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OFC vs. OCC wire - Page 2

post #16 of 46
Quote:
Originally Posted by JWolf View Post
 

Sorry, but you people are wrong. Different types of cables can sound different. You may not be able to measure this, but you can hear it.

 

there' a dude name 'a james randi give you a million dollars ifn' you can prove it

 

 

Quote:
Originally Posted by coinmaster View Post
 

So are you saying wire purity doesn't affect sound quality?

what are these impurities, do they have a chemical formula ?

copper is a pure element copper is copper at a molecular level

post #17 of 46
Quote:
Originally Posted by Brooko View Post
 

 

Actually - if you re-read what they've posted, you'll find they are correct.  Typically when a cable has produced a different sound for me, I've gone back and done measurements.  Every time I've done it, the cable has has slightly different resistance which has then raised or lowered the volume slightly.  When I volume match - the difference disappears.  It's not magic we're talking here - merely science.  If it is so easy to discern, then why is it that no-one has successfully ABXed under controlled conditions when two cables are compared?

 

If you want to send me a couple of different sounding cables - I'll measure them for you.


The resistance might have to be rather large to be significant. This works very much the same as how a potentiometer attenuates a signal. The value of the cable's resistance would have to be in series with the Amp's output impedance to form an attenuation network with the headphone's impedance. For example an Amp with a 1 Ohm output impedance would require a cable of 31 Ohms resistance to get a 6 dBV loss with a 32 Ohm headphone. Change the cable's resistance to 1 Ohm and you get a 0.528 dBV loss. Change the cable's resistance to 3 Ohms and you get a 1.02 dBV loss.

A change from 1 to 3 Ohms, as exampled above, might be more in the range of what might happen, which would result in a difference in less than 1/2 of a dBV. I'm not so sure this would do anything noticeable. With a high impedance headphone it shouldn't move the needle.

A Sennheiser HD558 has a wild impedance curve would combined cable resistance and Amp output impedance to deliver a large 100 Hz mid bass hump.

 

The Attenuation Factor = Headphone Impedance / (Headphone Impedance + Cable Resistance + Amp Output Impedance)

Using the Attenuation Factor one could calculate the dBV loss.

One could imagine that the varying impedance of a headphone would affect FR by acting like a volume control that changes with frequency due to the impedance change affecting the Attenuation Factor with the change of frequency. This is a passive filter circuit.

Edit: The cable resistance would have to be more than a couple of Ohms to play a significant part in the HD558 coloring the sound with its impedance curve.


Edited by StanD - 11/15/16 at 6:54pm
post #18 of 46

To illustrate - if you check my review of the MEE P1 - an IEM said to vary with cable changes - I decided to test it

 

http://www.head-fi.org/products/mee-audio-pinnacle-p1-high-fidelity-audiophile-in-ear-headphones-with-detachable-cables/reviews/16704

 

I graphed each of the cables, then volume matched and overlaid them.  The results speak for themselves.  The difference was volume and it was audible.  But rather than change cables - the cheaper option is simply just adjusting the volume :)

post #19 of 46
Quote:
Originally Posted by Brooko View Post
 

To illustrate - if you check my review of the MEE P1 - an IEM said to vary with cable changes - I decided to test it

 

http://www.head-fi.org/products/mee-audio-pinnacle-p1-high-fidelity-audiophile-in-ear-headphones-with-detachable-cables/reviews/16704

 

I graphed each of the cables, then volume matched and overlaid them.  The results speak for themselves.  The difference was volume and it was audible.  But rather than change cables - the cheaper option is simply just adjusting the volume :)


Looks like a spread of around 2.5 or 3 dB at 100  Hz. Some of it may be due to per instance acoustic coupling to the measuring rig. Did you get a chance to measure the resistance of each cable? In know that you said that you didn't get to measure the impedance of the drivers.

post #20 of 46
Quote:
Originally Posted by StanD View Post
 


Looks like a spread of around 2.5 or 3 dB at 100  Hz. Some of it may be due to per instance acoustic coupling to the measuring rig. Did you get a chance to measure the resistance of each cable? In know that you said that you didn't get to measure the impedance of the drivers.

