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Inside the iPod, Past and Present
We mentioned the iPod Shuffle dissection a couple of days ago. Reader UtahSaint writes "Electronic Design have got a neat little article giving non-Apple employees
an insight into the makings of the original iPod and the revisions made (on a technical level) with the 2nd and 3rd generation iPods. The third-generation iPod contains two power-management chips from Royal Philips Electronics, a TEA1211 and a PCF50605. The TEA1211 is a dc-dc converter that can switch automatically between step-down and step-up operation in response to changing input voltage. The PCF50605, a single-chip power-management unit (PMU), can adjust power-supply voltages to the lowest thresholds needed for functions in a particular power domain." And finally, sammykrupa writes "PC Mag has a great review of Apple's iPod Shuffle. It covers the quality of the audio output saying that it is has dead-flat frequency response, less harmonic distortion, and most notably, better bass response than its bigger siblings. The older iPods, especially the Mini, have been rightfully criticized for being somewhat deficient in bass, and although the bigger players have flat frequency response, they have trouble sustaining big bass notes."
Troll? It's hilarious, it's a paraphrase of our illustrious Taco's first comment on the iPod...
Actually, bass performance is one of the principal things i look for in portable devices when it comes to audio quality. In most music genres, if the bass "ooomph!" is lost the sound becomes lackluster, not to mention that good bass isolates you from outside sounds (for me, at least).
My Sony Minidisc does bass wonderfully, and even compensates a bit for it's limited maximum volume.
is a dc-dc converter that can switch automatically between step-down and step-up operation in response to changing input voltage.
Without examining the circuit myself, I could imagine that when the batteries fall below Vcc that the converter switches from step down to step-up to provide additional play time, until the batteries are completely drained.
Maybe someone can confirm/deny this.
Take the cheese to sickbay, the doctor should see it as soon as possible - B'Elanna Torres, "Learning Curve"
Not directly involving the iPod, but this week's I Cringely has a discussion of how the new Mac Mini may be a move by Apple to get into the movie distribution business, trying to repeat with video the success they've had with the iPod for audio. He has some interesting speculation on synergy from Pixar (which Jobs also controls) and Sony ("...you don't get the head of Sony at your event just to sell camcorders"). Well worth a read.
"Prepare for the worst - hope for the best."
You forgot one crucial piece in the first part of that: the amplifier stages.
The crappiest set of speakers and headphones will sound much better through a decent preamp and amplifier than the most expensive speakers and headphones will sound through a $19.99, underpowered clearance special.
If, in fact, all media players have identical, real-world response, then you'd be correct. This is seldom the case, though. A lot of manufacturers skimp on the preamp and amplifier stages in audio equipment to save a few bucks because, after all, digital is digital.
There's so little difference between politics and jihad lately...
There can most certainly be sound quality differences amongst various players. The DAC (digital to analog converter) and the amplifier itself both contribute greatly to how well the output sounds.
Most every portable player anymore uses an integrated chip to perform the MP3 playback and amplification and many players from different brands will use the same chips. The implementation of the circuitry however can still make a significant difference.
But for the really discerning audiophiles, the only way to get decent sound from a portable player is to use an external headphone amp that utilises higher quality components and generally operates at higher supply voltages which helps provide more generous amplifier headroom. There really is a difference and you can hear it readily with better quality headphones.
I thought it was:
1st gen: Buttons around wheel, mechanical wheel
2nd gen: Buttons around wheel, touch wheel
3rd gen: Separate touch buttons under screen, touch wheel
4th gen: Click wheel
...and that's all there is to it.
Probably no secret features.
Standard USB specifies the existence of hosts (with Type-A connectors) (such as desktop computers) and peripherals (with Type-B connectors) (such as hard drives, cell phones, digital cameras, etc.) Hosts are not supposed to connect to each other, and neither are peripherals.
The USB-To-Go specification was created in order to allow pseudo-peripheral devices to connect to each other (e.g., you might connect your cell phone to camera so that the phone can send the data, even though both of these are peripherals to your Mac). By connecting the fifth pin of the type-B connector to ground, Vcc, or letting it float, you indicate to the other (type-B) device whether you want to act as the host, act as the peripheral, or whether you just behave like a standard USB device.
Coincidentally, most of the mini-B connectors sold these days are 5-pin, because legacy devices can just leave the fifth pin floating. From the manufacturer's point of view, there is no reason to have two types of interchangable items in stock. So my guess is that AAPL bought what was for sale on the market.
--js
By saying dead-flat frequency response, it means that the IPod is able to play all the audible frequencies at the same volume. Take for example, your typical after-market car stereo. It will tend to have way too much bass, which makes the music sound muddy. And that means it does not have a flat frequency response. With a flat frequency response, if you want it to sound bass heavy, you can adjust the EQ (i.e. turn up the bass), and make it sound that way. On something bass heavy, you have to turn it down just to make it sound normal. That's why it is desired, it means you can accurately play back the audio that was recorded.
I'm a mastering engineer and hang out on mastering web boards, and the iPod came up in conversation.
FWIW, a tech heavyweight (trying to remember if it was Bruno Putzeys?) said they'd measured the iPod and got a perfect 10K tone out of the bugger with virtually unmeasurable sidebands.
NOT easy. That outperforms a heck of a lot of high-quality CD players, never mind mp3 portables. iPods apparently have very good tech if you know how to measure them. Jitter is what that 10K tone test measures, and it performed very, very well, I'm told.
I do not buy that missing out on low and high end thing either
Look at the chart, it's all there - that's how our ears work. We aren't good at hearing lo and hi frequencies, so if we listen to material with a flat response, we perceive the 1kHz-4kHz range as being "louder".
because then we should be going to live performances with EQ-adjustable ears, which we don't.
At live performances, we have engineers whose job it is to equalise the performance material both according to the properties of the venue, and the frequency range of the music itself. Live sound is a very different case to portable audio and the two aren't really comparable.
Besides, most music does happen within that 1kHz-4kHz range
I'm sorry, but that's completely wrong. Vocals fall into that range, as do the fundamentals and initial harmonics of a few instruments, but since that range is relatively small (the best of us can hear everything between 20Hz and 22kHz, as well as the fact that frequencies outside our audible range can combine with those that are within range and have a very audible effect), there is more than enough material falling outside that range for us to palm it off as "accompaniment". Think about your average band setup - vocals, guitar, bass guitar, drums. The guitar will spend some time in the lo freq ranges, the bass will be there 100% of the time, and the kick drum likewise. Above 4kHz we've got the rest of the guitar work, and most of the drum kit. Try setting up a graphic EQ in the music player of your choice, attenuate everything outside 1k-4k and see how it sounds. Now come back and tell me that most music "happens within that range" it's simply not true.
Music does sounds livelier and closer to the source without EQ
A very broad and naiive statement, and again one that is completely untrue. Do you think when you listen to your favourite album that no EQ has gone into the production of it all? By the time sounds hit the recording medium, they'll have gone through at least two EQ processors, and that's before mastering. At the user end, true, most people see a GEQ and twiggle around with the sliders and then realise "Hey, I've cocked it all up", but if you use it properly and actively pick out frequency ranges in the material you're listening to and adjust accordingly (minor adjustments, nothing ridiculous), you can very effectively tune your setup to your own personal tastes, making tracks sound a lot livelier.