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PONO - Neil Youngs portable hi-res music player - Page 47

post #691 of 4644
Quote:
Originally Posted by miceblue View Post


Apple devices can already play back 24-bit files though. XD
Up to 24/48
 

 

Laptops, but not the portables, right?  My iPods and CLAS only play up to 48/16.  iTunes on the laptop will play 24 bit files, but the portables is where it would be great to be able to play higher def music if you choose.

post #692 of 4644
Quote:
Originally Posted by fiascogarcia View Post

Quote:
Originally Posted by miceblue View Post

Apple devices can already play back 24-bit files though. XD

Up to 24/48

 

Laptops, but not the portables, right?  My iPods and CLAS only play up to 48/16.  iTunes on the laptop will play 24 bit files, but the portables is where it would be great to be able to play higher def music if you choose.
No, I meant iDevices.

I can play 2CELLO's IN2ITION album just fine on the iPhone 4S with the stock Music app.


http://www.hdtracks.com/in2ition
post #693 of 4644

can someone who actually knows about these things give some more info on pono using 5 ohms? The people complaining about it haven't really given much info as to why it is bad while some have pointed out why it is not.

post #694 of 4644
Quote:
Originally Posted by Saraguie View Post
 

Of course I open my mouth and whatcha know..................

 

http://appleinsider.com/articles/14/04/10/rumor-apple-to-offer-hi-res-24-bit-tracks-on-itunes-in-coming-months

 

Is it possible the popularity of the Pono project and Neil's banging the drum brought it to Apple's attention?

Interesting times ahead! If Apple are the first industry behemoth to jump, can the other big hitters like Amazon be far behind?

post #695 of 4644
Quote:
Originally Posted by RogerWilcoSQ View Post

can someone who actually knows about these things give some more info on pono using 5 ohms? The people complaining about it haven't really given much info as to why it is bad while some have pointed out why it is not.

Quote:
Originally Posted by miceblue View Post

Quote:
Originally Posted by hughscot View Post

Curious as to why 5 ohms would be a negative?  
As a general rule for bass control:
Headphone Impedance / Output Impedance >= 8

With a 5 Ω output impedance, that typically works well with headphones of 40 Ω or more. Anything less and the bass response will probably affected in a negative way (looser, woolier, etc.) and is especially bad with multi-driver earphones, where the phase linearity and output impedance values can change a lot based on the frequency.

Like so: http://rmaa.dfkt.tk/Comparisons/32%20Ohm%20Multi-Armature%20-%20Cowon%20J3%2C%20Sansa%20Clip%2B%2C%20Sony%20A845%2C%20Hifiman%20HM-801.htm
or
http://rmaa.dfkt.tk/Comparisons/Hifiman%20HM-801%20-%20Impedances.htm
Here's another instance of why a higher output impedance is bad:
http://www.innerfidelity.com/content/meridian-explorer-case-study-effects-output-impedance

Or you can just Google "damping factor."
http://en.wikipedia.org/wiki/Damping_factor
post #696 of 4644

This was just sent out by email following the 5 ohm reference.

 

"Some have expressed concerns about the output impedance of the PonoPlayer being 5 ohms. It is important to note that it is trivial to make the output impedance arbitrarily low -- simply add more and more and more feedback. The problem is that this will make the player sound worse, not better!

All products designed by Ayre (since its inception 21 years ago) have no negative feedback. This results in a more natural sound because feedback can only attempt to correct for an error after it has occurred -- clearly an impossibility. If negative feedback actually worked as people claim, then all products would sound the same because the negative feedback would eliminate the errors. But not all amplifiers sound the same, so feedback is clearly not the answer!

The reason that output impedance is somewhat important is that the impedance of headphones almost always vary with frequency. If the output impedance of the headphone driver circuit is too high, then there will be a voltage divider action between the impedance of the headphone and the output impedance of the headphone amplifier that results in audible frequency response errors.

Now, to some extent this is meaningless as all headphones have inherent frequency response errors anyway. It may be that some headphones (through sheer luck) may produce an overall flatter frequency response with an amplifier that has a high output impedance. But luck and hope are not good ways to design things.

Instead, the goal it to reduce the output impedance to a point that is low enough that there are no meaningful frequency response errors with almost any headphone on the market. In the real world this means that the output impedance of a headphone amplifier should be less than about 10 ohms or so. Lower impedances will result in lower frequency response errors due to the interaction between the output impedance of the headphone amplifier and the headphone impedance itself. But lowering the output impedance through the use of feedback will introduce new sonic problems that are much worse than the original problem.

The only other way to reduce the output impedance of the headphone amplifier is to increase the idle current in the amplifier circuit. This is fine for a home stereo where there is virtually unlimited power available from any wall socket. But a portable player is a different animal altogether. Increasing the idle current of the amplifier will obviously shorten the battery life of the device. The art of engineering is the art of compromise. And when you have a chance to listen to the PonoPlayer, we promise that you will be more than happy with the choices we have made.

The 5 ohm output impedance of the PonoPlayer is the best overall compromise which minimizes interactions between the headphone amplifier and the headphone while maintaining good battery life, and completely avoiding the sonic problems created by the use of negative feedback. Thanks for reading this, and thanks for your questions.