 

All the impedance curves matched within about 0.5 dB right across the spectrum when I volume matched the IEMs.  I haven't measured the resistance of the cables yet - will make a note to that when I've cleared my review queue a bit.

post #21 of 46

If you were making your own cable, what wire would be best to use?

post #22 of 46
Quote:
Originally Posted by Brooko View Post
 

 

All the impedance curves matched within about 0.5 dB right across the spectrum when I volume matched the IEMs.  I haven't measured the resistance of the cables yet - will make a note to that when I've cleared my review queue a bit.


Did you ever measure the resistance of the cables? It's hard to believe that the MEE cables would have such a high resistance as to reduce the volume by 2.5 dB. What was the output impedance of the amp that was used?

post #23 of 46
Quote:
Originally Posted by needmoretoys View Post
 

Did you ever measure the resistance of the cables? It's hard to believe that the MEE cables would have such a high resistance as to reduce the volume by 2.5 dB. What was the output impedance of the amp that was used?

 

I always use the FiiO A3 (under 0.2 ohm output impedance).  That way I have complete consistency around the measurements.

 

So I got my M-M out, and quickly ran a measurement.  the resistance of the M-M's connecting wires is 1.0 ohms.

 

The positive connection on the spc cable (center pin) is measuring 2.3 ohms - so the actual resistance of just the cable is 1.3 ohms

 

The negative connection on the spc cable (outer connection) is measuring 9.7 ohms - so the actual resistance of just the cable is 8.7 ohms   

post #24 of 46
Quote:
Originally Posted by Brooko View Post
 

 

I always use the FiiO A3 (under 0.2 ohm output impedance).  That way I have complete consistency around the measurements.

 

So I got my M-M out, and quickly ran a measurement.  the resistance of the M-M's connecting wires is 1.0 ohms.

 

The positive connection on the spc cable (center pin) is measuring 2.3 ohms - so the actual resistance of just the cable is 1.3 ohms

 

The negative connection on the spc cable (outer connection) is measuring 9.7 ohms - so the actual resistance of just the cable is 8.7 ohms   


Adding up all the wires resistances and considering the impedance of the IEMs it should have around a 2 dB loss. Headphones and IEMs can sometimes be considerably off their spec'd impedance so having a 2.5 dB loss is quite feasible. 

post #25 of 46
Quote:
Originally Posted by StanD View Post
 


Adding up all the wires resistances and considering the impedance of the IEMs it should have around a 2 dB loss. Headphones and IEMs can sometimes be considerably off their spec'd impedance so having a 2.5 dB loss is quite feasible. 


True if those resistance measurements are for the MEE cables and the other cables had near zero resistance.

post #26 of 46

It's hard to imagine any reasonable conductor having such high resistances.

100 feet of 30AWG wire has a resistance of 10 Ohms.

post #27 of 46
Quote:
Originally Posted by Speedskater View Post
 

It's hard to imagine any reasonable conductor having such high resistances.

100 feet of 30AWG wire has a resistance of 10 Ohms.

 

He's clearly doing the test with a 2-wire meter, which makes such low-resistance measurements nearly matters of opinion. :)

 

This needs to be done with a 4-wire meter, or something sufficiently close, like the 2x4 feature on Tek's DMM4020.

post #28 of 46
Quote:
Originally Posted by tangent View Post
 

 

He's clearly doing the test with a 2-wire meter, which makes such low-resistance measurements nearly matters of opinion. :)

 

This needs to be done with a 4-wire meter, or something sufficiently close, like the 2x4 feature on Tek's DMM4020.


I'm sure that's true. Some low budget Ohm meters get into trouble at under 10 Ohms. While others can read in tenth's of an Ohm.

Short the two probes together, the reading with a good budget meter will be a fraction of an Ohm. Then you can measure the cable and subtract that probe value.

 

A skilled technician can make a DIY 4 terminal meter.

post #29 of 46
Quote:
Originally Posted by JWolf View Post
 

Sorry, but you people are wrong. Different types of cables can sound different. You may not be able to measure this, but you can hear it.

Agree. I have heared the difference. And that is probably also the reason why others also pay that much to buy those good expensive cables, otherwise a decent looking, robust, ergonomic cheaper one should be fine already.

post #30 of 46

IMO belief takes over when you don't accurately compare SQ. Some things that affect perception:

  • Echoic Memory
  • Equal Loudness Contour -- Fletcher Munson
  • Expectation Bias
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