One of the more annoying things about consumer electronics is that many of our toys come with marketing hype but little in the way of measurements. Australian PC User noticed this too, and commissioned an independent lab to measure several DAP/PMPs they were evaluating at the end of 2010. Some will argue that the figures are useless in isolation, but those of us who have a current Nano/iTouch/iPhone will almost certainly find the sound quality better than previous generations. I have no idea how audible any of this is, with the possible exception of SNR, where I definitely want as high a number as I can get.
Sadly, this is far from definitive, and I know Creative players are about as popular as bubonic plague on HF, and none of the Sony players tested ranks very highly here - whatever, here they are. If nothing else, it confirmed for me that the current Nano is using the highly lauded DAC from the current Touch/iPhone. Its also some consolation for those of us who like to believe we get what we pay for, Apple Australia's outrageous price gouging notwithstanding. I wont be buying another Nano, but its good to see them putting the iPhone DAC in the other models - the Classic could definitely use the upgrade, IMO.
Key
Players
P1 - iTouch, Sept 2010, 289 AUD (8GB)
P2 - Nano, Sept 2010, 229 AUD (16gb)
P3 - Creative Zen, X-FI 2 16GB, 149 AUD
P4 - Sony NWZE453 4GB, 99 AUD
P5 - Sony NWZS754 8GB, 159 AUD
P6 - Sony NWZB153F 4GB, 69 AUD
Measurements
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M1 - max output (mV RMS)
M2 - THD @ 50hZ (30kHz)
M3 - THD @ 1kHZ (30kHz)
M4 - THD @ 15kHZ (30kHz)
M5 - SNR (-1dBrFS @ 1kHz) flat
M6 - SNR (-1dBrFS @ 1kHz) A-weighted
a. THD - Total Harmonic Distortion is the ratio of unwanted harmonic frequencies generated by the player when fed a single-frequency sine wave tone. Lower is better, and the '30kHz filtering' used in these measurements reportedly measures the audible distortion.
b. SNR - Signal-to-Noise Ratio : ratio of loudest sound the player can make compared to the players general level of electrical background noise. The A-weighted figure reportedly gives us a better idea of how our ears perceive different frequencies. Ideally, this value would be infinite - not sure how many DAPs can manage that - but higher is clearly better.
c, Max output - I have no idea what a 'millivolt root mean squared' looks like in the wild, but it certainly sounds impressive. Personally, I want this number to be HUGE.
| P1 | P2 | P3 | P4 | P5 | P6
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M1 | 987.4 | 987.4 | 529.5 | 438.1 | 438,4 | 458.3
M2 | .003% | .003% | .015% | .015% | .011% | .029%
M3 | .005% | .005% | .010% | .011% | .010% | .026%
M4 | .035% | .035% | .107% | .130% | .130% | .109%
M5 | 47.9 | 47.9 | 35 | 44.5 | 44.4 | 48.1
M6 | 99.2 | 99.2 | 86 | 93.9 | 90.6. | 91
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On the face of it, the X-Fi 2 isnt in the same league as the Nano/iPhone, but the big surprise for me was player 6. I'll leave it to the experts to determine exactly what the above means to folk with normal hearing, but if I was looking for a small, inexpensive player with good signal-to-noise ratio, on the basis of these numbers its hard to go past the Sony NWZB153F. I guess it comes down to the audible impact of those THD numbers - I dont have golden ears, but you may have. Very few here are going to bother with a 4GB player, but as a gift it seems to make a lot more sense than the 2GB Shuffle (* see note below). Load it with 4GB of LAME rips from your Britney collection (pun intended) and you are guaranteed to put a smile on someone's face ;)
Of course, none of the above tells us anything about the sound signature, but I would dearly love to see these figures (at a minimum) accompany every new source, be it portable or whatever. I dont know how much PC User had to pay the lab in question, but it would be a pittance compared to the marketing budget for new DAP releases. I guess its just not as important as getting the marketing blurb written.
(PS the output power ratings are for the Australian models of each player - I have no idea what the European 'nanny state' regulations may have done to players made for that part of the world. It may go a long way to explaining why the Sony players listed above have such nominally low ratings - beats me)
Note: I also have the measurements for the Shuffle, btw - close to the Nano, but not quite as good, and that lines up with my own time with both players. Just wish Apple would get over their obsession with making these little guys ever smaller.
