Recent News and Articles

« Back

Audio quality of iPod Video

Audio quality of iPod Video

Starting from July 2015 testing scheme for digital audio players was modified. Instead of Koss Porta Pro headphones the plain resistive load of 33 Ohm is used now. Also accuracy of the test file processing for analog circuits was improved substantially. Unfortunately resulting new ratings of DAPs are not compatible with the old ones, so the latter were removed. Sorry.

New info, if any, about iPod Video will be posted above this disclaimer. Previous article about iPod Video along with the results of its listening test is under this disclaimer for archival purposes.

 

iPod Video by Apple


iPod Video

iPod Video which belongs to the 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 below:

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, 0 dB: totally different).

Sine@1kHz
88dB SPL
White noise
88dB SPL
J.S.Bach
82dB SPL
Bass
83dB SPL
Castanets
80dB SPL
French male speech
84dB SPL
Glockenspiel
77dB SPL
Harpsichord
79dB SPL
Postscriptum
80dB SPL
Mike Oldfield
83dB SPL
Quartet
85dB SPL
-68.72 (L) -24.58 (L) -27.24 -26.22 -30.39 -30.03 -32.90 -18.51 -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.

 

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.

 


Update. 2015 August 22

Deprecated results of previous listening test of Portable Players. For archival purposes only.

Deprecated results of listening tests of portable players

Comments
No comments yet. Be the first.

What is SoundExpert

SoundExpert - How it works SoundExpert (SE) is a crowdtesting service that provides audio quality ratings of sound equipment and technologies such as mp3, aac, wma ... encoders, portable players, sound cards, amplifiers ...

The ratings are based solely on results of blind listening tests when listeners don't know the particular device they test. So the values are completely unbiased and free from any marketing and advertising noise.

SoundExpert provides ratings thanks to visitors who take part in testing. The more number of participants - the more devices and technologies could be tested. The ratings are computed in real time while new grades are returned by visitors. The testing procedure is simple and short enough that anyone, including you, can participate. Just download a test file (<3Mb), listen it (<15s) and send back your judgment. Details are in test file. The more accurate grades - the more reliable ratings.

SoundExpert is independent non-commercial research project. It's in beta state because it uses new audio metrics and corresponding listening test design which are not widely adopted by audio engineers. The key feature of this new method is possibility to hear sound artifacts which are normally beyond threshold of human perception. So, please, use these ratings with caution. Detailed but still easy to understand explanation of SE internal mechanics is in the article "SoundExpert - How it works".

The main idea behind this service is consumer control over sound quality measurements of various audio equipment on the market. SE, being a distributed human project, combines tiny efforts of audio enthusiasts for carrying out this task.