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Apple iPad Audio
First Generation (2010-2011)

© 2011 KenRockwell.com. All rights reserved.

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April 2011   All Reviews    Audio Reviews   Apple Reviews

How to Play DVD Movies on your iPad, iPod Touch or iPhone.

A Recording Engineer's Guide to the Secrets of iTunes and iPod.

 

adorama

 
B&H Photo - Video - Pro Audio

Ritz Camera

I personally buy from Adorama, Amazon, Ritz, B&H, Calumet and J&R. I can't vouch for ads below.

 

Audio Playback

Overall

The analog audio output jack of the AirPort Express, plugged directly as a line-output into audiophile gear, is great.

From 100 feet away, signal-to-noise ratio is 102.5 dB, channel balance is within 0.03 dB, frequency response is +0, -3 dB from 8 Hz to over 22 kHz from mere 44.1 kHz files, and THD + Noise is 0.01% (better than most tube gear) from a 128 kbps AAC file.

For these analog tests I used a specialized VP-7721A analog laboratory audio analyzer.

I didn't test the digital output. Don't try to test the digital output at home; you can't just plug it into a DAC and analyze that output; all that does is test your DAC. To test the digital output, you need a specialized laboratory analyzer that looks at the digital signal itself for eye patterns and jitter spectra, and then analyzes its data content directly in the digital domain.

 

Measurements, Analog Output

Output Voltage

(a standard CD player is 2 V RMS.)

Maximum gain, unloaded, 0 dB FS at 1 kHz, Tektronix TX3:

Left Channel

0.9509 V RMS.

-0.44 dBV.

1.78 dBu.

 

Right Channel

0.9439 V RMS.

-0.50 dBV.

1.72 dBu.

 

Maximum gain, 75Ω load, 0 dB FS at 1 kHz, Tektronix TX3:

Left Channel

0.8931 V RMS.

-0.98 dBV.

1.24 dBu.

 

Right Channel

0.8839 V RMS.

-1.07 dBV.

1.15 dBu.

 

Left/Right Channel Balance

0.06 dB at full gain, unloaded.

0.09 dB at full gain, 75Ω load.

 

 

Output Impedance

Loaded with a Tektronix 75Ω ±0.025% termination versus the unloaded input of the Tektronix TX3, the output voltage drops to 93.7825%.

Algebra tells us that the source impedance is 5Ω at 1 kHz.

 

Frequency Response

Signal: -20 dB FS sine wave, 44.1 k samples per second, 1,411 k bits per second AIFF file on iPod Touch.

iPod at maximum gain.

Loaded with the 100 kΩ load of the analyzer:

5 Hz: -0.2 dB

8 Hz: -0.1 dB

10 Hz: -0.0 dB

20 Hz: 0.0 dB

50 Hz: 0.0 dB

100 Hz: 0.0 dB

200 Hz: 0.0 dB

500 Hz: 0.0 dB

1 kHz: 0.0 dB

2 kHz: 0.0 dB

5 kHz: 0.0 dB

7 kHz: 0.0 dB

10 kHz: 0.0 dB

12.5 kHz: 0.0 dB

15 kHz: -0.05 dB

17.5 kHz: 0.0 dB

20 kHz: 0.0 dB

22 kHz: -0.35 dB

 

75Ω load:

5 Hz: -0.2 dB

8 Hz: -0.1 dB

10 Hz: -0.0 dB

20 Hz: 0.0 dB

50 Hz: 0.0 dB

100 Hz: 0.0 dB

200 Hz: 0.0 dB

500 Hz: 0.0 dB

1 kHz: 0.0 dB

2 kHz: 0.0 dB

5 kHz: 0.0 dB

7 kHz: -0.1 dB

10 kHz: -0.4 dB

12.5 kHz: -0.4 dB

15 kHz: -0.6 dB

17.5 kHz: -0.7 dB

20 kHz: -0.9 dB

22 kHz: -1.3 dB

 

Signal-to-Noise Ratio

103 dB, 400 Hz - 30 kHz band, maximum gain, paused, 100 kΩ load.

101 dB, 5 Hz - 30 kHz band unweighted, maximum gain, paused, 100 kΩ load.

 

THD + Noise

Source: 128 kbps AAC file created in iTunes from a 44.1 kHz Rohde & Schwarz test CD, 1 kHz, 0 dB FS played on iPod Touch.

iPod Touch set to maximum gain.

100 kΩ load of the analyzer:

0.02% THD + N, 30 kHz measurement bandwidth.

0.067%, 80 kHz measurement bandwidth.

0.86%, 700 kHz measurement bandwidth.

 

75Ω load:

0.025% THD + N, 30 kHz measurement bandwidth.

0.052%, 80 kHz measurement bandwidth.

0.59%, 700 kHz measurement bandwidth.

 

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Mr. & Mrs. Ken Rockwell, Ryan and Katie.

 

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