Cable comparison

[John Duncan]

So, I was bored tonight. I connected my laptop to the tape out of my amp, and recorded the first drum beat of "What's the matter here" by 10,000 Maniacs. I did it first with a rubbish interconnect between CDP and Amp, and then with a pair of gothams. Then I did a spectrum analysis using Audacity.

The differences in frequency response were the following (averaged over these frequency bands):

0 - 5khz - 1.764151811db 5khz - 10khz - 2.865038365db 10khz - 15khz - 4.381241462db 15khz - 20khz - 5.675948707db

 

[Thaiman]

Firstly....yes, you must be bored (Why not try to learn some Bark at the moon guitar solo)
and 2ndly I can't format the damm posts again!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[Alec]

[quote user="JohnDuncan"]So, I was bored tonight. I connected my laptop to the tape out of my amp, and recorded the first drum beat of "What's the matter here" by 10,000 Maniacs. I did it first with a rubbish interconnect between CDP and Amp, and then with a pair of gothams. Then I did a spectrum analysis using Audacity.

The differences in frequency response were the following (averaged over these frequency bands):

0 - 5khz - 1.764151811db
5khz - 10khz - 2.865038365db
10khz - 15khz - 4.381241462db
15khz - 20khz - 5.675948707db[/quote]

im thick. you'd have to spell out the implications. and also, did they sound diferent? Oh, and ive got audacity but no idea how to use it - you jsut became my "go to" guy. It must really feel like im stalking you lately. please dont call tha cops!

 

[gpi]

Well, what's the difference between the 'rubbish' i/c and the Gotham?

Also, shouldn't you have two sets of figures?

I too need this explaining in words of no more than two syllables and nice and slowly.

 

[Anonymous]

I think he's talking about the diference in frequency response BETWEEN THE TWO CABLE TESTS (sorry for the capitals used-don't have any way of underlining or enhancing). That is: one cable gave a consistently higher signal output than the other. The difference between the two cables is at minimum 1.7 db at it's max 5.6 db.

 

[gpi]

OK, got it now.

So it would be good to do the same test again but between the Gotham and something more expensive.

 

[Anonymous]

Hi John.

Quite dramatic differences there, more than I would have expected. Are the Gothams expensive?

Regards Ed

 

[John Duncan]

No, they're cheap - £9.95 for my short ones. And they were the ones that had the lower output across the board (in about 80% of the 8,000-odd frequencies measured).

 

[John Duncan]

[quote user="gpi"]OK, got it now.

So it would be good to do the same test again but between the Gotham and something more expensive.[/quote]

Yeah, and I got all my cables out of my drawer, but by the time I'd managed to do two I'd lost the will to live.

 

[gpi]

I have socks and pants in my drawer.

 

[Anton90125]

[quote user="JohnDuncan"][quote user="gpi"]OK, got it now.

So it would be good to do the same test again but between the Gotham and something more expensive.[/quote]

Yeah, and I got all my cables out of my drawer, but by the time I'd managed to do two I'd lost the will to live.[/quote]

Actually I must be quite sad as I find it quite interesting. How does the software do the test? By a square wave or pulse and look at the harmonics generated or by a frequency sweep? Does the software also compare phase distortion?

 

[John Duncan]

[quote user="gpi"]I have socks and pants in my drawer.

[/quote]

I have more than one drawer. But then I do live in Teddington.

 

[John Duncan]

[quote user="Anton90125"][quote user="JohnDuncan"][quote user="gpi"]OK, got it now.

So it would be good to do the same test again but between the Gotham and something more expensive.[/quote]

Yeah, and I got all my cables out of my drawer, but by the time I'd managed to do two I'd lost the will to live.[/quote]

Actually I must be quite sad as I find it quite interesting. How does the software do the test? By a square wave or pulse and look at the harmonics generated or by a frequency sweep? Does the software also compare phase distortion?
[/quote]

Dunno. I just clicked on "Analyze". I do think though that in order for this to be (a bit) more scientific, I should be using a more consistent source - like generated sine waves at certain frequencies or something. Got any ideas?

 

[Anton90125]

[quote user="JohnDuncan"]

Dunno. I just clicked on "Analyze". I do think though that in order for this to be (a bit) more scientific, I should be using a more consistent source - like generated sine waves at certain frequencies or something. Got any ideas?[/quote]

Other then use a signal generator,oscilloscope and take lots of readings (like I did when I was an undergrad) I am not sure.

I did see a documentary which described a process which KEF used to look at the frequency/phase response of a speaker under test. They put a pulse through the system and and analysised the results. I presume they did some Fourier on it to get data. When you do a simple frequency test (single tone) you must also do a phase analysis to get a handle on what is actually going to happen when you put a real life signal ie a complete mess of harmonics.

I have seen expensive software that can do this kind of thing (or since you are a mathematician and pc savey maybe write your own software?) but its not really worth buying it unless you are planning to make a business out of building/selling cable.
I would go to a one of those radio hams fairs and pick up a sh frequency generator and oscilloscopes.

 

[gpi]

[quote user="JohnDuncan"][quote user="Anton90125"][quote user="JohnDuncan"][quote user="gpi"]OK, got it now.

