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My cable test enterprise - Page 28

post #406 of 438

I'm getting the impression that much of the issues that people are putting down to jitter are really other electrical problems instead.  I think jitter has become a catch-all word for these things.

post #407 of 438

Indeed, a <50ps jitter means that the signal path is as short and clean as can be...I don't recall where I read it exactly, but a noisy ground/interferences are said to increase jitter drastically. I think I also read that there's an audiophile company licensing TC's "jetPLL" audio band jitter attenuation technology in their DAC.

 

You can find zillions raving reviews about TC's BMC-2/Konnekt 6 and they're using a pretty good DAC from AKM, the only problem is the cheapo opamps...NJM2068 isn't what I would call audiophile grade by any stretch of the imagination(try OPA827/OPA1641). Pro-audio gear does more than audiophile equipment for less, but they use nasty sounding SMPS PSU's and cheapo dual opamps...can't get it all I guess.

 

The audiophile market is too much of a niche for TC to bother, plus swappable opamps/PSU's mean more RMA in the end because of careless ppl plugging them the wrong way. And stubborn design engineers refuse to believe that every opamp adds its own coloration to the sound...a 2134/5532(and at best 4562) is all that's required in their opinion(look at the Benchmark DAC-1).

post #408 of 438
Quote:
Originally Posted by Currawong View Post

I'm getting the impression that much of the issues that people are putting down to jitter are really other electrical problems instead.  I think jitter has become a catch-all word for these things.


It is one suggestion after another for supposed causes of audible differences, which few want to actually test using their ears alone, yet find the space to accuse others of being somehow deaf and unable to enjoy music.

 

Indeed, it is worth pointing out that this thread was about frequency testing of analogue cables, jitter has been trolled (which Currawong is something I know you do not like happening) into the thread to introduce another distraction to get away from having to answer the really difficult question

 

- is any of this actually audible?

- can we tell the differences with our ears alone?

 

The answer so far is unlikely and no.

 

post #409 of 438

 

Originally Posted by Prog Rock Man View Post

 

this thread was about frequency testing of analogue cables


The very basic FR measurements that have been posted in this thread so far wouldn't allow to differentiate a rusty coat hanger from a solid UPOCC silver wire....and saying that both would sound the same is ludicrous, to say the least.

post #410 of 438
Thread Starter 



 

Quote:
Originally Posted by leeperry View Post

 


The very basic FR measurements that have been posted in this thread so far wouldn't allow to differentiate a rusty coat hanger from a solid UPOCC silver wire ....and saying that both would sound the same is ludicrous, to say the least.


Other people have done the coat hanger and deliberately bad cables tests already and they still show up as not audibly different when listening tested by humans who simply do not know which one they are listening to. That a massive obvious audible difference that reviewers and buyers alike will wax lyrical about cannot be verified by unsighted tests and cannot survive digitization ....earlier in this thread I sent one of the members a copy of a test file and a copy of the same file that had gone through a D---A----D process where I recorded the anlog output of a CD player playing the file. The recipient was unable to detect the extra A/D stage, just as Uncle Ivor back in the 80s..
 

post #411 of 438

Yeah, this was a bait to the legendary "coat hanger Vs Monster cable" shootout, thank you for pointing it out. Most likely run in a non-acoustically corrected room, so the inoccent victims of this test were listening to the room more than to the cables. Also, it's rather clear that analytical headphones will always provide a much clearer and less distorted sound than the aforementioned test conditions.

 

So what we've learned is that anything that conducts electricity will always sound identical, oh my...what a breakthrough[:e-te]

 

skin effect = snake oil

intra-pair skew = snake oil
inter-pair skew = snake oil
Far End Crosstalk(FEXT) = snake oil

Shielding from EMI/RFI = who needs it? images?q=tbn:ANd9GcQa6EAUqkmXPrxKRf_dhh4UP_dO7tSU3blYo3j7xa2CB3kFAClOdU1HAW8

 

Basically, it's been thorougly and empirically shown(and also double proofed, w/ hands tied in the back) that we could use the most impure iron alloy to transport audio...it doesn't matter *whatsoever*. I see a great business scheme here, someone shall start selling HDMI 1.4 cables made out of rusty recycled coat hangers...much like the ppl who turn antique phones into cell phone hands-free kits. The anti-technology approach has its charms, I'll give you that.

