[edwardsean]

Hi,

Sometime ago there was mention that Vinnie would also imod the Nano. Is there any news on that?

 

[rxc]

Last I heard the iMod Nano is on permanent hold.

 

[Hifivoice]

Hi Vinnie,

Quote:

Originally Posted by Vinnie R. /img/forum/go_quote.gif Actually, I don't know if I didn't have enough coffee this morning or what, but that peak in the top end actually doesn't look that bad (0.5dB is not much, especially at such a high frequency that our headphones or ears might not even be able to hear ). Like I just said, I must of not carefully looked at this plot (I was extremely busy today and in a big rush in general today). I don't think that the moderate peaking has much to do with my impressions I quoted above. I think it is just the overall sound of this dac + built-in output stage... whoever makes this part!

A measurement like the frequency response only shows part of the characteristics of a device. That's why I've also added the phase response, impulse response and step response.

My experience as speaker filter designer and DAC filter designer is that small deviations in a frequency range can be heard. The difference between a rising curve from 20Hz to 20kHz or a decending curve from 20 to 20kHz are clearly audible. A rising curve sounds more "analytical, metallic, zizz", whereas a decending curve sounds more "acoustical, harmonic rich". This experience is shared by more people that develop audio equipment. This is something that I can hear with the iPod Classic as well. Though it sounds precise, tight and crisp, it adds a "mettalic haze" to voices, making them "more electronic", and "less acoustic".

Whether it is the frequency response on itself, or the phase response that is associated with such a response, is for me an unanswered question. There are many indications (and publications) showing that we are very sensitive to timing deviations. Take for instance the difference between a Butherworth or Besselfilter. With both of them you can create curves with a passband ripple within 0.1dB, but their group delay in the passband already shows deviations, and both filters are reported to have their own sonic characteristics.

As one can see is that the iPod Classic has a significant phase (and hence group delay) deviation in the passband. This is also shown by the impulse response and step response. Furthermore, by comparing the minimum phase with the measured phase, one can conclude that the phase deviation is caused by a non-linear effect.

I'm not an expert in the field of DA conversion, but these differences could as well be caused by sigma-delta conversion or noise-shaping techniques, where non-linear operations in the frequency domain are applied.

Nevertheless, to summarize about the sound quality in sonic terms, the 6G sounds precise, crisp, but lacks stereo image and has an electronic haze to the sound. The 5G sounds less precise, but its timbre contains more harmonic information and sounds less electronic. For me, the 5G is closer to how I experience acoustic music in real life, and for me is the better sounding device overall. This is not to say that the 6G is a bad sounding device! It's just less than the 5G. (I've added this to my web pages).

Regarding measuring versus hearing. If there is an audible difference, there must be a measurement that can show the difference. The point is that the interpretation of measurements is not always simple or straightforward. The measurements I've published only show a part the electrical transfer function of the device. To end with a quote that we very oftenly use at work: "Measurements are knowledge, but you have to know what you measure".

Marc

 

[lolittle]

Marc, have you ever experienced an iMod (preferably 5g or 5.5g)? I sure would like to hear you opinions on that (seeing as I just ordered one from Ken at ALO)...

 

[unclejr]

Quote:

Originally Posted by Hifivoice /img/forum/go_quote.gif Regarding measuring versus hearing. If there is an audible difference, there must be a measurement that can show the difference. The point is that the interpretation of measurements is not always simple or straightforward. The measurements I've published only show a part the electrical transfer function of the device. To end with a quote that we very oftenly use at work: "Measurements are knowledge, but you have to know what you measure". Marc

Hey Marc,

From my time in science research, I firmly hold the belief that differences should be measurable. I suppose that the standard argument against this is that we may not have the technical ability to probe these differences in a meaningful way. I'd extend that by saying that perhaps we are not sophisticated enough (yet) to know what to look for and what to quantify. That is certainly the case in my field, as it is pretty young, and we don't quite know what to look for and how to find it. And your point is quite salient as well; interpretation is arguably one of the primary sources of subjectivity into any scientific endeavor.

I do hope you get your hands in a 5th gen iMod to see what you think!