So it would be good to do the same test again but between the Gotham and something more expensive.[/quote]

Yeah, and I got all my cables out of my drawer, but by the time I'd managed to do two I'd lost the will to live.[/quote]

Actually I must be quite sad as I find it quite interesting. How does the software do the test? By a square wave or pulse and look at the harmonics generated or by a frequency sweep? Does the software also compare phase distortion?
[/quote]

Dunno. I just clicked on "Analyze". I do think though that in order for this to be (a bit) more scientific, I should be using a more consistent source - like generated sine waves at certain frequencies or something. Got any ideas?[/quote]

Just dress like this and get an assistant. I'll help you.

 

[matengawhat]

john i am not sure if this is possible or works on the same principle but is there any way you can compare the frequency range of an album on both cd and vinyl to see how much the frequencies ranges have been altered to fit on our little silver friend?

 

[Anonymous]

[quote user="matengawhat"]john i am not sure if this is possible or works on the same principle but is there any way you can compare the frequency range of an album on both cd and vinyl to see how much the frequencies ranges have been altered to fit on our little silver friend?[/quote]

Good thinking..........

 

[Anonymous]

[quote user="matengawhat"]john i am not sure if this is possible or works on the same principle but is there any way you can compare the frequency range of an album on both cd and vinyl to see how much the frequencies ranges have been altered to fit on our little silver friend?[/quote]

It's vinyl that is the compromised media due to its inherent limitations and generally a well mastered CD will be far closer to the sound on the master tape.

 

[matengawhat]

eddy i would agree a well mastered cd could sound better but produces now have a tendency for turning every thing up loud to boost the low levels not talking low frequencies just the quiet sections which results in a over blown sound that on a £100 micro system prob sounds great but on anything more sounds like its played underwater

 

[gpi]

A 16bit/44.1 digital file is sufficient for storing music so that the analogue sound can be recreated to a totally satisfactory standard using modern DACs. A higher specification for the digital file is redundant or nearly so. This implies that in principle a CD (being merely a portable device for carrying the data and using 16bit/44.1) is all that is needed. In practice it is not quite so simple.

CDs are sometimes corrupted in manufacture so that reconstituting the intended digital file becomes difficult. CD playing on a stand-alone CD player is handicapped. There is a spectrum of performance available from CD ranging from badly recorded/badly mastered/badly manufactured/badly read to well recorded/well mastered/well manufactured/well read and this is without considering the quality of the DAC. Modern DACs are generally good to excellent and should not be an issue generally.

If everything is right with CD, all the way through to the 16bit/44.1 file, then it is a hard act to follow and certainly good enough. The record player/vinyl LP system is today an extremely refined version of a very old technology. The system is vulnerable to distortion and colouration from start to finish as well as inconvenient in use. Speed stability (under varying load) and rumble have to be addressed. It is actually impossible to get a truly clean sound off a record player. A moment's thought about the steps involved in the process should make this obvious. Nevertheless, very good and sometimes astounding results are possible. The system is good at recording and reproducing fine and subtle detail but poor on signal to noise ratio and dynamic range. Despite the inherent disadvantages in the system, the distortion and colouration need not be catastrophic and a very good euphonious sound is possible. Under contrived and exceptional circumstances it is just possible for an LP system to compete with a fully implemented CD (and easily beat a CD which is poorly implemented) but the virtue balance might be different. The LP system will have at least a trace of colouration. It is no surprise that the sound from an LP when everything is right is preferred to the sound from a CD when the latter is sabotaged by being poorly made or poorly read.

Try a little experiment for yourselves. Take a CD you consider to be badly mastered or manufactured and burn a copy of it onto a good quality CD-R, preferably at a slow speed to help prevent read/write errors. Your computer should make a very good copy of it. See if the CD-R copy sounds any different to the original.

 

[matengawhat]

good response and a good example of why a good £1000 pound record deck would kill a £1000 cd player - although i think most is down to the failing of the silver discs than a true benefit of vinyl!!!

 

[Anton90125]

imo , CD (16bit 44.1k) is not really that good. LP, even a cheap player has so much going for it. There is an inherent depth and ambiance which is mostly devoid in CD. SACD really gives you an idea of how far CD is behind. CD's main plus points are it is convenient ( you don't have to turn them over!),no wear and tear. Lets face it CD is based on technology developed in the late 70's (16bit 44.1k was cutting edge then)

An interesting interview by one of the very great audio electronics gurus:
Interviews Tim de Paravicini

http://www.stereophile.com/interviews/1107parav/index.html

 

[gpi]

[quote user="Anton90125"]
imo , CD (16bit 44.1k) is not really that good. LP, even a cheap player has so much going for it. There is an inherent depth and ambiance which is mostly devoid in CD. SACD really gives you an idea of how far CD is behind. CD's main plus points are it is convenient ( you don't have to turn them over!),no wear and tear. Lets face it CD is based on technology developed in the late 70's (16bit 44.1k was cutting edge then)

An interesting interview by one of the very great audio electronics gurus:
Interviews Tim de Paravicini

http://www.stereophile.com/interviews/1107parav/index.html[/quote]

And in 1969 they had the technology to get men to the moon and back.

16bit is 'good enough' but not ideal.

 

[Anton90125]

[quote user="gpi"]And in 1969 they had the technology to get men to the moon and back.

16bit is 'good enough' but not ideal.[/quote]

1201 and 1202 alarms not withstanding!