The iPod Compared
To get a better idea about the sound capabilities of the iPod, I've compared the iPod with other audio devices. This page gives a short overview of my impressions.
Furthermore, I've collected some info from magazines and the web, where the iPod is compared to other devices. The opinions of those magazines, although overlapping with some of my own observations, are not mine.
My own observations
Standalone. With a pair of decent headphones, the iPod sounds quite OK. Overall, the sound characteristic is still a bit on the shrill side, and lacking air around the sound sources (everything is "close to the ears"), and missing ambiance (warmth, bass). Before the firmware v2.1 update, the headphone output sounded harsh/stressfull, canned, lacking bass, authority, depth, diffuse field, and "silence between the notes" or "air". After the firmware v2.1 update, a lot of these issues are improved. There is way more authority, a full mature sound, and overall it is less oppressive at loud volumes. Compared to my Dell C400 laptop, iBook, PowerMac G5, Sony portable CD player, Palm Tungsten T3, the iPod excels in dynamic involvement, but without becoming oppressive.
Measurements show that one of the problems is lack of bass using normal 30 Ohm headphones (e.g. like the one supplied with the iPod !!!!). Because the line output seems to have a decent quality without these problems, the harsh sound is obviously caused by the headphones output. I'm wondering how much this has to do with the new electronics of the Wolfson chip, or whether a too low quality/low value capacitor has been applied in the output (220uF as shown by our measurements, and as adviced by Wofson (pdf)). The low value capacitor output could easily be compensated by an equalizer setting (even matched to typical impedances of headphones), but the iPod doesn't allow to download custom equalizer settings, and Apple doesn't provide the right one, which is a missed opportunity. I've posted a message on an iPodlounge forum, asking people to report about the issue, so that Apple takes the problem seriously, and solves it by an obvious patch in a new version of their Software Updater.
Another problem could be bad design of power supplies, crosstalk due to PCB design, or use of bad components. This might induce intermodulation distortion, which is hard to prevent.
Hifi equipment. I've compared the iPod both the headphone output and the line output of the iPod to other hifi equipment. Specifically, I've used a TEAC VDRS-10 CD player, my own constructed DA-convertor, an Audio Innovations Classic 25 amplifier, and DIY Audio Note E loudspeakers. On the iPod I played an uncompressed AIFF file via the line output of the docking station, and on the CD player I played the same track using the original CD. I've "amplified" the music files on the iPod in such a way that I obtained the same volume levels from both devices.
The line output shows minor differences between the iPod and the CD player, with the iPod sounding just a little bit more harsh. This implies that the electronics used for the line output of the iPod are sufficiently good and decent, but not at the top.
iPod compared: my observationsThese are the observations of other people, hence these are not my own observations.
Apple 2G iPod. I had the opportunity to compare a 2G iPod with a 3G iPod, using my Sennheiser HD497 and Etymotic ER-4Ps. Generally, the 2G sounds more relaxing and refined, though a bit less dynamically involved. Jochen Richter performed the same comparison after buying a 3G iPod replacing his 2G iPod. His observations and my impressions are the same:
At the end, Jochen sold his 3G in favour of his 2G.
Apple 4G iPod. My friend bought a 4G iPod. The overall impression of the sound quality is the same (bass, treble etc.) as with the 3G, though the grainy sound coming from AAC and MP3 files had disappeared.
iPod compared: others report
iRiver iHP 100. This seems to be the best sounding player around. Measurement of the audio outputs show high quality results (flat response from 20Hz-20kHz, as published in the German hifi magazine Stereoplay, 10-2003).
