gear. He discovered that one of their amps could damage your headphones. For this warning, he was banned from the Head-Fi forums: http://nwavguy.blogspot.com/2011/07/banned-at-head-fi.html

Section 2-29 of: http://nwavguy.blogspot.com/2011/07/o2-design-process.html And the entire article at: http://nwavguy.blogspot.com/2011/05/virtual-grounds-3-channel-amps.htm… Its easy to make something that amplifies, but he's trying to make something that provides specs maybe 10x to 10000x better than human hearing can detect, which is much harder. You can build something that outputs 0.1% THD and you won't be able to hear it, but he wants (wanted?) to build to 0.001% THD and he's got the rather expensive test equipment required to prove it. JDS labs sells a PCB for less than the cost of shipping (you'll spend more on UPS than on the board) or a full parts kit for $60. This has been around for years and I've been tempted but haven't built one. I just checked JDS and its still in production and in stock. Being CC- licensed there are probably other places to get PCBs and kits.

Or when you are annoyed by a shitty soundcard in your business notebook, get a Behringer external DAC/soundcard for $29 ( http://nwavguy.blogspot.de/2011/02/behringer-uca202-review.html )

This guy also built and open-sourced a universally admired headphone amplifier and DAC. His O2 amp: http://nwavguy.blogspot.bg/2011/07/o2-headphone-amp.html His O2 DAC: http://nwavguy.blogspot.bg/2012/04/odac-released.html JDS Labs and others sell them commercially for those who don't feel like building them by hand.

Nice, good and cheap amp ($19) mentioned at the bottom of the article, in case you need immediate boost over stock audio from your phone - http://nwavguy.blogspot.bg/2011/03/fiio-e5-headphone-amp.html

Although more complicated and expensive, another interesting amplifier project is the open source O2 amp: http://nwavguy.blogspot.com/2011/07/o2-headphone-amp.html

There's the minor issue of them not actually testing their designs perform as expected, at least one amp damaging some people's headphones as a result, and them denying the issue existed: http://nwavguy.blogspot.com/2011/07/banned-at-head-fi.html Though that's not really a problem with manufacturing in the US, it's more of a general audiophile industry problem.

Some of their products are worse than snake oil. When powering off, Schiit's Asgard amp can output enough DC to damage some headphones. One Head-Fi user recorded a video of this happening. NWAvGuy tried to get answers from Jason Stoddard and ended up being banned from the Head-Fi forums. The whole fiasco is summarized on NWAvGuy's blog.[1] Of course NWAvGuy isn't the most tactful person, but Head-Fi's reaction seems quite overzealous. 1. http://nwavguy.blogspot.com/2011/07/banned-at-head-fi.html

NwAvGuy is the truly interesting story, NwAvGuy was some anonymous person who went to audio forums and warred on Schiit pointing out technical problems with their products and the way they do their marketing. I guess someone said if he knew so much about audio why didn't he go out and design and build his own stuff and so he did exactly that designing a headphone amp that has "legendary" status, and then he disappeared... His headphone amp: http://nwavguy.blogspot.com.br/2011/07/o2-headphone-amp.html

Very interesting, could you use this to build a good analog amplifier? http://nwavguy.blogspot.com/2011/07/o2-headphone-amp.html Is there any way from genetic algorithms to learn from good human designs as starting points and breed the together? What about genetic algorithms for battery and solar cell design?

For me NwAvGuy is most famous for his Headphone & Amp Impedance article where he coined the 1/8th rule so many audiophiles refer to all the time. http://nwavguy.blogspot.se/2011/02/headphone-amp-impedance.html

If you're on a mac, you can obviate a lot of bit depth issues by opening /Applications/Utilities/Audio MIDI Setup.app. From there you can see all your audio input and output devices, and set their frequency and bit-rates. Most default to 44kHz/16-bit, but a saner setting is 44kHz/24-bit. You can see the objective differences between 16-bit and 24-bit output in NwAvGuy's measurements of the 2011 MacBook Air's DAC: http://nwavguy.blogspot.com/2011/12/apple-macbook-air-5g.html