Seriously, we could make millions [:cisco1:1]

 

Originally Posted by nick_charles View Post

 

earlier in this thread I sent one of the members a copy of a test file and a copy of the same file that had gone through a D---A----D process where I recorded the anlog output of a CD player playing the file. The recipient was unable to detect the extra A/D stage, just as Uncle Ivor back in the 80s..

 

OK, shoot! Just so you know, I passed this test successfully: http://www.head-fi.org/forum/thread/502889/so-who-can-abx-this-recording-from-the-source#post_6790330

post #412 of 438
Quote:
Originally Posted by leeperry View Post

The audiophile market is too much of a niche for TC to bother, plus swappable opamps/PSU's mean more RMA in the end because of careless ppl plugging them the wrong way. And stubborn design engineers refuse to believe that every opamp adds its own coloration to the sound...a 2134/5532(and at best 4562) is all that's required in their opinion(look at the Benchmark DAC-1).



There isn't sufficient evidence to claim all opamps sound different.  For the DAC-1 design the 5532 actually provided the best results based on the circuit implementation.

post #413 of 438


 

Quote:
Originally Posted by leeperry View Post

Yeah, this was a bait to the legendary "coat hanger Vs Monster cable" shootout, thank you for pointing it out. Most likely run in a non-acoustically corrected room, so the inoccent victims of this test were listening to the room more than to the cables. Also, it's rather clear that analytical headphones will always provide a much clearer and less distorted sound than the aforementioned test conditions.

 

.......


Whether the room was acoustically treated or not is another of your distraction arguments. So long as the room was the same for all, there is no issue.

 

Your comment about only analytical headphones leans towards the 'buy high end kit and you will hear the difference' argument of buyer justification. However that fails because forget Monster vs Coat Hanger and consider Monster vs Opus MM ($33,000 worth of cable) which also was indistinguishable.

post #414 of 438

How about a coathanger-based interconnect vs. something else?

post #415 of 438
Thread Starter 


Consolidated measuremnets into one post - also at beginning of thread --

 

See also http://www.head-fi.org/forum/thread/541818/some-cable-measurments-no-dbt-no-debate-just-measurements


 

Quote:
Originally Posted by nick_charles View Post

Cables arrived


All cables



Audioquest



Audioquest-unboxed


Blue jeans


Tartan (Belden)


Stocky


Monoprice


Audioquest-Blue-jeans-AR


 



Quote:
Originally Posted by nick_charles View Post

So the first order of business was to see how flat the response of each cable was.

First I generated a 40 second clip of white noise , I saved this as a Wav file and ran it through a spectrum analyser,
this is the reference point.

Then I burned the sample to CD and tested each of my CD players by playing it back and recording the analog
output to find the one most like the reference in shape and overall level. I settled on a Denon DCD910 analog
output which had the lowest deviation from the reference from 20 - 20K using stock cables.

Now I set about more critically measuring the response for the 4 cables I bought plus my own 77c specials.

To do this I played back the white noise sample and recorded it to my PC. To cater for random variations
I did each recording with each cable **10** times.

Each resulting wav file (70 of them, I tested the AQ cables aligned by the arrows and unaligned to test for the claimed directionality) was clipped to exactly 24.003628 seconds, each file is precisely
4.03 MB (4,234,284 bytes) all white noise. Due to careful editting ( the same protocol used for each file)
no wav file can differ from any other wav file in alignment by more than 1/1000th of a second.

Each file was then run through a spectrium analyser with 1024 sample points. Each spectrum was exported as a text file.

Then I started up Excel and I loaded each set of ten trials into a separate worksheet. This allowed me to see the Min, Max and Average levels for any frequency. Also it allowed me to see how much variation there was in any set of trials.