Stereoplay (10-2003) rates the sound quality at 37 points, with only 33 points for the iPod. The 19th issue 2003 of the computer magazine C'T Magazin shows a comparison between many HD based MP3-players. Their measurements show exactly the same characteristics, a flat response for the iRiver, and a bass attenuation of the iPod. Distortion for the iPod is reported to be 0,42% (which is quite some), where the iRiver measures 0,04%. They've also measured the headphones of all devices, and both the iRiver as well as the iPod headphones seem to be the best. C'T Magazine rates the devices using their original headphones, and in that respect the iPod seems the least worse of all (which only shows the terrible quality of the other headphones). They rate the iPod and iRiver both with a "+". The highest mark is a "++", which isn't assigned to any of the players (due to headphone restrictions). Battery time is reported to be 13.5h, compared to 8h for the iPod (ouch). Both C'T as well as Stereoplay conclude that the iRiver is the best buy, especially due to its lower price.
Creative Nomad Jukebox Zen NX. Measurements shown in C'T magazine show almost the same characteristics as the iPod, though with its original headphone it is rated lower for its sound quality. CHIP Magazine compares the Zen to the iPod Gen2, and rates the sound quality lower as well (89 points for the Zen, 100 points for the iPod), but again with the original headphones. Battery time is reported to be 10.5h. Distortion is measured at 0,05%. On several places on the web (e.g. iPodlounge) it is reported to sound better than the iPod.
Philips HDD 100. The Philips is rather new, and from design point of view the most serious competitor to the iPod. It has an incredible battery life (15h!!!), as tested by C'T Magazine. That's almost twice as long as the iPod. Distortion is 0,59%, which is much, though Guardian claims it sounds better than the iPod.
Stereoplay Magazine. The downloadable list of Stereoplay (pdf) shows a comparison overview, mentioning a sound rating of Creative Jukebox 3 (35 points), Hango PJB 100 (35 points), Creative DAP Jukebox (34 points), Apple iPod 2G (32 points), Archos Jukebox (30 points), and other non-HD based MP3 players. Their October 2003 issue compares the iPod 3rd gen (33 points) with the iRiver IHP 100 (37 points) and the Innoplus Phototainer (30 points). The graphs show a clear fall-off in bass for the iPod (left figure), whereas the iRiver has a straight response (right figure).
C'T Magazin. The 19th issue 2003 of C'T Magazin shows a comparison between many MP3-players, among which the Archos Jukebox Multimedia 120, Archos Jukebox Video AV 320, Creative Zen Nomad Jukebox Zen NX, Deltron Cinema Disk, Innoplus Phototainer PT-300P, iRiver iHP-100, Mambo-x Media-X, MPIO HD 100 and the Philips HDD 100. For each device they show measurements of line and headphone outputs. The iRiver shows the most flat response out of its headphone output. They also show measurements of the headphones delivered with all the devices, and basically you can see that both the iPod as well as the iRiver provide the best headphones. Regarding my own observations, this only shows the very poor quality of headphones delivered with other devices. Measurements show distortion of 0,42% for the iPod, which is only surpassed by the Philips (0,59%), but all the others are way lower (0,04% for the iRiver). The maximum output voltage of the iPod is 0,29V (EU restricted), whereas the iRiver is for instance 0,6V. Battery time of the iPod (30GB version) is reported to be 8h, the Zen 10,5h, the iRiver 13,5h, and the Philips 15h (twice as long!!!). It seems that Apple gets though competition, and has a job to do.
CHIP Magazine. In their September 2003 issue, the Dutch version of CHIP magazine compares the 2G iPod towards a Creative Jukebox 3, Creative Zen, Archos FM-Recorder and Pikaone Groovecase, all HD-based MP3 players. First of all, they praise the iPod headphones compared to the headphones delivered with all other devices. This only shows the very poor quality of headphones delivered in general with these devices. They use a Sennheiser PX-100 for all other comparisons. Considering measuments on the headphones output, the Creatives perform better (100 points) compared to the iPod (89 points), but the magazine concludes that the iPod sounds better (100 points) compared to the Creatives (89 points).
Stereophile and Hifi+ Magazine both discuss the iPod as a kind of audio device as part of the hifi chain. They are both positive about the line output capabilities. There is also this iPod 30G review, advocating AIFF usage.
The iPod can also be hooked up to a hifi system. An experiment has been performed at an audio exhibition, and the reactions where positive.
© Copyright 2003, Marc Heijligers