Neil Young readies Pono music service for expansion Part 3

One of my friends who is an Apple insider on the audio front swears this has been coming for some time. Still I wonder as many rumors have proven false.

I had a contractor over recently and he bragged that all his music fits on his phone and he buys everything from iTunes. I bit my tongue but it would sure be nice if I could have said "well the 24 bit files sound nice."

 

I basically agree with what you're saying here, but I'm curious if you're able to quantify (other than price) the technological attributes a headphone rig must possess to be sufficient to evaluate of the merits (or lack) of hi-rez.

 

An amp and DAC that sound clean. An amp that has a spacious headstage that envelops and surrounds your head and sounds outside of your head. Headphones that allow you to hear more detail and layers in the recording and hear deeper into reverb tails.

One of the things I think I've heard in high res is reverb or sustain from an acoustic guitar that seems to hang longer and layer over the notes that come next. That seems to affect tonality cause you've got tones layering over each other for a longer time than lower res. You need a headphone and gear that gives you a chance to hear that sort of thing and hear the layering. An AKG K701 or Senn HD600 are good headphones but not quite up to that, especially compared to better headphones. And of course you also need music and a recording that has those sorts of reverb or sustain going on.

 

Gabe Walters, Wednesday at 11:14 AM Report

But the sound through your stereo won't be in hi-rez, right?
If it isn't I'll probably cancel my pledge.

 

Apparently rumours are intensifying that Apple could make Pono DOA launching high-res audio with the new Led Zeppelin remasters.

http://robertmusic.blogspot.no/2014/03/led-zeppelin-and-future-of-hi-res-audio.html

http://www.hydrogenaudio.org/forums/index.php?showtopic=86929&st=100&p=862833&#entry862833

PS: I have skipped several pages in the thread so apologies if this has been already discussed.

 

The sound out from the headphone jack or the line out jack of the Pono player will be in high res, assuming you're playing a high res file.

A DAC outputs an analog signal. It's just that with the Pono player the analog out is from mini TRS (tip ring sleeve) jacks rather than from RCA jacks or balanced XLR jacks. You can get cables that convert from mini TRS to dual RCA so you can connect it to your big stereo system.

 

Yes, this has been discussed -- these rumours are, as far as I can tell, 100% based on the first blog you list though Hydrogen Audio does cite a German source that talks about possible updates to the iTunes store. I remain skeptical, though. The good news is that we don't have to wait long to find out.

 

Thanks, but what I was after was the technological attributes. You've helpfully provided examples of equipment that don't have good enough resolution to discern the nuance of hi-rez, but I was hoping to better understand precisely what technology in the DAC, amp, and headphones was required to achieve the necessary level of detail.

 

Huh? It would be high-resolution if you load high-resolution files onto the player's memory.

 

Magic.

 

I don't know what sort of specific technologies or specs or implementations would be necessary. I'm still trying to figure out what I'm hearing and if what I'm hearing is actually identifiable and real.

For headphones something better than the HD600 in terms of layering and low level detail (the Senns to have a veil of sorts).
For amps and DACs something that layers and is spacious and clean. I don't know what that is.

I've heard something different in some high res recordings compared to 16/44.1. At least I thought I have. I didn't hear that with my HD600 but did with my LCD-2. So now I'm curious to find out what the heck is going on and if something really is going on.

 

Do you have any experience with a Schiit Mjolnir? I'm thinking it would be a great "in between" for an existing Gungnir and LCD-2.

 

Thanks for the explanation, that good to hear.

 

I haven't heard the Mjolnir. Reviews that have compared its sound to other amps make me think it's not the style of amp sound I'm after. I'm also not that excited about an amp that is balanced only. The statement amp that Schiit has planned has me much more interested.

 

Maybe but they are all about improving photography and video so I believe audio will follow

 

Can someone comment on Pono having a 5 ohm output. There seems to be quite a discussion going on on that site and others as to why that is a strange choice. Supposedly the rule is you want the output of a device to be less than or equal to 1/8 the headphone impedance. So phones with 40 ohms or more would be peachy... But, I'm sure that rule is not a hard rule and Pono had a long explanation of why they chose that output. ... pasted here if anyone cares...


........ From Pono........
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.


They have also been using the Sennheiser Momentum headphones a lot with their testing and those are only 16 ohms.... so I'm sure the 1/8 rule is not a be all end all. Though some with custom IEM's are concerned....

thoughts?