 

[Pangaea]

I am sheepish to even leave remarks in a forum where Vinnie has spoken... but my 2 cents the ipod classic sounds very good. Dynamic and musical. It does not match my 4G iMod but it is similar to my iAudio 7- however the 7 does win out due to effective EQing. The iPod's EQ still sucks. But SQ off is rockin on the new classic.

 

[elnero]

Quote:

Originally Posted by Pangaea /img/forum/go_quote.gif I am sheepish to even leave remarks in a forum where Vinnie has spoken... but my 2 cents the ipod classic sounds very good. Dynamic and musical. It does not match my 4G iMod but it is similar to my iAudio 7- however the 7 does win out due to effective EQing. The iPod's EQ still sucks. But SQ off is rockin on the new classic.

Are you talking about out of the headphone or the dock output?

 

[KB]

Quote:

Originally Posted by Pangaea /img/forum/go_quote.gif I am sheepish to even leave remarks in a forum where Vinnie has spoken... but my 2 cents the ipod classic sounds very good. Dynamic and musical. It does not match my 4G iMod but it is similar to my iAudio 7- however the 7 does win out due to effective EQing. The iPod's EQ still sucks. But SQ off is rockin on the new classic.

Pangaea,

Dont be sheepish. Everyone is going to hear and see things a bit different. Both Vinnie and I respect the fact that everyone sees and hears through his or her own lens. Some people really like the sound of the stock 6G, including myself. While the sound quality is not as good as a iMod, I feel for the money its a very very good product.

Ken

 

[Pangaea]

Thanks Ken! elnero- I have yet to try the 6Gen thru an amp. All of my listening is done thru the the HP out. Other than my imod I am really trying to get away from carrying an amp with me.

 

[kichu1979]

Quote:

Originally Posted by Vinnie R. /img/forum/go_quote.gif I see some posts where people are calling it a Cirrus Logic part. I do not see a Cirrus part anywhere on that board, and that dac certainly says "APPLE" so where is this talk about Cirrus coming from? I must be missing something Any info would be appreciated.

Probably because of this article

http://thescotsman.scotsman.com/busi...?id=1455152007

 

[Hifivoice]

Quote:

Originally Posted by lolittle /img/forum/go_quote.gif Marc, have you ever experienced an iMod (preferably 5g or 5.5g)? I sure would like to hear you opinions on that (seeing as I just ordered one from Ken at ALO)...

I use my iPod mainly as portable device, i.e. I use it at work or on business trips with a pair of headphones. This means I'm less interested in the line output of the iPod, so no iMod. For the 6G, the measurement problems also reveal themselves also at the line output. For in-home audio, I'm a bit critical about my sources. A good CD player for me is still the way to go: www.ayre.com

I would love an SPDIF output on my iPod! That would by-pass all analog electronic circuitry, and I would suspect that a decent jitter-free signal can be produced.

As for the iMod, and as far as I can tell from reading Vinnie seems to be doing a very well job.

Marc

 

[som4ew]

Marc,have you tried the 1.01 iPod update?

 

[gabeg]

Quote:

Originally Posted by som4ew /img/forum/go_quote.gif Marc,have you tried the 1.01 iPod update?

This is available already?

 

[spraggih]

Quote:

Originally Posted by kichu1979 /img/forum/go_quote.gif Probably because of this article http://thescotsman.scotsman.com/busi...?id=1455152007

There was another article whose veracity was questioned stating some of the same things. As far as the Internet goes this article looks legitimate.

I wonder how the iTouch will sound given the article states it uses the Wolfson DAC.

Haven't folks said the iPhone's SQ is poor?

[sorry this is probably all OT]

 

[OverlordXenu]

Quote:

Originally Posted by Hifivoice /img/forum/go_quote.gif I use my iPod mainly as portable device, i.e. I use it at work or on business trips with a pair of headphones. This means I'm less interested in the line output of the iPod, so no iMod. For the 6G, the measurement problems also reveal themselves also at the line output. For in-home audio, I'm a bit critical about my sources. A good CD player for me is still the way to go: www.ayre.com I would love an SPDIF output on my iPod! That would by-pass all analog electronic circuitry, and I would suspect that a decent jitter-free signal can be produced. As for the iMod, and as far as I can tell from reading Vinnie seems to be doing a very well job. Marc

Maybe you should check out the Pacemaker (pacemaker.net)...It has SPDIF out and its headphone out should be really good. It even has a real line-out!