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RMAA results for iPod Classic, Galaxy Nexus, FiiO E7
skamp
post Dec 9 2012, 11:51
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Well, the EMU shows a 0.5 dB bump at 30 Hz, but that's really nothing. I don't know how much the dampening factor is affected, and I'm not sure I could hear it. A comparison of the EMU to the O2 for that wouldn't be easy since I would have to physically plug and unplug my headphones from one to the other instead of just recording outputs and ABXing that.


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skamp
post Dec 10 2012, 14:58
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I followed these instructions and I measured the output impedance of the O2 at 0.5Ω, the Clip+ at 0.5Ω, the iPod Classic at 5Ω, the Galaxy Nexus at 12Ω, the EMU 0204 USB at 23Ω and my laptop at 71Ω.


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elfary
post Dec 14 2012, 11:05
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This thread is really interesting for me.

As a user of an iPod Classic 7G (MC297LL) bought in New York back in 2009 now it's being about time to think about the battery. Being in Europe at this time if i go the Apple route they will provide me with new iPod (EU capped). If i go my way i will have to open the iPod and risk the whole unit working condition.

Since i only listen thru multidriver balanced armatures (Westone UM3x and Shure SE420) when i want to do critical listenings i always amp the line out with an iBasso T3 (To get rid of the 5ohms of output impedance of the hp out).

Hence my main concern would be if the line out port is capped. It does not seem likely judging from the rmaa.

My secondary concern would be if from a subjetive point of view is there any QUALITY difference that is audible in the output of the stock 7G versus the Rockboxed 7g.

Since the Westone UM3x are really sensitive i don't think the volume cap will affect me even with soft recordings. And the SE420 at high volumes are not enjoyable from the hp out because the output impedance brings more forward the "already mid forwarded" sound of the SE420 transducers. But if quality is worse then i might go the risky DIY route to replace the battery.

BTW your last iPod Classic loaded RMAA was made with the unit running stock OS or Rockboxed?

Thanks a lot for all your work Skamp. Really appreciated.

This post has been edited by elfary: Dec 14 2012, 11:11
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skamp
post Dec 14 2012, 18:03
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QUOTE (elfary @ Dec 14 2012, 11:05) *
Hence my main concern would be if the line out port is capped. It does not seem likely judging from the rmaa.


My former measurements indicate that it is not.

QUOTE (elfary @ Dec 14 2012, 11:05) *
My secondary concern would be if from a subjetive point of view is there any QUALITY difference that is audible in the output of the stock 7G versus the Rockboxed 7g.


There is none, except for a proper EQ with Rockbox, as opposed to EQ presets on the original firmware, that sometimes induce heavy clipping.

QUOTE (elfary @ Dec 14 2012, 11:05) *
BTW your last iPod Classic loaded RMAA was made with the unit running stock OS or Rockboxed?


Rockboxed.


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elfary
post Dec 14 2012, 20:05
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QUOTE (skamp @ Dec 14 2012, 18:03) *
QUOTE (elfary @ Dec 14 2012, 11:05) *
Hence my main concern would be if the line out port is capped. It does not seem likely judging from the rmaa.


My former measurements indicate that it is not.

QUOTE (elfary @ Dec 14 2012, 11:05) *
My secondary concern would be if from a subjetive point of view is there any QUALITY difference that is audible in the output of the stock 7G versus the Rockboxed 7g.


There is none, except for a proper EQ with Rockbox, as opposed to EQ presets on the original firmware, that sometimes induce heavy clipping.

QUOTE (elfary @ Dec 14 2012, 11:05) *
BTW your last iPod Classic loaded RMAA was made with the unit running stock OS or Rockboxed?


Rockboxed.


Thanks a lot for all the input. I guess i could live quite well with a capped unit.

If you find the time to measure with the current gear the stock output it would be the ice on the cake.

And in any event thanks a lot and merry xmas!
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skamp
post Dec 15 2012, 11:05
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QUOTE (elfary @ Dec 14 2012, 20:05) *
Thanks a lot for all the input. I guess i could live quite well with a capped unit.


To be clear, Rockbox removes the volume limit.

QUOTE (elfary @ Dec 14 2012, 20:05) *
If you find the time to measure with the current gear the stock output it would be the ice on the cake.


I will if I ever switch back to the original firmware again. The only difference is probably just ~6 dB less dynamic range.


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skamp
post Feb 25 2013, 22:19
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I just got a Fuze+, it's pretty nice. I didn't bother with the original firmware at all, I immediately installed the latest Rockbox build, so I can't comment on it.
There's a slight hiss with my Shure IEMs (not with my Denons), but only when there's no music playing.
I measured the output impedance at 0.9Ω. Here are the RMAA measurements (loaded / unloaded). The frequency response looks kinda funky, but with 0.5 dB variations (at most), it doesn't matter.

I understand why some people hate the touchpad, but with Rockbox it's quite usable (sometimes even practical). The portrait-mode display is very efficient, as the album artwork can be displayed full screen with metadata below it. It's also very convenient for browsing large libraries. With the font I use (Helvetica, 15pt), it displays 20 lines, much more than my iPod Classic, and of course my Clip+.

This post has been edited by skamp: Feb 25 2013, 22:28


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mzil
post Feb 25 2013, 23:45
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Thanks for posting that.

Regarding
QUOTE
There's a slight hiss with my Shure IEMs (not with my Denons), but only when there's no music playing.


Do you mean while the music is stopped there is a slight hiss, but then when you start playing a file of digital silence it goes away?
Or the general background hiss of common music masks the slight hiss you hear while it's in play mode?

This post has been edited by mzil: Feb 25 2013, 23:49
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skamp
post Feb 26 2013, 00:01
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I realize that statement was ambiguous. Actually the hiss gets a bit more pronounced while playing 16 bit / 44.1 kHz silence. Only with the Shures though: with the Denons (25Ω), I hear zero hiss.

I didn't really hear any hiss with the Clip+, but I did hear some electronic noise (as reported by Rockbox users). The iPod Classic is 100% silent in all circumstances (including with the Shures).

This post has been edited by skamp: Feb 26 2013, 00:02


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skamp
post Feb 26 2013, 00:08
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It's strange that the noise and dynamic range values in the RMAA measurements (including those with the Shures attached) don't seem to be affected by it.


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Arnold B. Kruege...
post Feb 27 2013, 11:28
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QUOTE (skamp @ Feb 25 2013, 18:01) *
I realize that statement was ambiguous. Actually the hiss gets a bit more pronounced while playing 16 bit / 44.1 kHz silence. Only with the Shures though: with the Denons (25Ω), I hear zero hiss.


Dynamic range is generally independent of load unless the load is so heavy that it causes clipping.

If you hear noise with one set of IEMs and not the other then the difference is likely due to efficiency of the respective IEM


QUOTE
I didn't really hear any hiss with the Clip+, but I did hear some electronic noise (as reported by Rockbox users). The iPod Classic is 100% silent in all circumstances (including with the Shures).


Now you've lost me. Hiss is electronic noise.
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skamp
post Feb 27 2013, 11:49
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QUOTE (Arnold B. Krueger @ Feb 27 2013, 11:28) *
Now you've lost me. Hiss is electronic noise.


Pardon my layman terminology. The noise with the Clip+ is not hiss. The Rockbox website speaks of "CPU noise" (with certain hardware variants). It's the same kind of noise that I used to hear with my old HTC Legend smartphone.


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saratoga
post Feb 27 2013, 16:57
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Depending on what you are doing the voltage and clocks on the fuze plus change to conserve power. It's possible some settings have different noise. Power management was only recently implemented and not yet fully tested.
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