Correction about Converters 

The Ayre QA-9 ANALOG-TO-DIGITAL converter uses a moving average design with no undershoot, overshoot, and ringing but not the digital-to-analog converter in Ayre products."


Edited by hughscot - 4/11/14 at 6:01pm
post #697 of 4644
Mice, yes iDevices may play 24/48 but they down sample to 16/41, is my understanding.
I'd like to hear the song using the entire information.
post #698 of 4644
Quote:
Originally Posted by Saraguie View Post

Mice, yes iDevices may play 24/48 but they down sample to 16/41, is my understanding.
I'd like to hear the song using the entire information.
Oh does it? I didn't know that. Interesting that you mention "hear" though since you can't "hear" the differences between HD music and the equivalent down-sampled versions. XD
post #699 of 4644
Quote:
Originally Posted by hughscot View Post
 

This was just sent out by email following the 5 ohm reference.

 

Some have expressed concerns about the output impedance of the PonoPlayer being 5 ohms. It is important to note that it is trivial to make the output impedance arbitrarily low -- simply add more and more and more feedback. The problem is that this will make the player sound worse, not better!

All products designed by Ayre (since its inception 21 years ago) have no negative feedback.

 

'No negative feedback' is Ayre's marketing position however the reality is a little different when the types of DACs are taken into acoount. All S-D type converters (the ones that Ayre use exclusively) rely on negative feedback internally. So I would guess that Charles Hansen only thinks feedback is bad in analog circuits, not digital ones. Or that he ignores feedback in digital circuits to maintain a certain marketing image.

 

On the issue of 'more and more feedback' - its not trivial just to add more feedback because more feedback leads to more likelihood of instability - there's always a frequency where negative feedback turns into positive and this limits the amount that can be applied. Most certainly not trivial.


Edited by Sapientiam - 4/11/14 at 5:38pm
post #700 of 4644
Quote:
Originally Posted by miceblue View Post

Now...suppose the Pono music store offers 24/192, 24/96, or 16/44.1 versions of an album. What version is Average Joe Consumer going to buy?

16/44.1 which is the standard CD quality, or 24/96 which is a studio-recording format? Is the 16/44.1 version the actual CD master, or is it the studio-recording master down-sampled? Let's say Average Joe Consumer has fallen into the marketing trap of an aura surrounding the whole high-resolution format containing 29138471038516 times more information than a CD.
ETC...

This may have already been said as i am replying a week late, but one of the promises of the pono store is free upgrades. ie, once you buy a piece of music, it becomes available to you at all qualities and if a higher quality version is ever released, you will get this for free. 

 

Now i agree with you and feel that they are messing around a bit with the advertising when claiming that cd quality is worse. however, i dont think they are really conning anyone out of their money, seeing as you aren't paying each quality individually.

post #701 of 4644

Yeah, the output impedance being this high seems to be a potential issue, especially for people with customs. I don't know how much it will affect the listening experience, but it seems like a bit of a gamble (which I'm not willing to do).

post #702 of 4644

I'm curious.. is the 1/8 rule a pretty hard rule. (output impendance of source should be equal or less than 1/8 of headphones)  Cause Pono has been testing the player  (5 ohms output) with Momentum's a lot and those are only 16 ohms. That kinda kills that rule doesn't it?

post #703 of 4644
Quote:
Originally Posted by Saraguie View Post

Mice, yes iDevices may play 24/48 but they down sample to 16/41, is my understanding.
.
sorry but Mr. saraguie is correct.

Cyperlabs blog has a good summary.

http://www.cypherlabs.com/bit-rate-frequency/

Of course one can load all sorts of files on to a touch/iphone etc but it is downsampled to 16/48 even with external dac/amps.


Headphones only
u8utusan.jpg




Approved apple usb-A port(same result across idevice dac/amps i have tested)
u5ajy2e8.jpg



Or if you want to go in the back door using the CCK in this case to hifi-m8 usb-b for full effect. International+ etc.
uja9e4yb.jpg


As for the impedance rule at 1/8 i have even heard it recommended at 1/10. This is more of a problem for multidriver iems generally.

My hifi-m8 has three settings at 11.2.1 ohm.its good for testing.

A good page that lists sources and amps and their output impedances

http://monoadc.blog64.fc2.com/blog-entry-99.html

____________________________________________

Sorry, pictures came out larger than expected.
Edited by ExpatinJapan - 4/12/14 at 12:04am
post #704 of 4644
5Ω is nearly the same output impedance as the iPod Classic, which is 5.5Ω. Here are some frequency response charts with various headphones / IEMs (for perfect audio, the lines should be flat):

Denon AH-D2000, 25Ω:


Shure SE425, 22Ω:


Ultimate Ears TripleFi 10, 32Ω:


The effect will likely be minimal in most cases. The TF10's shown here are one of the most problematic pair of IEMs on the market.
Edited by skamp - 4/12/14 at 12:04am
post #705 of 4644

I, for one, am willing to give it a shot, regardless of the output impedance. It wouldn't be the first, or last, time that something that is less than perfect on paper pulls it all together in the end.

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