 

The 5 ohm output impedance isn't too much of a big deal for me. I don't do multi driver IEMs, I don't do IEMs in general. I don't like the sound of IEMs being in my ear. So optimizing for a low output impedance just to suit the IEM users isn't in my personal best interest. Though making a portable that compromises the frequency response of $1000+ IEMs isn't going to be popular with those who have $1000+ IEMs for portable use. On the other hand, if you've got $1000+ IEMs you've likely also have a $300+ portable amp that matches well with your IEMs so the issue is moot. Use the portable amp with the Pono. You were going to use the portable amp anyways.

My personal preference for headphone sound is full size around the ear headphones. And in that class my preference is planar magnetics. Plenar magnetics aren't affected by output impedance. So this issue is even more moot for me. Maybe the soon to be released Oppo PM-1 and PM-2 planars will be the ultimate Pono full size headphone? Maybe. I hope that the PM-1 and PM-2 actually are that good. I'd buy a PM-1 or PM-2 for that purpose before I'd buy a $1000 custom IEM. For me the purpose of an IEM would be to block external noise so I could listen in nosy environments. I don't spend much potential listening time in such environments so the reason for me to have an IEM is even more moot. For purposes like airplane trips I'm perfectly satisfied listening to full sized closed headphones in that environment even though I can still hear the engine noise and cabin noise through the headphones. I don't need to block external noise more than that. And I certainly don't need a noise canceling headphone for airplane flights to be able to enjoy some music (noise canceling headphones suck).

As for standard dynamic headphones, I am in general agreement with the opinion of the Pono team that the effects of 1 ohm vs. 5 ohm output impedance aren't that important in general listening. The effects of output impedance generally seem to affect the bass and lower mid bass. The bass regions of most headphones seem to be so arbitrarily optimized for a specific output impedance that it generally doesn't really matter except for a select few headphones.

The 5 ohm output impedance isn't a big deal for me. The world needs to move on to full size planar magnetics and on ear planar magentics anyways. Then the issue will be even more moot.

One situation where very low output impedance is important is when auditioning headphones. You want an amp with a very low output impedance when auditioning headphones so the amp will less affect the sound of the headphone. That way you are comparing the sound of various headphones on a more equal footing rather than how well the headphones compare with an amp that has higher output impedance.

So not a big deal for me. Make the player and the built-in amp sound good with the headphones people are likely to be using. Those using multi driver IEMs can use an external amp if their particular IEMs are so negatively affected by a 5 ohm output impedance.

 

If they can charge a few bucks more for an upgraded file, why not? They make more money, the record label makes more money, the artist (theoretically) makes more money, and the consumer gets (theoretically) a better-sounding product. I see no downside. The mass-market can still buy the regular 256kbps AAC files like they always have.

 

I'd like to have the option for lossless 16/44.1 or even 24/44.1 downloads. That would be an improvement over lossy (I won't pay for lossy downloads). But high res? Yikes. That gets confusing for the consumer. Those of us here who read the hardware section of the SH forum can understand and deal with it. But the average consumer? No. So much added confusion. That sort of confusion will drive more people away from iTunes rather than generate more business. Managing high res files and managing how to sync them to portables and other devices is very confusing. Too confusing for normal people. Bad for business if you're marketing to the mass market.

Maybe if the hardware market starts taking baby steps to supporting high res in phones, tablets, streaming radios, other streaming devices, and other consumer audio devices. Maybe. But it's going to take a lot of baby steps to get the market to arrive there. You aren't going to get the mass market to be there by offering a giant step right to high res iTunes.

 

You didn't get the joke? I shoulda put a smiley on it.

 

It could be done just as one or two extra buttons on the iTunes Store: regular, lossless, high-res -- three choices. Not that big a deal. It's no different from a standard-def movie download or a high-def movie download, and they've been doing that for years. Again, I don't see a down side with them offering high-res, especially if millions of high-res files are already sitting on their servers.

 

Putting a button in the iTunes store for high res is the easy part.
Would consumers understand or even know what high res audio is? Would consumers know how to even get iTunes to play the file at the proper resolution? Would they even know if their equipment can do high res playback? Just configuring and getting iTunes (on Mac or Windows) to properly play a high res file at the correct resolution is something only audio geeks know about. I don't see it being very consumer friendly. My brother has no idea what high res audio is. He's not alone in not knowing what it is, how to play it, and what hardware supports it.

 

If Apple started selling high-res downloads, they would likely update iTunes to play back the files at their full resolutions.

 

What benefits will this have over something like the FiiO X3 or X5 which have great reviews and are available now? Big Neil fan, looking at getting into high rez, deciding whether to back the Pono. Cheers

 

On the Kickstarter comments page from the PonoMusic team: