Maybe there’s some active herbal extract in the snake oil base. Until we’ll see actual noise levels, including how they carry from the card to the output of some chosen reference player (or set of players), I’d consider the actual effect rather doubtful.
Cf. cellphones. The players typically work well there even during the activity of the RF part. The transmitter takes a LOT of power, in narrow pulses, with corresponding impact on the power bus noise. Sometimes the voltage dip is enough to switch the phone off when the battery is weaker or more worn. Compared with this, the amplitude of the SD card noise is really really negligible.
Are they saying that the digital MP3 data values read from the card contains fewer bad bits, or that the digital data lines from the card are less contaminated by analog noise?
I swear to gods, I read your comment, the URL, and halfway through the article before I realized it was “Pono Player” instead of “Porno Player”. I was trying to figure out why they were trying to be serious if they named the product that…
And they would control the analog noise on the data bus… how? The micro SD card is a single chip, made by the billions using fabrication masks developed once per design generation.
There’s simply no room for modification of this part for the audiophile market. That is to say, the chip designers would chortle derisively at the suggestion of such a thing.
The card is two chips, actually; the flash, and to it glued a chip with the controller. (And the pair can come cheaper than a flash chip alone, due to the testing done by the controller instead of by time-consuming operation done on the manufacturing line, if I remember correctly.)
The controller will likely be the magic here. There can be tricks with shifting the clock pulses a little, so they aren’t entirely in phase, so instead of adding together to one large dip on the power bus they make two smaller dips easier to filter. Or using spread-spectrum clock that forms flatter wider peaks in the frequency spectrum of the noise instead of fixed-clock that forms a narrow intense peaks of the base frequency and the harmonics.
Or maybe staging power-demanding operations so they don’t occur simultaneously.
There may be also some other software-implemented tricks with impact to EMI reduction, along similar lines.
Check the old “Tempest Fur Elize” software that manipulates patterns on the monitor to broadcast music over FM band. (There are also similar demos using memory bus to broadcast.) The same principle can be used the other way, to minimize the emissions over audio frequency band instead of maximizing them for demo purposes. Along these lines, there are special Tempest-reducing fonts, which have edges “softened” in the way that minimizes the high frequency emanations on their edges, reducing readability after interception.
Also, they could have integrated a flat capacitor onto the card itself.
Just speculating here…
You know it, I know it, the chip developers know it (though for cases where it matters there are the techniques described above), but audiophiles are queuing and Sony is laughing on the way to the bank.
Sometimes I am thinking about buying an oil press and some snakes…
That’s a lot of theorizing about what they could do to the tiny card to make it better.
Remember that the SD card’s data bit rate is many MHz, which is utterly invisible to an audio amplifier. So there’s no point in doing anything to that. The only thing that would matter would be the page read rate, which is also likely to be supersonic.
Oh, wait, I forgot that audiophiles can hear into the MHz.
By the way, spread spectrum doesn’t reduce EMI. It only makes it fit under the certification line on the FCC’s spectrum analyzer. But what do I know? I only make spectrometers for radio telescopes.
It’s much more likely that the packaging guy was told by the marketing guy to have the words “for premium sound” printed on one production run of generic Micro SD cards.
This is bullshit. Every audiophile knows that the digital “fuzz” coming off inferior quality memory chips is what gives the music “warmth” and “depth.”
Yup. Unless modulated at lower frequency and serving as a carrier (see the cellphone-proximity “GSM buzz”).
Back of the envelope check: Page size, 2048 bytes. (Well, 2112, but count 2048 for the sake of the argument.) MP3 bitrate, say 256 kbit/sec, 32 kbyte/sec. This gives 16 page reads per second, which is not exactly an ultrasound.
Let’s count a wav, 16 bit stereo 44.2 kHz. 176,8kbyte/sec, Gives 86.32 page reads per second.
That looks to me unexpectedly low… But I am time-strapped now so will recalculate later (or alternatively, please check yourself.)
That’s a given! And they have the resolution that rivals the bit depth of the most modern ADCs, and can detect jitter that is outside of the resolution of the best affordable scopes.
Yes. That’s why I specified the peaks going wider and flatter. The total energy, the area under the peak, is the same.
I have read articles by people who not only claim that certain brands of hard disks are better for audio than others but that a copy of a file on that same disk will inevitably sound different because some of the bits get “flipped” whatever that means. And then there’s this: http://www.audioquest.com/usb-digital-audio/forest
Snake oil salesmen have nothing on the audiophile market.
That’s actually pink noise you insensitive clod! but then you’d need an audiophile quality monitor to properly distinguish between a rendering of a square vs a sine wave as its meant to be experienced.
The review does point out that the Pono has a good preamp and DAC. These are two components where quality can make a palpable audio difference, since they are not just moving bits around. OTOH, really fantastic DACs and preamps exist on chips that can be had for a few dollars in bulk, you don’t need to spend high prices for great sound. Even some phones already have pretty good DACs built in (though only a few can handle high bitrates, something that will surely change within a year or two). For example my Nokia 520, which I bought recently for under $30 without a contract, has nearly flat frequency response.
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