For instance the biggest difference between any two trials for any frequency with the Stock cables was 0.056db, the average difference between the max and min value for all frequencies for stock cables was 0.032 db.

Tartan cable 0.032 and 0.014
BlueJeans 0.047 and 0.016
AQ G-Snake Not Aligned 0.061 and 0.016
AQ G-Snake Aligned 0.038 and 0.013
AQ Sidewinder Not 0.050 and 0.014
AQ Sidewinder Aligned 0.044 and 0.014


 



Quote:
Originally Posted by nick_charles View Post

The way that the recording was set up meant that each recoding was always at a slightly lower absolute level than the reference. Thus the best cable by definition at any frequency would have the highest value or the lowest attenuation from the reference. This made life easy.

In no case did any cable boost any frequency above the reference level.

Each set of 10 trials for each cable was averaged and the results fed into the worksheet with the reference values.

The maximum difference found between any two cables at any frequency point was 0.029db. The average difference between the best and worst cable across all frequencies was 0.012db. Note that the identity of best and worst cable did differ between frequencies.


 



Quote:
Originally Posted by nick_charles View Post

Two of the cables I purchased are supposed to be directional. I recorded samples using the Audioquest G-Snake and Audioquest Sidewinder both correctly aligned and incorrectly aligned. I recorded 10 samples with each of the 4 combinations.

The G-Snake correctly aligned was in fact measurably different from the G-Snake incorrectly aligned. When I fed the results into SPSS the result was significant.

Before anyone gets excited the maximum difference at any frequency was 0.022db and the average difference was 0.001db. For the Sidewinder the maximum difference was 0.011db and the average difference at all frequencies was 0.002db.


 



Quote:
Originally Posted by nick_charles View Post

Do any of these cables roll off any more than any others. I tested the differences in level between 1K and 20K, 2K and 20K, 3K and 20K, 4K and 20K, 5K and 20K, 6K and 20K, 7K and 20K, 8K and 20K, 9K and 20K, 10K and 20K, 11K and 20K, 12K and 20K, 13K and 20K, 14K and 20K , 15K and 20K and finally between 16K and 20K.

The maximum difference in roll-offs between any two cables for any two frequencies was 0.016db


 



Quote:
Originally Posted by nick_charles View Post

Stock(77c) vs Sidewinder ($60) , max diff 0.020db, ave difference 0.009 db
Stock(77c) vs G-Snake ($35) , max diff 0.013db, ave difference 0.003 db
Stock(77c) vs Blue Jeans($26.75), max diff 0.014db, ave difference 0.004 db
Stock(77c) vs Tartan ($5) , max diff 0.009db, ave difference 0.003 db

Tartan ($5) vs Sidewinder ($60) , max diff 0.014 , ave difference 0.006db
Tartan ($5) vs G-Snake ($35) , max diff 0.009 , ave difference 0.003db
Tartan ($5) vs BJC ($26.75) , max diff 0.007 , ave difference 0.002db

BJC($26.75) vs Sidewinder($60), max diff 0.011 , ave difference 0.005db
BJC($26.75) vs G-Snake ($35), max diff 0.012 , ave difference 0.004db

Sidewinder vs G-Snake max diff 0.018 , ave difference 0.009db


 



Quote:
Originally Posted by nick_charles View Post

The differences are so small as to be utterly and totally meaningless.

Nevertheless in an absolute numerical sense, if you insist , the best cable was the Sidewinder ($60) which consistently had the lowest attenuation , and the worst cable was the G-Snake ($35) which consistently had the highest attenuation. But we are talking 100ths of a db here.

But all these cables behaved absolutely identically , none had anything which could even remotely be called a personality, none changed the signal more than any other in any material way.

Next step music recordings and listening tests...Spreadsheet available from

http://www.mediafire.com/download.php?nkmzxdnm2n3


 



Quote:
Originally Posted by nick_charles View Post

I just loaded my dataset up into SPSS and ran a repeated measures ANOVA with cable type as a covariate and some ANOVAs between cables.

