Thursday, June 20, 2013

Smart Phone Considerations

[Massively revised and rewritten on June 23, 2013, after several days experience with Samsung Galaxy S4.]

First of all, a smart phone needs to be a phone.  I need something from which I can hear people most clearly.  Often, in louder office and mall environments, I did not find my iPhone G3 earpiece loud enough, or it was rolled off in the upper midrange, and it wasn't fully intelligible.  It is hard to know how much of the rolloff is caused by the cellular system, and the phone and the user on the other side.  But even when there is rolloff in the cellular system, it helps to have the earspeaker have a full upper frequency range loudspeaker, to get the most out of the limited signal as possible.  If for example, the telephone system were to employ a 3kHz cutoff, if the speaker also has a 3kHz cutoff, the resulting cutoff is 1.5 kHz.  To have no significant effect as these things are usually considered (less than 0.1dB change within the stated bandwidth) it would be necessary for the speaker to have 30Khz response.

Now in saying all this, and all I do say, I am not Bell Labs, who for one did enormous research into how a telephone should work in terms of balancing the bandwidth and so on.  And now, I would sustpect major smart phone companies also do such research, as well as knowing the body of now understood principles, as well as putting their best ideas into the design.  But at least from the beginning of the modern smart phone era, beginning with the stylish iPhone, it has seemed to many users that voice communications was taking a back seat to computer and video applications, as well as style.  So if that truly was the goal of the manufacturers, it doesn't matter how much research was being done, the priorities were wrong, and the priorities need to be right.  Even for nerds like me, voice communication is #1.

I have wondered if earspeakers should be round holes vs straight lines, or fully ear enveloping.  I think fully ear enveloping would be best, followed by roundish holes then straight lines--but this is all just a guess based on analogy with planar, linear, and point sources in audio, but at such small distances as an earspeaker, diffractive and dispersive effects are only at very high frequencies.

I am finding the frequency response and loudness to be ok so far with my Samsung Galaxy S4 (no loud mall experience yet) which has a straight line ear interface, and because the speaker is near the edge, I can tilt the phone away from the ear and still get good sound, perhaps even better.  In a very loud environment, one could perhaps get better performance with hole-in-the-middle-of-the-glass earspeaker if it could be fully pressed against the outer hear, thereby both blocking and directing sound.  The iPhone has some offset of the hole from the edge, but not enough to provide very much blocking.  Though generally I do not like pressing my ear up against flat glass, especially if it is hot, as all smart phones I have tried get to be fairly quickly, so the greater ability to tilt the phone away with the Samsung is probably the bigger advantage.  I suspect neither would do well in high noise environments at 85dB and up.

Neither is sufficient in high light environments for sure, and there iPhone actually appears a tad better (almost slightly visible) so far in direct sunlight (but angled away of course), but possibly same or worse when hand shaded, when Samsung's greater contrast helps.

My first test with the S4 was miserable, but that was due to reception and transmission factors.  In general, I am finding S4 to have much better audibility than my 4 year old iPhone G3, which has the classing hole-in-the-glass-half-inch-from-edge interface, but possibly an outdated worn and dirty speaker.

It would be good to see earspeaker performance objectively reviewed as to frequency response, distortion, maximum levels, and so on.  Of course, interpreting objective measurements (as well as what to measure) is pretty subjective, and interpretation even moreso.  So one has to have an open mind about such things, but that has been demonstrated in decades of decades of objective audio reviewing (including in the mostly subjective Stereophile).

One of the reasons I didn't select the HTC One instead was that it has higher SAR.  Samsung seems to have by far the best SAR numbers of the three, though they seem to vary in all the accounts I've seen.  I also think it makes sense, that a plastic case would make it easier to have radio energy directed away from the user rather than toward the user.  Apple iPhone 5 does slightly better in SAR than HTC.


One thing I find almost laughable is the obsession with how phones physically look, and especially whether they have a metal or plastic case.  A tiny piece of aluminum covering my phone does not make me feel much more like a rich man.  Well engineered plastic, especially tough polycarbonate, can be just as good or better.  Especially in a smart phone, where the most visible part is the front which is basically just a piece of glass in current smart phones.  The back is what you hold away from your face.  It merely needs to feel nice, which polycarbonate can do as well as metal.  Likewise with being strong and resistant to dropping--and there is a big advantage in having a consumer replaceable cover in case it does get dented or scratched, though the bigger advantage is with regard to being able to remove the cover to replace the battery and add a memory card.

I find nothing "cheap" feeling about the physical appearance of the Samsung Galaxy S4, especially in black.  When ordered in black, when the phone is turned off, it is essentially identical in appearance above to the highly esteemed (in appearance) iPhone.  If only such obsessions as the metal case obsession were turned to important things, such as voice quality and reliability, we'd all be better off.

I confess that silver tone that's not actual aluminum does actually look a bit cheap.  In that regard, however, the chrome accent around the face button on the Samsung is fine, though I worry about it wearing off over time.

One place where style is more important is in the actual active screens.  I found the default Samsung busy and obnoxious, disorganized, unhelpful, filled with adware and bloatware which can't easily be deleted.  I'm gradually getting it better by turning things off.  I sympathize with those who root and overwrite the default system.  I believe that is far easier with Android than iOS, and I might do it eventually.

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