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Audio quality of iPod Video
June 23, 2012 12:17 PM
iPod Video by Apple


iPod Video

iPod Video which belongs to fifth generation of iPods was introduced in 2005 and still loved by many demanding listeners of portable players. Powerful output with excellent sound quality (Wolfson audio chip on-board) made the player iconic. Not surprising that a lot of them are still in use. Adding iPod Video to SE rating system we place an anchor point on SE quality scale making the whole scale a bit more meaningful. And this is the first non-smartphone in the section "Portable audio players". Should be the one at least.

Preliminary conclusions in short:

  • Technical measurements of distortions are good and usual for premium audio players

  • Predominance of odd harmonics in sine wave reproduction may theoretically lead to some harshness of the sound

  • As many players iPod Video smears slightly music passages with fast transients

  • The above technical features can't be used for judging final audio quality of iPod Video. Please, refer to the results of listening tests for the purpose. Participation is welcome!

 

Difference levels for SE standard set of samples and signals are in the Table 1.

Table 1: Difference levels [dB] of signals and samples transferred through iPod Video. The values show how much output waveform differs from input one (-∞dB: perfectly similar, 0dB: totally different).
Sine@1kHz

88dB SPL		White noise

88dB SPL		Bass

83dB SPL		Castanets

80dB SPL		French
male
speech

84dB SPL		Glockenspiel

77dB SPL		Harpsichord

79dB SPL		J.S.Bach

82dB SPL		Postscriptum

80dB SPL		Mike
Oldfield

83dB SPL		Quartet

85dB SPL
-68.72 (L)-24.58 (L)-26.22-30.39-30.03-32.90-18.51-27.24-20.88-11.80-30.60
-68.83 (R)-24.59 (R)

 

The values are quite usual. The nature of sine wave distortion is unpleasant - odd harmonics prevail over the even ones (see Audio 1). Usualy this makes the sound harsh and causes fatigue when listening long. Though the level of such distortion in iPod Video is relatively low (-69dB) to cause any dramatic consequences for its sound.

 

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(vorbis@160 or mp3@165 depending on your browser)

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(24sec, mono, FLAC:927Kb

Audio 1: Sinusoidal signals: reference and output from iPod Video with sound artifacts amplified to +69dB

 

More serious problems could arise from some weakness in reproduction of fast transients in sound. SE sample "Mike Oldfield" clearly shows this even at small level (+4dB) of artifacts amplification. It looks like it is a common problem for all portable players - sound bursts are smeared. Probably this is a feature of energy-saving design of integrated headphones amplifiers.

 

***

SoundExpert thanks Ivasha for his still in use iPod Video and possibility to record SE test samples on his device.

As usually SoundExpert reminds you that final conclusion about audio quality of any device added can be made only after completing of SE listening tests and any technical parameters could be misleading when evaluating perceived sound quality. So we encourage you to take part in our listening tests. All SE ratings, including iPod Video one, exist only thanks to visitors like you. Testing is short and easy, visit our Testing Room for simple 1-2-3 instruction.

Please, remember, downloading a test file from SoundExpert you will not necessarily get a test file of iPod Video. SoundExpert testing is blind testing – you don't know the device you test. This is the only reliable way of getting true audio quality ratings, free from any cheating and various human senses other than perception of sound quality. After you have sent your grade you will see the device you tested.

Best regards,
SE Team.

By Serge Smirnoff
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