11 September 2005

Sound tests (not rigorous)

This week, Apple announced a new product called the iPod nano. This, of course, created a wave of iPod desire which simultaneously pleased many ('more toys!') and pissed off many others ('I've already have an iPod, grrr!!'). It's difficult to decide which category I fall into.

Now, the hypothesis is that the people at One Infinity Loop has been improving their product offering. To convince myself of this hypothesis, I did a back-of-the envelope, limited-to-ears/brain-interface, doesn't-conform-to-the-Scientific-Method experiment to test the audio output between a 2nd generation 20GB iPod (bought in the good old days of 2002 when iPod was still Mac-only and favourite green-eye monster bait for all those Windows people) and a 1GB iPod shuffle. It's a little like comparing apples with oranges, given that the two products have quite different designs and specifications. However, since they both play the same set of music, it's fair game (just like apples and oranges are both fruits: fair game), methinks.

1. Downloaded Star Wars Ep III soundtrack (160kbps) onto both devices.

2. Set iPod to no EQ setting. Locate experiment in quiet place. Standardise volume output as much as possible using ear/brain response to the first bar of the music.

3. Used old ear phones that came with iPod for general 'environment in crowded subway' testing

Results: Like many have noted elsewhere, I noted that the Shuffle gave a bass response which was both louder and clearer in comparison to the rest of the audio range. No obvious difference for middle and higher registers. Overall, the Shuffle gave a clearer, more crisp experience.

Note: Hints of strings being plucked strings could be discerned from the iPod; same set of strings being plucked are very clearly heard in Shuffle.

The same results are generally true for most other music types with well defined percussion rhythms.

To repeat the experiment:

1. Downloaded Mahler's Second Symphony, Fifth Movement (128kbps) onto both devices.

2. Set iPod to no EQ setting. Locate experiment in quiet place. Standardise volume output as much as possible using ear/brain response to the first bar of the music.

3. Used Shure's E2 in-ear ear phones (see also 'tinnitus in abnormally quiet environment')

Results: there's an soft but appreciable background hiss from the Shuffle, which wasn't there with the iPod. This is most likely due to impedance matching between the player and the ear phones, but mechanical insulation effects are also likely. Also, the solid state electronics give a very soft, high pitch whine with each press of the 'scroll wheel' button, which is cool from a geeky point of view, but highly annoying to a musician's ear. (One can argue weakly that it resembles analogue hissing from vinyl, but this hiss isn't 'vinyl warm'; it's more 'dentist's drill'.)

Despite the hissing (which your brain happily ignores once the music becomes loud), the Shuffle gave a better technical performance, especially with the bass response. The balance between the low, middle and higher registers was more pleasing than what the iPod gave. This was demonstrated quite clearly by the time the choir sings its second triple-piano entrance two thirds into the movement. (The first entrance is way too intense to be anything but a test of your hearing's lower threshold).

In terms of atmosphere though, iPod gave a better performance. In general, the iPod gave a better feel when it comes to classical music, and the Shuffle performed better for anything that isn't classical music.

Overall, the Shuffle is still the better of the two, given its size and form factor, and the kind of music one listens to in busy subways and commuter buses.

It'd would be interesting to find out if the iPod nano has the same hissing problem with 'sensitive' earphones, given its size and flash memory design. Maybe it's time to head down to the neighbourhood Apple shop.

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