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Old

How Beats Conquered The World (via The Verge)

Posted 13th June 2014 at 12:04 AM by rjm
Updated 13th June 2014 at 12:44 PM by rjm

Original article, by Ben Popper

~ my spin ~

There was the iPod. It was cool, and the distinctive while earbuds that came with it showed people you had an iPod, so they were cool, too. A few audiophiles invested in better IEMs, but they tended to be expensive and discreet and anyway were only ever a niche thing.

Meanwhile the Japanese headphone makers - JVC-Kenwood, Sony, Audio Technica - tried competing with the iPod, and they came up with a spectrum of earbuds and headphones of every shape, price, and color. They sold as commodities, but none developed any real kind of identity or reputation. Certainly there was little effort at building a brand.

On the other side, Grado, AKG, and Sennheiser continued doing pretty much what they always did, making nice, expensive headphones for home/studio/DJ use.

Neither group addressed the obvious hole in the market: non-audiophiles wanting "good" sounding over-ear...
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Old

A "music cafe", Kyoto.

Posted 13th January 2014 at 09:45 PM by rjm

A small corner of audio heaven, for anyone willing to pay the 500 yen cover charge.
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Old

Hi-end audio, as seen from outside the bubble.

Posted 3rd June 2013 at 11:28 PM by rjm
Updated 3rd June 2013 at 11:32 PM by rjm

In early May Trent Wolbe traveled to the High End trade show in Munich, Germany. This is part one of a two part series exploring the cutting edge of audiophile technology.

By Trent Wolbe, writing for The Verge. A feature on high end audio part 1 and part 2.

Quote:
It was halfway through the next selection, a quietly seductive 24 / 192 recording of “Cielito Lindo,” that I realized I was enjoying the music quite a lot, not because I particularly enjoy bossanova versions of Mexican classics, but because the Evolution One speakers were recreating one of my favorite things about eating psychedelic mushrooms.
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Old

A poll. Basic electronics and DIY audio.

Posted 2nd April 2013 at 01:46 AM by rjm
Updated 4th May 2013 at 10:54 PM by rjm

It came up at the help desk, but I want to put this before diyaudio.com members generally:

I feel strongly that people who build audio equipment as a hobby should take it upon themselves to obtain a basic understanding of both the practical and theoretical aspects of electronics. Take a trip to the library and read through the first couple of chapters of electronics textbooks, that kind of thing.

It's more than just the safety aspect, I think of it as a basic necessity...

So, how many people here are familiar with the following statement?

The impedance of a capacitor is -j/([omega]C)

Familiar as dirt? Never heard of it before?
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Old

The Front End

Posted 19th November 2012 at 04:26 AM by rjm
Updated 22nd November 2012 at 05:18 AM by rjm

The most disruptive audio technology since the CD, since the advent of stereo actually, is ... the iPod. You can lump in mp3, iTunes, and digital distribution in there if you want, but itís the iPod, the physical device, which has more than anything re-defined what we think of as an audio system in the twenty first century. Shelves of physical media and a playback unit, or, if you preferred, broadcast content, has been displaced by a handheld, personal, portable jukebox. The audio component system of the 1970ís (media, sources, preamp, amp, speakers) has faded into obsolescence, replaced by powered speakers, headphone amplifiers, desktop audio, compact ďspeakers+amplifierĒ systems the ubiquitous "dock" fronting a traditional amplifier-speaker system.

Audio is missing the front end.

Because it isnít an iPod, Iím sure of that. Its day is done. No, it's pretty clear to me that the front-front end of the future is settled: Its the internet. The cloud....
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Old

My Nexus 7 Tablet

Posted 12th November 2012 at 06:54 AM by rjm
Updated 18th November 2012 at 04:03 AM by rjm

The Nexus 7 is cheap. I paid 19,800 yen for my 16 GB model, shipping and tax inc., and it came with 2,000 Yen credit to buy apps and movies and such in the online Google Play store. And yes, its plastic, even the silver metallic trim around the edge is just a silver-coated plastic part. It is solid, however; sturdy, well-built, and good-looking. The back is covered in grippy, dimpled rubber that feels like leather. The screen is a little dim, but high resolution (800x1280) ~220pi, pretty to look at and easy to read.