The results show that for these cables there was no significant effect on changing cable, no cable was significantly different from any other. Frequency also did not alter the result, no cable was significantly different at any frequency.

The other result was that there was much more variation between trials than between cables, this is entirely predictable as a cable is a passive device and and ADC is not, so my decision to average 10 trials was justified. Amusingly the repeated measures variation was significant. Remember this was a variation of no more than 0.056db between any two trials for any given cable at any frequency, but when you have 4600+ data points little differences become statistically significant.


 



Quote:
Originally Posted by nick_charles View Post

I just tested the Sidewinder vs the stock cable using a cymbal crash with lots of harmonics and transients. To cut a long story short there were miniscule differences between the two cables as before , never more than 0.68db and averaging 0.046db from 20 - 20K. I have graphed the reference cymbal crash, and the two cables - differences are miniscule.




 



Quote:
Originally Posted by nick_charles View Post

Stock and Sidewinder

Complex set of square waves from 10hz to 10000hz, maximum difference 0.027, average diference 0.0028



 



Quote:
Originally Posted by nick_charles View Post

New test of Sidewinder vs Stock cable with cymbal crash
-------------------------------------------------------

Max difference 0.102340db average difference 0.003539db

Average overall signal
Stock------------ Sidey ------------ difference
-37.743888 ******-37.742651 ****-0.001237







This graph shows the stock cable with the sidewinder dropped by 20db so you can see the patterns




For the Anoraks - the distribution of differences against frequency




And finally difference vs signal level



 



Quote:
Originally Posted by nick_charles View Post

With many thanks to Maxvla I have a 0.5m Zu Oxyfuel on loan for testing. I ran the cymbals test and compared the results against the stock cable.

The max variation was 0.08db at 129hz and -54db, the average difference is 0.001408db.



 



Quote:
Originally Posted by nick_charles View Post

These were done using a five second sample of digital silence and recorded back via the ADC. I ran the tests ( 10 trials) for both stocky and the Zu Oxyfuel.

Average Noise levels Stock -95.7975db.........Zu Oxyfuel -95.8598db

This is quite close to the theoretical noise levels for 16 bit systems



Low frequency noise pattern
---------------------------



I also did a few tests on my $2.11 Monoprice and the $60 Sidewinder. Interestingly each cable has a distinct noise pattern with specific low level spikes at different frequencies.

To place these noise figures in context, here is the noise juxtaposed against the cymbals crash.




In absolute terms the stock cable is the worst for noise with three low frequency spikes between -78 and -76db , how relevant this would be for normal music listening is arguable. Early tests suggest that the Monoprice is as good as the most expensive cables for noise, but I will need to run 10 trials.


 



Quote:
Originally Posted by nick_charles View Post

This text is between a DH labs BL-1 Series II Silver Plated Copper cable and the solid copper Sidewinder with the cymbals sample.

Maximum difference is at 19488hz where the difference is -75.3254db to
-75.3695db i.e a difference of 0.0441db, average difference from 20 to 20K is 0.0014 db. See graph below




 



Quote:
Originally Posted by nick_charles View Post

Noise pattern fro DH Labs cable - nothing unusual here, low levels of background noise at an average of -95.63db and a few spikes at ~ -86db pretty much the same as the Zu




 



Quote:
Originally Posted by nick_charles View Post

White Noise tests 20 - 20K
-------------------------
Maximum difference at any frequency = -0.00436 db , the Monoprice cable has less attenuation at all frequencies, the average difference = - 0.00266 db.

No graph posted, no point , impossible to see the deviations.


 



Quote:
Originally Posted by nick_charles View Post

For these tests I made a slight change to my protocol I used a 16K FFT analysis which translates to 7K sample points. Since I have all the original wav files I may redo them with a smaller FFT later if it is a bust.

