Power Cords - Search For Sample Recordings

[MLXXX]

foo_abx 1.3.4 report

foobar2000 v1.1.1

2011/03/07 00:07:46

File A: C:\users\dtv\My Documents\Powercordupload\A-take1.wav

File B: C:\users\dtv\My Documents\Powercordupload\B-take1.wav

00:07:46 : Test started.

00:10:08 : 01/01 50.0%

00:10:19 : 02/02 25.0%

00:10:35 : 03/03 12.5%

00:11:01 : 04/04 6.3%

00:11:29 : 05/05 3.1%

00:12:00 : 06/06 1.6%

00:13:07 : 07/07 0.8%

00:19:43 : 08/08 0.4%

00:34:27 : 09/09 0.2%

01:00:49 : 10/10 0.1%

01:01:04 : Test finished.

----------

Total: 10/10 (0.1%)

Above is a report provided by foobar2000 tonight. As the test progressed, my hearing became less sensitive to differences, and I took longer before I could feel confident I had correctly identified X. I found it helped to change the replay conditions, e.g. moving closer to a speaker, or applying some treble boost, at times. Unless the brain is challenged with a newish sounding sound, it can coast along without listening attentively. I frequently changed the segment of the 10 second matched files I was listening to.

These files are much harder to tell apart than I had anticipated! They can be found at post #98.

[myrantz]

foo_abx 1.3.4 report

foobar2000 v1.1.1

2011/03/07 00:07:46

These files are much harder to tell apart than I had anticipated! They can be found at post #

98

.

This is one more than me... How do you actually get the report out? Must have missed that option. When I did the test last time, I have no idea what A or B was...

2nd question, how do you actually record with your Essense ST? Via the line in from your PC case?

[MLXXX]

How do you actually get the report out? Must have missed that option.

When you click the Exit button on the ABX dialogue box, a save dialogue box launches.

When I did the test last time, I have no idea what A or B was...

I can reveal which is which, if anyone wishes to know. (Only one person has offered a guess, so far.)

2nd question, how do you actually record with your Essense ST? Via the line in from your PC case?

I used one of the 6.5mm sockets of the Essence ST card for line input. (The driver in Ubuntu made it easy to set what card connectors took the input, and what connectors delivered the output.)

EDIT:

The Essence card is an audiophile quality device, and I used it because it happened to be on hand. However I see no reason why the line input of any modern pc could not be used for recordings, if there exists a difference in audio output brought about by changing a power cord, that is audible to human ears.

Edited March 7, 2011 by MLXXX

[MLXXX]

In the spirit of getting the ball rolling ...

Some people in subjective comparisons have described a power cord as giving a brighter or duller sound.

I thought my CD player "B" gave a brighter sound, at times. Today I confirmed that objectively, though there isn't much in it.

To the nearest 0.1dB, the measured response from a test CD was as follows:

[b]Freq	A	B
Hz	dB	 dB[/b]		
12.5	-0.3	-0.3
25	0	-0.1
50	0	0
100	0	0
200	0	0
400	0	0
800	0	0
1600	0	0
3200	0	0
6400	-0.1	-0.1
12800	[color="#FF0000"]-0.3[/color]	-0.1
15000	[color="#FF0000"]-0.4[/color]	-0.2
16000	[color="#FF0000"]-0.4[/color]	-0.2
17000	[color="#FF0000"]-0.5[/color]	-0.2
18000	[color="#FF0000"]-0.5[/color]	-0.2
19000	[color="#FF0000"]-0.6[/color]	-0.3
20000	[color="#FF0000"]-0.6[/color]	-0.3

The above illustrates that if one audiophile device is giving an audibly brighter sound over another, this may reflect in the measured steady tone frequency response of the two devices. The difference in audible brightness although relatively subtle for the human ear, is clearly revealed in the measurements. For example, Player A produced 0.3dB less output than Player B, when playing an 18KHz sine wave.

The absolute accuracy of the above figures may be in doubt as I didn't calibrate the sound card used to capture the analogue output (a Xonar Essence), e.g. with a precision signal generator. Nevertheless the figures show the Player B maintained a higher treble output than Player A, at around 12.8KHz and above. (As a further test, using the sound card to record its own output, the treble response for the test file was closer to that of Player B. The apparent treble roll-off was much less pronounced than with player A.)

I've transferred the above figures to a chart (using OpenOffice Calc): Comparative frequency response CD Players A and B

Edited March 14, 2011 by MLXXX

[DamianW]

So before doing the test which CD player sounded better to you and after doing the test which do you now think it better.

[MLXXX]

So before doing the test which CD player sounded better to you and after doing the test which do you now think it better.

Subjectively

I had never used my blu-ray player for CDs before. I had noticed a distinctive sound from the Denon, or at least thought I had. The test tended to confirm my impression of the Denon. I think I would prefer Player B, but I'd need to listen to a variety of discs before being able to express a decided opinion.

I haven't so far revealed which player is which. (I've invited guesses!)

Objectively

A drop off of around 0.5dB is pretty minor. It's not unusual for response to start dropping off well before the Nyquist frequency (22.05KHz).

I did try to measure THD but the harmonics were at too low a level, with both players, to get a reading.

I don't think the frequency response tests of themselves enable firm conclusions to be drawn as to which player is "better" but Player B would have a slight edge on paper, as its low frequency drop off is at such a low frequency as to be negligible, but it maintains a high frequency response over audible frequencies better than Player A.

(I didn't attempt to burn a pulse test to a CD and compare playback but I suspect the responses would be quite different, based on the audible impression of short intense chords when I listened to the the Vivaldi Four Seasons piece.)

Edited March 15, 2011 by MLXXX