With a 7" screen and default portrait orientation the device is closer in spirit to a large smartphone than a small tablet. A giant, wi-fi only smartphone. It's a handy size for reading paperback-format books, comics, and news articles, but not so hot for magazine format publications and A4-formatted journal articles. Browsing the web is generally fine, but the experience varies widely depending on the individual layout of the web page. As you might expect,...
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Old

Akihabara, lost to the maids.

Posted 20th September 2012 at 11:51 PM by rjm
Updated 23rd September 2012 at 11:24 PM by rjm

A maid cafe is, as far as I can make out - and wikipedia confirms - a cafe/light restaurant staffed by girls who dress up as anime characters or doll-like maid costumes. Chatting with customers is encouraged, so the atmosphere is more social than a regular cafe. Its also more expensive, and the food worse. (from what I can judge from the menus: its what my nine year old daughter might make if left alone in the kitchen...) They advertise by by having the staff stand around - in costume - on busy street corners nearby handing out small cards.

This is a phenomena that started about 5-6 years ago, or at least started to go mainstream then. Ground zero for maid cafes is the "nerd districts" where computers, comic books, and video games were sold: Akihabara in Tokyo, Nipponbashi in Osaka.

Growth appears to be exponential: every time I visit either region (I'm in Tokyo right now, staying near Akihabara) the number of maid cafes (and therefore maids on the street)...
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Old

modest base requirements for a line stage

Posted 22nd June 2012 at 06:44 AM by rjm
Updated 29th June 2012 at 05:38 AM by rjm

Copied from this post, for reference.

Quote:
Originally Posted by RNMarsh
Here are my own modest base requirements for a line stage (similar for power amp):

1. Open loop BW of 40KHz or more (-3dB)... 20KHz min.
2. IM and THD of less than .001% at 1v rms into 30 ohms for any frequency between 20Hz and 20KHz.
3. No coupling caps on input or output or in feedback path.
4. No use of dc servo circuits to track and correct dc offset and drift.
5. No more than 6-8 transistors (excluding power supply).
6. S/N ref 1 volt rms and without weighting of at least -130dB (input can be shorted or terminated).
7. No significant harmonics above the 2nd and 3rd.
8. Closed loop gain between 12 and 20 dBv
9. Low Zout (less than a fraction of an Ohm at any audio freq).
10. Distortion not be changed by source Z.
11. Transistors should be low cost and not be exotic, hard to obtain, very expensive or no longer manufactured.

There might
...
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Old

Bypassing, Goldilocks, and the Sound of Nothing

Posted 31st May 2012 at 06:28 PM by rjm
Updated 1st June 2012 at 11:53 PM by rjm

Douglas Self writes,
Quote:
The 5532 and 5534 type op-amps require adequate supply decoupling if they are to remain stable, otherwise they appear to be subject to some sort of internal oscillation that degrades linearity without being visible on a normal oscilloscope. The essential requirement is that the positive and negative rails should be decoupled with a 100 nF capacitor between them, at a distance of not more than a few millimeters from the op-amp; normally one such capacitor is fitted per package as close to it as possible.
He's someone who should know. Anyway, it doesn't take much digging on the internet to confirm beyond reasonable doubt that bypass caps should be as close to the op amp power pins as possible. So thinking about my previous experiments with bypassing the Sapphire, by adding bypass caps around the transistors I also effectively also added a bypass for the op amp, but a rather poor one as the power-pin-to-power-pin round trip loop distance is probably 10...
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Old

Headphone Amplifier Gain

Posted 2nd April 2012 at 08:45 AM by rjm
Updated 2nd April 2012 at 11:43 AM by rjm

I posted this earlier today, but I think it deserves to be put in the blog - if nothing else so I can find it again next time ... and there always seems to be a next time when it comes to calculating headphone amplifier gains.

Starting at the beginning, the encoded data on a CD goes from 0 to 1 in 2^16 steps, but in a typical CD player or soundcard, the DAC output is -2.8 V to 2.8 V or 2 V rms or 6 dB. Many sources, such as phono stages and portable audio, are lower, perhaps as low as 250 mV.

How loud the sound is depends on the source signal amplitude, the position of the volume control, the circuit gain, and the impedance and sensitivity of the headphones.

As a practical matter, most people would want the volume control at the 9-10 o'clock position for "normal" listening.

For standard "line level" source, the gain required to keep the volume control at a 9-10 o'clock varies depending on the impedance...
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