Noise differences ranged from
Freq (Hz)SilverCopperdiff
1418-101.0146-92.8366-8.1781
1421-100.8319-95.2206-5.6112
1416-100.7780-95.2324-5.5456
541-99.8670-96.9008-2.9662
15111-97.3906-95.1398-2.2508
538-99.8972-97.7621-2.1351

to

Freq (Hz)SilverCopperdiff
721-79.8842-95.098515.2143
301-80.4885-95.816915.3284
299-79.8153-95.577015.7617
719-79.4283-95.246215.8179
121-65.8202-82.408316.5881
600-79.7158-96.373216.6574
118-66.7071-83.371416.6642
363-80.7216-98.865118.1435
358-73.5922-99.016525.4243
361-70.9139-98.449627.5356


Silver Average Noise level = -97.8339 db
Copper Average Noise level = -99.5085 db
Average difference = 1.6746 db



 



Quote:
Originally Posted by nick_charles View Post

Averages
silvercopperdiff
-35.1717-35.19860.0269


Range of differences from

Freq (Hz)silvercopperdiff
10864-31.2361-31.1511-0.0850
12037-34.3904-34.3113-0.0791
19598-64.2617-64.1956-0.0661
17821-60.0233-59.9590-0.0643
18050-53.2547-53.2003-0.0544
19668-64.8693-64.8172-0.0521


to

Freq (Hz) silvercopperdiff

17870-58.5000-58.59830.0983
12029-32.1039-32.20500.1011
19679-68.4469-68.55140.1045
19663-66.2487-66.38070.1321
121-53.2967-53.58550.2888
118-55.8897-56.20280.3131





Differences vs frequency


 

Quote:
Originally Posted by nick_charles View Post

Average difference levels from 3hz to 20Khz

Silver copper diff
-12.2418-12.26050.0188


Range of differences
Freq(Hz)Silvercopperdiff
19237-12.7538-12.76280.0090
19902-13.4680-13.47800.0100
19862-13.2093-13.21950.0102
19657-13.5434-13.55390.0105

to
Freq(Hz)Silvercopperdiff
12880-12.7116-12.73470.0231
16422-13.0786-13.10170.0232
8454-12.6774-12.70070.0233
8064-11.8652-11.88850.0233
18594-13.4783-13.50170.0234
17286-13.2584-13.28180.0234
11666-13.2417-13.26540.0237
7580-11.4654-11.48910.0237
19113-13.3649-13.38870.0238
10933-12.7789-12.80300.0241

Differences vs frequency
-----------------------




Pattern of Frs against Frequency




This image does show that my ADC and /or CD player is not perfect at higher frequencies as it does roll off



 

 



 


 

post #416 of 438

What a colossal waste of bandwidth and space, not to mention time.  IMHO  tongue.gif

post #417 of 438
Thread Starter 
Quote:
Originally Posted by kwkarth View Post

What a colossal waste of bandwidth and space, not to mention time.  IMHO  tongue.gif


You are of course entitled to your opinion. Others might consider 303 posts dedicated to the "sound" of capacitors unverified by any real listening test to be a similar waste or the hundreds of posts elsewhere dedicated to the unverified sound of different RCA, digital and even USB cables a similar waste, you pays yer money and yer takes yer choice.

 

post #418 of 438
Quote:
Originally Posted by nick_charles View Post


You are of course entitled to your opinion. Others might consider 303 posts dedicated to the "sound" of capacitors unverified by any real listening test to be a similar waste or the hundreds of posts elsewhere dedicated to the unverified sound of different RCA, digital and even USB cables a similar waste, you pays yer money and yer takes yer choice.

Yes, black holes disturb the space-time continuum.  wink.gif
 

post #419 of 438

Thanks Nick, that's excellent.  Now just type it up in LaTeX and publish it!  wink_face.gif

post #420 of 438

Quote:
Originally Posted by kwkarth View Post

What a colossal waste of bandwidth and space, not to mention time.  IMHO  tongue.gif


That's a pretty inappropriate thing for an admin to say about the dedication and careful effort displayed in this thread from one of Head-Fi's better contributors. Not to mention the other members who provided feedback and volunteered their own cables for this. IMHO too, of course. I for one value the research that's been done here.

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