So these cable threads got me wondering...

[Dubai]

Originally Posted by moooooo

I was determined to see if i could try and measure some concrete difference only by changing only a mic cable

http:\\audio.rightmark.org

RMAA software.

[Zownd]

I would be more interested in seeing this with cables that are equal in length

[tenkas]

Does anyone knows why there is a high frequency lift?

I used to believed it would be a high frequency lost you would get...

How did you plug or unplug the cables from the mic? You might have moved the mic (even a micro meter could make all the diffenrece)

[Dubai]

Originally Posted by Zownd

I would be more interested in seeing this with cables that are equal in length

ive measured cables with RMAA, <1 meter that have incredible distortion, and hi frequency roll off.
"CAT Microphone cable"

and 6meter Proel DieHard cables that have near perfect "better than the converters" measurements.

long cable test are a good test.

[Dubai]

Originally Posted by tenkas

Does anyone knows why there is a high frequency lift?

I used to believed it would be a high frequency lost you would get...

How did you plug or unplug the cables from the mic? You might have moved the mic (even a micro meter could make all the diffenrece)

yes, better to test with RMAA software, no mic placement variable, tweeter break in variable, amplifier warm up variable, crossover heat variable, etc...

[moooooo]

Originally Posted by Dubai

yes, better to test with RMAA software, no mic placement variable, tweeter break in variable, amplifier warm up variable, crossover heat variable, etc...

I repeated the test many times and every time it was the same. I tested one cable then another then changed back to the first again and it overlapped almost perfectly with the first test. This to me eliminates the possibility of things such as mic placement or amplifier warm up variable affecting the result sufficiently to render the results invalid.

[moooooo]

Originally Posted by tenkas

Does anyone knows why there is a high frequency lift?

I used to believed it would be a high frequency lost you would get...

How did you plug or unplug the cables from the mic? You might have moved the mic (even a micro meter could make all the diffenrece)

I was VERY careful not to move the mic, i did not unplug the cable from the mic itself. I plugged the 25ft cable attached to the mic either straight into the input (for the short cable test) or into the other cables for the long cable test.

[Dubai]

Originally Posted by moooooo

I was VERY careful not to move the mic, i did not unplug the cable from the mic itself. I plugged the 25ft cable attached to the mic either straight into the input (for the short cable test) or into the other cables for the long cable test.

it wont hurt to make the test with RMAA software, to see other variables like noise floor, IMD, THD, etc...

[terry j]

if you are using REW to do the test, why can you not simply put the cable in the loop in the mixer...along the lines of the loopback test when you set up rew.

no mics, no drivers or room, no changes other than the cable, see what happens. measure the FR of the cables itself.

[moooooo]

Originally Posted by terry j

if you are using REW to do the test, why can you not simply put the cable in the loop in the mixer...along the lines of the loopback test when you set up rew.

no mics, no drivers or room, no changes other than the cable, see what happens. measure the FR of the cables itself.

that is good suggestion although in this case i wanted to see the effect on a microphone specifically. The way the cable affects the sound depends on what it is plugged into. Take a guitar for high impedance pickups for example where long cables can attenuate the high end severely.

[moooooo]

Here is the result using RightMark



White = Long cable
Green = Short cable

[QuaA]

The increase in high frequency response could be attributed to stray electromagnetic field forces being induced to the cable. Shielding on cables aims to prevent/lower this. With longer cable runs there is more wire-area exposed and more potential for stray EMF to find its way into the wire.

Stray EMF could come from all sorts of electrical components nearby (computers, electronics--or even the AC lines that power them running throughout a building), even radio frequencies from antennas.

As a general rule, engineers avoid inducing unwanted noise by crossing known EMF carrying lines at a perpendicular axis to minimize coupling.

[djmukilteo]

Your seeing a level difference at those specific frequencies...all of the peak frequencies are there on both cables only the levels are different. This is probably cable capacitance effect that occurs and is more pronounced at higher frequencies...

[dysenterygary]

Thanks for posting! A while ago I did similar tests and found basically the same thing; the largest difference was from about 8k and up. I also found some differences in the very low frequencies as well.