Proper Digital Audio Playback

The PonoPlayer got it right, whether they survive as a business or not.

There is a right way and a quick way to build a digital audio playback circuit.

The following information comes from Charlie Hansen, the designer of the Pono audio chain, and the excellent review by Tyll Hertsens. I’m putting it into it’s own post so other audio device builders get inspired.

  • EVERYTHING from DAC to jacks is DC coupled. No coupling caps anywhere.
  • Everything is TRULY balanced from the DAC chip all the way to the output jacks. There is no virtual ground needed, as we have true +/- rails from the switching power supply. The raw rails go to SUPER low noise regulators, of which there are a TON.
  • The audio circuitry has their own dedicated +/- regulators.
  • All of the digital circuitry runs off of positive voltage only
  • Three or four separate dedicated regulators there — one for the audio master clocks, another for the digital side of the DAC chip and a third for the rest of the digital circuitry.

“NOBODY builds portable players that are fully-discrete, fully-balanced, and zero-feedback. This all makes a huge difference.”

— Charlie Hanson of Ayre Audio

That’s what happens after the DAC, in the analog stage.



Regarding the file quality and DAC behavior before the analog stage, we have more details from Charlie:

 

  • Brickwall filtering creates massive time smear.
  • The human ear/brain is already known to be exquisitely sensitive to time smear.
  • DBT and AB/X are really only sensitive to differences in frequency response. Using these tools for anything to do with music is like pounding a nail with a screwdriver. Ain’t gonna work.

Specifically, one of the massive benefits of a higher sampling rate is not extended bandwidth.

Instead, it allows for gentler filters to be used.


In the case of the Ayre QA-9 A/D converter, the anti-aliasing filters have zero ringing or time smear for double and quad sample rates. (Only one cycle of ringing for single rates — something has to give somewhere…)

When Ayre designed the PonoPlayer’s audio circuitry, we held back nothing.

We gave it everything that could fit within the constraints of the budget, physical space, and battery life.

Every single secret we discovered went into the PonoPlayer. The digital filter is taken directly from our own products.

Movie Lovers Coalesce The Vapors Around Streaming

It’s not just music lovers realizing that streaming has a long way to go to match physical media.

Film lovers see the same issues:  degraded quality, no extras, no ownership, unknown/ temporary access.

We give up a lot for the convenience of streaming.  #SaveTheAudio ?  #SaveTheVideo


PonoPlayer is the Stereophile 2015 Digital Product Of The Year

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Ignore those who wouldn’t know good sound if their life depended on it.

The PonoPlayer is winning awards and impressing nearly everyone who hears it.

I’m referring to those that have some idea what they are doing and hearing. First the Rocky Mountain Audio Product of the Year, now Stereophile’s Digital product of the year.

It’s sad but understandable that rave reviews from all kinds of audio blogger types against 2 bad reviews by mainstream tech blogs (Yahoo! and Ars Technica), that those bad reviews would spawn more snark and negativity from uninformed bloggers who have never even heard the device.

These tech sites are all hooked into Googleverse and generate the highest page views, so when you search PonoPlayer you see negative results listed ahead of good reviews.

Here’s what you need to know: Stereophile just awarded PonoPlayer their Digital Product of the Year.

They said it was the least-close category, that’s how impressive the PonoPlayer is at it’s price point.


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Here’s plenty more good reviews if you need convincing that this is the best sounding $500 device made:

Scot Hull – Part-Time Audiophile – 11/19/14
Michael Sawh – Trusted Reviews – 1/8/15
Rick Schmidt – Home Theater High Fidelity 2/9/15
 What Hi-Fi? – 2/13/15
Ty Pendlebury – C-Net – 3/12/15
Sam Berkow – SIA Acoustics – 3/16/15
John Atkinson – Stereophile – 3/23/15
Raymond Wong – Mashable – 3/23/15
Tyll Hertsens – Inner Fidelity – 3/26/15

 

How You Hear Music

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Listening 101

1. Directionality – Where is that sound coming from? Where exactly is that hi-hat sitting in the mix? Is the band in front of me or all around me?

2. Delay/Roomspace – Am I in a large room, small room, outside? Was this music recorded in a large room or small room? Was the recording room rounded, square, long?

3. Quality/timbre of instruments – Is that an electric guitar? Do I like the tone of it? Do I like that keyboard patch? How about the singer’s voice?

4. Stereo soundstage – Do I hear 2 guitars doubling each other, or 1 guitar with a wide delay? Is the singer front and center, or is he singing 2 parts, 1 left, 1 right? How wide are the drums set in the mix?

5. Timing of musicians and recording – Do the various delays work together musically, or are they clashing and changing the feel of the song? Are the drummer and bass player locked in? Is the 2nd percussion player ahead, behind, or on the beat?

6. Quality of recording – Is this the best version of this song? Is the distortion in the track intentionally added by the artist or is it in the format?

7. Clarity and breadth of EQ – Are most of the pleasing frequencies present, and are the harsh, brittle frequencies diminished?  Do the various instruments and voices blend and work with each other as layers, or do they cover each other?

8. Noise floor – Is there a hum or buzz in this recording? Is it from a bad recording, or a loud instrument, or something wrong in my system?

9. Phase – If things were recorded in phase you don’t notice it. If things are out of phase with each other, various comb filtering and aliasing artifacts appear in your music.

10. Digital loss/compression – Has this file been reduced from the original? Did they remove things they hope I can’t hear to make the file smaller?  Are there compression artifacts in the mix.

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There’s 10 things to listen to without even thinking about frequency range. 10 things most internet audio experts never take into account.


Becoming a better listener makes you a smarter consumer. It will drive you to enjoy your current collection again and find new music that moves you.

It will also hopefully drive you to push for higher quality. If you must stream, go 16/44 lossless. If you collect, get as much hi-res as possible and play it for as many people as you can.

#SaveTheAudio

Word of the Day: Provenance

Provenance - Noun : originsourceplace of originbirthplace, fountrootspedigreederivationroot

You hear it on antiques shows and now you hear about it in digital music, and it’s actually pretty cool because it’s about credits and the people behind the music.

One of the many complaints about mp3 was “where are the credits?”.  Sorry, go to the website. But the website can update all the time, what if I just want the proper credits for my own music lover nerdiness?

There’s a more serious side to it also, one of attribution and authenticity. Algorithms can now determine what song is playing and credit the composer and lyricist, but they cannot determine origin of the file (which version from which mastering session).

As MP3 fades in popularity and we look to the next digital format, efforts are being taken to improve this issue of provenance in music. Sites like ProStudioMasters.com list details of which version you are buying but standardization is needed here.


My provenance proposal, off the top of my head:

Top level (spine):  Artist / Song / Cover art

Sub level (liner): Lyrics / Liner notes / Additional artwork

Physical level (provenance): Year / Composer / BPM / ISRC / Label / Label Number / Original Mix date / Original Mix format / Remaster Date / Remaster format


[This data could be used by next-gen streaming too, giving lots of interesting information and images to be displayed while the song streams.]